Question Bank: M3

Avascular necrosis

40-year-old woman has received corticosteroid therapy for asthma for the past 10 years. She has had pain in her right hip for the past month. On examination there are no abnormal findings. MR imaging of the hip shows that the medullary cavity of the femoral head, which normally has high signal intensity of fatty marrow, contains prominent vertically orientated linear striations of low signal (similar to the 'asterisk sign' seen on CT imaging). The medullary cavity is surrounded by a sharp line of low signal intensity representing intact cortical bone. What lesion involving bone is she most likely to have?

S. Aureus

5-year-old boy is brought to the pediatrician because he has developed facial skin lesions over the past 4 days. On examination there are multiple small 0.3 to 0.8 cm diameter pustules covered by a honey-colored crust on his upper neck, cheeks, and forehead. The crusts are removed and the lesions heal over the next week. What infectious agents is most likely responsible for development of this boy's skin lesions?

Penetrating trauma

55-year-old man with a history of poorly controlled diabetes mellitus has developed painful enlargement of his leg during the past 6 days. On physical examination he has a 10 x 20 cm area of warmth and tenderness with swelling in the soft tissues of the left upper anterior thigh. A fasciotomy is performed and microscopic examination of tissue debrided shows necrotizing fasciitis. What risk factor is most likely to precede the onset of this condition?

Ewing Sarcoma

A 'small round blue cell' tumor involving bone is a?

Sarcoptes scabiei

A 10-year-old child complains of intense itching of his hands. Physical examination reveals several linear gray-brown lesions from 2 to 6 millimeters in length that appear in the skin between his fingers. Some of these lesions have been excoriated by scratching. What infectious agents is most likely to produce this boy's skin lesions?

Juvenile idiopathic arthritis

A 10-year-old girl has complained of joint pain for the past 2 years. The pain is localized to her knees and ankles; it occurs either with or without movement. The arthralgias are accompanied by fever. On physical examination she has a temperature of 37.8°C. There is no deformity of her knees. She has generalized lymphadenopathy. Her antinuclear antibody test is positive. What form of arthritis does she most likely have?

Ringworm

A 12-year-old boy has had a skin lesion appear on his trunk over the past week. On physical examination there is a 2 x 3 cm ovoid erythematous slightly raised lesion on his left upper chest. The lesion exhibits central clearing to leave a serpiginous border. A scraping of the lesion is performed and microscopically there are fungal elements present consistent with Trichophyton rubrum. What common term is most often used to describe these lesions?

Myoglobinuria

A 13-year-old boy fatigues easily and complains of cramping pain with exercise 'all over' after only a few laps around the track in his high school physical education class. If he rests briefly, he can continue for a few more laps. At rest, or with activities of daily living, he experiences no myalgias. One day, the coach makes him continue much longer, and he notes passing dark urine an hour later. On physical examination he has normal range of motion and agility, with no evidence for muscle wasting. Muscle strength is 5/5 in all extremities. Deep tendon reflexes are 2+. Laboratory studies show an absence in elevation of blood lactate, but an increase in blood ammonia, following exercise. What laboratory test findings is most characteristic for his underlying disease?

Salmonella

A 14-year-old West African man has a history of multiple episodes of sudden onset of severe abdominal pain and back pain lasting for hours. Each time this happens, his peripheral blood smear demonstrates numerous sickled erythrocytes. A hemoglobin electrophoresis shows 94% Hgb S, 5% Hgb F, and 1% Hgb A2. He now has a painful right hip that is tender to palpation. A radiograph reveals irregular bony destruction of the femoral head. What infectious agent is most likely responsible for his findings?

Contains woven bone

A 16-year-old boy falls on his right arm while he is going down a series of steps on in-line skates. On physical examination there is swelling with pain in the upper arm. A radiograph of the arms shows a humeral fracture. The fracture is set and the arm placed in a cast because the fracture callus that forms during the first month while the arm is in the cast is not as strong as the surrounding bone. What is the most likely cause for this weak callus?

Osteosarcoma

A 16-year-old boy has noted pain in his left knee after each hockey practice session for the past month. On examination there is tenderness to palpation of his left knee, with reduced range of motion. A plain film radiograph of the left leg reveals a mass of the proximal tibial metaphysis that erodes bone cortex, lifting up the periosteum where reactive new bone is apparent. The mass does not extend into the epiphyseal region. A bone biopsy is performed and microscopic examination shows atypical, elongated cells with hyperchromatic nuclei in an osteoid stroma. What neoplasm is he most likely to have?

Sickle cell anemia

A 16-year-old girl has had recurrent infections and episodes of acute chest, back, and abdominal pain since early childhood. She now develops pain and swelling in her right hip for the past 2 days. On examination there is warmth with overlying erythema of the right hip. A radiograph shows focal osteolysis of the acetabulum. Laboratory studies show peripheral blood neutrophilia. A blood culture grows Salmonella enterica. What chronic underlying disease does this girl most likely have?

Hemangioma

A 16-year-old girl is bothered by a skin lesion on her face. She cannot remember when it first appeared, but she doesn't like it anymore. Her mother states that the lesion has not changed since early childhood. On physical examination there is a 0.7 cm diameter dome-shaped red nodule on her right cheek just lateral to her nose. It is smooth, firm, and non-tender. What is the most likely diagnosis?

Localized anaphylaxis

A 17-year-old girl has the onset of 'hives' over the past 3 hours. On physical examination there are irregular, slightly raised, erythematous patches from 1 to 6 cm in size over all surfaces of her body. The lesions are pruritic. The lesions gradually fade over the next day without therapy. What is the most likely diagnosis?

Verruca vulgaris (warts)

A 19-year-old man has a lesion on his hand that has been enlarging for the past 3 months. On physical examination there is a tan, flat, 1 cm rough-surfaced, non-tender papule on the dorsum of his left hand. Without therapy, this lesion recedes over the next 2 years. What is the most likely diagnosis?

Bursitis; Synovial-lined bursal sacs that are adjacent to joints can become inflamed and distended with watery fluid, more often in males engaging in excessive manual labor or exercise.

A 21-year-old college student has noted increasing pain and soreness in his left shoulder after a summer bucking bales of hay (heavy lifting and turning motions) while at a ranch. On physical examination he can hardly adduct his left arm to the level of his shoulder. An aspiration of the subacromial region is performed and clear fluid is obtained. What is the most likely diagnosis?

Ankylosing spondylitis

A 22-year-old man has persistent lower back pain and stiffness that diminishes with activity. Over the next 10 years he develops hip and shoulder pain with decreased range of motion. On physical examination at age 42 he has diminished lumbar lordosis with decreased lumbar spine mobility. He has no other major medical problems. What is his most likely diagnosis?

Marfan Syndrome

A 22-year-old woman has had increasing dyspnea and orthopnea for the past year. On physical examination she is tall, with arachnodactyly and dislocating ocular lenses. A chest x-ray shows pulmonary edema and a prominent aortic arch. What inherited condition is the most likely diagnosis?

Osteochondroma

A 23-year-old man notes some minor discomfort over the lateral aspect of his right knee after a day working in a cramped cubicle (because IT put the 'desktop' workstation on the floor). On physical examination he has a palpable 'bump' in this region. A radiograph of the knee reveals a lateral bony projection from the lower femoral metaphysis. There is no adjacent soft tissue swelling. The lesion is excised and is composed of a 3 cm stalk of bony cortex capped by cartilage. What is the most likely diagnosis?

Congenital myopathy

A 25-year-old G2 P1 woman gives birth following an uncomplicated pregnancy to a term girl infant. The infant displays mild generalized muscular weakness. As she matures, the weakness remains mild and relatively nonprogressive. Her serum creatine kinase is 55 U/L and her antinuclear antibody test is negative. On physical examination her deep tendon reflexes are normal and there is no significant muscle wasting. The child does not have myalgias or arthralgias. She has normal mental function. What is the most likely etiology for this child's disease?

No significant changes. She has systemic lupus erythematosus. The myalgias and arthralgias of this condition are unlikely to be accompanied by significant inflammation.

A 25-year-old woman has had episodes of myalgia involving nearly every major muscle group of her extremities for the past 2 months. She also has chest pain. On physical examination she is afebrile. Her lungs are clear on auscultation but there is dullness to percussion. She has no joint deformities. Laboratory studies show her antinuclear antibody test and double stranded DNA test are positive. She has pericardial and pleural effusions seen on a chest CT scan. What findings is she most likely to have on microscopic examination of a muscle biopsy?

Human papillomavirus infection

A 26-year-old woman has noted a slowly enlarging genital lesion for the past 3 months. On physical examination she has a 1.2 cm diameter soft, tan to white lesion with a cauliflower-like appearance on the left labia of the vulva. What is most likely to have contributed to the development of this lesion?

Inflammation with necrosis. These findings suggest rhabdomyolysis.

A 29-year-old man has had a mild respiratory tract infection with non-productive cough and fever for the past 3 days. Over the next 2 days he has decreased urine output, and his urine has a dark brown color. On physical examination he has muscle tenderness. Laboratory studies show his serum urea nitrogen is 39 mg/dL with creatinine 4.1 mg/dL and creatine kinase 621 U/L. A urinalysis shows sp gr 1.025, pH 6, and blood 4+, with negative protein, glucose, and ketones. Urine microscopic examination shows no casts, no WBCs, and no RBCs. What microscopic findings is most likely to be present in a muscle biopsy from this man?

Sweat Gland ducts

A 29-year-old man incurs a burn injury to his lower leg when boiling water is spilled from a pot on the stove. On physical examination there is marked erythema over a 10 x 15 cm area on the anterior left thigh. A dressing is placed over this area. A week later there is sloughing of the skin. Regeneration of this burned area without the necessity for skin grafting occurs over the next month. What structures are most likely the source for proliferating cells to re-epithelialize the surface?

Erythema multiforme

A 29-year-old man is bothered by a 'cold sore' on his upper lip. After a week, he notices the appearance of several rounded, slightly erythematous lesions on the palms of his hands averaging 0.4 to 0.8 cm in size. Each of the lesions has a targetoid appearance with a central dark red area. After a course of acyclovir, the lesions on his hands disappear. What condition did he most likely have on his hands?

Myositis with lymphocytic infiltrates

A 29-year-old woman has had increasing muscular pain, particularly involving her upper arms and legs, not related to exercise, for the past year. She has had increasing difficulty swallowing for the past two months. Her fingers now often become blue to pale and painful when exposed to cold. On physical examination she has 4/5 muscle strength in extremities. Range of motionis normal. She is afebrile. What light microscopic features is most likely to be present in a muscle biopsy from this woman?

Botulism

A 3-month-old infant has been listless and feeding poorly for the past 3 days. Constipation is present. On examination the infant has marked muscle weakness, hyporeflexia, hypotension, sluggish pupils, and dry mouth. What infectious disease is she most likely to have?

Osteitis fibros cystica

A 30-year-old healthy man has experienced headaches for the past month. On physical examination there are no abnormal findings. Laboratory studies show a serum calcium of 12.3 mg/dL with phosphorus of 2.2 mg/dL and albumin of 4.3 g/dL. What bone lesion is most frequently associated with these findings?

Becker Muscular Dystrophy

A 30-year-old man has exhibited slowly progressive muscle weakness over the past 5 years. He has no myalgias. He now has difficulty ambulating and picking up heavy objects, even though he used to be a weightlifter. On physical examination there is 4/5 motor strength in proximal muscle groups. Laboratory studies show a serum creatine kinase of 467 U/L. A deltoid biopsy is performed and on microscopic examination shows variation in fiber size; immunohistochemical staining shows only focal positivity for dystrophin around the fibers. What is the most likely diagnosis?

