Kidney path questions

A 24-year-old man is awakened at night because of severe lower abdominal pain that radiates to the groin. The pain is very intense and comes in waves. The next morning, he notices blood in his urine. He has no underlying illnesses and has been healthy all his life. On physical examination, he is afebrile and has a blood pressure of 110/70 mm Hg. Laboratory studies show serum: Na+ 142 mmol/L K+ 4 mmol/L Cl− 96 mmol/L CO2 25 mmol/L Glucose 74 mg/dL creatinine 1.1 mg/dL calcium, 9.1 mg/dL phosphorus 2.9 mg/dL. Urinalysis shows a pH of 7; specific gravity of 1.020; and no protein, glucose, ketones, or nitrite. The patient is advised to drink more water. He likes iced tea and consumes large quantities over the course of a hot summer. He continues to have similar episodes. Which of the following substances is most likely to be increased in his urine? A) Calcium oxalate B) Cystine C) Magnesium ammonium phosphate D) Mucoprotein E) Uric acid

A) This patient has ureteral colic from the passage of a stone down the ureter. About 70% of all renal stones are composed of calcium oxalate crystals. Patients with these stones tend to have hypercalciuria without hypercalcemia. - Uric acid stones and cystine stones are radiolucent and tend to form in acidic urine. - Cystine stones are rare. - Triple phosphate (magnesium ammonium phosphate) stones tend to occur in association with urinary tract infections, particularly infections caused by urease-positive bacteria, such as Proteus. - Mucoproteins may coalesce into hyaline casts, which are too small to produce signs and symptoms.

Which of the following clinical features is least likely to be seen in nephritic syndrome? A. Hyperlipidemia B. Hypertension C. Oliguria D. Periorbital edema

A. Hyperlipidemia is not a typical clinical feature of nephritic syndrome. In nephrotic syndrome, the excessive urinary loss of protein, triggers hepatic synthesis of proteins including albumin and lipoprotein. The synthesis of lipoproteins results in increased production of lipids and a resultant hyperlipidemia. B. Nephritic syndrome is due to underlying inflammatory damage of the glomerulus, which causes glomerular dysfunction and decreased glomerular filtration rate (GFR). Decreased GFR leads to fluid retention, and the augmented renin response leads to salt retention, which cause hypertension. C. Nephritic syndromes are characterized by injury to the glomerulus, which leads to glomerular dysfunction and decreased glomerular filtration rate (GFR). Decreased GFR causes the body to conserve water with a resultant decrease in the volume of urine output (Oliguria). D. In nephritic syndrome, decreased glomerular filtration due to underlying glomerular injury leads to fluid retention. An augmented renin response leads to salt retention. Fluid and salt retention cause tissue edema, seen more commonly in the face and less commonly peripherally

A 54-year-old man with nephrotic syndrome from membranous nephropathy presents to the Emergency Department with generalized abdominal discomfort that has persisted for the past four hours accompanied by fever and nausea. The patient demonstrates diffuse abdominal tenderness with rebound and involuntary guarding. Dullness to percussion is appreciated over the lateral abdomen and flank areas and fluid wave test is positive. Examination of the liver is unremarkable. Liver function tests and lipase are normal. A paracentesis is performed and analysis of the peritoneal fluid is consistent with spontaneous bacterial peritonitis. Which of the following best explains the mechanism of ascitic fluid build-up in this patient? A. Decreased oncotic pressure within abdominal blood vessels B. Increased hydrostatic pressure within abdominal blood vessels C. Increased oncotic pressure within abdominal blood vessels D. Increased permeability of abdominal blood vessels

A. This patient has nephrotic syndrome with ascites complicated by spontaneous bacterial peritonitis. Nephrotic syndrome is characterized by hypoalbuminemia due to loss of albumin in the urine. Low serum albumin leads to a decreased plasma oncotic pressure and as a result, intravascular fluid shifts into the interstitium. Thus, the decreased intravascular oncotic pressure from hypoalbuminemia in the setting of nephrotic syndrome has driven the ascitic fluid build-up in this patient.

A 58-year-old woman dies of a cerebral infarction. Laboratory findings before death included serum urea nitrogen level of 110 mg/dL and creatinine level of 9.8 mg/dL. At autopsy, the kidneys are small (75 g) and have a coarsely granular surface appearance. Microscopic examination shows sclerotic glomeruli, a fibrotic interstitium, tubular atrophy, arterial thickening, and scattered lymphocytic infiltrates. Which of the following clinical findings was most likely reported on the patient's medical history? A) Rash B) Hypertension C) Hemoptysis D) Lens dislocation E) Pharyngitis

B) These findings describe end-stage renal disease, the appearance of which is similar regardless of the cause (e.g., vascular disease or glomerular disease). With advanced renal destruction, hypertension almost always supervenes, even if it was absent at the onset of renal disease. Many such cases are referred to as "chronic glomerulonephritis" for want of a better term. - A rash might have preceded the postinfectious glomerulonephritis. - Hemoptysis occurs in Goodpasture's syndrome. - Lens dislocation is a feature of Alport syndrome Mutations in the COL4A5 (X-linked), or COL4A3 and COL4A4 (autosomal recessive) genes result in absence of the collagen IV network from the basement membranes of the cornea, lens capsule, and retina) - Pharyngitis with group A streptococcal infection may precede postinfectious glomerulonephritis.

