UWorld 4/6
A 66-year-old man comes to the hospital due to sudden-onset chest pain and dyspnea. The patient has a history of asthma and gastroesophageal reflux disease but says his current symptoms feel different than what he usually experiences. An ECG is consistent with ST-elevation myocardial infarction, and an emergent cardiac catheterization is performed. Evaluation of the left and right coronary arteries reveals left-dominant circulation. A stenotic region is identified in one of the coronary vessels just before the origin of the artery supplying the atrioventricular node. Which of the following arteries is most likely affected? A. Anterior interventricular artery (%) B. Left circumflex artery (%) C. Left diagonal artery (%) D. Right coronary artery (%) E. Right marginal artery (%)
B. Left circumflex artery (55%)
A 4-year-old boy is brought to the office due to a progressively worsening cough for the past 2 days that is productive of yellow sputum. A year ago, he was found to have bilateral lower-lobe pulmonary infiltrates on chest x-ray and was diagnosed with pneumonia. The patient has since had 2 additional episodes of pneumonia, each requiring antibiotics for improvement of symptoms. His current chest x-ray again reveals bilateral lower lobe infiltrates. Further testing shows a high chloride content in his sweat. Which of the following abnormalities is most likely to be seen in this patient? A. Abnormal post-translational processing of a transmembrane protein (%) B. Decreased transcription of a transmembrane protein (%) C. Increased conductivity of a transmembrane chloride channel (%) D. Presence of a truncated transmembrane protein on the cell surface (%) E. Transmembrane protein with increased regulatory response to cAMP and ATP (%)
A. Abnormal post-translational processing of a transmembrane protein (%) The most common CFTR gene mutation (found in approximately 70% of cases) is a 3-base pair deletion of phenylalanine at amino acid position 508 (ΔF508). This mutation causes impaired post-translational processing (eg, improper folding and glycosylation) of CFTR, which is detected by the endoplasmic reticulum. As a result, the abnormal protein is targeted for proteasomal degradation, preventing it from reaching the cell surface. Certain drugs (eg, lumacaftor) can partially correct this folding defect, leading to expression of functional CFTR.
A 36-year-old woman comes to the office due to dyspnea and weakness that are brought on while doing ordinary chores around the house. The patient has no other medical conditions and takes no medications. She does not use tobacco, alcohol, or illicit drugs. Her mother had similar symptoms and died at age 42. After an extensive workup, a lung biopsy is performed. Light microscopy of the tissue sample shows medial hypertrophy, intimal fibrosis, and decreased intraluminal diameter of the small branches of the pulmonary artery. Which of the following is the most appropriate pharmacotherapy for this patient's current condition? A. Bosentan (%) B. Clopidogrel (%) C. Enalapril (%) D. Etanercept (%) E. Indomethacin (%)
A. Bosentan (%) Pulmonary hypertension causes specific morphologic findings in the branches of the pulmonary arteries, including increased arteriolar smooth muscle thickness (medial hypertrophy), intimal fibrosis, and significant luminal narrowing. In the setting of severe hypertension, lesions can progress to form interlacing tufts of small vascular channels called plexiform lesions. These changes can occur in both pulmonary hypertension due to underlying cardiac, lung, or thrombotic disease and in pulmonary arterial hypertension (PAH). PAH most commonly presents as dyspnea and exercise intolerance in women age 20-40. This patient's family history is suggestive of the familial form of PAH, which is most often caused by inactivating mutations involving the proapoptotic BMPR2 gene. The resulting increase in endothelial and smooth muscle cell proliferation leads to vascular remodeling, elevated pulmonary vascular resistance, and progressively elevated pulmonary arterial pressure. Although lung transplantation is the definitive treatment for PAH, medical therapy targeting the effects of endothelial dysfunction can help improve symptoms. Bosentan is an endothelin-receptor antagonist that blocks the effects of endothelin (a potent vasoconstrictor that also stimulates endothelial proliferation). Bosentan therapy decreases pulmonary arterial pressure and lessens the progression of vascular remodeling and right ventricular hypertrophy.