Giant cell tumor

A 30-year-old man has pain about his left knee that has been worsening 'for weeks'. On physical examination the left knee appears larger than the right, and there is tenderness to palpaption. A radiograph reveals a 7 cm lytic lesion involving the epiphyseal region of the distal femur with a 'soap bubble' appearance. The lesion is curretted, and histologically there are numerous multinucleated cells in a stroma with plump to spindle shaped mononuclear cells. What is the most likely diagnosis?

Celiac Disease

A 31-year-old man notes itchy bumps on his elbows and knees for the past 2 weeks. On examination there are groups of vesicular lesions on extensor surfaces of elbows and knees. A punch biopsy of a lesion is examined microscopically shows collections of neutrophils at the tips of dermal papillae. With immunofluoresence granular deposits of IgA are localized to the tips of dermal papillae. What underylying disorder is he most likely to have?

Avascular Necrosis

A 31-year-old professional athlete has received numerous corticosteroid injections into his left hip region over the past 4 years. Over the past 2 months he has increasing pain with left hip movement. On examination he has decreased range of motion of his left hip, and extremes of hip motion cause pain. A plain radiograph demonstrates the presence of joint-space narrowing. What condition is he most likely to have?

osteogenesis imperfecta

A 32-year-old primigravida has a screening ultrasound scan at 20 weeks gestation that shows fetal skeletal abnormalities including long bone shortening. Femora and humeri are less than the 5th percentile for age. Normal numbers of fingers and toes are present. The internal organs appear to be normal in size. She gives birth at 37 weeks gestation to a stillborn male. On examination the fetus has extremities that are malformed and shortened. A postmortem radiograph reveals multiple long bone fractures. What is the most likely diagnosis?

Myositis ossificans

A 35-year-old man notes pain in his upper outer left arm increasing over the past 2 weeks. He incurred a traumatic blow to this arm a month ago, but there was no fracture and the pain went away in 2 days. On exam there is a firm mass palpable on the dorsal aspect of the left arm in the region of the triceps. A radiograph shows a 5 cm mass with peripheral calcification. A month later a repeat radiograph shows a 4 cm mass with more extensive calcification. What is this lesion most likely to be?

Plasma cells and lymphocytes; the proliferative synovitis (pannus) of rheumatoid arthritis shows extensive chronic inflammation.

A 35-year-old woman has experienced painful swelling of the proximal interphalangeal joints of both hands and feet for the past 3 weeks. On physical examination there is warmth, tenderness, and swelling of MP and PIP joints. Laboratory studies show an elevated rheumatoid factor. What is is most likely to be present in these affected joints?

Sporothrix schenckii

A 35-year-old woman notes a ulcerated nodule on her right forefinger that has persisted for the past 2 weeks. On examination the nodule is 6 mm in diameter. There is redness and swelling of subcutaneous forearm lymphatics. Tissue obtained from the nodule microscopically shows granulomatous inflammation and small cigar-shaped budding yeasts. Further history reveals that she enjoys gardening and has many floribundas (small-sized roses). What infectious agent is most likely present?

Distant metastases; This thickness of her pigmented lesion puts her at risk for metastases and a poor prognosis.

A 38-year-old woman comes to her physician for a routine check of her health status. On physical examination she has a 1.2 cm irregular, darkly pigmented 'mole' on the skin of her upper back. Excisional biopsy of the lesion is performed. Microscopic examination shows a malignant melanoma that is 2 mm in thickness, with margins clear. What prognoses is most likely regarding this woman's skin lesion?

Osteoporosis

A 38-year-old woman has severe systemic lupus erythematosus with renal complications. She is treated with long-term corticosteroid therapy. What bone disease is she most likely to develop?

Malignant melanoma

A 39-year-old man has become concerned regarding a skin lesion on his chest which has enlarged from 1 cm to 1.5 cm over the past 3 months. It has become darker, and has developed irregular borders. On physical examination he has a slightly raised, asymmetrical, irregularly pigmented brown to black lesion on the skin of his right upper chest. What is his most likely diagnosis?

Psoriasis

A 39-year-old man has noted the appearance of scaling patches on his elbows, knees, and scalp over the past 6 months. On physical examination these lesions are 1 to 4 cm in diameter with a salmon pink to silvery gray appearance. He has yellow-brown discoloration with thickening and pitting of his fingernails. A punch biopsy of one lesion is performed and on microscopic examination shows thinning of the stratum granulosum, downward projection of the rete pegs, small neutrophilic aggregates in the superficial epidermis, and marked overlying parakeratosis. Therapy with methotrexate and UVA light reduces the size of the lesions. What is the most likely diagnosis?

Tick

A 39-year-old woman has a chronic arthritis involving knees, then ankles and wrists over the next month. She recalls a ring-like rash on her left arm 6 months ago. Laboratory studies show serologic positivity for Borrelia burgdorferi. What is the most likley vector for her illness?

Mycetoma

A 40-year-old man living in the Sudan has had a swollen left foot for the past year. On examination there is an 8 cm area on the dorsum of his foot with subcutaneous swelling and induration and multiple draining sinus tracts to the skin surface that contain yellow to orange 1 mm granules. Examination of a granule microscopically shows numerous gram positive long filamentous rods. What is the most likely diagnosis?

Deer tick bite

A 41-year-old woman has noted a ring-like rash 5 cm in diameter involving the skin of her right calf, along with fever, for the past 3 days. On physical examination her temperature is 37.5°C. She has enlarged tender lymph nodes palpable in the right inguinal region. These findings subside in two weeks' time. A month later she is bothered by arthralgias and myalgias. Serologic testing is positive for Borrelia burgdorferi. Two years later she develops a debilitating arthritis involving knees and hips. What infection most likely occurred in this woman?

Myotonic Dystrophy

A 42-year-old man has had increasing muscular weakness over the past 2 years, with both his arms and legs mainly affected. Other men and women in his family have been similarly affected. He has such severe difficulty chewing his food that he is on a liquid diet. His eyelids droop so much that he can no longer drive a vehicle. On physical examination he has symmetrical muscle atrophy, most marked in hands and forearms, and sternocleidomastoids. Deep tendon reflexes, sensation, and cranial nerve function are intact. A muscle biopsy is performed and on microscopic examination shows myofiber atrophy, mainly of type I fibers, with central nuclei and ring fibers. Genetic testing reveals a mutation with increased CTG repeats. What is the most likely diagnosis?

Anti-citrullinated peptide antibody; She has a rheumatoid nodule, a peculiar form of granulomatous inflammation that can be seen in the soft tissues of persons with rheumatoid arthritis

A 42-year-old woman has noted a 'bump' on her elbow that has slowly enlarged over the last 4 months. On physical examination there is a firm, non tender, 1 cm rounded subcutaneous mass over the extensor surface of the left forearm. The nodule is excised and on microscopic examination shows an area of central necrosis surrounded by palisading epithelioid cells. What laboratory serologic test findings is most likely to be present in this woman?

Staphylococcus aureus

A 44-year-old man incurred a traumatic compound, comminuted fracture of his left tibia. A year later he continues to have pain in his lower left leg. There is a draining sinus tract to the overlying skin. A radiograph reveals tibial deformity with sequestrum surrounded by involucrum. What infectious agents is most likely present in this man's left tibia?

Depth of the lesion

A 44-year-old woman is concerned about the change in colour with recent increase in size of a pigmented lesion on her left shoulder. On physical examination the 1.3 cm diameter, brownish-black, nodular lesion has irregular borders. This lesion is completely excised. Microscopically, the lesion is composed of large, pleomorphic cells with enlarged nuclei that have prominent large nucleoli. The scant cytoplasm of these cells contains a fine black pigment. What parameter is most important in determination of the prognosis for this patient?

rheumatoid arthritis; The pannus contains florid chronic inflammatory infiltrates with many plasma cells.

A 45-year-old woman has had increasingly severe disability because of deformities of her hands, with 'swan neck' deformities and ulnar deviation, which makes it difficult to use both her hands. Reconstructive surgery is performed on the thumb and first finger of her right hand. Microscopic examination of tissue excised from these joints shows destructive pannus in proximal interphalangeal joints. What is the most likely diagnosis?

Brugia malayi

A 46-year-old man living in Vanuatu (South Pacific) has noted progressive enlargement of his left leg and scrotum for the past 6 years. On examination he has painless enlargement with a doughy consistency on the left below the inguinal ligament. What organism is most likely to cause his findings?

Brown recluse spider bite

A 46-year-old plumber comes to his physician because of a persistent skin lesion that has not healed in the past 3 months. On physical examination there is a 2 cm circumscribed necrotic ulcer on his right arm. Topical corticosteroid cream and antibiotics have no effect on the lesion. It is excised. What is the most likely diagnosis?

Corticosteroid (prednisone)

A 48-year old previously man has developed pain in his hips that has gotten worse over the past 5 months. On physical examination there is pain on passive motion at both hips that limits range of motion. A radiograph of his pelvis shows flattening of femoral heads with collapse on the right. MR imaging shows a double line with outer low intensity reactive subchondral zone with inner high signal intensity zone on T2 weighted scans in each femoral head. Ingestion of what drug is most likely to have led to these findings?

rheumatoid arthritis (RA)

A 49-year-old man has complained of episodes of joint pain for over 10 years. This pain has occurred mostly in his hands and feet, and in a remitting and relapsing pattern. On physical examination there are deformities of his hands involving the fingers, with swan-neck deformities and ulnar deviation. His condition improves following methotrexate therapy. What is the most likely diagnosis?

Anti-citrullinated peptide

A 49-year-old man has complained of episodes of joint pain for over 10 years. This pain has occurred mostly in his hands and feet, and in a remitting and relapsing pattern. On physical examination there are deformities of his hands involving the fingers, with swan-neck deformities and ulnar deviation. His condition improves following methotrexate therapy. What serologic test is most likely to be positive in this man?

Fibromatosis

A 49-year-old woman has noted increasing difficulty with movement of her left hand for the past 2 years. On examination she cannot completely extend the left middle finger. In the palm of her hand at the base of this finger there is an ill-defined mass that is very firm to palpation. What will microscopic examination of this excised mass most likely show?

Achondroplasia

A 5-year-old boy measures at the 5th percentile in height for age. On physical examination most of his decreased height is due to very short legs. However, his trunk and head appear normally proportioned for age. He is of above average intelligence and becomes an orthopedic surgeon. His parents and relatives are not affected by this disorder. What is the most likely diagnosis?

Defective DNA repair

A 5-year-old girl is kept indoors during the day on the advice of the family physician, who has determined that there is a family history of skin cancers which occur at a young age. Microscopically, these are squamous cell carcinomas. What molecular mechanisms in her keratinocytes best explains why this child is at risk with sun exposure?

Osteoarthritis

A 50-year-old man has experienced pain in his right knee for the past 4 years. As he moves about during the day, the pain decreases somewhat. The pain is worse when walking for longer distances. On physical examination there is no joint swelling, warmth, or erythema, but he does have decreased range of motion. What condition is he most likely to have?

Basal cell carcinoma

A 51-year-old man from the Everglades of Florida who has lived by himself for many years finally came to a physician after losing the vision in his right eye. On physical examination there is a large fungating, infiltrative mass on his face that extends across the right orbital region and the bridge of the nose to impinge upon the epicanthal fold on the left. What is the most likely diagnosis?

