An asymptomatic 10-year-old is diagnosed with autosomal dominant polycystic kidney disease (ADPKD) after a screening ultrasound shows multiple bilateral macrocysts. Her father has the same condition. Disease caused by pathogenic variants in the PKD1 gene is associated with what clinical course compared to variants in the PKD2 gene?
A 7-year-old girl with a history of failure to thrive and recurrent nephrolithiasis is diagnosed with distal (Type I) renal tubular acidosis. She is started on bicarbonate replacement therapy. Despite correction of her metabolic acidosis, she continues to have significant hypercalciuria. Which medication, when added to her regimen, would be most effective at reducing her urinary calcium excretion and risk of future stones?
A full-term newborn’s renal anatomy is being reviewed. During development, nephron formation is typically complete by 34-36 weeks of gestation. Which of the following structures is correctly located within the renal cortex?
A 3-week-old infant develops a unilateral flank mass, gross hematuria, and thrombocytopenia. The mother had severe preeclampsia during pregnancy. An ultrasound with Doppler confirms renal vein thrombosis. What is the recommended initial treatment for a newborn with bilateral renal vein thrombosis?
A 16-year-old female presents with intermittent muscle cramps and fatigue. Her laboratory workup is notable for a serum potassium of 2.8 mEq/L, serum bicarbonate of 29 mEq/L, and serum magnesium of 1.3 mg/dL. A 24-hour urine collection reveals low calcium excretion and elevated magnesium excretion. Which genetic defect is the most likely cause of her condition?
A 7-year-old girl is brought to the clinic for red-colored urine. Her urinalysis is heme-positive, but a microscopic analysis of the centrifuged urine shows no red blood cells. Which of the following is the most likely cause of her findings?
A 7-year-old girl with a history of frequently relapsing nephrotic syndrome presents to the emergency department with a fever of 39.1°C (102.4°F), diffuse abdominal pain, and rebound tenderness. A paracentesis is performed, and the fluid analysis shows a leukocyte count of 400 cells/μL. This presentation is highly suggestive of spontaneous bacterial peritonitis. Which organism is most commonly responsible for this complication?
A critically ill 14-year-old in the intensive care unit develops oliguria and a rising serum creatinine following a septic episode. To help differentiate between prerenal azotemia and established acute tubular necrosis (ATN), a urine sample is sent for analysis. Which set of findings would most strongly support a diagnosis of ATN over prerenal injury?
A 15-year-old is found to have persistent proteinuria on multiple routine urinalyses. A first morning urine sample is collected immediately upon waking. The dipstick is negative for protein, and the protein-to-creatinine ratio is < 0.2. What is the most likely diagnosis?
An 8-month-old infant is evaluated for failure to thrive. Laboratory studies reveal a normal anion gap metabolic acidosis with a serum pH of 7.28, serum bicarbonate of 15 mEq/L (low), and normal potassium. A urine sample collected at the same time shows a pH of 5.2. Which of the following is the most likely diagnosis?