A community health task force is preparing to launch a campaign promoting obesity awareness and education in the area. The task force studies epidemiologic data from the county health department, which show that the prevalence of obesity is 3 times higher in a cluster of 5 specific ZIP codes compared to the county average. The task force leader approaches a reputed physician working at a local university to ask for assistance in understanding this pattern. Which of the following should be performed first to understand the etiology of the disparity in obesity prevalence? A. Cross-sectional analysis of demographic attributes and health behaviors across community ZIP codes (%) B. Observational study tracking leptin levels and weight outcomes in a representative cohort of community residents (%) C. Quality improvement study assessing medical provider adherence to national obesity screening, monitoring, and treatment guidelines across ZIP codes (%) D. Qualitative survey assessing obesity-related beliefs, attitudes, and knowledge in a representative community sample (%) E. Randomized controlled trial examining the relationship between primary care weight counseling and obesity incidence (%)
A. Cross-sectional analysis of demographic attributes and health behaviors across community ZIP codes (%) Obesity is a multifactorial condition with genetic, environmental, and behavioral causes. In this community, obesity prevalence is significantly higher in specific ZIP codes, indicating a possible health disparity (ie, preventable health differences associated with social, environmental, or economic disadvantage). Obesity-related health disparities represent a major public health concern with increased prevalence, severity, and complications affecting vulnerable communities. Such disparities involve factors relating to health care (eg, provider screening and treatment, access to care), patients (eg, diet and activity, health knowledge), and neighborhood (eg, density of grocery stores, which influences dietary patterns; crime rate, which influences physical activity). Given the multifactorial nature of obesity and related disparities, the first step in researching this community's trend is to generate hypotheses. This is best achieved through cross-sectional analysis of demographic and behavioral data, which is relatively easy to perform and can depict multiple risk factors at one point in time (a "snapshot") to: reveal differences in distribution (prevalence) of demographic factors (eg, poverty, ethnicity, insurance status) across ZIP codes. identify variables correlated (associated) with obesity risk (eg, poverty is more prevalent in high-obesity ZIP codes). generate hypotheses (eg, poverty increases obesity risk by decreasing ability to consume foods promoting optimal weight). Other study designs are more appropriate for testing or refining hypotheses following broader cross-sectional analysis. (Choices B and D) Like cross-sectional analysis, cohort studies and qualitative surveys offer observational data for generating hypotheses. However, each of these approaches focuses on a single, patient-related hypothesis (eg, leptin, patient knowledge and attitudes) for obesity differences. Cross-sectional analysis involving this community's demographic factors is a better first step, as it can analyze multiple potential influences and tailor hypotheses to this setting. (Choice C) Quality improvement studies analyze and test clinical processes (eg, providing obesity screening) affecting health care quality. They are less useful for generating broad hypotheses for community epidemiological patterns (eg, obesity trends). (Choice E) Randomized controlled trials are more appropriate for testing (rather than generating) hypotheses; such trials would be premature at this stage. Moreover, this approach tests only health care factors whereas cross-sectional analysis can assess how other risk factors correlate to obesity risk in this community
A. Lamellar bone structure resembling a mosaic pattern (%) B. Osteoid matrix accumulation around trabeculae (%) C. Spongiosa filling medullary canals with no mature trabeculae (%) D. Subperiosteal resorption with cortical thinning (%) E. Trabecular thinning with fewer interconnections (%)
A. Lamellar bone structure resembling a mosaic pattern (%)Choice A) Disorganized lamellar bone in a mosaic pattern is a characteristic finding in Paget disease of bone. Serum calcium and phosphorus are normal in these patients. B. Osteoid matrix accumulation around trabeculae (% (Choice B) Osteoid matrix accumulation around trabeculae is seen in vitamin D deficiency. Histologically, there is excessive unmineralized osteoid with widened osteoid seams. Patients typically have low urinary calcium.) C. Spongiosa filling medullary canals with no mature trabeculae (%) Choice C) Osteopetrosis ("marble bone disease") is characterized by persistence of the primary spongiosa in the medullary cavity with no mature trabeculae. It is caused by decreased osteoclastic bone resorption, resulting in accumulation of woven bone and diffuse skeletal thickening. D. Subperiosteal resorption with cortical thinning (%) E. Trabecular thinning with fewer interconnections (%)(Choice E) Trabecular thinning with fewer interconnections is characteristic of postmenopausal osteoporosis. Although long-standing PHPT causes thinning of cortical bone, the trabecular architecture remains relatively preserved.