Chondrosarcoma

A 51-year-old man has noted constant, dull right hip pain for the past 3 months. On physical examination he has diminished range of motion of the right hip. A radiograph reveals a 10 x 13 cm mass involving the right ischium of the pelvis. The mass has irregular borders and there are extensive areas of bony destruction along with some scattered calcifications. The lesion is resected, and grossly the mass has a bluish-white cut surface. What is the most likely diagnosis?

Peptic Ulcer

A 54-year-old man continues to take naproxen for arthritis pain. He finds the medication effective. He develops abdominal pain. What complication has most likely occurred in this man?

Actinic keratoses

A 55-year-old diving instructor from Cancun, Mexico, has noted the appearance and growth of multiple skin lesions for the past 4 years. On physical examination he has 10 lesions from 0.5 to 1 cm in size on his face, arms, and dorsa of both hands. They are rounded, flat, tan-brown to slightly erythematous lesions with a rough, sandpaper-like consistency. What is the most likely diagnosis?

Pemphigus vulgaris

A 56-year-old man has had mouth ulcers for 2 months but for the past week has developed blisters over pressure points on his body, particularly scalp, face, and trunk. On examination there are 0.3 to 2 cm vesicles and bullae filled with clear fluid. A punch biopsy of a lesion examined microscopically shows prominant acantholysis with intra-epidermal blister formation. With immunofluorescence there is a net-like pattern of IgG deposits around keratinocytes. His condition improves with immunosuppressive therapy. What is the most likely diagnosis?

Decubitus ulcer

A 56-year-old man with amyotrophic lateral sclerosis has been bedridden for the past year. He is found to have a 2 cm diameter area of eroded skin extending to underlying soft tissue over the sacral region of his back. What is the most likely diagnosis?

Osteomyelitis

A 56-year-old woman has a 27 year history of poorly controlled diabetes mellitus. She develops an ulceration on the ball of her foot that does not heal for 2 months. What complication involving bone is she most likely to develop?

Hyperuricemia

A 58-year-old man has the sudden onset of severe pain in his left great toe. There is no history of trauma. On examination there is edema with erythema and pain on movement of the left 1st metatarsophalangeal joint, but there is no overlying skin ulceration. A joint aspirate is performed and on microscopic examination reveals numerous neutrophils and needle-shaped crystals. Over the next 3 weeks, he has two more similar episodes. On physical examination between these attacks, there is minimal loss of joint mobility. What laboratory test findings is most characteristic for his underlying disease process?

Atypical chondrocyte

A 61-year-old man complained of dull but constant pain in his arm for the past 3 years. On physical examination there is a firm but tender area on palpation of the upper left arm. A plain film radiograph shows a 6 cm mass involving the proximal humerus which is eroding the bone and lifting the periosteum. Metastases are not present on nuclear medicine scanning. After resection, the mass is found to be firm and have a bluish-white appearance on sectioning. What microscopic findings is most likely to be characteristic for this mass?

Herpes zoster

A 65-year-old man has been undergoing chemotherapy for treatment of a small cell anaplastic carcinoma of the right lung. He has been bothered for 3 weeks by an outbreak of pruritic lesions in a 2 x 14 cm area along the right trunk. On physical examination these skin lesions are 0.1 to 0.3 cm clear vesicles, some of which have been excoriated, ruptured, and become secondarily infected. What is the most likely diagnosis?

Staphylococcus aureus

A 66-year-old man with diabetes mellitus develops a fever with chills over the past 5 days. On examination he has a non-healing 3 cm ulceration over the right calcaneus. A week later a radiograph shows calcaneal lytic destruction with adjacent periosteal reaction. Surgical debridement is performed. What is culture of the debrided material most likely to grow?

Paget disease

A 69-year-old man has noted increasing back and leg pain for 3 years. He has greater difficulty hearing on the left. On physical examination he has decreased range of motion at the hips. Radiographs reveal bony sclerosis of the sacroiliac, lower vertebral, and upper tibial regions. His hats don't even fit him anymore. He now has orthopnea and pedal edema. Laboratory studies show a serum alkaline phosphatase of 264 U/L. What condition is he most likely to have?

Osteoarthritis

A 69-year-old man has noted pain, but no swelling, of his hands for over a decade. On physical examination there is prominence with tenderness to palpation of the distal interphalangeal joints. Ankylosis of these joints has not occurred. Radiographs over the past 5 years have documented progressive erosion of articular cartilage, followed by subchondral sclerosis and formation of osteophytes in the DIP joints as well as the vertebrae. What condition is he most likely to have?

Staphylococcus aureus

A 7-year-old child has the acute onset of fever and leg pain. On examination her temperature is 37.5°C. There is decreased range of motion from marked tenderness with swelling and erythema over the left hip. A joint aspirate yields cloudy fluid with decreased viscosity. Her WBC count is increased from neutrophilia and bandemia. What is a blood culture from this child most likely to grow?

Treponema pallidum (syphilis)

A 72-year-old man has had a progressive dementia for the past 5 years, along with worsening congestive heart failure. He walks with a widened gait. On examination there is a soft tissue mass palpable in his left knee region along with local pain and swelling. A radiograph shows bony destruction of the left knee joint. What infectious agent is most likely to cause these findings?

Basal cell carcinoma

A 72-year-old man has noted a slowly enlarging nodule on his lower eyelid for the past 3 years. On physical examination this lesion is a 0.7 cm firm mass with a pearly appearance and central umbilication. The lesion is excised, the margins of the excision are clear, and it does not recur. What is the most likely diagnosis?

Congestive heart failure; he has Paget disease

A 75-year-old man has complained of lower back pain for 8 years. As part of a workup for a persistently elevated lymphocytosis, he has a right posterior iliac crest marrow biopsy performed. On microscopic examination hematopoiesis is normal, but the bone spicules are thickened with irregular cement lines forming a mosaic appearance with both increased osteoblastic and osteoclastic activity. What condition is most likely to occur in conjunction with his underlying bone disease process?

Clostridium tetani

A 76-year-old man is repairing a fence in the pasture. He incurs a deep barbed wire cut to his left hand. He washes the wound and put on a band-aid. There is still some redness and swelling around this cut a week later. He now begins to experience dysphagia and back pain. On physical examination he has increased tone in the masseter muscles, a rigid abdomen, and stiff proximal limb muscles. What clostridial species is most likely to produce his illness?

Ehlers-Danlos syndrome

A 9-year-old girl experiences a laceration to her forearm with minimal trauma. On examination she is of normal height. She has hypermobility of her joints and skin that is hyperextensible. What inherited condition is the most likely diagnosis?

Stevens-Johnson syndrome

A 9-year-old girl has developed a skin rash over the past 2 days. On physical examination there are vesicular lesions from 1 to 5 cm in diameter on her extremities and trunk. There are 2 lesions on her buccal mucosa. These lesions have a central red nodule surrounded by a zone of erythema. This child was given antibiotic therapy for a otitis media one week ago. What is the most likely diagnosis?

Rickets

A bone disorder caused by calcium deficiency due to insufficient intake or metabolism of 25 OH vitamin D.

Malignant Melanoma

A change in the size along with asymmetry, irregular border, and variable color of a 'mole' should suggest the possibility of a:

Colchicine

A clinical study has shown effectiveness of a drug in both cancer patients and gout patients. This drug disrupts microtubule formation. What drug is most likely used in this study?

Jock Itch

A clinical study is performed of male subjects from 15 to 50 years of age who had superficial skin infections. One group of these subjects had erythematous, scaling patches from which skin scraping specimens were obtained. It was observed that fungal elements typical for Trichophyton rubrum were present. What condition did this group most likely have?

Remain the same; the gross appearances of most nevi hardly seem to change over time.

A clinical study is performed with Caucasian subjects between 15 and 40 years of age who have at least one 'mole' on their skin which was excised. The microscopic appearances of these lesions are analyzed. Most of these lesions are diagnosed as nevi, and most have varying shades of brown pigmentation. It is observed that these nevi evolve from junctional to compound to intradermal lesions with increasing age of the patient. The nevus cells appear similar to melanocytes by immunohistochemical staining pattern. What outcome is most likely to occur in patients with these nevi?

Neutrophils

A common finding in the stratum corneum of individuals with psoriasis is the presence of?

Pompe disease, which affects the cardiac muscle

A deficiency of acid maltase leads to:

Osteoarthritis

A former center for a professional football (American) team retired in his 30's after a career of more than a decade. He now finds that he has some stiffness in his right knee in the morning, which soon abates, but by the end of the day he is taking non-steroidal anti-inflammatory medications for pain. On physical examination there is diminished range of motion of the right knee, but no warmth or swelling. What is the most likely diagnosis?

Colchicine

A gout drug that is a microtubule inhibitor; binds intracellular protein.

SLE

A malar rash (rash on the cheeks and bridge of the nose) is commonly seen in:

Paget disease

A mosaic pattern of osteolysis and osteosclerosis is characteristic for:

Febuxostat

A non-competitive xanthine oxidase inhibitor; inhibits the conversion of hypoxanthine to uric acid.

Osteoarthritis; loss of articular hyaline cartilage

A pathologic study is performed involving patients with a history of arthritis. These patients had femoral heads submitted to surgical pathology following resection and placement of hip prostheses. The pathologic findings observed by microscopic examination of these specimens are analyzed. What finding is most likely to be seen with the greatest frequency in these patients?

Systemic lupus erythematosus (SLE) with immune complex deposition at the dermal-epidermal junction

A positive antinuclear antibody test goes with autoimmune conditions such as:

Borrelia burgdorferi (Lyme disease)

A previously healthy 35-year-old woman has noted a ring-like rash on the skin of her left lower thigh for the past 3 days. This is followed 2 months later by arthritis that involves several joints in succession, including right hip, left knee, and left elbow. What infectious agent is most likely to cause these findings?

Muscular dystrophy

A problem of progressive, more proximal, weakness unrelated to exercise.

Acanthosis nigricans

A skin condition marked by thick, velvety, hyperpigmented (dark) plaques that usually affect areas with skin folds like the axillae, groin, and posterior neck.

Osteogenesis imperfecta

A social worker refers a 2-year-old child to the physician because of suspected child abuse with multiple bone fractures. On physical examination, the child has blue sclerae, diminished hearing in both ears, and misshapen teeth. There are no external contusions or lacerations of the skin. Radiographs of the child's extremities show recent and healing long bone fractures. What is the most likely diagnosis?

Tinea corporis

A superficial dermatophyte infection that may produce an annular lesion. As the center of the lesion heals, the border becomes ring-like.

Eye

A year following multiple bites of black flies (Simulium) 43-year-old man from Cameroon in Africa has developed papular pruritic skin lesions on his lower extremities over the past 3 months. On examination the nodules are firm and non-tender with dry, scaling skin with focal depigmentation. There is inguinal lymphadenopathy. What additional tissue sites is most likely to be involved by this infection?

Endochondral bone formation

Achondroplasia is a form of short-limbed dwarfism, but the problem is in what type of bone formation?

Endochondral ossification; inhibiting chondrocyte growth

Achondroplasia is associated with gain of function mutations of the FGFR3 gene that impair what type of ossification?

keratin deposition and increased sebum production

Acne vulgaris is caused by occlusion of pilosebaceous follicles due to excess (2):

Septic Arthritis

Affected joints are swollen, painful, and warm to the touch. The knee is involved in over 50% of the cases. Patients usually have systemic evidence of infection such as fever and chills.

