A 50-year-old man comes to the office for evaluation of abdominal fullness and mild right flank pain.  He also reports a weight loss of 4.5 kg (10 lb) over the past 2 months.  The patient has no other medical issues and works in a local industrial chemical manufacturing facility.  Examination shows a soft abdomen.  Ultrasound reveals a mass in the right kidney.  A subsequent abdominal CT scan confirms the presence of a large right renal mass with evidence of necrosis.  The patient undergoes a right total nephrectomy.  The specimen is shown below.

This patient’s lesion most likely originated from which of the following portions of the kidney?

A 54-year-old previously healthy man comes to the office due to several weeks of leg swelling.  He has had no fever, chest pain, or dyspnea.  The patient has a 40-pack-year smoking history but does not use alcohol or illicit drugs.  He is afebrile and vital signs are within normal limits.  On physical examination, there is symmetric pitting edema of the lower extremities bilaterally.  The abdomen is soft and nondistended.  A mobile left flank mass can be palpated.  There are several vertically oriented tortuous veins on the lower abdominal wall.

Item 1 of 2

Which of the following structures is most likely obstructed in this patient?

Item 2 of 2

Further evaluation of the patient reveals microscopic hematuria.  Laboratory results are as follows:

Which of the following is the most likely cause of this patient’s hematologic findings?

A 12-year-old boy is brought to the clinic because of facial puffiness.  Examination shows periorbital edema.  Urinalysis reveals:

A biopsy image representative of this patient’s disease process is shown below.

Which of the following additional findings is most likely to be present in this patient?

A 67-year-old man comes to the office due to generalized weakness, easy fatigability, anorexia, and intermittent nausea for the past several months.  He also says that he is “itching and scratching a lot.”  Physical examination shows bilateral lower extremity pitting edema and skin excoriations.  Laboratory results show a serum creatinine level of 3.4 mg/dL and a blood urea nitrogen level of 48 mg/dL.  A renal biopsy is performed.  Light microscopy of the tissue sample shows widespread narrowing of the renal arterioles with deposition of homogeneous, glassy material in the vessel walls that stains pink with periodic acid-Schiff (PAS) stain.  This patient most likely has which of the following underlying conditions?

A 60-year-old woman is being evaluated for abnormal renal function.  She is found to have a serum creatinine of 2.2 mg/dL on routine laboratory monitoring; her creatinine level a year ago was 1.2 mg/dL.  The patient has a history of nonischemic cardiomyopathy and systolic heart failure and has been on a stable medical regimen for the past 2 years.  She has no dyspnea, fever, rash, or lower extremity swelling but has been taking ibuprofen for 2 weeks due to left knee osteoarthritis.  Urinalysis reveals the following:

Ibuprofen is discontinued, and her kidney function returns to normal in a week.  Which of the following best explains this patient’s transient deterioration in renal function?

A 46-year-old woman is admitted to the hospital with dehydration secondary to excess output from an ileostomy.  Five years ago, the patient had a total colectomy with a diverting ileostomy for colon cancer.  For the last 6 months, she has had increased output from the ileostomy and has been admitted to the hospital twice with similar episodes of dehydration.  On the second day of admission, she reports right flank pain.  X-ray of the abdomen reveals a nonspecific bowel gas pattern with no evidence of renal calculi.  Ultrasound of the abdomen shows a 4-mm stone in the distal right ureter.  The patient is treated with analgesics and the stone passes spontaneously.  Microscopic analysis of the stone reveals a pure uric acid stone.  Which of the following is the most likely underlying mechanism leading to stone formation in this patient?

A 10-year-old boy is brought to the office due to dark brown urine that he first noticed yesterday after swimming practice.  Blood pressure is 130/80 mm Hg.  Physical examination is normal with the exception of bilateral periorbital edema.  Laboratory results are as follows:

Which of the following is the most likely diagnosis?

A 26-year-old previously healthy man comes to the office with a 3-week history of shortness of breath, cough, and hemoptysis preceded by an upper respiratory tract infection.  He has no fever, night sweats, or weight loss.  His blood pressure is 150/85 mm Hg and pulse is 86/min and regular.  Physical examination reveals bilateral inspiratory crackles and lower extremity edema.  His creatinine is 4.1 mg/dL.  Urinalysis shows proteinuria and hematuria with dysmorphic red blood cells.  Bilateral pulmonary infiltrates are seen on chest x-ray.  He is also found to have an increased carbon monoxide diffusing capacity (DLCO) on pulmonary function testing.  Antibodies directed against which of the following is most likely to be associated with this patient’s condition?