34-year-old woman has recurrent throbbing headaches that occur several times a month and cause significant distress. They are accompanied by nausea and photophobia. She has had 5 emergency department visits for these headaches over the last 6 months. During office visits, her blood pressure ranges from 140/90 mm Hg to 150/95 mm Hg. Neurologic examination is unremarkable. The patient is prescribed metoprolol and is advised that the medication is expected to decrease the frequency of headaches and also lower blood pressure in the long term. Which of the following best explains this medication's effect on blood pressure? A. Decreased level of circulating catecholamines (%) B. Decreased level of circulating renin (%) C. Increased atrioventricular nodal conduction rate (%) D. Increased renal sodium and water retention (%) E. Long-term increase in peripheral vascular resistance (%)
B. Decreased level of circulating renin (%) Beta blockers inhibit release of renin from renal juxtaglomerular cells through antagonism of beta-1 receptors on these cells. Inhibition of renin release prevents activation of the renin-angiotensin-aldosterone pathway, which results in decreased vasoconstriction and decreased renal sodium and water retention.
A 67-year-old man has recurrent witnessed episodes of loss of consciousness while shaving. The episodes are characterized by a feeling of faintness followed by loss of consciousness, and each episode resolves after less than a minute. Blood pressure is 130/80 mm Hg and pulse is 80/min and regular; there are no significant changes in blood pressure or heart rate with supine and standing positions. Cardiac auscultation is normal with no murmurs or extra sounds. There are no neck bruits and the lungs are clear to auscultation. Which of the following factors is most likely contributing to this patient's symptomatic episodes? A. Activation of atrioventricular nodal reentrant circuit (%) B. Decreased systemic vascular resistance (%) C. Increased pulmonary vascular resistance (%) D. Intermittent complete heart block (%) E. Polymorphic ventricular tachycardia (%)
B. Decreased systemic vascular resistance (%) This patient with recurrent episodes of syncope while shaving most likely has carotid sinus hypersensitivity (CSH). When carotid sinus baroreceptors detect increased blood pressure, the brainstem responds by increasing parasympathetic tone (slows the heart rate) and reducing sympathetic tone (induces vasodilation). In some individuals, especially elderly men, the carotid sinus baroreceptors become overly sensitive to tactile stimulation, triggering an exaggerated vasovagal response with marked peripheral vasodilation (ie, decreased systemic vascular resistance). This can cause a transient reduction in cerebral perfusion that manifests as presyncope (eg, faintness, lightheadedness) or syncope. As with other etiologies of syncope, cerebral perfusion quickly returns and symptoms resolve within 1-2 minutes. In addition to shaving, rubbing of a shirt collar while dressing or turning the head is another common cause of syncope due to CSH
This patient has cough, fever, weight loss, and an upper lobe lesion on chest x-ray, raising strong suspicion for active pulmonary tuberculosis. Mycobacterium tuberculosis cannot be visualized on Gram stain due to the high lipid content (mycolic acid) of its cell wall. Most cases are diagnosed by acid-fast sputum testing and culture, but tissue microscopy typically shows granulomas characterized by epithelioid histiocytes and multinucleated Langhans giant cells. Granulomas often form after tissue macrophages encounter pathogens or substances that cannot be easily digested or removed. M tuberculosis can evade intracellular killing by macrophages and reproduce within phagolysosomes. Infected macrophages present mycobacterial antigens to naïve CD4 helper T cells in pulmonary lymph nodes and secrete IL-12, which induces activated T helper cells to differentiate into T helper subtype 1 (Th1) cells. Proliferating Th1 cells migrate to sites of infection, where they release interferon-gamma, which activates macrophages, improves intracellular killing of ingested mycobacteria, and recruits additional macrophages by increasing production of tumor necrosis factor-alpha. Activated macrophages can also limit the spread of mycobacteria by differentiating into epithelioid and giant cells that surround residual foci of mycobacteria, trapping them inside the necrotic, cheese-like area of a caseating granuloma F. Interferon-gamma (%)