Which of the following best describes the pathologic features of dense deposit disease? A. The deposition of amyloid proteins in the mesangium B. The deposition of an unknown substance in the glomerular basement membrane C. The deposition of fibrin and plasma protein in Bowman's space D. The deposition of immune complexes in the subepithelial space

B. Dense deposit disease has a distinctive pathologic appearance of electron dense deposition within the wall of the glomerular basement membrane. The glomerular basement membrane eventually transforms into a long irregular and extremely electron-dense ribbon and on electron microscopy, it will look like a thick black line is tracing the capillaries throughout the glomerulus. Dense deposit disease occurs due to underlying overactivation of the alternative complement pathway, usually due to an autoantibody against the checkpoint protein c3 convertase. A. Amyloidosis is associated with nephrotic syndrome. The appearance of amyloid is seen by staining the slide with congo red, which demonstrates apple-green birefringence C. Plasma proteins and fibrin deposit in the crescents formed in rapidly progressive glomerulonephritis. The crescents obliterate Bowman's space. D. Poststreptococcal glomerulonephritis is associated with immune complex depositions in the subepithelial space

A 35-year-old woman presents with acute renal failure, oliguria, and hypertension. The patients has a past history of systemic lupus erythematosus (SLE), but she reports that she has not been compliant with her medications. A kidney biopsy is performed and slides are prepared. The light microscopy reveals mesangial proliferation and thickened capillary walls in the endothelium. Immunofluorescence reveals a granular staining pattern. Which of the following nephritic syndromes is most likely? A. Dense deposit disease B. Diffuse proliferative glomerulonephritis C. Membranoproliferative glomerulonephritis D. Pauci immune glomerulonephritis

B. Diffuse proliferative glomerulonephritis is classically associated with lupus. The pathology involves DNA-anti-DNA immune complex deposition with resultant mesangial and epithelial proliferation and inflammatory damage. It is also characterized by subendothelial deposits. These subendothelial immune-complexes surround the capillary, and on light microscopy the capillary walls will look thickened and are often described as "wire-loops". In most cases, diffuse proliferative glomerulonephropathy progresses to chronic kidney disease, though corticosteroids and cyclophosphamide may help slow the progression.

Which of the following sets of clinical findings best characterizes nephritic syndrome? A. Hematuria, no proteinuria, normal BUN and creatinine B. Hematuria, proteinuria between 100 mg and 3.5 g protein per 24 hr, acutely elevated BUN and creatinine C. No hematuria, no proteinuria, acutely elevated BUN and creatinine D. No hematuria, proteinuria greater than 3.5 g protein per 24 hr, normal BUN and creatinine

B. Nephritic syndrome is an inflammatory condition which causes hematuria, renal azotemia, and proteinuria. The range of proteinuria is usually below nephrotic level (3.5 g/day). Inflammation usually involves underlying immune complex deposition, which leads to damage of the glomerulus. As a result of direct damage to the capillary walls, glomerular basement membrane, and podocytes, red blood cells pass directly into the urine. Damaged glomeruli have decreased function, which reduces the glomerular filtration rate, leading to an increased BUN and creatinine. Damage to the glomerular basement membrane and podocytes leads to a loss of the negatively charged barrier, which causes proteinuria.

A 37-year-old male HIV patient not on anti-retroviral therapy undergoes a renal biopsy for evaluation of nephrotic syndrome. The biopsy results indicate a high likelihood of fast disease progression, with a more than 50 percent chance that this patient will develop end stage renal disease within the next 2 years. Which of the following histological descriptions concerning the glomerulus is most consistent with this patient's prognosis? A. Effacement and fusion of podocytes B. Glomeruli without evidence of glomerular damage and glomeruli with evidence of glomerular damage and sclerosis along some segments of the glomerulus C. Normal appearance on light microscopy D. Subepithelial deposits with spike and dome appearance on electron microscopy

B. This patient with HIV likely has HIV-associated nephropathy (HIVAN), which histologically is a form of focal segmental glomerulosclerosis (FSGS). FSGS has a progressive disease course, and frequently progresses to end stage renal disease. At least 50 percent of patients with FSGS will develop end stage kidney disease within 10 years, and the collapsing form of FSGS associated with HIVAN exhibits the most rapid disease progression. HIVAN disease progression to ESRD can be prevented or reversed by antiretroviral therapy. Focal segmental glomerulosclerosis causes sclerosis of the glomerulus (i.e., the kidney's filtering apparatus), which can be seen on light microscopy. The sclerosis is focal, affecting only some glomeruli, and segmental, affecting only some segments of the glomerulus.

A 58-year-old woman with rheumatoid arthritis and type 2 diabetes mellitus undergoes a renal biopsy for diagnostic evaluation of nephrotic syndrome. She has a 20-year remote history of intravenous heroin abuse but denies use of illicit drugs for the past 10 years. Histology reveals damage of the glomerular architecture with obliteration of the glomerular capillaries and material deposits that appear pink when stained with Congo red and display an apple-green birefringence in polarized light. Which of the followings best characterizes the pathogenesis of this patient's diagnosis? A. Autoantibodies directed against phospholipase A2 receptor on podocytes B. Deposition of misfolded proteins C. Heroin-induced glomerular injury D. Nonenzymatic glycosylation

B. This patient with nephrotic syndrome has a renal biopsy that reveals histological findings characteristic of renal amyloidosis. Amyloidosis is a systemic disorder that involves the deposition of misfolded proteins in various tissues. In early renal amyloidosis, there are focal amyloid deposits within the mesangium. In later renal amyloidosis, amyloid obliterates glomerular capillaries. The amyloid appears pink when stained with Congo red and displays a classic apple-green birefringence in polarized light. C. Chronic heroin abuse can cause secondary focal segmental glomerulosclerosis (FSGS). FSGS causes sclerosis of the glomerulus which can be seen on light microscopy. The sclerosis is focal, affecting only some glomeruli, and segmental, affecting only some segments of the glomerulus.

A 25-year-old man has a 5-year history of celiac sprue. Several days after a mild upper respiratory infection, he begins passing dark red brown urine. The dark urine persists for the next 3 days and then becomes clear and yellow, only to become red-brown again 1 month later. There are no remarkable findings on physical examination. Urinalysis shows a pH of 6.5; specific gravity 1.018; 3+ hematuria; 1+ proteinuria; and no glucose or ketones. Microscopic examination of the urine shows RBCs and no WBCs, casts, or crystals. A 24-hour urine protein level is 200 mg. A renal biopsy specimen from the glomeruli of this patient is most likely to show which of the following alterations? A) Subepithelial electron-dense deposits B) Granular staining of the basement membrane by anti-IgG antibodies C) Mesangial IgA staining by immunofluorescence D) Diffuse proliferation and basement membrane thickening E) Thrombosis in the glomerular capillaries

C) IgA nephropathy, also known as Berger's disease, can explain the presence of recurrent hematuria in a young adult. Nephrotic syndrome is not present, and mesangial IgA deposition is characteristic. The initial episode of hematuria usually follows an upper respiratory infection. IgA nephropathy occurs with increased frequency in patients with celiac disease. - Granular staining of basement membrane with IgG antibodies denotes immune complex deposition, which may occur in postinfectious glomerulonephritis. - The subepithelial deposits are seen on electron microscopy, patients with these changes have nephritic syndrome. - Diffuse proliferation and basement membrane thickening denote membranoproliferative glomerulonephritis. In this condition, IgG and C3 are deposited in the glomeruli. - Glomerular capillary thrombosis is typical of hemolytic-uremic syndrome.