A 65-year-old woman is treated with gentamicin for an abdominal infection complicated by multidrug-resistant organisms.  After a week of treatment, the patient’s urine output decreases noticeably, and serum creatinine rises to 2.3 mg/dL.  She has no previous kidney disease, and baseline kidney function was normal prior to the initiation of therapy.  The patient has remained afebrile for 24 hours.  Blood pressure is 130/80 mm Hg and pulse is 80/min.  Examination shows moist mucous membranes.  There is no rash.  Results of urinalysis are as follows:

Fractional excretion of sodium is >2%.  Histologic examination of the patient’s kidneys would most likely show which of the following?

A 34-year-old man is being evaluated for acute hematuria and oliguria.  He has no chronic medical conditions and takes no medications on a regular basis.  Blood pressure is 170/100 mm Hg.  Blood urea nitrogen is 38 mg/dL and serum creatinine is 4.5 mg/dL.  The patient undergoes a kidney biopsy and the following microscopic changes are seen after silver staining to highlight the glomerular tuft:

The area marked with an arrow is likely to have abnormal deposition of which of the following substances?

A 72-year-old man is brought to the emergency department due to diarrhea and vomiting for the last 24 hours.  The patient’s daughter states that he has been unable to take in much fluid during this time.  He has hypertension treated with hydrochlorothiazide, which he has not taken since the onset of symptoms.  Blood pressure is 90/60 mm Hg and pulse is 105/min.  Examination shows dry mucous membranes.  Urinalysis reveals concentrated urine with a specific gravity of 1.030.  Which of the following changes in renal plasma flow (RPF), glomerular filtration rate (GFR), and filtration fraction (FF) are most likely to be present in this patient as compared with the normal state?

A 64-year-old man who recently moved to the area comes to the office for a new patient evaluation.  He has chronic low back pain, resulting from an injury 8 years ago, for which he uses several over-the-counter analgesics.  Most recently, the patient has been taking naproxen daily.  He has no other joint pain, fever, rash, urinary symptoms, or other medical conditions.  Blood pressure is 135/70 mm Hg and pulse is 78/min.  Examination shows trace lower extremity edema.  Neurologic and musculoskeletal examinations reveal no abnormalities.  Laboratory results show blood counts within normal limits, blood urea nitrogen of 12 mg/dL, and serum creatinine of 2.0 mg/dL.  Urinalysis reveals 1+ protein and 3-4 white blood cells/hpf.  Renal ultrasound demonstrates bilateral shrunken and irregular kidneys with a few papillary calcifications.  Which of the following is the most likely cause of this patient’s renal dysfunction?

A 7-year-old boy is brought to the office due to swelling of the hands and feet.  Two weeks ago, the patient was treated for anaphylaxis following a bee sting.  During the past 10 days, he has had progressive hand and foot swelling, and his pants feel tighter than usual.  The patient’s urine has also become frothy.  Examination shows periorbital edema and pitting edema of the hands and feet, as well as mild ascites.  Lungs are clear to auscultation.  Urinalysis results are as follows:

Biopsy of this patient’s kidneys would most likely show which of the following microscopy findings?

A 68-year-old man comes to the office due to intermittent, painless blood in his urine.  He has no other symptoms.  The patient uses transdermal testosterone for chronic hypogonadism and erectile dysfunction.  He has smoked a pack of cigarettes daily for 40 years; he drinks 2 shots of vodka every day and 2 glasses of wine once a week.  He works as an operations manager for a large beverage company and frequently travels to Mexico.  Vital signs are within normal limits.  Abdominal examination shows no abnormalities.  On digital rectal examination, the prostate is smooth with no nodules.  Urinalysis is positive for >50 red blood cells/hpf; there are no casts or dysmorphic blood cells.  Urine cytology is positive for malignant cells.  Renal ultrasonogram reveals normal kidneys.  Which of the following is a major risk factor for this patient’s current condition?

A 30-year-old man is admitted to the hospital due to seizures.  The repeated, prolonged tonic-clonic seizures were terminated with intravenous lorazepam in the emergency department.  Medical history is significant for amphetamine abuse.  The patient develops decreased urine output 24 hours after hospital admission.  Temperature is 37.1 C (98.8 F), blood pressure is 140/90 mm Hg, pulse is 88/min, and respirations are 18/min.  Examination shows bibasilar lung crackles and mild edema of the lower extremities.  Laboratory results are as follows:

Which of the following is the most likely cause of this patient’s kidney injury?