64-year-old man comes to the clinic due to several weeks of persistent cough, fever, and weight loss. He smokes a pack of cigarettes daily and drinks 10-12 beers on weekends. Chest x-ray reveals an infiltrate in the left upper lobe. The patient is prescribed broad-spectrum antibiotic therapy for both aspiration and community-acquired pneumonia, but his symptoms worsen despite taking the medication as prescribed. Sputum Gram stain does not reveal any organisms. Lung biopsy findings are shown in the image below: Which of the following substances is most important for driving the development of this patient's observed microscopic lesion? A. C3a (%) B. Fibroblast growth factor (%) C. Granulocyte-macrophage colony-stimulating factor (%) D. IL-4 (%) E. Interferon-alpha (%) F. Interferon-gamma (%)
Patients with severe emphysema typically have chronic CO2 retention leading to chronic respiratory acidosis with metabolic compensation (high PaCO2, compensatory high bicarbonate, slightly acidic pH), often accompanied by hypoxemia PaO2<_____
75 mm Hg on room air
A 26-year-old man comes to the emergency department due to fever, right flank pain, and difficulty walking for the past 3 days. A week ago, the patient was treated with cephalexin for bacterial folliculitis. He was diagnosed with type I diabetes mellitus 10 years ago and takes subcutaneous insulin. Temperature is 38.9° C (102° F). During the medical interview, the patient lies supine on the examination table with his right hip and knee flexed and the limb externally rotated. On physical examination, he resists passive extension of the limb due to worsening of the pain. This patient's pathological process most likely involves which of the following muscles? A. Obturator externus (%) B. Psoas major (%) C. Quadratus lumborum (%) D. Rectus femoris (%) E. Transversus abdominis (%)
B. Psoas major (%) This patient most likely has a psoas abscess. The psoas muscle arises from the transverse processes and lateral aspects of the 12th thoracic through 5th lumbar vertebrae. It then courses downward across the pelvic brim anterior to the hip joint capsule and deep to the inguinal ligament to insert into the lesser trochanter of the femur via a tendon shared with the iliacus muscle. The iliacus and psoas muscles act as the major hip flexors. Psoas abscesses can occur due to direct spread of infection from an adjacent structure (eg, vertebral bodies, appendix, hip joint) or from hematogenous or lymphatic seeding from a distant and sometimes unknown site (in this case, the patient's skin infection). Risk factors include diabetes mellitus, intravenous drug use, HIV infection, and other forms of immunosuppression. Signs and symptoms of a psoas abscess include fever, back or flank pain, inguinal mass, and difficulty walking. Pain is exacerbated by movements that cause the psoas muscle to be stretched or extended (which causes irritation of the muscle fibers), such as extension at the hip (ie, psoas sign). As such, patients frequently position themselves to reduce discomfort by minimizing psoas stretching, particularly with hip flexion, external rotation, and lumbar lordosis. The psoas sign can also occur in acute appendicitis when the appendix is retrocecal (ie, located behind the cecum), as the inflamed appendix lies upon the right psoas muscle, causing irritation
PAH most commonly presents as dyspnea and exercise intolerance in women age 20-40. This patient's family history is suggestive of the familial form of PAH, which is most often caused by inactivating mutations involving the proapoptotic _____ gene. The resulting increase in endothelial and smooth muscle cell proliferation leads to vascular remodeling, elevated pulmonary vascular resistance, and progressively elevated pulmonary arterial pressure
BMPR2
A 50-year-old non-smoking female is found to have a round lesion in the right upper lobe of her lung. Transthoracic biopsy is scheduled to obtain tissue for histological examination. Which of the following would favor the diagnosis of hamartoma in this patient? A. Alveolar growth pattern without invasion (%) B. Neuroendocrine markers on electron microscopy (%) C. Cartilage tissue in the biopsy sample (%) D. Squamous pearls in the biopsy sample (%)
C. Cartilage tissue in the biopsy sample (%) This incidentally discovered solitary lung nodule (or "coin lesion") is probably benign, but malignant and metastatic disease must be ruled out via tissue biopsy. The most common benign lung tumor is a hamartoma (also called pulmonary chondroma). Hamartomas usually present as incidental findings on chest x-ray, with the appearance of a well-defined coin lesion with "popcorn calcifications." A hamartoma is an excessive growth of a tissue type native to the organ of involvement. The lung is the most common location. Lung hamartomas often contain islands of mature hyaline cartilage, fat, smooth muscle and clefts lined by respiratory epithelium. (Choice A) Bronchioloalveolar carcinoma is a variant of adenocarcinoma. It almost always arises at the lung periphery and has a characteristic distribution along the alveolar septae without vascular or stromal invasion. On chest x-ray it appears as a peripheral mass or as a pneumonia-like consolidation. (Choice B) Neuroendocrine markers are seen in small cell carcinoma of the lung and carcinoids. (Choice D) Squamous (keratin) pearls are characteristic of