A 60-year-old, previously healthy man sees his physician because he feels feverish and weak. He reports passing dark-colored urine on several occasions during the past month, but has no urinary frequency, dysuria, or nocturia. On physical examination, his temperature is 37.8°C, and blood pressure is 125/85 mm Hg. A dipstick urinalysis shows 4+ hematuria; 1+ proteinuria; and no glucose or ketones. Which of the following procedures is the most appropriate in management of this patient? A) Straining of urine for calculi B) Urine microbiologic culture C) Abdominal CT scan for renal mass E) Percutaneous renal biopsy

C) Painless hematuria in an older adult suggests a renal neoplasm. The additional presence of constitutional symptoms, such as fever and weakness, should raise the suspicion of a renal cell carcinoma. A. Urinary tract calculi usually cause severe, colicky pain when they are passed. B. Urinary tract infections are not characterized by recurrent hematuria without fever or other signs of acute inflammation. Nephrotic syndrome, which manifests with proteinuria, typically is not associated with hematuria. (dont confuse with Nephritic syndrome which is associated with hematuria) E. A renal biopsy has a low yield in a patient without an acute-onset renal disease, and it is an ineffective way of diagnosing tumors.

A 50-year-old woman has had fever and flank pain for the past 2 days. On physical examination, her temperature is 38.2°C, pulse is 81/min, respirations are 16/min, and blood pressure is 130/80 mm Hg. Urinalysis shows no protein, glucose, or ketones. The leukocyte esterase test is positive. Microscopic examination of the urine shows numerous polymorphonuclear leukocytes and occasional WBC casts. Which of the following organisms is most likely to be found in the urine culture? A) Mycobacterium tuberculosis B) Mycoplasma hominis C) Escherichia coli D) Group A streptococcus E) Cryptococcus neoformans

C) The clinical features in this patient are typical of urinary tract infection, and Escherichia coli is the most common cause. The WBCs are characteristic of an acute inflammatory process. The presence of WBC casts indicates that the infection must have occurred in the kidney because casts are formed in renal tubules. Most infections of the urinary tract begin in the lower urinary tract and ascend to the kidneys. Hematogenous spread is less common. - Mycobacterium tuberculosis causes the rare "sterile pyuria"; however, renal tuberculosis typically does not manifest as an acute febrile illness. - Mycoplasma and Cryptococcus are rare urinary tract pathogens. - Group A streptococcus is best known as an antecedent infection to poststreptococcal glomerulonephritis, an immunologically mediated disease in which the organisms are not present at the site of glomerular injury.

A 32-year-old man has developed a fever and skin rash over the past 3 days. Five days later, he has increasing malaise and visits his physician. On physical examination, the maculopapular erythematous rash on his trunk has nearly faded away. His temperature is 37.1°C, and blood pressure is 135/85 mm Hg. Laboratory studies show a serum creatinine level of 2.8 mg/dL and blood urea nitrogen level of 29 mg/dL. Urinalysis shows 2+ proteinuria; 1+ hematuria; and no glucose, ketones, or nitrite. The leukocyte esterase result is positive. Microscopic examination of urine shows RBCs and WBCs, some of which are eosinophils. What is the most likely cause of this patient's condition? A) Urinary tract infection B) Congestive heart failure C) Antibiotic use D) Streptococcal pharyngitis E) Poorly cooked ground beef

C) These findings are typical of drug-induced interstitial nephritis. Various drugs can cause this condition, including sulfonamides, penicillins, cephalosporins, the fluoroquinolone antibiotics ciprofloxacin and norfloxacin, and the antituberculous drugs isoniazid and rifampin. Acute tubulointerstitial nephritis also can occur with use of thiazide and loop diuretics, cimetidine, ranitidine, omeprazole, and nonsteroidal antiinflammatory drugs. The disease manifests about 2 weeks after the patient begins to use the drug. Elements of type I (increased IgE) and type IV (skin test positivity to drug haptens) hypersensitivity are present. WBCs, but not eosinophils, may be present in the urine of a patient with a urinary tract infection. Congestive heart failure can lead to acute tubular necrosis, but it is not associated with a rash or proteinuria. Poststreptococcal glomerulonephritis could account for the proteinuria and hematuria seen in this patient, but not for the rash because the strains of group A β-hemolytic streptococci that cause a skin infection precede by weeks the development of glomerulonephritis. Hemolytic-uremic syndrome can occur after ingestion of strains of Escherichia coli that may be present in ground beef.

All the following are true regarding nephrotic syndrome EXCEPT: A. Fatty casts may be appreciated on urinalysis B. Hypercoagulable state is mediated by proteinuria with loss of antithrombin III C. Pathogenesis is mediated primarily via inflammatory cellular infiltration D. Patients may have increased risk of encapsulated bacterial infections

C. Inflammatory cellular infiltration underlies the glomerular injury in nephritic syndrome. However, cytokines and not inflammatory cellular infiltrate primarily underlie the glomerular injury and structural derangements in nephrotic syndrome.

Which of the following findings best characterizes nephrotic syndrome? A. Hyperalbuminemia, proteinuria < 3.5 g/24 hr, hypercoagulability, hyperlipidemia B. Hypoalbuminemia, proteinuria < 3.5 g/24hr, hypocoagulability, hyperlipidemia C. Hypoalbuminemia, proteinuria > 3.5 g/24 hr, hypercoagulability, hyperlipidemia D. Hypoalbuminemia, proteinuria > 3.5 g/24 hr, hypercoagulability, hypolipidemia

C. Nephrotic syndrome results when the selectively permeability of the glomerular basement membrane is impaired, allowing the leakage of many types of molecules across the membrane. Nephrotic syndrome is characterized by marked proteinuria, which is at least 3.5 grams of protein lost in the urine each day for an adult. The excessive urinary loss of albumin, or hyperalbuminuria, leads to decreased serum albumin level with resultant hypoalbuminemia. Lipoprotein synthesis with resultant hyperlipidemia occurs as the liver ramps up protein synthesis in response to the decrease in serum albumin. Additionally, loss of the anticoagulant antithrombin III in the urine results in increased thrombin activity, leading to a hypercoagulable state.