A 28-year-old man is hospitalized following a motor vehicle collision complicated by severe hemorrhage.  Over the next 8 hours his urine output is markedly decreased.  Laboratory results reveal elevated blood urea nitrogen.  The patient is given aggressive intravenous fluid hydration.  After 24 hours of therapy, urine output is increased and blood urea nitrogen declines toward normal.  Which of the following additional laboratory abnormalities suggests that this patient’s initial oliguria is a compensation for volume contraction?

A 54-year-old man comes to the physician due to blood in his urine and abdominal discomfort that occurred 2 days ago.  He was moving potted plants around his porch when he started having pain in his abdomen.  Afterward, he noticed blood in his urine but says it resolved the following day.  He has a history of hypertension.  The patient does not use tobacco, alcohol, or illicit drugs.  Physical examination shows no abnormalities.  CT scan of the abdomen with contrast is shown below.

Which of the following is the most likely diagnosis?

A 60-year-old woman comes to the emergency department due to left flank pain and hematuria.  Medical history is significant for recurrent urinary tract infections and hypothyroidism.  Blood pressure is 130/80 mm Hg and pulse is 80/min.  Physical examination shows left flank tenderness.  CT scan of the abdomen is shown below:

Urinalysis for this patient would most likely show which of the following?

A 15-year-old girl is brought to the clinic for evaluation of swelling around her eyes that developed over the past week.  The patient is a cheerleader, and she had been taking ibuprofen daily for the last 3 months for various sprains and aches after practice.  She has no chronic medical conditions.  Vital signs are normal.  On physical examination, there is moderate periorbital edema with bilateral lower extremity pitting edema.  Serum creatinine is 0.5 mg/dL and serum albumin is 2.1 g/dL.  Urinalysis shows 4+ protein and negative blood.  Multiple regions of the kidney are biopsied, and a representative image is shown below:

Which of the following is the most likely diagnosis?

A 54-year-old man comes to the hospital due to acute-onset right flank pain associated with nausea.  Five years ago, the patient had nephrolithiasis; the renal calculi passed spontaneously with intravenous fluids.  Review of systems is positive for occasional palpitations.  Other medical problems include hypertension, obesity, and obstructive sleep apnea.  Temperature is 38 C (100.4 F), blood pressure is 170/98 mm Hg, pulse is 90/min, and respirations are 18/min.  Cardiopulmonary examination shows no abnormalities.  Right flank tenderness is present.  Urinalysis demonstrates 2+ red blood cells and no white blood cells or protein.  A representative kidney specimen is shown below:

Which of the following is the most likely diagnosis?

A 54-year-old man hospitalized with an acute myocardial infarction goes into cardiac arrest.  The patient is resuscitated successfully and transferred to the cardiac intensive care unit where he remains hemodynamically stable.  However, on the second day of hospitalization, his urine flow diminishes to 400 mL/day.  Blood pressure is 115/68 mm Hg and pulse is 78/min.  Laboratory results are as follows:

Urine sediment microscopy reveals muddy brown casts.  Which of the following renal structures are most likely to demonstrate signs of ischemic injury?

A 44-year-old woman comes to the emergency department due to acute-onset, severe, right lower quadrant abdominal pain, nausea, vomiting, and hematuria over the last 4 hours.  She had a similar episode of acute pain a year ago, but it resolved in a few hours and she did not seek medical intervention.  The patient has no other medical conditions and takes no medication.  She smokes a pack of cigarettes daily.  She is sexually active and has never been pregnant.  Temperature is 36.9 C (98.4 F), blood pressure is 140/90 mm Hg, and pulse is 102/min.  There is mild tenderness to deep palpation in the right lower quadrant.  Laboratory results are as follows:

Which of the following is the most likely cause of this patient’s current condition?

A 72-year-old man comes to the emergency department due to sudden-onset, severe abdominal pain accompanied by nausea.  He has a history of coronary artery disease and recently underwent cardiac angiography.  The patient is a current smoker with a 30-pack-year history.  After initial evaluation, he undergoes emergency laparotomy.  A segment of small intestine is resected.  On microscopic examination, there are several large-caliber vessels with needle-shaped cholesterol clefts in their lumens, as shown in the image below.