A 56-year-old woman is brought to the emergency department due to a 2-day history of high fever, headache, mild confusion, and dry cough. She also has mild abdominal discomfort and watery diarrhea. The patient recently returned from a cruise to Hawaii. Her other medical problems include hypertension and hyperlipidemia. She has smoked 1 pack of cigarettes daily for over 20 years. Her temperature is 40 C (104 F), blood pressure is 104/63 mm Hg, pulse is 85/min, and respirations are 24/min. Lung examination reveals lower lobe crackles with no wheezing. Her abdomen is soft, non-distended, and non-tender. Chest x-ray shows bilateral lower lobe interstitial infiltrates. Which of the following additional findings is most likely to be present in this patient? A. Elevated circulating eosinophil count (%) B. Gram-positive diplococci on sputum Gram stain (%) C. Low serum sodium (%) D. Positive polymerase chain reaction assay for influenza A RNA (%) E. Presence of cold agglutinins (%)
C. Low serum sodium (%) Legionellosis can be divided into Pontiac fever (an acute, flu-like, self-limited disease) and the more common Legionnaires' disease. Legionnaires' disease should be suspected in patients with recent exposure to contaminated water (sporadic cases or common-source outbreaks in cruise ships, spas, hospitals, or air-conditioned hotels), radiographic evidence of pneumonia (typically patchy infiltrates that may progress to consolidation), high fever (>39 C [102.2 F]) sometimes associated with relative bradycardia, neurologic symptoms (eg, confusion, headache), and gastrointestinal (GI) symptoms (eg, diarrhea). Risk groups include the elderly or immunocompromised, smokers, alcoholics, and patients with chronic obstructive pulmonary disease. Because Legionella pneumophila is a faintly staining gram-negative bacillus that is facultatively intracellular, Gram stain typically shows many neutrophils but few or no organisms. Legionella is often diagnosed by urinary antigen testing; it grows on selective medium (buffered charcoal yeast extract [BCYE]). The most common laboratory abnormality is hyponatremia, frequently associated with Legionella but not other causes of pneumonia. The hyponatremia may be related to inappropriate antidiuretic hormone secretion and/or renal tubulointerstitial disease impairing sodium reabsorption (possibly due to either direct effect of Legionella, cytokines, or natriuretic peptides). Elevated transaminases are also common
As part of an experiment, radiolabeled ATP is injected into skeletal muscle. During muscle contraction, the labeled ATP is observed to attach to the sarcomere. This attachment causes immediate: A. Calcium binding to troponin C (%) B. Tropomyosin displacement from the groove on the actin molecule (%) C. Myosin head detachment from the actin filament (%) D. Cross-bridge formation (%) E. Myosin light chain phosphorylation by a specific enzyme (%)
C. Myosin head detachment from the actin filament (%)
Obesity-related health disparities affect vulnerable populations (eg, lower socioeconomic status) and arise from patient, health care, and community-related factors. ______ analysis can identify specific risk factors (eg, insurance status, health behaviors) correlated to obesity in different settings, helping to generate hypotheses for further research.
Cross-sectional
A 28-year-old woman comes to the office to establish care. She recently moved to New York to begin a job as a copy editor at a major newspaper. She has no known medical problems. The patient is in a monogamous relationship with her husband. She usually eats fast food for lunch, and she and her husband cook in the evenings. She goes to the gym about once every 2 weeks. The patient's temperature is 36.7 C (98 F), blood pressure is 118/64 mm Hg, pulse is 60/min, and respirations are 14/min. Her BMI is 24.6 kg/m2. Physical examination is unremarkable. Laboratory results are within the normal range. Counseling this patient regarding diet and exercise habits would be an example of which of the following? A. Case finding (%) B. Cognitive-behavioral therapy (%) C. Community-level intervention (%) D. Health promotion (%) E. Health risk assessment (%) F. Precontemplative stage intervention (%) G. Tertiary prevention (%)
D. Health promotion (%) According to the World Health Organization, health promotion is "the process of enabling people to increase control over their health and its determinants, and thereby improve their health". Examples include improving dietary habits (limiting fat intake, consuming fruits and vegetables), exercising regularly, abstaining from smoking, and losing weight if needed. Health promotion typically falls under primary prevention, which is preventing a disease process from getting established
