A 12-year-old boy with a history of end-stage kidney disease secondary to primary focal segmental glomerulosclerosis (FSGS) receives a living-related kidney transplant. One week after transplantation, he develops anasarca and his urine protein:creatinine ratio is > 10. A biopsy of the allograft is performed. What is the most likely finding that explains his clinical deterioration?
A neonate is born with bilateral flank masses, oligohydramnios on prenatal ultrasound, and significant respiratory distress requiring immediate intubation. An abdominal ultrasound shows markedly enlarged, uniformly hyperechogenic kidneys. What is the most significant cause of perinatal demise in infants with severe autosomal recessive polycystic kidney disease?
A 9-month-old boy presents with a history of recurrent hypernatremic dehydration, inconsolable crying, and poor weight gain. Laboratory tests show a serum osmolality of 310 mOsm/kg and a simultaneous urine osmolality of 150 mOsm/kg. An intranasal dose of vasopressin fails to increase his urine osmolality. What is the most appropriate long-term oral medication to help reduce his urine output?
A 9-year-old boy presents with recurrent episodes of gross hematuria and dysuria. His renal ultrasound is normal. A 24-hour urine collection reveals a calcium excretion of 6 mg/kg/day, confirming idiopathic hypercalciuria. Besides dietary sodium restriction, what class of medication can be used to normalize urinary calcium excretion and resolve symptoms?
A 3-week-old infant, born prematurely following a pregnancy complicated by polyhydramnios, presents with severe salt wasting and dehydration. Labs show hypokalemic, hypochloremic metabolic alkalosis and hypercalciuria. His serum renin and aldosterone levels are markedly elevated. In addition to electrolyte and fluid replacement, which medication is often used to ameliorate the symptoms of this condition?
A 4-year-old boy is brought to the clinic with a 5-day history of progressive swelling around his eyes and in his legs. His urinalysis reveals 4+ proteinuria and a spot urine protein:creatinine ratio of 4.5. He has no significant hypertension or gross hematuria. After confirming the diagnosis of nephrotic syndrome, which of the following is the most appropriate next step?
A 13-year-old boy with chronic kidney disease (CKD) Stage 4 due to renal dysplasia has a height that is less than -2 standard deviations for his age and a growth velocity below the 25th percentile. He has adequate caloric intake, and his acidosis and renal osteodystrophy are well-managed. What is the most appropriate next therapeutic intervention to improve his linear growth?
A 2-year-old boy is diagnosed with cystinosis after presenting with growth failure and polyuria. His evaluation confirms the presence of Fanconi syndrome. Which of the following laboratory findings would be expected as part of his global proximal tubular dysfunction?
You are managing a 10-year-old girl with Stage 3b CKD. Her labs show normal serum calcium, normal serum phosphorus, and a 25-hydroxy vitamin D level of 35 ng/mL. However, her parathyroid hormone (PTH) level is progressively rising above the target range for her CKD stage. What is the earliest pathologic driver responsible for this rise in PTH?
A 6-year-old child with a recent history of pharyngitis presents to the clinic with periorbital edema, hypertension, and cola-colored urine. A urinalysis shows 3+ blood and 2+ protein with red blood cell casts. What is the most likely category of his acute kidney injury (AKI)?