Given these findings, the patient is at highest risk for which of the following complications?

A 12-year-old girl is brought to the clinic by her parents after she is found to have hypertension by her school nurse.  The patient has no symptoms and reads a book during the office visit.  Her family immigrated to the United States 2 months ago, and she has not received routine well-child care.  The patient has had several episodes of fever and abdominal pain, which her parents treated with over-the-counter antibiotics available in her country of origin.  Blood pressure is elevated on several readings in the office.  There is no family history of hypertension.  Renal ultrasound reveals dilated calyces with overlying cortical atrophy bilaterally, mostly in the upper and lower poles.  Which of the following is the most likely cause of this patient’s condition?

A 24-year-old woman comes to the office for the evaluation of joint pain, fatigue, edema, and weight gain for the past four weeks.  She has no previous medical conditions except for recurrent oral ulcers.  The patient takes no medications and does not use tobacco, alcohol, or illicit drugs.  Blood pressure is 130/80 mm Hg and pulse is 80/min.  Examination shows oral mucosal ulcers, facial puffiness, and 3+ peripheral edema.  Swelling, erythema, and tenderness are noted over the bilateral metacarpophalangeal and proximal interphalangeal joints.  Cardiopulmonary examination reveals no abnormalities.  Twenty-four-hour urine protein excretion is 4.5 g.  Serum antinuclear antibodies are present.  Kidney biopsy shows glomerular capillary wall thickening with no increase in cellularity.  When the sample is stained with methenamine silver, irregular spikes protruding from the glomerular basement membrane are seen.  This patient most likely has which of the following conditions?

A 46-year-old woman being evaluated for irregular vaginal bleeding is found to have invasive cervical carcinoma.  She undergoes total abdominal hysterectomy and bilaeral salpingo-oophorectomy.  Pelvic lymphadenectomy was also performed, during which several enlarged nodes around the pelvic vessels were resected.  A week after the surgery, the patient begins to experience left-sided flank pain that radiates to the groin.  Her temperature is 36.1 C (97 F), blood pressure is 120/70 mm Hg, and pulse is 84/min.  On physical examination, there is a ballotable left flank mass.  Which of the following most likely accounts for this physical examination finding?

A 44-year-old man is brought to the hospital after being found unresponsive.  Temperature is 35.6 C (96.1 F), blood pressure is 120/80 mm Hg, and pulse is 110/min.  He is responsive only to pain and has dry mucous membranes.  The patient’s condition is initially treated with intravenous fluids, and his mental status slowly improves, but urine output decreases and flank pain develops.  A renal biopsy reveals marked ballooning and vacuolar degeneration of proximal renal tubules; multiple oxalate crystals are observed in the tubular lumen.  Which of the following is most likely responsible for this patient’s acute kidney injury?

A 7-year-old boy is brought to the office by his mother due to facial puffiness that is especially noticeable in the morning.  He has a history of mild, intermittent asthma that is well controlled with albuterol as needed.  Temperature is 36.1 C (97 F), blood pressure is 98/62 mm Hg, and pulse is 89/min and regular.  Physical examination shows bilateral lower extremity pitting edema.  Nephrotic-range proteinuria consisting mainly of albumin is revealed on urinalysis.  Which of the following mechanisms is the most likely cause of this patient’s abnormal laboratory findings?

A 41-year-old woman is being evaluated for peripheral edema.  The patient has gained 6.8 kg (15 lb) over the past 8 weeks.  Her urine is “frothy.”  She has no other medical problems and takes no medications.  The patient does not use tobacco, alcohol, or illicit drugs.  Blood pressure is 140/90 mm Hg and pulse is 80/min.  Examination shows generalized edema.  Heart sounds are normal.  The abdomen is soft and nontender.  Serum creatinine is 1.1 mg/dL.  Urinalysis shows 4+ protein, 0-3 leukocytes/hpf, and oval fat bodies.  Serum contains IgG4 antibodies to the phospholipase A2 receptor (PLA2R), a transmembrane protein abundant on podocytes.  Which of the following is the most likely diagnosis?