68-year-old man comes to the emergency department due to a 1-week history of increasing leg and abdominal swelling. The patient has a history of pulmonary hypertension and cor pulmonale from advanced chronic obstructive pulmonary disease. Other medical conditions include hypertension and gout. Physical examination shows scattered rhonchi, prolonged expiratory phase of expiration, mild ascites, and extensive edema of the abdominal wall and lower extremities. The patient is hospitalized and intravenous loop diuretic therapy is begun. Two days later, acetazolamide is added to his treatment regimen. Which of the following most likely prompted the additional therapy in this patient? A. Hyperuricemia (%) B. Hypokalemia (%) C. Inadequate diuresis (%) D. Metabolic alkalosis (%) E. Prerenal azotemia (%)
D. Metabolic alkalosis (%) Loop diuretics (eg, furosemide) inhibit the Na+-K+-2Cl− transporter in the ascending loop of Henle to stimulate potent excretion of Na+ and water and reduce total body fluid volume. Electrolyte abnormalities are common with the use of loop diuretics; metabolic alkalosis occurs due to the following mechanisms: Sodium and water losses induced by diuretic therapy cause increased aldosterone-mediated renal excretion of H+ and K+. Loop diuretics cause relatively greater loss of Cl− than Na+, resulting in decreased total body electronegativity. In response, the kidneys retain more HCO3−, the second most abundant anion in the body, to maintain electrochemical balance. This metabolic alkalosis can have important implications because it stimulates compensatory hypoventilation that may hinder weaning from mechanical ventilation in critically ill patients. Carbonic anhydrase inhibitors (eg, acetazolamide) help offset the metabolic alkalosis; these drugs inhibit the reabsorption of sodium bicarbonate (NaHCO3) in the proximal tubule, leading to increased HCO3− excretion. The metabolic acidosis that is generated reduces blood alkalinity to help normalize pH
46-year-old woman is hospitalized for recurrent renal colic. She has passed 2 urinary stones during the last 2 years. The most recent stone contained 80% calcium phosphate and 20% calcium oxalate. The patient also has diffuse aches and pains and has a history of peptic ulcer disease, for which she takes famotidine daily. Laboratory results are as follows: Serum sodium 140 mEq/L Serum potassium 4.0 mEq/L Serum chloride 103 mEq/L Serum creatinine 0.8 mg/dL Serum calcium 12.0 mg/dL Serum phosphorus 2.4 mg/dL 24-hour urinary calcium excretion 350 mg (normal: 100-300) Which of the following changes in bone structure is most likely associated with this patient's condition? A. Lamellar bone structure resembling a mosaic pattern (%) B. Osteoid matrix accumulation around trabeculae (%) C. Spongiosa filling medullary canals with no mature trabeculae (%) D. Subperiosteal resorption with cortical thinning (%) E. Trabecular thinning with fewer interconnections (%)
D. Subperiosteal resorption with cortical thinning (%) This patient with recurrent calcium nephrolithiasis and hypercalcemia most likely has primary hyperparathyroidism (PHPT). Besides kidney stones, classic manifestations include bone pain, gastrointestinal disturbances (eg, peptic ulcer disease), and psychiatric symptoms (ie, "bones, stones, abdominal groans, and psychologic moans"). However, asymptomatic hypercalcemia is the most common presentation. 85% of cases are caused by a parathyroid adenoma, but PHPT can also be due to parathyroid hyperplasia or, rarely, parathyroid cancer. Excess parathyroid hormone causes hypercalcemia via the following mechanisms: Increased renal tubular Ca2+ reabsorption (although most patients have net hypercalciuria due to the increased filtered calcium load) Increased renal production of 1,25-dihydroxyvitamin D (which in turn increases gastrointestinal Ca2+ absorption) Increased bone resorption (via osteoclast activation) Patients usually also have hypophosphatemia due to decreased phosphate reabsorption in the proximal renal tubules. Because of the increased bone resorption, PHPT often leads to osteoporosis. However, unlike the typical osteoporosis of aging, which predominantly affects trabecular bone, osteoporosis in PHPT is most pronounced in the cortical (compact) bone of the appendicular skeleton (eg, pectoral girdle, pelvic girdle, limbs). Cortical thinning is characteristic and appears radiologically as subperiosteal erosions. More advanced disease can present as osteitis fibrosa cystica, characterized by granular decalcification of the skull ("salt-and-pepper skull"), osteolytic cysts, and brown tumors.