Tyrosinase

Albinism is caused by a defect in what enzyme?

Bone formation and osteoblast activity

Alkaline phosphatase is a biochemical marker of:

Pompe Disease

Alpha-glucosidase deficiency causes what glycogen storage disease?

Osteoid osteoma

An 11-year-old boy has complained of pain in the region of the right upper thigh for 2 weeks. This pain is worse at night and is relieved by aspirin. On physical examination no abnormal findings are noted. A radiograph of his right leg reveals a small lucent area in the proximal femoral cortex surrounded by sclerotic bone. What is the most likely diagnosis?

Ewing Sarcoma

An 11-year-old boy has pain in his left leg that has persisted for 3 weeks. On physical examination his temperature is 37.9°C. A radiograph of the leg reveals a mass in the diaphyseal region of the left femur with overlying cortical erosion and soft tissue extension. A bone biopsy is performed and the lesion on microscopic examination shows numerous small round blue cells. Karyotypic analysis of these cells shows t(11;22). What neoplasm does he most likely have?

Clostridium tetani

An 18-year-old man is plowing a field on a hillside. The tractor strikes a large rock and tips over, pinning him underneath. The ground is muddy, and he is able to work his way free. He discovers a deep, penetrating puncture wound to his calf. He walks home and washes the soil off the wound site and puts a bandage over it. A week later the wound is healing, and the leg is not swollen, but he begins to experience generalized muscle spasms, with stiffness and pain in his shoulders and back. He has difficulty with eating and swallowing, with painful stiff jaw and facial muscles. What organism is most likely responsible for these findings?

Aneurysmal bone cyst

An 18-year-old woman has noted pain and swelling of her right distal thigh associated with activity for the past year. She has no history of any trauma. On examination after performing physical exercise, there is tenderness on palpation above the right knee. Radiographs show an expansile, eccentric, lytic lesion located in the metaphysis of the distal femur that is surrounded by a rim of reactive new bone as a host response. What bone disease is she most likely to have?

X-Linked Recessive; Duchenne Muscular Dystrophy

An 8-year-old boy gets tired easily and can be outrun by his 5-year-old brother. On physical examination he has 4/5 strength in lower extremities, even though his legs appear well-developed. Laboratory studies show his serum creatine kinase is 550 U/L. A gastrocnemius biopsy shows marked interstitial fibrosis with atrophy of many muscle fibers and increase in size of other fibers, but no inflammation. Immunohistochemical staining with antibody to dystrophin shows a lack of staining around the myofibers. Over the next 5 years, he becomes progressively weaker until he is confined to a wheelchair. What inheritance patterns is his disease most likely to have?

Osteoporosis of bone with accelerated bone loss leading to the propensity for fractures. Physical inactivity further accelerates bone loss and decreases muscle mass and agility that contribute to falls.

An 80-year-old woman has had no major medical problems, but she has never been physically active for most of her life. One day she falls out of bed and immediately notes a sharp pain in her left hip. She is subsequently unable to ambulate without severe pain. Radiographs show not only a fracture of the left femoral head, but also a compressed fracture of T10. What condition is she most likely to have?

Seborrheic keratoses

An 83-year-old man has noted slowly enlarging skin lesions for the past 15 years. On physical examination he has multiple 0.3 to 1.4 cm coin-like, lightly pigmented, velvety-surfaced lesions on his face and upper chest. They are not painful and do not bleed when rubbed.

calcium pyrophosphate

An 83-year-old man has pain in his left knee a day after playing golf. On examination there is warmth, tendnerness, and swelling of the left knee. A radiograph of the knee shows chondrocalcinosis. What type of crystal is most likely to be identified in a joint aspirate from his left knee?

Calcium pyrophosphate crystals; pseudogout

An 85-year-old man has had episodes of pain and decreasing joint motion of wrists, elbows, shoulders, and ankles for weeks at a time during the past 2 years. On physical examination there is no joint deformity or swelling, but there is warmth. A joint aspirate is performed and cloudy fluid with diminished viscosity obtained. What is most likely to be seen on microscopic examination of this aspirate?

UV radiation exposure, which damages DNA

An important risk factor for developing malignant melanoma is what type of exposure?

Ewing Sarcoma

Anaplastic small blue cells are characteristic of what malignant bone tumor that occurs in children and adolescents?

Metaphysis

Aneurysmal Bone Cysts are typically solitary at what part of the bone?

SLE

Anti-double-stranded DNA antibodies and anti-Smith antibodies are associated with:

Actinomyces

Are a form of long filamentous bacteria that may produce soft tissue infections?

Langerhans Cells

Are antigen-presenting cells found in the epidermis.

Desmosomes

Are attachments between keratinocytes in the stratum granulosum?

Enchondroma

Are benign cartilagenous tumors that are located within bone?

Nevi

Are benign lesions that typically remain stable for years. They are rounded and often slightly pigmented.

Giant Cell Tumors

Are benign tumors derived from osteoclasts. These tumors are locally aggressive and are associated with pain and swelling along with pathologic fractures.

Osteochondromas

Are benign/ cartilage-forming tumors that most commonly occur in adolescent males. Patients with this neoplasm present with pain or pathologic fractures in the metaphysis of long bones.

Channelopathies

Are characterized by myotonia and periodic paralysis with an onset usually in childhood.

No

Are chondrosarcomas usually lytic lesions?

seborrheic keratosis

Are common in the elderly and distributed on the face and upper chest. They have an irregular surface and are often pigmented.

Osteosarcomas

Are composed of spindle cells that make osteoid?

Scales

Are dry flaky pieces of the stratum corneum shed from the skin?

Bullae

Are large (greater than 1 cm) fluid-filled blisters?

Osteochondromas

Are not true neoplasms but an exaggeration of the growth plate. They may cause discomfort because they project outward from the bone.

Males

Are osteosarcomas more common in males or females?

Fibromatoses

Are proliferations of connective tissues that form an ill-defined mass with deformity. Though histologically benign, they are not circumscribed and have a nasty habit of recurring following excision. The most common superficial sites are palmar and plantar regions.

Seborrheic Keratoses

Are slowly expanding warty-surfaced lesions of the head and trunk in older persons?

Macules

Are small (less than 1cm), flat lesions?

Hemangiomas

Are usually bright red to blue and slightly elevated or flat. They do not regress. They generally do not change size much over time. Their colour comes from the proliferation of capillary or cavernous vascular channels in the upper dermis.

Palisading nuclei

BCCs tend to form nests of atypical basaloid cells, with the peripheral cells arranged with their long axes in parallel:

epidermal hyperplasia (acanthosis)

Biopsy of acanthosis nigricans lesions shows:

Lichen Planus

Biopsy of this skin disorder's lesions show hypergranulosis, irregular acanthosis (which causes a "sawtooth" appearance), and lymphocytic infiltrates at the dermal-epidermal junction.

Pemphigus vulgaris

Biopsy of this skin disorder's lesions shows acantholysis, retention of basal keratinocytes (which characteristically resemble a row of tombstones), and deposition of IgG in the intercellular spaces of the epidermis.

Dermatitis herpetiformis (particularly the elbows)

Biopsy of this skin disorder's lesions shows deposits of IgA and formation of microabscesses at the tips of dermal papillae.

Psoriasis

Biopsy of this skin disorder's lesions shows hyperkeratosis (with thickening of the stratum spinosum and thinning of the stratum granulosum), parakeratosis, elongation of the rete ridge, and Munro microabscesses.

Hydroxyapatite

Bisphosponates bind to calcium found in?

Colchicine

Blocks neutrophil-mediated inflammatory responses induced by monosodium urate crystals.

Osteomyelitis

Bone disorder accompanied by signs of infection with fever, pain, swelling, erythema, and warmth.

Rickets and osteomalacia

Both conditions are caused by calcium deficiency due to insufficient intake or insufficient metabolism of vitamin D.

- Joint Trauma - Hyperparathyroidism - Hemochromatosis

CPPD associated conditions:

Myotonic dystrophy

CTG repeats in the DMPK gene cause:

Pseudogout

Calcium pyrophosphate deposition is associated with what type of gout?

Chondrosarcomas

Can appear in older persons. They are most often central in location (axial skeleton or proximal long bones).

Osteoid osteoma

Can be painful lesions, but they are located within the bone cortex. A small nidus is surrounded by sclerotic bone.

Clostridium perfringens

Can cause gas gangrene, which typically causes crepitus on palpation, a rare subtype of necrotizing fasciitis.

Clostridium tetani

Can produce an exotoxin that leads to tetanic muscle contractions. High-risk patients have incurred necrotic or gangrenous wounds, frostbite, crush or avulsion injuries, burn wounds, or wounds contaminated with dirt, feces, soil, or saliva.

Ankylosing spondylitis

Causes increasing deformity of the vertebral column in middle age to older adults with HLA B27.

Parakeratosis

Causes the typical scale on psoriatic plaques and pits in the nails.

Septic Arthritis

Ceftriaxone is used in patients with:

Drug eruptions are one form of acute eczematous dermatitis.

Cephalosporin, Langerhans cells activate, itchy oozing plaques.

Atopic Dermatitis (Eczema)

Characterized by dry skin and an intensely pruritic rash that involves the face, scalp, and the extremities.

Rheumatoid arthritis

Chronic inflammation with synovial proliferation (pannus) is more a feature of:

Dermal collagen loss, which manifests as skin thinning (atrophy) and stretch marks

Chronic use of topical corticosteroids causes:

Impetigo, a superficial epidermal infection that leads to collections of neutrophils under the stratum corneum

Classic "honey-colored crust"

Basal cell carcinoma -Can also have rolled (thickened) edges with an ulcerated center

Classic appearance of a translucent pearly nodule with telangiectasias (dilated subepidermal blood vessels)

osteogenesis imperfecta

Classic features of this disease include extreme bony fragility and blue sclera.

Muscular contractions

Clostridium tetani as a wound contaminant releases an exotoxin that can lead to marked:

Psoriasis

Collections of neutrophils in the stratum corneum are a hallmark of what skin disorder?

Type IV (Cell Mediated) hypersensitivity

Contact dermatitis is what type of hypersensitivity reaction?

Contact dermatitis (Type IV hypersensitivity) in which the onset is delayed by 1 to 3 days following exposure, and the lesions persist for a week or two. The lesions can be macular and/or papular.

Contact with an agent such as poison ivy would produce a:

There can be diffuse muscle weakness and some muscle wasting with long-term corticosteroid use or with Cushing syndrome.

Corticosteroid excess

Type II

Corticosteroid therapy can produce atrophy of what muscle type?

Proximal

Corticosteroid-induced myopathy typically leads to distal or proximal muscle weakness?

osteoblasts

Corticosteroids decrease the mRNA production of what cell type?

NF-κB and phospholipase A2

Corticosteroids exhibit an anti-inflammatory effect by inhibiting:

secondary hyperparathyroidism and bone resorption

Corticosteroids increase renal phosphate excretion to promote:

Osteogenesis imperfecta (OI)

Crowded osteocytes with reduced collagen are found in the bones of patients with what disorder?

Dermatitis herpetiformis

Dapsone is the first-line treatment of choice for:

Cori Disease

Debranching enzyme deficiency causes what glycogen storage disease?

Psoriasis

Decreased thickness of the stratum granulosum is seen in:

Osteomalacia

Defective mineralization of newly-formed osteoid results in:

melanin

Defects in tyrosinase caused absent or reduced production of what pigment?