A 57-year-old male diabetic patient with poor glycemic control develops worsening albuminuria accompanied by generalized edema. He undergoes renal biopsy for evaluation of diabetic nephropathy. Which of the following histological findings would best confirm this diagnosis? A. Diffuse thickening of the glomerular basement membrane seen on light microscopy B. Obliterated capillaries with hyaline deposition in some segments of the glomerulus seen on light microscopy C. Pink, round deposits of laminated mesangial matrix alongside the glomerular capillaries seen on light microscopy D. Podocyte effacement and fusion seen under electron microscopy

C. Pink, round deposits of laminated mesangial matrix alongside the glomerular capillaries describes the Kimmelstiel-Wilson nodules that are pathognomonic of diabetic nephropathy. These Kimmelstiel-Wilson nodules are particularly seen in later stage of diabetic nephropathy when nodular glomerulosclerosis occurs. A. Although thickening of the glomerular basement membrane is an early finding of diabetic nephropathy, it is not specific to diabetic nephropathy. Diffuse thickening of the glomerular basement membrane can also be seen in membranous nephropathy for instance. B. Obliterated capillaries with hyaline deposition in some segments of the glomerulus describes the segmental sclerosis characteristic of focal segmental glomerulosclerosis. Nodular glomerulosclerosis (diabetic nephropathy) causes sclerosis as well. D. Podocyte effacement and fusion is a nonspecific finding, as it can be seen in minimal change disease, focal segmental glomerulosclerosis, and diabetic nephropathy.

A 7-year-old boy presents with his mother to the pediatrician. His mother reports dark colored urine and a "bout of the sniffles." Past history includes a recent diarrheal illness and gross hematuria. On exam, vitals are normal and the child is well appearing. There is mild periorbital swelling. Which of the following best describes the underlying pathogenesis of this child's presentation? A. Excessive activation of the alternative complement pathway B. Hypersensitivity reaction to recent streptococcal infection C. Robust mucosal immunity with excessive levels of circulating IgA D. Systemic autoimmune disease with autoantibodies to cellular DNA

C. This child presents with classic IgA nephropathy with periodic gross hematuria with an intercurrent upper respiratory or gastrointestinal illness. The nephritic syndrome is due to an underlying aberrant IgA response, which is secreted by mucosal cells. The IgA levels are high and the IgA itself is abnormally glycosylated. The extra IgA forms immune complexes which causes an inflammatory response with cellular proliferation in the mesangium B. Poststreptococcal glomerulonephritis presents with hematuria about 1-3 weeks after a streptococcal throat or skin infection. This child, however, presents with concurrent illness and hematuria. Postreptococcal glomerulonephritis is a type III hypersensitivity reaction with IgG and complement deposition along the mesangium, subendothelium, and subepithelium.

A 56-year-old female with rheumatoid arthritis and diabetes mellitus presents with progressively worsening edema and fatigue over the past month. Her diabetes has been well controlled with diet and exercise and she was started on penicillamine 4 weeks ago for rheumatoid arthritis therapy. Her recent screening mammogram was normal but she has not had a colonoscopy. Laboratory workup reveals nephrotic range proteinuria and hypoalbuminemia. Complete blood cell count demonstrates microcytic, hypochromic anemia. Renal biopsy histology reveals electron-dense deposits between the glomerular basement membrane and epithelial cells with expansion of the basement membrane between these deposits. Testing for anti Phospholipase A2 receptor (anti-PLA2R) antibodies is negative. Which of the following is the most likely etiology of this patient's presentation? A. Diabetes Mellitus B. Idiopathic C. Occult malignancy D. Penicillamine

C. This patient who presented with nephrotic syndrome has membranous nephropathy most likely secondary to occult colon cancer. The histological description "electron-dense deposits between the glomerular basement membrane and epithelial cells" describes subepithelial deposits and "expansion of the basement membrane between these deposits" describes the characteristic spike and dome appearance of these subepithelial immune deposits seen under electron microscopy in membranous nephropathy. The negative test for anti-Phospholipase A2 receptor (anti-PLA2R) antibodies suggests a secondary cause of membranous nephropathy. Membranous nephropathy can be secondary to solid tumors including cancers of breast, lung, prostate, and colon. In this patient who is above the age of 50 years and has never had a screening colonoscopy and is now found to have an iron deficiency (i.e. microcytic, hypochromic) anemia, occult colon cancer should be highly suspected as it is the likely cause of membranous nephropathy. B. Patients with primary or idiopathic membranous nephropathy tend to test positive for anti-PLA2R antibodies.

A 35-year-old male is hospitalized for evaluation of rapidly declining kidney function. He has had many episodes of hemoptysis and hematuria in the past. His workup includes a kidney biopsy. Light microscopy shows distorted glomerular architecture with crescent-forms centrally. Immunofluorescence is performed which reveals a linear pattern. Which of the following best describes the underlying mechanism of this patient's presentation? A. Antibodies against bacterial antigens B. Antibodies against neutrophil cytoplasmic antigens (ANCA) C .Antibodies against type-4 collagen D. Excessive production of IgA

C. This patient presents with a classic history of pulmonary (hemoptysis) and renal hemorrhage (hematuria) which is consistent with a diagnosis of Goodpasture's syndrome. The presence of crescents and declining kidney function suggest anti-GBM antibody-mediated RPGN. This type of RPGN involves IgG autoantibodies directed against type IV collagen in the GBM (and also the pulmonary capillaries). Another distinguishing feature is the linear pattern on immunofluorescence microscopy. Rapidly declining kidney function along with ANCA can be: - Granulomatosis Polyangiitis, also called Wegners which has PR3-ACNA or c-ACNA. But this will have weak (Pauci) staining and involves kideny + Lung + nasal symptoms. - Microscopic Polyangiitis which has mpo-ANCA or p-ANCA. This will also have weak (Pauci) staining, but WILL NOT involve nasal symptoms or granulomas