A 28-year-old woman comes to the gynecologist, who has provided routine care for the past 10 years. She has not menstruated for 2 months and had a positive home pregnancy test last week. Although she hopes to have children in the future, she has been under "a lot of stress lately" and caring for a child is "the last thing I need right now." A qualitative β-hCG pregnancy test confirms she is pregnant and the patient requests that the gynecologist terminate the pregnancy as soon as possible. The gynecologist prefers not to perform abortions on moral grounds but does have training in the procedure. Which of the following is the most appropriate course of action by the gynecologist? A. Agree to perform the abortion as the procedure is within the physician's scope of practice and training (%) B. Encourage the patient to reconsider as she wants to have children someday and future fertility is not guaranteed (%) C. Encourage the patient to take additional time to consider her options (%) D. Explain that, on moral grounds, the physician is unable to either perform or refer the patient for the procedure (%) E. Provide the patient with resources for providers who will perform abortions (%) F. Recommend psychological counseling to help the patient cope with stress and sort through her feelings about abortion (%)
E. Provide the patient with resources for providers who will perform abortions (%)
A 46-year-old man comes to the office with chest pain and dyspnea on exertion. He has no known medical problems and leads a sedentary lifestyle. He is a lifetime nonsmoker. Noninvasive cardiac testing is nondiagnostic. Left and right heart catheterization is planned. During the procedure, the catheter records periodic pressure changes with a maximum of 25 mm Hg and minimum of 2 mm Hg. The catheter is advanced further, and then shows periodic pressure changes with a maximum of 25 mm Hg and a minimum of 10 mm Hg. Assuming the results of the procedure are normal, the first set of readings was most likely obtained from which of the following locations? A. Left atrium (%) B. Left ventricle (%) C. Pulmonary artery (%) D. Right atrium (%) E. Right ventricle (%)
E. Right ventricle (%) Right-sided pressures in the heart are lower than left-sided pressures due to lower resistance in the pulmonary vasculature. Right ventricular diastolic pressure is similar to right atrial/central venous pressure (1-6 mm Hg), whereas pulmonary artery diastolic pressure is slightly higher (6-12 mm Hg) due to resistance to flow in the pulmonary circulation.
A 10-year-old girl is brought to the office due to sneezing, rhinorrhea, and nasal congestion and itching. The symptoms began 2 days ago after she arrived at a family farm for a summer vacation. The patient has spent a few days visiting the farm during previous summer seasons. She had no symptoms at her first visit 2 years ago but recalls having similar symptoms last year. She has had no respiratory symptoms while residing in another state the rest of the year. The patient has no prior medical conditions and takes no medications. On physical examination, the nasal turbinates are enlarged and bluish; clear rhinorrhea is present. Allergic response to a farm allergen is suspected. Which of the following processes most likely occurred during the first farm visit 2 years ago? A. Antibody receptor aggregation (%) B. Complement activation (%) C. Mast cell degranulation (%) D. Release of interferon gamma (%) E. T-lymphocyte induction (%)
E. T-lymphocyte induction (%) This patient with allergic rhinitis (eg, location-based sneezing and rhinorrhea; bluish, congested nasal turbinates) likely became sensitized to farm allergens during her first visit. Allergic rhinitis is a form of type 1 hypersensitivity, a process that involves sensitization and elicitation phases. Sensitization occurs when inhaled antigens penetrate the nasal epithelium and are presented on major histocompatibility complex (MHC) class II molecules, causing activation of naive T-helper (Th) cells. The release of cytokines (eg, IL-25, IL-33) from the nasal epithelium causes Th cells to differentiate into Th2 cells that secrete IL-4, IL-13, and other lymphokines that stimulate B cell maturation and production of IgE antibodies. Antigen-specific IgE antibodies then bind to the high-affinity IgE receptor on mast cells, priming the patient for an allergic response. Repeat exposure to the inhaled antigens (eg, on subsequent visits to the farm) cross-links IgE antibodies on the surface of the mast cell, leading to IgE receptor aggregation, which causes mast cell degranulation (Choices A and C). This releases histamine and other vasoactive mediators that lead to nasal inflammation, producing the allergic response. Subsequent exposure to the same antigen can lead to further allergen priming, worsening symptoms over time
pneumonia with diarrhea is highly suggestive of
Legionnaires' disease