Myopathic

Degeneration and regeneration of myofibers are features of what type of diseases?

-Elevated PTH - Elevated serum and urinary Calcium - Low serum phosphate

Describe the routine lab work of a patient with primary hyperparathyroidism:

Ganglion cyst

Develop in the connective tissue of a tendon sheath or joint capsule and are usually seen in the wrist?

Acanthosis

Diffuse epidermal hyperplasia is known as?

Osteoblasts

Does PTH bind to osteoblasts or osteoclasts?

Spongiosis

Edema of the epidermis

Mycetoma

Encompasses a variety of infectious agents that produce subcutaneous infections extending into deep soft tissues and even bone. The tissue reaction ranges from chronic abscessing inflammation to granulomatous inflammation. There may be so many organisms that they produce visible granules (yellow to orange to brown) exuding from draining sinus tracts onto the skin surface.

Sunlight exposure

Endogenous vitamin D production occurs with:

Stevens-Johnson Syndrome and TEN

Epidermal necrosis is seen in what skin disorders?

Herpes simplex infection

Erythema multiforme is a condition that typically follows an infection, often:

EWSR1 gene on chromosome 22 to the FLI1 gene on chromosome 11.

Ewing Sarcoma is associated with translocation of what gene?

Neuroectoderm cells

Ewing sarcomas are malignant tumors derived from what undifferentiated cells?

Actinic keratoses

Exhibit hyperkeratosis (thickening of the stratum corneum) and parakeratosis (retained nuclei in the stratum corneum).

dystrophic muscular diseases

Extensive fibrosis and loss of myofibers can be seen in the end stage of many muscular diseases, particularly:

CDKN2A

Familial melanoma is most commonly due to mutations in what gene?

Osteosarcoma

Features of this malignancy include a Codman triangle (tumor that breaks through cortex and lifts the periosteum) and a "sunburst" appearance caused by the formation of tiny bone fibers in the periosteum.

Extracellular matrix

Fibronectin is a component of the:

Acetylcholine receptor degradation

For the past 4 months a previously healthy 37-year-old woman has noted increasing fatigue toward the end of the day. She makes more mistakes while typing, and she can hardly keep her eyes open. She seems better in the morning after a good night's sleep. A month later she has difficulty swallowing and speaking. She does not have myalgia or arthralgia. On physical examination she has 5/5 motor strength in extremities, but 4/5 after repetitive motion, with return to 5/5 after administration of edrophonium. Deep tendon reflexes are normal. What pathologic abnormalities is most likely to be present in this woman?

Malignant melanoma

Gain-of-function mutations in the BRAF gene can result in overactivation of growth signals that can lead to:

McArdle disease

Glycogen deposits appear with myophosphorylase deficiency

Xanthine oxidase inhibitors (Allopurinol and Febuxostat)

Gout Drugs: Side effects include GI upset, hepatic toxicity, and decreased metabolism of azathiprine and 6-MP

Neurogenic muscular diseases such as amyotrophic lateral sclerosis

Grouped atrophy of myofibers is a feature of what type of muscular diseases?

C. botulinum

Growing in poorly preserved canned foods elaborates a neurotoxin that leads to paralysis.

Ankylosing spondylitis

HLA-B27 is often positive in:

Cartilage

Has a bluish-white cut surface?

The brown recluse spider (Loxosceles)

Has a cytotoxic venom that produces extensive tissue necrosis.

Myotonic dystrophy

Has an autosomal dominant pattern of inheritance, with increased CTG repeats in the DMPK gene. This disease can also have features including cataracts, frontal baldness, testicular atrophy, heart disease, and dementia.

Dermatitis herpetiformis

Has urticaria of grouped vesicles on extensor surfaces in young adults, often associated with celiac disease. IgA antibodies are implicated in the pathogenesis.

Chondrosarcomas

Have atypical chondrocytes with cartilagenous matrix. They often form a bulky mass without distinct borders.

B. malayi and Wuchereria bancrofti

He has lymphatic filariasis. Repeated and prolonged infection results in the filarial worms blocking lymphatic channels to produce pronounced lymphedema. The most common species of filarial worms involved are:

Ankylosing spondylitis

He probably is also HLA B27 positive. There is a progressive bony ankylosis, especially of sacroiliac joints and spine.

- Actinic keratoses -Squamous cell carcinoma - Melanoma - Basal cell carcinoma

His job entails sun exposure which puts him at risk for what type of skin disorders?

Keratinocytes that do not mature normally and retain nuclei in the stratum corneum

Histologic findings in psoriasis include parakeratosis which are:

Koilocytes- epithelial cells with perinuclear cyctoplasmic clearing

Histologic findings of verruca vulgaris include epidermal hyperplasia and a thickened stratum granulosum with:

dermal-epidermal junction

Histopathological examination of lichen planus lesions often shows band-like (sawtooth-like) lymphocytic infiltration at the:

Botulism

Hours after consuming a meal that included home-canned peas, a man and his wife began to develop weakness and progressive respiratory failure 3 hours later. On physical examination they now have 3/5 motor strength in all extremities. Deep tendon reflexes are normal. They are afebrile. What infective disease are they most likely to have?

Leads to bone resorption

How does increased osteoclast activity contribute to the hypercalcemia seen in hyperparathyroidism?

BRAF inhibitor

How would you most likely treat a melanoma?

Stratum corneum

Hyperkeratosis involves thickening of what epidermal skin layer?

Neutrophils

Impetigo leads to a collection of what cell types under the stratum corneum?

Macrophage colony stimulating factor (M-CSF) and expression of receptor activating RANK-L.

In bone, PTH directly activates osteoblasts. These cells activate osteoclasts by secretion of:

Osteoblasts

In bone, PTH directly activates:

Clostridium botulinum

In poorly canned foods, with no acidity, this organism can grow and release an exotoxin that interferes with release of cholinergic neurotransmitters. The botulinum neurotoxin enters the bloodstream and is transported to peripheral cholinergic nerve terminals, including neuromuscular junctions, postganglionic parasympathetic nerve endings, and peripheral ganglia.

Dense collagen bundles; This is a description of a typical 'keloid' that forms as a consequence of an exaggerated healing response.

In the 3 months following a traumatic laceration to the right upper chest, a 36-year-old African-American man notes the development of disfiguring nodular scarring in the region of the healed laceration. On examination there is a 1 x 4 cm subcutaneous area with an irregular firm, nodular appearance. Scar revision with excision of the lesion is performed. What microscopic appearances is this excised tissue most likely to show?

Mouse and Deer

In the US, the primary reservoir host for Borrelia burgdorferi, is the:

Pompe Disease

In the classic infantile form of this disease, glycogen accumulates in lysosomes in the heart and the muscles. A baby with cardiomegaly and hypotonia should bring this disorder immediately to mind. An enlarged tongue is a classic finding.

Paget's disease

In this condition, accelerate bone remodeling occurs, leading to bony overgrowth at focal locations in the skeleton; the skull is a common site.

Bullous pemphigoid

In this condition, the blisters do not show acantholysis of keratinocytes, and the blisters extend down to the basement membrane below the stratum basale?

Paget Disease

In this condition, there is both proliferation and destruction of bone that leads to an increase in size of the affected bone and increased blood flow that predisposes to congestive heart failure to account for these findings. Narrowing of bony canals traversed by peripheral or cranial nerves can lead to nerve palsies.

Paget's Disease

In this disease, histologically, the bone has a mosiac pattern with thick cement lines.

spondylolisthesis

In this disorder, the vertebral body, pedicles, and facets 'slips' forward to produce back pain, and limited motion. Symptoms are often bilateral.

Osteoarthritis

In this type of arthritis, the articular surface becomes worn or damaged with time, leading to pain and loss of mobility?

Sporotrichosis

Infection may spread along lymphatics (lymphocutaneous sporotrichosis). A papule or nodule develops at the site of innoculation and can ulcerate and drain.

Colchicine

Interferes with the inflammasome complex found in neutrophils and monocytes.

Fibrous dysplasia

Is a benign lesion of the diaphysis with irregular woven bone in a fibrous matrix?

Pemphigus vulagaris

Is a blistering autoimmune disease seen in older adults.

C perfringens

Is a cause for gas gangrene of soft tissues, typically as a consequence of trauma with wound contamination.

degenerative osteoarthritis

Is a common and progressive condition that becomes more frequent and symptomatic with aging. There is erosion and loss of articular cartilage with joint space narrowing. There is minimal inflammation.

Desmoglein-1

Is a desmosome protein that attaches keratinocytes to one another in the stratum granulosum?

Ewing Sarcoma

Is a diaphyseal lesion of long bones in children with characteristic small round blue cells?

Osteopetrosis

Is a disorder of increased bone density.

Myasthenia gravis

Is a form of type II hypersensitivity in which there are autoantibodies directed against acetylcholine receptors on skeletal muscle motor end plates.

Pompe Disease

Is a glycogen storage disease that can present with myopathy and exercise intolerance. Is usually diagnosed in infants and young children who present with failure to thrive along with myopathy and, sometimes, hypertrophic cardiomyopathy and/or macroglossia.

Myophosphorylase deficiency (McArdle's disease)

Is a glycogen storage disease that presents with myalgias, rhabdomyolysis, myoglobinuria, and early fatigue from exercise due to inability to break down glycogen for use as energy in muscle tissues.

Vibrio vulnificus

Is a gram-negative, lactose-fermenting bacteria found in marine environments that can cause soft tissue infections, as well as gastroenteritis?

Calcitonin

Is a hormone produced by the thyroid which binds to osteoclasts and inhibits bone resorption.

Fibrous dysplasia

Is a localized, abnormal proliferation of fibrous tissue in bone arranged with haphazard trabeculae of woven bone?

Osteoid osteomas

Is a painful solitary lesion of children and young adults in the diaphysis of a bone?

Lambert-Eaton Syndrome

Is a paraneoplastic syndrome, most often associated with small cell anaplastic carcinoma of the lung, that resembles myasthenia gravis?

Nodular fasciitis

Is a peculiar exaggerated reaction to injury, though a history of trauma is elicited in a minority of cases. It tends to be fast-growing over weeks. Most occur in arm, chest, or back.

myositis ossificans

Is a peculiar reaction to injury with a repair reaction and dystrophic calcification, typically organizing from the outside into the center?

Osteoarthritis

Is a progressive, degenerative, non-inflammatory process seen most often with aging, trauma, or any 'wear and tear' of joints, particularly with joints that get a lot of use or are weight-bearing. Pain is the major problem.

Acne

Is a pustular process from blockage of pores of adnexal structures.

Salmonella

Is a rare cause for septic arthritis, except in sickle cell disease.

Bullous pemphigoid

Is a rare condition producing flaccid bullae in older persons on inner thighs and flexor surfaces. It is a type II hypersensitivity reaction with immunoglobulin and complement deposited along the epidermal basement membrane and directed at hemidesmosomes.

Teripratide

Is a recombinant form of parathyroid hormone which increases osteoblast activity and inhibits bone resorption.

seborrheic keratosis

Is a round, flat, coinlike plaque that varies in diameter from mm to several cm's and occurs most often in middle aged to older persons. Microscopically they have hyperkeratosis, acanthosis, focal hypergranulosis, and papillomatosis adjacent to normal epidermis. Squamous and basaloid cells resembling normal epidermal basal cells constitute the bulk of the lesion. Variable melanin pigmentation within basaloid cells is seen as well as pseudo-horn (keratin) cysts.

Raloxifene

Is a selective estrogen receptor modulator.