For the past 6 months, a 72-year-old woman has noticed a slowly enlarging mass on the urethra. The mass causes local pain and irritation and is now bleeding. Physical examination shows a 2.5-cm warty, ulcerated mass protruding from the external urethral meatus. There are no lesions on the labia or vagina. A biopsy specimen of the lesion is most likely to identify which of the following? A) Embryonal rhabdomyosarcoma B) Leiomyoma C) Papilloma D) Squamous cell carcinoma E) Syphilitic chancre

D) Carcinoma of the urethra is uncommon. It tends to occur in older women and is locally aggressive. - An embryonal rhabdomyosarcoma (sarcoma botryoides) is a rare tumor that occurs in children. - Benign tumors, such as a leiomyoma or papilloma, are typically well circumscribed and do not ulcerate. - Syphilis produces indurated, painless lesions, rather than ulcerated, warty masses.

After eating a cheeseburger, French fries, and ice cream for dinner one night, a 6-year-old girl develops nausea, mild abdominal cramping, and a slight fever. Three days later, her parents notice that she is passing dark stools and dark urine and appears fatigued and weak. On physical examination, she has a temperature of 37.9°C, pulse of 88/min, respirations of 18/min, and blood pressure of 140/90 mm Hg. Scattered petechiae are present on the extremities. Laboratory findings show a serum creatinine level of 2.2 mg/dL and urea nitrogen level of 20 mg/dL. Urinalysis shows a pH of 6; specific gravity 1.016; 2+ hematuria; and no protein or glucose. A renal biopsy specimen shows small thrombi within glomerular capillary loops. Which of the following diseases is most likely to produce these findings? A) Postinfectious glomerulonephritis B) Wegener granulomatosis C) Hereditary nephritis D) Hemolytic-uremic syndrome E) IgA nephropathy

D) Hemolytic-uremic syndrome is one of the most common causes of acute renal failure in children. It most commonly occurs after ingestion of meat infected with verocytotoxin-producing Escherichia coli, most often serotype O157:H7. The toxin damages endothelium, reducing nitric oxide, promoting vasoconstriction and necrosis, and promoting thrombosis. With supportive therapy, most patients recover in a few weeks, although perhaps one fourth progress to chronic renal failure. Postinfectious glomerulonephritis occurs several weeks after an infection, usually with group A β-hemolytic streptococci. Wegener granulomatosis is a vasculitis that most often occurs in adults. Hereditary nephritis may occur in childhood; it is progressive and is not related to vascular disease. An IgA nephropathy most often occurs in young adults; it is not accompanied by vascular changes.

A 63-year-old man has noted increasing back pain for 7 months. He has had three respiratory tract infections with Streptococcus pneumoniae within the past year. On examination, he has pitting edema to his thighs. Laboratory studies show total serum protein, 9.6 g/dL; albumin, 3.5 g/dL; creatinine, 3 mg/dL; urea nitrogen, 28 mg/dL; and glucose, 79 mg/dL. Urinalysis shows proteinuria of 4 g/24 hr, but no glucosuria or hematuria. Abdominal CT scan shows enlarged kidneys without cysts or masses. A renal biopsy specimen shows deposits of amorphous pink material within glomeruli, interstitium, and arteries with H&E stain. Which of the following diseases is he most likely to have? A) Analgesic nephropathy B) Diabetes mellitus C) Membranous glomerulonephritis D) Multiple myeloma E) Systemic lupus erythematosus F) Wegener granulomatosis

D) There is a large amount of serum globulin, back pain from lytic lesions, immunosuppression with recurrent infections, and amyloid deposition enlarging the kidneys, all consistent with multiple myeloma. This AL amyloid deposition occurs in 6% to 24% of myeloma cases. Analgesic nephropathy can lead to tubulointerstitial nephritis and papillary necrosis. - His serum glucose is not in the range for diabetes mellitus, and the pink deposits seen with nodular or diffuse glomerulosclerosis are not amyloid. - The pink-staining, thickened capillary loops of membranous glomerulonephritis represent immune deposits, not amyloid. - Systemic lupus erythematosus can result in immune deposits to produce "wire loop" thickening of glomerular capillaries.

A 7-year-old boy is recovering from impetigo. Physical examination shows a few honey-colored crusts on his face. The crusts are removed, and a culture of the lesions grows group A Streptococcus pyogenes. He is treated with antibiotics. One week later, he develops malaise with nausea and a slight fever and passes dark brown urine. Laboratory studies show a serum antistreptolysin O titer of 1:1024. Which of the following is the most likely outcome? A) Development of rheumatic heart disease B) Chronic renal failure C) Lower urinary tract infection D) Complete recovery without treatment E) Progression to crescentic glomerulonephritis

D) These findings are characteristic of poststreptococcal glomerulonephritis. The strains of group A streptococci that cause poststreptococcal glomerulonephritis differ from the strains that cause rheumatic fever. Most children with poststreptococcal glomerulonephritis recover, although perhaps 1% develop a rapidly progressive glomerulonephritis. Progression to chronic renal failure occurs more frequently in affected adults. A urinary tract infection is not likely to accompany poststreptococcal glomerulonephritis because the organisms that caused the immunological reaction are no longer present when symptoms of glomerulonephritis appear.

A 49-year-old man goes to his physician for a checkup and is found on physical examination to have a blood pressure of 160/110 mm Hg, but no other abnormalities. Laboratory studies show serum glucose of 75 mg/dL, creatinine of 1.3 mg/dL, and urea nitrogen of 20 mg/dL. His plasma renin is elevated. CT angiography shows marked stenosis of his renal arteries. He is treated with an angiotensin-converting enzyme inhibitor. A week later, he has a headache for which he takes ibuprofen. Over the next day, his urine output decreases. A reduction in which of the following chemical mediators most likely caused his reduced urine output? A) Aldosterone B) Histamine C) Nitric oxide D) Prostaglandin E) Tumor necrosis factor

D) This patient's hypertension is due to renal vascular constriction, typical for renal arterial atherosclerosis. In the face of reduced renal blood flow, his glomerular filtration rate (GFR) is maintained by prostaglandin mediated vasodilation of afferent arterioles and angiotensin II-mediated vasoconstriction of efferent arterioles. The angiotensin-converting enzyme inhibitor decreases efferent arteriolar vasoconstriction and decreases glomerular capillary perfusion pressure. Nonsteroidal anti-inflammatory drugs such as ibuprofen inhibit prostaglandin synthesis and lead to vasoconstriction that reduces renal blood flow and reduces GFR. - Aldosterone is increased with increased renin and angiotensin production and leads to reduced sodium excretion. - Histamine is a vasodilator from mast cell granules that plays a role in acute inflammatory processes, but not blood pressure regulation. - Tumor necrosis factor plays a role in many inflammatory processes, but not renal blood flow. - Nitric oxide is a vasodilator, but does not have a significant effect on capillary blood flow.