A 21-year-old man is brought to the emergency department due to diffuse muscle aches and weakness.  He has also noticed darkening of his urine.  The patient recently joined the military and was participating in rigorous training exercises in hot weather earlier in the day.  He has no significant medical conditions and takes no medications.  Medical evaluation and laboratory testing performed prior to military enlistment showed no abnormalities.  Temperature is 36.7 C (98 F), blood pressure is 100/60 mm Hg, pulse is 105/min, and respirations are 16/min.  Physical examination shows dry mucous membranes and muscle tenderness over the bilateral thighs and calves.  Laboratory results are as follows:

Which of the following urine microscopy findings is most likely to be seen in this patient?

A 76-year-old man comes to the office due to bilateral flank pain and nausea.  The patient has not urinated for 24 hours.  Medical history is significant for diet-controlled type 2 diabetes and degenerative arthritis of the knee.  He occasionally takes naproxen for pain.  Temperature is 36.9 C (98.4 F), blood pressure is 140/90 mm Hg, and pulse is 90/min.  Cardiopulmonary examination reveals no abnormalities.  Abdominal examination shows suprapubic fullness.  Mild bilateral costophrenic angle tenderness is present.  Laboratory results show a blood urea nitrogen level of 32 mg/dL and creatinine level of 2.6 mg/dL.  Four weeks ago, laboratory studies were normal.  Which of the following is the most likely cause of this patient’s renal dysfunction?

A 73-year-old man comes to the emergency department with unstable angina.  He undergoes coronary angiography via the femoral approach.  A stent is placed in the right coronary artery, and the patient is discharged.  He returns to the emergency department 2 days later with blue discoloration of his right toe.  He has pain and mild tingling in the affected toe.  Medical history is significant for hyperlipidemia and coronary artery disease.  On physical examination, the right toe appears cyanotic, and there is livedo reticularis affecting the right thigh.  Peripheral pulses in the lower extremities are bilaterally palpable.  Serum creatinine is 2.8 mg/dL (preoperatively it was 1.0 mg/dL).  Which of the following histopathologic findings would most likely be seen on biopsy of this patient’s kidney?

A 21-year-old man comes to the emergency department due to 1 day of left flank pain and gross hematuria.  He reports passage of small blood clots in urine but has had no dysuria or similar symptoms in the past.  The patient has no other medical problems and does not take any medications.  He does not use tobacco, alcohol, or illicit drugs.  His younger sister has sickle cell disease.  His temperature is 36.7 C (98 F), blood pressure is 126/70 mm Hg, and pulse is 100/min.  Abdominal and genitourinary examination is unremarkable.  There is no costovertebral angle tenderness.  Which of the following is the most likely cause of this patient’s hematuria?

A 16-year-old boy is brought to the emergency department with sudden onset of left-sided abdominal pain and blood in his urine.  The pain waxes and wanes in intensity and does not improve with rest or position changes.  He has a lengthy history of similar pain episodes, but this is the first time he has had gross hematuria.  Physical examination shows costovertebral angle tenderness on the left side.  Microscopic examination of the urine is shown below.

Further laboratory evaluation is most likely to reveal which of the following abnormalities in this patient?

A 70-year-old man is brought to the hospital by his son for evaluation of worsening fatigue.  The patient has not seen a physician in the past 15 years.  He takes naproxen occasionally for knee arthritis.  Physical examination of the prostate shows no abnormalities.  Laboratory results are as follows:

Urine sediment is unremarkable.  Ultrasound examination shows bilateral small kidneys and no hydronephrosis.  Kidney biopsy shows intimal thickening and luminal narrowing of the renal arterioles with evidence of glomerular sclerosis.  Which of the following is most likely responsible for this patient’s kidney disease?

A 5-year-old girl is brought to the clinic due to 2 days of dark red urine.  The patient was treated for facial impetigo a month ago.  Blood pressure is 140/90 mm Hg.  Urinalysis reveals hematuria, mild proteinuria, and occasional red blood cell casts.  Which of the following glomerular changes are most likely to be present within this patient’s kidneys?

A 54-year-old woman is brought to the hospital due to fever, nausea, vomiting, and confusion.  For the past 3 days, she has had dysuria and increased frequency of urination.  Medical history is significant for recurrent urinary tract infections and primary hypertension.  Family history is insignificant.  Temperature is 39.2 C (102.6 F), blood pressure is 90/50 mm Hg, pulse is 102/min, and respirations are 24/min.  Examination shows right flank tenderness.  The patient subsequently undergoes nephrectomy, and a cut section of the resected kidney is shown in the image below.

Further evaluation of this patient would most likely reveal which of the following?