Lichen planus

Is a self-limited disease that usually disappears in a year or two. There are pruritic, flattened, purplish papules on the skin, and white to reticulated areas on mucous membranes. Microscopically, there is a dense, band-like uper dermal infiltrate of lymphocytes.

Ewing Sarcoma

Is a small round blue cell tumor?

carbuncle

Is a subcutaneous necrotizing inflammation formed from a cluster of furuncles.

Probenecid

Is a sulfa drug that blocks reabsorption of uric acid in the proximal tubule and blocks secretion of penicillin int the urine?

abaloparatide

Is a synthetic analogue of human parathyroid hormone-related protein and increases osteoblast activity and inhibits bone resorption.

McArdle

Is accompanied by muscle cramping and rhabdomyolysis?

Pemphigus vulgaris

Is an autoimmune blistering disorder characterized by antibodies against desmoglien-3?

Bullous pemphigoid

Is an autoimmune blistering disorder in which antibodies target hemidesmosomes?

Pemphigus vulgaris,

Is an autoimmune blistering disorder where antibodies are formed against desmoglein proteins?

McArdle Disease

Is an inborn error metabolism, with lack of the myophosphorylase enzyme involved with the glycolytic pathway of energy metabolism. It leads to cramping muscle pain with exercise.

osteogenesis imperfecta

Is an inherited disorder of type I collagen synthesis, leading to 'brittle bones' with high risk for fractures?

Dermatitis herpetiformis

Is an itchy red rash with papules and vesicles, most commonly affecting the elbows, knees, trunk, and buttocks.

Pemphigus vulgaris

Is associated with anti-desmosomal IgG antibodies, which are deposited in a net-like pattern around epidermal cells.

C. perfringens

Is associated with wound infections leading to gas gangrene.

Gout

Is caused by an inflammatory reaction to the deposition of monosodium urate crystals in joints, most commonly the great toe and knee.

Bullous pemphigoid

Is caused by antibodies directed at basement membrane antigens, damaging the hemidesmosomes so that there is suepidermal blistering.

Scabies

Is caused by infection with the little mite which likes to burrown in the epidermis, typically between the fingers, producing itching lesions.

Pemphigus vulgaris

Is characterized by blisters resulting from a type II hypersensitivity reaction with IgG antibodies directed at desmoglein which glues keratinocytes together.

Acanthosis

Is diffuse epidermal hyperplasia (thickening)?

Rickets

Is due to a deficiency of vitamin D in children with growing bones?

Clostridium difficile

Is found in the intestinal tract, and it can overgrow and produce a toxin that leads to pseudomembranous colitis in persons whose bowel flora has been altered by long-term, high dose antibiotic therapy.

Scabies

Is most often seen on the hands, with linear burrows in the superficial epidermis.

Liposarcoma

Is one of the most common soft tissue malignancies of adults and can be found in deep soft tissues such as thigh and retroperitoneum. Microscopically, one looks for lipoblasts as evidence of the cell of origin?

Teriparatide

Is recommended for patients with osteoporosis who cannot tolerate bisphosphonates?

Dermatitis herpetiformis

Is related to IgA antibodies damaging the reticulin fibers that anchor the epidermal basement membrane. Affected persons can have celiac disease from dietary gluten sensitivity.

Celecoxib

Is sub-classified as a selective COX-2 inhibitor, and it causes fewer ulcers and less bleeding than other "non-selective" NSAIDs.

Borrelia burgorferi

Is the causative agent for Lyme disease that may be accompanied by a chronic arthritis.

Tick

Is the main vector responsible for transmission of Borrelia burgdorferi, the underlying pathogen in Lyme disease.

S. aureus

Is the most common cause for pyogenic osteomyelitis?

Membranous ossification

Is the process by which flat bones form like the skull?

The A Band

Is the region of the sarcomere where actin and myosin overlap. This band does not change in size during contraction.

Erythema multiforme

Is thought to be a hypersensitivity response to drugs or infection. The lesions can be macules, papules, vesicles, or bullae. There is often a target-like appearance to the erythema.

Impetigo

Is usually a highly contagious staphylococcal or streptococcal skin infection with a honey-colored crust involving the face of a child.

Osteosarcoma

Is usually seen in the metaphyseal region and destroys cortex of bone. Very atypical cells with osteoid production are seen microscopically.

Avascular necrosis

It can occur from corticosteroid use, which focally reduces blood flow, as well as trauma that disrupts the blood supply, and decompression (as in diving) with formation of nitrogen bubbles in small vessels, hemoglobinopathies, and infections, among others. The overlying bone cortex will eventually collapse and impair joint function.

Ankylosing Spondylitis (AS)

It is a chronic inflammatory disease that causes inflammation of the spine and sacroiliac joint

Onchocerciasis (Onchocerca volvulus)

It is more of a nuisance than a life-treatening condition. The worms from this infection live in the subcutaneous tissues and the eyes.

Osteoid

It is the unmineralized, organic portion of the bone matrix formed by osteoblasts.

Glucocorticoids

Its use is one of the most important causes of avascular bone necrosis (AVN), also called osteonecrosis.

Tinea cruris

Jock itch would be more scientifically termed:

Squamous cell carcinoma

Keratin pearls are associated with what type of malignancy?

Squamous cell carcinomas

Keratin pearls, concentric layers of abnormal keratinized squamous cells, are seen in:

seborrheic keratosis

Keratin-filled cysts, or horn cysts, are seen in:

Cauliflower-like warts

Koilocytosis (cytoplasmic clearing around the nucleus) is seen in HPV infection. HPV infection typically causes:

Osteochondroma

Lateral projection of growth plate from the bone cortex is associated with what neoplasm?

Pemphigus vulgaris

Leads to antibodies against desmosomes, the attachments between keratinocytes. This causes acantholysis (detachment) of keratinocytes and bullae that extend only to the stratum spinosum leaving the stratum basale intact.

Rheumatoid arthritis

Leads to marked joint deformity, typically of small joints in hands and feet. The pain usually persists for weeks to months.

Inhibits pyrimidine synthesis

Leflunomide MOA:

Rheumatoid arthritis

Leflunomide, is sued in patients with what disorder?

Ewing Sarcoma

Lesions are usually diaphyseal in location and can extend into soft tissues.

flexural surfaces of the wrists

Lichen Planus generally affects what part of the upper extremities?

stratum granulosum and stratum corneum

Lichen planus causes what layer of the epidermis to thicken?

Acantholysis

Loss of connections between keratinocytes

B burgdorferi

Lyme disease is caused by what spirochete that produces a rash followed by arthritis. Meningitis, neuritis, and carditis are additional complications. The tick may be found on deer and mice.

Osteosarcoma

Malignant bone tumor derived from osteoblasts. Patients present with a painful, enlarging mass in the metaphysis of long bones and may develop pathologic fractures.

McArdle's disease

Many patients experience the second wind phenomenon, in which symptoms improve after a brief period of rest. Treatment often involves aerobic exercise programs and nutritional supplementation, although evidence of benefit is limited.

Marfan syndrome

Marfanoid habitus, lens dislocatons, and cardiovascular abnormalities are seen in this autosomal dominant condition with variable expression?

Myophosphorylase deficiency

McArdle's disease is associated with what enzyme deficiency?

Stratum basale

Melanocytes are located within what layer of the epidermis?

BRAF

Melanoma; most likely contains in activation mutation in:

rheumatoid arthritis

Methotrexate is used to treat patients with:

Renal Failure

Most cases of gout (90% or more) have an elevated serum uric acid and are 'primary gout' from overproduction or underexcretion of uric acid, but usually without an identifiable cause. Underexcretion of uric acid is potentiated by:

HLA-B27

Most patients have a genetic predisposition to the disease. Up to 95% of patients test positive for HLA-:

Desmoglein 3

Mucous membranes contain what desmosome protein?

Psoriasis

Munro microabscesses (collections of neutrophils in the stratum corneum) and a thinned stratum granulosum are findings in:

Muscular Dystrophy

Muscle fibrosis and fatty infiltration is typical of what type of disorder?

Marfan syndrome, which affects the connective tissue of the cardiovascular system most severely.

Mutations of the fibrillin gene are present with:

Type II (antibody mediated) hypersensitivity

Myasthenia gravis is a form of what hypersensitivity?

Actinomyces

Mycetoma encompasses a variety of infectious agents that produce subcutaneous infections extending into deep soft tissues and even bone. The tissue reaction ranges from chronic abscessing inflammation to granulomatous inflammation. There may be so many organisms that they produce visible granules (yellow to orange to brown) exuding from draining sinus tracts onto the skin surface. Causative organisms include long filamentous bacteria, most often:

DMPK

Myotonic dystrophy is an autosomal dominant condition characterized by increased CTG trinucleotide repeats in a gene encoding for myotonin protein kinase. What is the particular gene?

DMPK

Myotonic dystrophy is the most common adult muscular dystrophy, but the severity of the disease varies, most likely with the number of CTG repeats, which tend to increase in subsequent generations. This is type 1, an autosomal dominant disease, from mutation of what gene?

GI Tract ulceration

NSAIDs have the complication of:

Osteoarthritis

Narrowing of the vertebral disc space, subchondral sclerosis (thickening of subchondral bone), osteophyte (bone spur) formation, and subchondral cysts (cracks in the bone that fill with synovial fluid) are symptoms of what bone disorder?

Acute suppurative arthritis

Neisseria gonorrheae infection can produce what type of arthritis?

Melanocytes

Nevi (moles) are formed by clusters of?

Urate transporter-1 (URAT1)

Normally facilitates uric acid excretion in the urine.

Melanoma

Occur in sun exposed areas and tend to be pigmented. They tend to enlarge faster than either squamous cell carcinomas or basal cell carcinomas.

Osteoarthritis

Often involves a larger, weight-bearing joint. The pain usually diminishes somewhat initially with movement, but recurs with reuse or prolonged use of the affected joint.

Increased osteoclast (bone breakdown) activity relative to osteoblast (bone formation) activity

On the cellular level, osteoporosis is characterized by:

Nevi

Or 'moles', can be pigmented and raised and can be multiple, but they are rarely more than 1 cm in size.

Hyperparathyroidism

Osteitis fibrosa cystica lesions are filled with osteoclasts and can have a cystic appearance on radiography. In some cases the osteoclast proliferation is so florid that a 'brown tumor' is formed. There is an association with what hormonal imbalance?

Osteoclasts

Osteitis fibrosa cystica lesions are filled with what type of cells?

Articular surface

Osteoarthritis involves mainly the overlying:

Type 1

Osteogenesis imperfecta is a disorder of what type of collagen synthesis?

Osteosarcoma

Osteoid production by a malignant bone neoplasm is characteristic for:

Osteosarcoma

Osteoid production is characteristic for what type of neoplasm?

Carbonic anhydrase II; generates bicarbonate and acid

Osteopetrosis is inherited as an autosomal recessive disorder and caused by deficiency of the enzyme:

Gonococcal urethritis

Over the past 4 days, an 18-year-old man has developed marked pain and swelling in his right hip that makes movement difficult. He has no history of major medical problems. On physical examination there is pain on movement with diminished range of motion of the hip. A joint aspirate from the hip reveals cloudy fluid that on microscopic examination shows numerous neutrophils but no crystals. What condition is most likely to have preceded development of his hip problem?