A 5-year-old girl presents to the pediatrician with her mother because of "cola-colored" urine. Three weeks ago she had a skin infection with perioral honey crust-like lesions. The child is mildly ill appearing. Labs show mildly elevated BUN and creatinine but urine output is normal. Which of the following features are most likely to be seen on microscopic examination of the kidney? A. A thickening of the glomerular capillaries resembling chicken wire on light microscopy B. Crescent moon shapes in Bowman's space C. Splitting of the glomerular basement membrane resembling tram tracks on light microscopy D. Subepithelial humps seen on electron microscopy

D. Acute poststreptococcal glomerulonephritis (PSGN) presents with hematuria about 1-3 weeks after a streptococcal throat or skin infection. This child, presents with delayed hematuria (cola colored urine) following impetigo. Postreptococcal glomerulonephritis involves immune complex deposition with IgG and complement deposition along the mesangium, subendothelium, and subepithelium. In this child, diagnosis can be confirmed by testing the levels of anti-DNAse B because anti-streptolysin O may be falsely low due to its degradation by oils in the skin. The appearance of PSGN on electron microscopy is classically described as subepithelial humps. A. Diffuse proliferative glomerulonephritis is characterized by subendothelial immune complex deposition, with thickening of the capillaries. The appearance on light microscopy is classically described as wire looping. B. Rapidly progressive (crescentic) glomerulonephritis (RPGN) is characterized by rapid renal decline and the presence of crescents in the glomerulus. C. Membranoproliferative glomerulonephritis, often due to underlying chronic infection such as viral hepatitis. Appearance on light microscopy is classically described as tram track.

A 35-year-old woman presents with acute renal failure, oliguria, and hypertension. The patients has a past history of systemic lupus erythematosus (SLE), but she reports she has not been compliant with her medications. Workup reveals a diagnosis of diffuse proliferative glomerulonephritis. Which of the following is the best treatment choice for this patient? A. Broad spectrum antibiotics B. Conservative care and reassurance only C. Kidney transplant D. Steroids and cyclophosphamide

D. This patient has diffuse nephritis and is therefore at high risk for progression to end-stage renal disease (ESRD); thus, aggressive therapy is required. Patients with lupus nephritis require immunosuppression with corticosteroids and cyclophosphamide. This patient may be given intravenous methylprednisolone at up to 1 g/day for 3 days, which may be tapered over a month to a maintenance dose of daily prednisone taken over the next 2 years.

A 45-year-old man with nephrotic syndrome from membranous nephropathy presents to the Emergency Department after sudden onset of flank pain accompanied by gross hematuria and left testicular swelling. Physical exam reveals normal testicular size and consistency and distended left scrotal veins that feel like a bag of worms when palpated. Urinalysis reveals red blood cells without dysmorphic features or casts. Which of the following is the most likely diagnosis of this patient? A. Glomerulonephritis B. Nephrolithiasis C. Pyelonephritis D. Renal vein thrombosis

D. This patient with nephrotic syndrome is most likely suffering from a left renal vein thrombosis. Nephrotic syndrome induces a hypercoagulable state via the loss of antithrombin III in the urine. Renal vein thrombosis can be a complication of this hypercoagulable state. In addition to the sudden onset of flank pain and gross hematuria, if the left renal vein is involved then the left testicular vein can be blocked causing left-sided varicocele

A 63-year-old man with prostate cancer develops nephrotic syndrome. Renal biopsy reveals electron dense antibody immune deposits located between the epithelium and glomerular basement membrane. Testing for ANA and anti-PLA2R (Phospholipase A2 receptor) antibody is negative. Which of the following identifies the likely underlying antigen of the antibodies found in the immune deposits? A. Antigen is double stranded DNA B. Antigen is glomerular basement membrane collagen C. Antigen is podocyte D. Antigen is prostate tumor

D. This patient's renal biopsy reveals electron dense subepithelial immune deposits and is thus consistent with membranous nephropathy. The pathogenesis of primary membranous nephropathy involves autoantibodies directed against the phospholipase A2 receptor on podocytes. That anti-PLA2R antibody is negative in this patient indicates membranous nephropathy of secondary nature. The antigen is not on the podocyte, but rather is some other chronic antigen to which the body is exposed. Membranous nephropathy can be secondary to solid tumors, including tumors of the colon, lung, breast, and prostate. Thus, the underlying antigen involved in the membranous nephropathy in this patient is most likely the prostate tumor C. The pathogenesis of primary membranous nephropathy involves autoantibodies directed against the phospholipase A2 receptor on podocytes. However, this patient tested negative for anti-PLA2R antibody

A 6-year-old boy presents to the clinic for evaluation of worsening edema over the past 2 weeks. His edema started around his eyes, apparent more so in the morning time, but it now involves his lower extremities and scrotal region. Three weeks ago he had an upper respiratory infection which resolved spontaneously. His blood pressure is appropriate for his age and height. Laboratory workup reveals hypoalbuminemia and nephrotic range proteinuria selective for albumin. Serum creatinine and complements levels are normal. A presumptive diagnosis is made and therapy with oral prednisone is initiated. The patient's condition resolves over the next 4 weeks. What is the most likely diagnosis of this patient? A. Focal segmental glomerulosclerosis B. Hereditary angioedema C. Membranous nephropathy D. Minimal change disease

D. This pediatric patient's presentation is classic for minimal change disease. Nephrotic syndrome often develops several weeks after an upper respiratory infection. Minimal change disease causes selective leakage of albumin (i.e. selective albuminuria) due to the loss of negative charge on the glomerular basement membrane. Patients with minimal change disease have normal blood pressure and their kidney function remains normal throughout the course of the disease. Minimal change disease responds well to steroid treatment, a feature which can confirm the diagnosis and obviate the need for renal biopsy in many cases.

