Stony kidneys in a child: Clue to a rare diagnosis

Abstract

alanine-glyoxalate transaminase. Type 2 is caused by the deficiency of cytosolic enzymes glyoxalate reductase and D-glycerate dehydrogenase. Type 3 results from a primary increase in the absorption of oxalate from the gastrointestinal tract.Classic presentation is nephrocalcinosis with nephrolithiasis, which leads to renal failure in early adulthood. Once the kidneys fail, oxalate accumulates in the body and gets deposited at various sites. Preferred A five-year-old boy presented to the Emergency Department with altered sensorium. He had nausea, with occasional vomiting and anorexia for the past one week. His parents denied any history of fever, diarrhea or a significant past medical history or significant family history. The child was unconscious, afebrile, with a pulse rate of 68/minute, blood pressure of 140/80 mmHg and respiratory rate of 17/minute. The systemic examination was unremarkable.Urinalysis showed calcium oxalate crystals in abundance and blood investigations revealed elevated urea and creatinine levels. A twenty-four hour urinary oxalate was found to be elevated.Abdominal radiographs showed bilateral diffusely dense kidneys [Figure 1]. Ultrasonography revealed normal-sized kidneys with a smooth outline and uniformly raised cortical echogenicity. No calculus or hydronephrosis was present. Non-contrast computed tomography (NCCT) showed diffusely increased density of both the kidneys with calculi in the gall bladder [Figure 2]. Based on the findings of urinalysis and imaging characteristics, a diagnosis of primary hyperoxaluria was suspected and later confirmed on liver biopsy.Primary hyperoxaluria is a group of autosomal recessive disorders caused by deficient metabolism of glyoxalate to glycine, leading to an increased production of oxalate that gets deposited in various organs. At least three different types of hyperoxalurias are known.