Patients with cirrhosis complicated by abdominal ascites may develop a hepatic hydrothorax, which is a transudative, usually right-sided pleural effusion that results from passage of intraabdominal fluid into the chest cavity through small fenestrations in the _____
diaphragm
A 48-year-old, previously healthy woman is seen in the clinic for community-onset bacterial pneumonia. Chest x-ray reveals dense consolidation of the right middle lobe. Her pulse oximetry is 90% on room air. The patient is treated with appropriate antibiotics. Two days later, the patient feels well overall and her pulse oximetry is improved to 98% on room air. Examination reveals unchanged crackles and egophony from her previous visit. Which of the following processes best explains this patient's improved oxygenation? A. Decreased alveolar consolidation (%) B. Decreased hemoglobin oxygen-binding affinity (%) C. Increased erythrocyte production (%) D. Restored hypoxic pulmonary vasoconstriction (%)
This patient has community-acquired bacterial pneumonia with lobar consolidation (ie, alveoli filled with pus) and hypoxemia. Continued blood flow (perfusion) through these gasless (nonventilated) alveoli results in severe ventilation-perfusion (V/Q) mismatch, the mechanism of hypoxemia. The normal response to local alveolar hypoxia is hypoxic pulmonary vasoconstriction (HPV). Hypoxia is detected by mitochondria in pulmonary vascular cells, stimulating smooth muscle contraction. HPV limits blood flow to nonventilated alveoli, shunting it toward better-ventilated ones, preserving V/Q matching to optimize oxygenation. However, HPV is impaired (released) by inflammatory states such as acute pneumonia or sepsis. Proinflammatory cytokines cause regional vasodilation, resulting in hyperemia (↑ perfusion) to affected lung areas, further lowering the V/Q ratio and worsening the hypoxemia. Once treatment is initiated, vasoactive inflammatory mediators are downregulated over the ensuing hours to days and HPV is restored. This occurs prior to resorption of alveolar debris and fibrinous edema, a slower process carried out by alveolar macrophages. Therefore, radiographic clearance of pneumonic infiltrates often lags weeks behind clinical improvement in oxygenation. A repeat chest x-ray obtained at this time would demonstrate unchanged consolidation, consistent with her crackles and egophony (Choice A) D. Restored hypoxic pulmonary vasoconstriction (%)
A 35-year-old woman is brought to the emergency department due to severe right leg pain. She is a concert pianist with no known medical issues. During rehearsal, she began experiencing cramping of the right foot that did not improve with stretching or rest. The pain quickly spread to her calf, and the patient now rates the pain as 9 out of 10 in intensity. On examination, the right foot and calf appear pale and cool compared with the left, and sensation is diminished. Right-sided dorsalis pedis and posterior tibial pulses are absent, and the popliteal pulse is barely palpable. Emergency embolectomy is performed and a gelatinous mass causing arterial occlusion is successfully removed. Histopathologic section of the mass is shown in the exhibit. Which of the following is the most likely origin of this patient's embolus? A. Aortic valve (%) B. Descending aorta (%) C. Left atrium (%) D. Left ventricle (%) E. Mitral valve (%)
This patient presented with acute limb ischemia, as evidenced by the 6 Ps: pain, pallor, poikilothermia (coolness to touch), paresthesia, paralysis, and reduced or absent pulses. The ischemia resulted from systemic embolization of a gelatinous mass, with histopathology demonstrating an amorphous extracellular matrix with scattered stellate myxoma cells in mucopolysaccharide ground substance; this is consistent with tumor fragments from an atrial myxoma. Myxomas are the most common primary cardiac neoplasm. Approximately 80% of these benign tumors originate in the left atrium. Patients can initially present with nonspecific constitutional symptoms (eg, fatigue, low-grade fever, weight loss) or systemic embolization (eg, stroke, mesenteric ischemia, acute limb ischemia), as in this patient. In addition, the tumor can cause position-dependent obstruction of the mitral valve, leading to signs and symptoms that mimic mitral valve stenosis (eg, dyspnea, cough, mid-diastolic murmur)
clinical association with large cell carcinoma
gynecomastia galctorrhea
What structure is in front of the esophagus? What structure is behind the esophagus?
in front: left atrium behind: descending aorta
the individual alpha and beta subunits of hemoglobin act like
myoglobin
Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandin synthesis. Patients with intravascular volume depletion (eg, cirrhosis) are dependent on the vasodilatory effects of prostaglandins to maintain adequate _____ and _____. NSAID use in this population reduces glomerular filtration rates and blunts the effects of loop diuretics, leading to sodium and water retention
renal plasma flow and glomerular filtration