Which of the following underlying disease processes is most closely associated with a diagnosis of membranoproliferative glomerulonephritis? A. Aberrant mucosal immunity B. Antecedent streptococcal infection C. Chronic ANCA-associated vasculitis D. Chronic viral hepatitis

D. Membranoproliferative glomerulonephritis is classically associated with chronic antigenic stimulation from diseases such as chronic viral hepatitis B or C, chronic bacterial infections, autoimmune disease, lymphomas, or monoclonal gammopathies. Light microscopy shows hypercellularity and enlarged, lobular glomeruli and a split basement membrane.

Which of the following is least likely to be seen in pauci-immune crescentic glomerulonephritis? A. Antineutrophil cytoplasmic antibodies (ANCA) B. Crescents C. Fulminant kidney failure D. Granular immunofluorescence

D. Pauci-immune glomerulonephritis does not involve the formation of immunoglobulin or complement complexes; therefore, the immunofluorescence will not show staining. Immune-mediated rapidly progressive glomerulonephritis (RPGN) will show granular patterns anti-GBM will show a linear pattern on immunofluorescence. A. Pauci-immune glomerulonephritis can be associated with underlying p-ANCA or c-ANCA vasculitides, such as microscopic polyangiitis or granulomatosis with polyangiitis, respectively. B. A defining pathologic feature of immune, pauci-immune, and anti-GBM mediated RPGN is the formation of crescents along with a rapid decline in kidney function. Crescent formation is caused by epithelial cell proliferation from the capsule (parietal), which eventually causes distortion of the glomerular architecture with obliteration of Bowman's space. C. A defining feature of immune, pauci-immune, and anti-GBM mediated RPGN is its association with rapid decline in kidney function. Clinically, there is a precipitous reduction in the glomerular filtration rate (GFR) by at least half, from a period of days to months.

The parents of a 6-year-old girl notice that she has become increasingly lethargic over the past 2 weeks. On examination by the physician, she has puffiness around the eyes. Her temperature is 36.9°C, and blood pressure is 100/60 mm Hg. Laboratory findings show a serum creatinine level of 0.7 mg/dL and urea nitrogen level of 12 mg/dL. Urinalysis shows a pH of 6.5; specific gravity 1.011; 4+ proteinuria; and no blood or glucose. The 24-hour urine protein level is 3.8 g. The child's condition improves after glucocorticoid therapy. Which of the following findings by electron microscopy is most likely to characterize this disease process? A) Subepithelial electron-dense humps B) Reduplication of glomerular basement membrane C) Areas of thickened and thinned basement membrane D) Increased mesangial matrix E) Effacement of podocyte foot processes

E) A child with nephrotic syndrome and no other clinical findings is most likely to have lipoid nephrosis, also called minimal change disease. The term minimal change disease reflects the paucity of pathologic findings. There is fusion of foot processes, which can be seen only by electron microscopy. - Subepithelial electron-dense humps represent immune complexes and are seen in postinfectious glomerulonephritis. - Variability of basement membrane thickening may be seen in Alport syndrome. - The mesangial matrix is expanded in some forms of glomerulonephritis (e.g., IgA nephropathy) and other diseases, such as diabetes mellitus, but not in minimal change disease.

A 15-year-old boy has been passing dark-colored urine for the past month. On physical examination, he has bilateral sensorineural hearing loss and corneal erosions. Urinalysis shows a pH of 6.5; specific gravity 1.015; 1+ hematuria; 1+ proteinuria; and no ketones, glucose, or leukocytes. The serum creatinine level is 2.5 mg/dL, and the urea nitrogen level is 24 mg/dL. A renal biopsy specimen shows tubular epithelial foam cells by light microscopy. By electron microscopy, the glomerular basement membrane shows areas of attenuation, with splitting and lamination of lamina densa in other thickened areas. What is the most likely diagnosis? A) Acute tubular necrosis B) Berger disease C) Membranous glomerulonephritis D) Diabetic nephropathy E) Alport syndrome

E) Alport syndrome is a form of hereditary nephritis. Hematuria is the most common presenting feature, but proteinuria is often present and may be in the nephrotic range. Patients progress to chronic renal failure in adulthood. Most patients have an X-linked dominant pattern of inheritance, but autosomal dominant and autosomal recessive pedigrees also exist. The foamy change in the tubular epithelial cells and ultrastructural alterations of the basement membrane are characteristic features. The genetic defect results from mutation in the gene for the α-5 chain of type IV collagen. - Acute tubular necrosis follows ischemic or toxic injuries to the kidney and does not involve glomeruli. - Berger disease, or IgA nephropathy, is a form of glomerulonephritis that does not produce tubular epithelial changes. - Membranous glomerulonephritis generally produces a nephrotic syndrome and deposition of immune complexes in glomerular basement membrane. - Nodular and diffuse glomerulosclerosis are typical changes in diabetic nephropathy.

A 28-year-old, previously healthy man suddenly develops severe abdominal pain and begins passing red urine. There are no abnormalities on physical examination. Urinalysis shows a pH of 7; specific gravity 1.015; 1+ hematuria; and no protein, glucose, or ketones. The patient is given a device to use in straining the urine for calculi. The next day, the patient recovers a 0.3-cm stone that is sent for analysis. The chemical composition is found to be calcium oxalate. What underlying condition is most likely to be present? A) Gout B) Acute cystitis C) Diabetes mellitus D) Primary hyperparathyroidism E) Idiopathic hypercalciuria

E) Calcium oxalate stones are the most common type of urinary tract stone. Approximately 50% of patients with calcium oxalate stones have increased excretion of calcium without hypercalcemia (high blood Ca). The basis of hypercalciuria is unclear. Most uric acid stones are formed in acidic urine and are not related to gout. It is thought that these patients have an unexplained tendency to excrete acidic urine. At low pH, uric acid is insoluble, and stones form. Infections can predispose to the formation of magnesium ammonium phosphate stones. - Diabetes mellitus is an uncommon cause of urinary tract lithiasis; although infections are more common in diabetics, most are not caused by urea splitting bacteria. - Hyperparathyroidism predisposes affected individuals to form stones containing calcium, but few patients with urinary tract stones have this condition.