Systemic lupus erythematosus (SLE)

Over the past 4 months a 25-year-old woman has noted the appearance of a skin rash on her face when she spends more than an hour in the sun. On physical examination there is an erythematous skin rash on her cheeks and across the bridge of her nose. Laboratory studies show a positive anti-nuclear antibody (ANA) test with a titer of 1:256 and anti-double stranded DNA titer of 1:256. A punch biopsy of non-sun exposed skin is performed. Immunofluorescence staining on this normal skin reveals band-like deposition of IgG and C3 at the dermal-epidermal junction. What immunologic disorder is she most likely to have?

Basal cell carcinoma

Palisading nuclei surrounding nests of atypical basaloid cells are seen in:

rheumatoid arthritis

Pannus formation is characteristic for:

Dermatitis herpetiformis

Papules and vesicles on the knees and elbows are seen in:

Retained nuclei in the stratum cornuem

Parakeratosis is a common finding in psoriasis which is histologically depicted by:

Psoriasis and Actinic Keratosis

Parakeratosis, retained nuclei in the stratum corneum. Is often associated hyperkeratosis in other skin disorders like:

Osteochondromas

Patients dealing with this neoplasm are usually adolescent males who develop pain or pathologic fractures in the metaphysis of long bones?

Ankylosing Spondylitis (AS)

Patients with this disorder develop lower back pain before the age of 40 that improves with exercise and is worse at night?

Pemphis vulgaris

Patients with this disorder present with flaccid intraepidermal bullae, painful oral blisters, and a positive Nikolsky sign.

Ewing Sarcoma

Patients with this malignant brain tumor present with a painful, warm, and swollen bone mass and frequently develop fever and leukocytosis.

Osteoid osteoma

Patients with this tumor present with bone pain and swelling that is worse at night and responds to NSAIDs?

RA

Patients with this type of arthritis present with the gradual onset of symmetric joint inflammation (classically in the metacarpophalangeal and proximal interphalangeal joints) and prolonged morning stiffness that improves throughout the day.

desmoglein proteins

Pemphigus vulgaris, is an autoimmune blistering disorder where antibodies are formed against:

Acid Maltase Deficiency

Pompe's disease is associated with what enzyme deficiency?

Rickets and Osteomalacia

Poorly-mineralized bone matrix is characteristic of what bone disorders?

Trichinella spiralis larvae

Pork products (or wild game meat) that are poorly cooked and have come from animals fed improperly may be a source for:

Male Predominance

Primary malignant tumors of bone have what type of predominance?

Fibroblasts

Produce collagen and are more numerous with the gross appearance of firm, white scar tissue.

Fibroblasts

Produce collagen as part of the scar formation that follows an injury.

Osteoid osteomas

Produce considerable pain for their small size. They are located in the bone cortex, with a central nidus surrounded by sclerotic bone.

Botulism

Produces neuromuscular paralysis following ingestion of the pre-formed neurotoxin that is elaborated by the bacteria that have grown in poorly preserved canned foods.

Mycobaterium tuberculosis

Professional golfer Phil Mickelson continues to promote adalimumab (Humira). He receives twice monthly injections. His disease is arrested, but the joint damage cannot be reversed. What infectious complications is most likely to occur with this medication?

Pseudogout

Pseudogout typically involves what anatomical location?

stratum spinosum

Psoriasis causes a thickened:

stratum granulosum

Psoriasis causes a thinned or absent:

Stratum spinosum

Psoriasis leads to a thickened:

Stratum spinosum

Psoriasis leads to, diffuse epidermal hyperplasia (thickening) with thickening of the:

Osteoclasts

RANK is expressed on the surface of?

Osteoblasts

RANKL is found on the surface of what cells?

Francisella tularensis

Rabbits are reservoir hosts of:

Chlamydia

Reactive arthritis is an autoimmune phenomenon that can follow an infection, typically non-gonococcal urethritis with:

Rasburicase and Pegloticase

Recombinant uric acid oxidases that degrade uric acid into water soluble elements that are excreted by the kidneys.

Vitiligo

Refers to an area of depigmentation of the skin.

Osteomyelitis

Represents an ongoing infection that produces marked bone deformity, not just joint narrowing.

Pemphigus vulgaris

Results from antibodies to the desmoglein components of adhesive desomosomes linking keratinocytes.

dysplastic nevus syndrome

Results in the presence of many nevi of varying sizes with varying shades of tan to brown to black pigmentation on many skin surfaces. There is an increased risk for melanoma.

Parakeratosis

Retained nuclei in the stratum corneum

Tubular necrosis and renal failure.

Rhabdomyolysis may follow some infections, such as influenza, or may be seen with vigorous exercise or muscle trauma. Myoglobinuria can lead to acute:

myotonic dystrophy

Ring fibers are seen with:

Sickle cell anemia

Salmonella osteomyelitis is a feature seen in patients with what disorder?

myophosphorylase enzyme deficiency

Sarcolemmal glycogen deposition is a feature of McArdle syndrome, a form of glycogen storage disease from what enzyme deficiency?

McArdle syndrome

Sarcolemmal glycogen deposition is a feature of what glycogen storage disease?

Alkaline phosphatase

Serum level of what enzyme is elevated in Paget's disease?

Encysted larvae (Trichinella spiralis)

Severe myalgia with fever are present in a 28-year-old man 3 weeks after he returned from a camping trip to Alaska. On that trip, he and his fellow travelers hiked extensively. They ate wild game they cooked themselves. On physical examination he has 4/5 proximal motor strength in extremities, with tenderness to palpation of large muscle groups. A CBC shows a total WBC count of 14,600/microliter, Hgb 14.8 g/dL, Hct 45.0%, MCV 93 fL, and platelet count 215,000/microliter. WBC differential count shows 66 segs, 5 bands, 10 lymphs, 7 monos, and 12 eos. His serum creatine kinase is 640 U/L. What finding is a muscle biopsy most likely to show?

Recombinant uric acid oxidases (Rasburicase and Pegloticase)

Side effects include precipitatoinof gout flares, anaphylaxis, and hypersensitivity reactions.

rheumatoid arthritis (RA)

Small joints (such as the hand) are more likely to be involved. There is proliferative synovitis with lymphocytes and plasma cells, not neutrophils.

Ewing sarcoma

Small round blue cells are characteristic for a:

True gout

Sodium urate deposition is associated with what type of gout?

Melasma

Some pregnant women get subtle facial pigmentation, either as small lesions or as blotches, known as:

Sporothrix schenckii

Sporotrichosis describes a focal skin infection from local trauma with introduction of what organisms, which inhabit plant materials such as splinters, thorns, or mulch. Infection may spread along lymphatics (lymphocutaneous sporotrichosis)?

Keratinocytes

Squamous cell carcinomas, are a type of skin cancer derived from:

stratum granulosum

Staphylococcal Scalded Skin Syndrome (SSSS) only affects what layer of the epidermis?

Impetigo, with honey-coloured crusting lesions of the face

Staphylococcal and streptococcal infections of the skin in children often present as:

Pyogenic arthritis; a joint aspirate may yield cloudy synovial fluid with high cell count (mostly neutrophils) and decreased viscosity.

Staphylococci are the most common causes for what type of arthritis?

furuncle

Starts as a Staphylococcus aureus infection of a hair follicle.

Ultraviolet B

Sunburn cells are apoptotic keratinocytes in the epidermis caused primarily by what type of radiation?

Type III Hypersensitivity

Systemic lupus erythematous is what type of hypersensitivity reaction?

Recombinant parathyroid hormone

Teriparatide is a:

Synaptobrevin

Tetanospasmin ascends axons to the spinal cord and CNS and produces clinical manifestations of tetanus: headache, diaphoresis, muscular stiffness and spasms with difficulty swallowing, and rigidity of abdominal muscles. The action of the A part of this exotoxin stops affected neurons from releasing the inhibitory neurotransmitters GABA (gamma-aminobutyric acid) and glycine by selective cleavage of what component of synaptic vesicles?

GABA (gamma-aminobutyric acid) and glycine

Tetanospasmin ascends axons to the spinal cord and CNS and produces clinical manifestations of tetanus: headache, diaphoresis, muscular stiffness and spasms with difficulty swallowing, and rigidity of abdominal muscles. The action of the A part of this exotoxin stops affected neurons from releasing the inhibitory neurotransmitters:

Systemic lupus erythematosus

The ANA test is most often positive in cases of other autoimmune diseases such as:

Achondroplasia

The FGFR gene mutations are associated with skeletal dysplasias, such as:

Osteosarcoma

The Rb gene is a tumor suppressor gene. If both copies of the gene are mutated, then the risk for malignancy is increased. One of the malignancies that can occur is:

systemic lupus erythematosus

The anti-double stranded DNA positivity is most specific for:

Osteogenesis imperfecta

The blue sclerae, hearing loss, and dental abnormalities are characteristic for:

Osteoporosis

The bone resorption that accompanies hyperparathyroidism can cause:

sarcoplasmic reticulum

The calcium needed to generate muscle contraction is derived from what structure?

Erythema multiforme

The classic "target lesion" has a center that is dark, vesicular, or eroded, with a surrounding red or purple ring

monosodium urate crystals

The diagnosis of gout is confirmed by the presence of what type of crystals?

UV radiation

The formation of covalent bonds between adjacent thymine and cytosine bases creates pyrimidine dimers. This increases the risk of developing gain-of-function mutations in the BRAF gene. These DNA lesions are caused by exposure to:

hypercalcemia and hypophosphatemia

The hallmark laboratory features (2) of hyperparathyroidism are:

Ankylosing Spondylitis (AS)

The hallmark of this disease is characterized by the slow onset of chronic back pain before the age of 40.

Verruca vulgaris

The image depicts a koilocyte which is indicative of what condition?

Basement membranes

The immune complex deposits present in the 'normal' skin are typical for SLE. The rash is caused by deposition of immune complexes, which tend to be trapped along:

Osteopetrosis

The infantile form presents with seizures, intellectual disability, hydrocephalus, and cranial nerve palsies.

metacarpophalangeal (MCP) joints and the proximal interphalageal (PI) joints

The joints of the hand mainly involved with RA are the:

S. aureus

The most common cause of pyogenic osteomyelitis is:

Osteogenesis imperfecta type II

The perinatal lethal form, which has both autosomal recessive and autosomal dominant inheritance patterns.Osteogenesis imperfecta is an inherited disorder of type I collagen synthesis, leading to 'brittle bones' with high risk for factures.

Lichen Planus

The presence of planar, purple, polygonal, pruritic, papules and plaques on the extensor surface (shins) and oral lace-like reticular lesion (Wickham striae) indicate a diagnosis of:

xeroderma pigmentosa

The rare autosomal recessive condition in which faulty DNA nucleotide excision repair genes are unable to repair the damage of ultraviolet light in cross-linking pyrimidine dimer residues.

Grafting

The skin can regenerate from the epithelial cells lining dermal appendages such as sweat ducts and hair follicles that were not destroyed in a partial thickness burn. All epithelial structures are destroyed in a full thickness burn, which requires:

Ulcer at the site of pathogen entry

The skin finding associated with tularemia is an:

Brown recluse spider bite

The toxin introduced by this insect bite leads to necrosis and a non-healing ulceration. Surgical excision may be necessary.

Herpes zoster virus infection, also commonly called 'shingles'.

The virus can be latent within dorsal root ganglia but reactivate and spread along a dermatomal distribution.

Actinic Keratosis

These are irregular reddish areas in sun-exposed skin.

Aneurysmal bone cyst

These are located in the metaphysis and are expansile lesions.