A 25-year-old woman experiences sudden onset of fever, malaise, and nausea. On physical examination, her temperature is 38.2°C, pulse is 85/min, respirations are 18/min, and blood pressure is 140/90 mm Hg. A routine urinalysis shows 1+ proteinuria, 4+ hematuria, and no ketones or glucose. RBC casts are seen on microscopic examination of the urine. A renal biopsy is performed, and light microscopic examination shows marked glomerular hypercellularity with neutrophils in glomerular capillary loops. Immunofluorescence microscopy shows granular deposition of IgG and C3 in glomerular capillary basement membranes. Electron microscopy shows electron-dense subepithelial "humps." What is the most likely diagnosis? A) Goodpasture syndrome B) Systemic amyloidosis C) Membranous glomerulonephritis D) Diabetes mellitus E) Postinfectious glomerulonephritis

E) Postinfectious glomerulonephritis is one of many causes of a nephritic syndrome characterized by hematuria and RBC casts. Most children recover completely, but one in six adults may progress to chronic renal failure. Some cases may occur after a streptococcal pharyngitis (poststreptococcal glomerulonephritis). In other cases, such as this one, the preceding infection is so mild that patients give no history. - Goodpasture syndrome also may produce a nephritic syndrome, but there is linear deposition of antibody in the glomerular basement membrane. - Amyloidosis of the kidney mainly produces proteinuria without hematuria, as does membranous glomerulonephritis. - Nodular and diffuse glomerulosclerosis are characteristic of diabetic nephropathy.

A 26-year-old man is involved in a motor vehicle accident and sustains acute blood loss. He is hypotensive for several hours before paramedical personnel arrive. They stabilize the bleeding and transport him to a hospital, where he receives a transfusion of 3 U of packed RBCs. Over the next week, the serum urea nitrogen level increases to 48 mg/dL, the serum creatinine level increases to 5 mg/dL, and the urine output decreases. He undergoes hemodialysis for the next 2 weeks and then develops marked polyuria, with urine output of 2 to 3 L/day. His recovery is complicated by bronchopneumonia, but renal function gradually returns to normal. The patient's transient renal disease is best characterized by which of the following histologic features? A) Glomerular crescents in Bowman space B) Interstitial lymphocytic infiltrates C) Arteriolar fibrinoid necrosis D) Nodular glomerulosclerosis E) Rupture of tubular basement membrane

E) This patient's history is typical of ischemic acute tubular necrosis, which is often accompanied by rupture of the basement membrane (tubulorrhexis). An initiating phase that lasts approximately 1 day is followed by a maintenance phase during which progressive oliguria and increasing blood urea nitrogen levels occur, with salt and water overload. This is followed by a recovery phase during which there is a steady increase in urinary output and hypokalemia. Eventually, tubular function is restored. Treatment of this acute renal failure results in recovery of nearly all patients. - Crescents suggest a rapidly progressive glomerulonephritis that is unlikely to resolve. - Interstitial infiltrates suggest a chronic tubulointerstitial process. - Fibrinoid necrosis in arterioles is a feature of malignant nephrosclerosis, a serious condition that produces significant renal damage. - Nodular glomerulosclerosis is a feature of diabetic nephropathy and is a progressive condition that leads to chronic renal failure.

A 20-year-old woman, G1, P0, who is in the third trimester, has felt minimal fetal movement. An ultrasound scan shows a markedly decreased amniotic fluid index characteristic of oligohydramnios. She gives birth to a stillborn male fetus at 33 weeks' gestation. At autopsy, there are deformations resulting from marked oligohydramnios, including flattening of the facies, varus deformities of the feet, and marked pulmonary hypoplasia. Microscopic examination of the liver shows multiple epithelium-lined cysts and a proliferation of bile ducts. Which of the following best describes the appearance of the kidneys in this fetus? A) Bilaterally enlarged kidneys replaced by 1- to 4-cm, fluid-filled cysts B) Bilaterally shrunken kidneys with uniformly finely granular cortical surfaces C) Decreased overall size of the right kidney and normal-sized left kidney D) Irregular cortical scars in asymmetrically shrunken kidneys with marked calyceal dilation E) Marked bilateral renal pelvic and calyceal dilation with thinning of the cortices F) Normal-sized kidneys with smooth cortical surfaces G) Symmetrically enlarged kidneys composed of small, radially arranged cysts

G) Autosomal-recessive polycystic kidney disease (ARPKD) most often occurs in children and may involve the liver; most cases have mutations in the PKHD1 gene encoding for fibrocystin expressed in kidney, liver, and pancreas. By contrast, autosomal-dominant polycystic kidney disease (ADPKD) manifests with renal failure in adults and involves PKD1 and PKD2 gene mutations encoding for polycystin proteins found in renal tubules. Some less common forms of ARPKD are accompanied by survival beyond infancy, and these patients develop congenital hepatic fibrosis. Enlarged kidneys with 1- to 4-cm cysts are characteristic of ADPKD in adults. Perhaps the most common renal cystic disease seen in fetuses and infants is multicystic renal dysplasia (multicystic dysplastic kidney), in which the cysts and kidneys are variably sized. This disease can be focal, unilateral, or bilateral; however, congenital hepatic fibrosis is not present. Small, shrunken, granular kidneys typify end-stage renal diseases in adults. For oligohydramnios to be present, both kidneys must be affected, not just one. Irregular cortical scars with pelvicaliceal dilation may represent hydronephrosis complicated by infection in chronic pyelonephritis, a process that occurs in adults. Dilation with calyceal thinning can occur with obstructions in utero, such as posterior urethral valves in males or urethral atresia in males or females; liver lesions are not present in these cases. A cause of oligohydramnios other than abnormalities of the urinary tract (e.g., leakage of amniotic fluid with premature and prolonged rupture of membranes) could be present if the kidneys appear normal, but in this case the distinctive finding of congenital hepatic fibrosis points to ARPKD.