Basal Cell Carcinomas

These are nodular, expanding lesions in sun-exposed areas. Slow-growing but progressively enlarging lesion that does not typically have much pigmentation.

Bisphosphonates (Alendronate, oral)

These drugs impair the ability of osteoclasts to resorb bone, and also reduce adherence of osteoclasts to the surface of the bone Through these actions they inhibit bone resorption, leading to increased bone mass.

Herpes

These infections are usually vesicular?

Seborrheic keratosis

These tend to occur on the trunk and upper body of older individuals, then enlarge slowly over time and do not recede.

Giant cell tumor

These tumors expand the bone outward.

Hyperkeratosis

Thickening of the stratum corneum

Hypergranulosis

Thickening of the stratum granulosum

Achondroplasia

This autosomal dominant condition results in short-limbed dwarfism from defective cartilage proliferation at the growth plate.

The H Band

This band is located at the center of the sarcomere. This region shrinks during contraction.

Ehlers-Danlos syndrome

This disease results from abnormal collagen synthesis and there are a number of subtypes; most are autosomal dominant.

Epithelial cells

This hormone has actions on several cell types that lead to hyperalcemia. In the kidneys and the GI tract, PTH binds to what type of cells?

Ichthyosis

This is a form of Langerhans cell histiocytosis, with cutaneous seborrheic skin eruptions, as well as hepatosplenomegaly and lymphadenopathy. Most cases occur under 2 years of age.

Osteogenesis imperfecta, type I

This is a mild disease of 'brittle bones' from a defect in type 1 procollagen formation. Affected persons have blue sclerae and bone fractures. It is autosomal dominant.

Impetigo

This is a pyogenic infection with crusting, purulent lesions.

Ringworm

This is a superficial fungal infection on the skin of the body that produces circular lesions.

Osteogenesis imperfecta, type II

This is the worst form of OI and is lethal in utero. It is autosomal recessive.

Osteoid osteoma

This lesion has a central nidus surrounded by sclerotic bone.

Osteochondroma

This lesion usually produces a lateral projection from the bony cortex.

Osteitis fibrosa cystica

This localized bone lesion occurs most often in patients with hyperparathyroidism.

Clostridium perfringens

This organism in tissues causes marked necrosis with gas formation ('gas gangrene')?

Clostridium perfringens

This organism is associated with gas gangrene. In soft tissues, it can be introduced in association with trauma.

Yersinia pestis

This organism is associated with plague, in septicemia, pneumonic, and bubonic (lymphadenitis) forms.

Impetigo

This skin disorder primarily affects the epidermis and usually causes pustules that break down to form a golden crust?

Clostridium perfringens

This species is associated with necrotizing cellulitis or with gas gangrene.

Tinea versicolor

This superficial fungal infection from Malassezia furfur produces variably sized macules of varying color along with a fine scaling.

second degree, superficial partial thickness

This type of burn is usually red, moist, painful, and blanches with pressure. The burn affects the epidermis and the top part of the dermis

Acral lentiginous melanoma (ALM)

This type of melanoma can occur even in darker-skinned individuals, regardless of sun exposure.

Osteopetrosis

This uncommon inherited metabolic disorder leads to 'brittle bones' that predispose to fractures.

BRAF gene

This woman's history of an evolving skin lesion with irregular borders in a sun-exposed area is suspicious for malignant melanoma, a cancer that often has an underlying V600E mutation in what gene?

Sarcoptes scabiei

Three children with ages from 5 to 10 in a family are all affected by itching lesions on their hands for the past 2 weeks. On physical examination there are erythematous areas with superficial excoriation on the fingers and dorsa of the hands. These areas are linear to ovoid. Application of lindane-containing cream results in resolution of the lesions within a week. Infection with what organisms did these children most likely have?

Trichinosis

Three weeks following a vacation to Wisconsin, a family of four has developed fever, headache, weakness, malaise, and myalgia. They recall dining out in Milwaukee, boating and swimming in the Eau Claire river, visiting Uncle Dick's and eating some of his home-made sausage, and fishing in Green Bay. On physical examination they have muscle tenderness. Their symptomatology is best explained by what parasitic disease?

Malassezia furfur

Tinea versicolor is due to infection with:

Troponin which removes tropomyosin from the myosin binding groove

To initiate muscle contraction, calcium binds to:

Wheals

Transient, itchy, raised lesions that arise from edema in the dermis?

Onchocerciasis

Treating infected persons with ivermectin and black fly eradication have helped reduce the numbers of infections in Central Africa, Yemen, and focal regions of Central and South America.

Acral lentiginous melanoma (ALM)

Type of melanoma that affects the palms of the feet, soles of the hands, and underneath the nails.

Basal cell carcinomas

Typically appear on sun-exposed areas such as the face. They produce nodular masses with central ulceration.

Rheumatoid arthritis

Typically involves small joints of the hands and feet most severely, and there is a destructive pannus that leads to marked joint deformity.

Ankylosing spondylitis

Typically involves the spine. It is slowly progressive, beginning in the 3rd decade, and does not have a febrile component or lymphadenopathy.

Sporotrichosis

Typically produces a small nodule of inflammation.

Dopaquinone

Tyrosinase converts tyrosine to what precursor of the pigment melanin?

Wheals

Uritcaria is characterized by:

Corticosteroid

Usage increases the risk for avascular necrosis (osteonecrosis) of bone, which most often involves the hip at the femoral head.

Papilomavirus

Verruca vulgaris (warts) is caused by what virus?

HPV

Verruca vulgaris, or common warts, is caused by:

Less than -2.5

What T-score on a DXA scan is consistent with osteoporosis?

Infectious bacterial gases

What are the causes for crepitus?

Acetaminophen and NSAIDs

What are the first line therapies for osteoarthritis?

S. aureus

What are the most common bacterial causes of skin abscesses, collections of pus in the dermis or subcutaneous tissues?

Staph aureus and Strep species (gram positive bacteria)

What are the most common causes of septic arthritis?

Desmosomes

What are the protein attachments between keratinocytes?

Sun Exposure and Fair Skin

What are the risk factors associated with developing a melanoma?

Osteoclasts

What cell type resorbs bone?

Osteoblasts

What cells are osteosarcomas derived from?

Osteoblasts

What cells directly lay down woven bone in membranous ossification, and chondrocytes are not involved?

Degradation of cell membranes by phospholipase

What describes the mechanism of cellular damage caused by C. perfringens alpha toxin?

Calcium found in hydroxyapatite

What do bisphosphonates bind to?

Colchicine

What drug disrupts the polymerization of β-tubulin into microtubules, thereby preventing the activation, degranulation, and migration of neutrophils to sites of inflammation.

Colchicine

What drug is used for pseudogout prophylaxis?

Allopurinol and Febuxostat

What drugs used to prevent gout flares inhibit Xanthine Oxidase?

Decrease intestinal calcium absorption

What effect does corticosteroids have on intestinal calcium?

Xanthine oxidase

What enzyme catalyzes the conversion of hypoxanthine to uric acid?

Tropomyosin

What fills the binding groove between myosin and actin preventing binding?

Esophagitis

What is a common side effect of bisphosphonate therapy?

Herpes simplex virus

What is a common trigger for erythema multiforme (EM)?

Osteonecrosis

What is a rare complication of bisphosphonate therapy?

Obesity

What is a significant risk factor for arthritis of the knee and hips?

Osteoporosis

What is one of the complications of long-term therapy with corticosteroids?

Bacterial gastrointestinal or genitourinary infection (Yersinia)

What is reactive arthritis triggered by?

T-cell attack of melanocytes, leading to depigmented (white) patches in the skin

What is the cause of vitiligo?

Osteitis Fibrosa Cystica

What is the classic bony manifestation of untreated primary hyperparathyroidism?

Binds calcium at the initiation of a muscle contraction

What is the function of troponin C?

Inhibits myosin binding to actin

What is the function of troponin I?

Binds to tropomyosin and removes it from the binding groove for myosin between actin filaments to allow contraction

What is the function of troponin T?

Grouped atrophy

What is the hallmark of muscle atrophy of neurogenic origin?

Autosomal dominant; about half of cases represent spontaneous new mutations, and there is no family history

What is the inheritance pattern for achondroplasia?

X-Linked Recessive

What is the inheritance pattern of Duchenne Muscular Dystrophy?

Autosomal recessive

What is the inheritance pattern of Limb girdle dystrophy?

Autosomal Dominant

What is the inheritance pattern of Myotonic Dystrophy?

autosomal dominant

What is the inheritance pattern of osteogenesis imperfecta?

Elevated PTH, calcim, and alkaline phosphatase

What is the pattern of laboratory abnormalities found in a patient with primary hyperparathyroidism?

CD8 T cells killing of keratinocytes

What is the proposed mechanism behind Toxic Epidermal Necrolysis (TEN)?

The big toe (first metatarsal-phalangeal joint)

What joint is most often involved with gouty arthritis?

Myosin

What muscle filament hydrolyzes ATP for energy during muscle contraction?

Borrelia burgdorferi

What pathogen is responsible for lyme disease?

Hemidesmosomes

What proteins attach keratinocytes to the basement membrane between the dermis and epidermis?

Lichen Planus

What skin disorder causes lymphocytic infiltration of the dermal-epidermal junction?

TEN

What skin disorder causes necrosis of the entire epidermis and separation of the epidermis from the dermis?

The anti-citrullinated peptide/protein antibody (ACPA) and rheumatoid factor (RF)

What tests are useful for diagnosis of rheumatoid arthritis?

ACPA and rheumatoid factor

What tests have greater sensitivity and specificity for RA than other serologic tests?

Sarcoplasmic and Endoplasmic Reticulum Ca2+ ATPase (SERCA)

What transfers calcium from the cytosol into the sarcoplasmic reticulum?

Type I

What type of collagen is found in bone?

Alkaline (high pH; low H+)

What type of environments are necessary for calcium deposition in bone?

Type IV (Cell Mediated) hypersensitivity reaction that causes keratinocyte necrosis in the epidermis and subsequent exfoliation; mediated by T-Cells

What type of hypersensitivity reaction is Stevens-Johnson Syndrome?

When myosin hydrolyzes ATP releasing ADP

When does the myosin power stroke occur?

Metaphyseal region of older adults

Where are chondrosarcomas typically located?

Surface of the cortex of the diaphysis

Where are osteoid osteomas located?

At the periphery of the fibers

Where are striated muscle nuclei typically located?

The metaphyseal region of long bones; the location about the knee is most common

Where do most osteosarcomas arise?

Vertebra

Where do osteoblastomas usually arise?

In the distal interphalangeal (DIP) joints in the hands and feet.

Where does psoriatic arthritis commonly begin?

Wheals

Which of the following best describes these skin lesions?

Bisphosphonates

Which osteoporosis drugs have been linked to osteonecrosis of the jaw?

Myotonic dystrophy

While it can be associated with muscle pain and weakness, it causes symptoms at rest and is associated with delayed muscle relaxation following contraction (myotonia).

Osteoid osteoma

X-ray findings demonstrate a small central lucency (i.e.,dark area) with sclerotic margin and cortical thickening.

Ewing Sarcoma

X-ray findings include layering near the periosteum with splitting of the cortex ("onion skin").

Azathiprine

Xanthine oxidase inhibitors (Allopurinol and Febuxostat) interact with what drug?

Streptococcus pyogenes

is a common cause of cellulitis, which can develop into necrotizing fasciitis?

Trichinosis

is an acute inflammatory myositis due to the larvae of Trichinella spiralis.