CORTICAL-PREDOMINANT NEPHROCALCINOSIS AS AN EARLY RADIOLOGIC MARKER OF FULMINANT INFANTILE PRIMARY HYPEROXALURIA TYPE 1: A CASE REPORT

Background: Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disorder of glyoxylate metabolism leading to hepatic oxalate overproduction, progressive nephrocalcinosis, and early end-stage renal disease (ESRD), particularly in its severe infantile form. Early radiological recognition is critical for prompt metabolic and genetic evaluation. 
Case Presentation: A 3-month-old infant born to consanguineous parents presented with status epilepticus secondary to severe acute kidney injury (AKI), anuria, profound electrolyte disturbances (hyponatremia 113–122 mmol/L; hyperkalemia 6.8 mmol/L), metabolic acidosis (pH 7.00), and severe anemia (Hb 4.3 g/dL). Renal ultrasound demonstrated bilaterally normal-sized kidneys with diffuse, intense hyperechogenicity involving both cortex and medulla, complete loss of corticomedullary differentiation, and no obstruction. The pattern appeared cortical-predominant. Follow-up ultrasounds confirmed persistent symmetric “bright kidney” appearance. Non-contrast CT revealed dense symmetric cortico-medullary nephrocalcinosis (>100–200 HU) without obstructing calculi or hydronephrosis. Renal biopsy showed abundant birefringent calcium oxalate crystals, highly suggestive of oxalate nephropathy in the context of infantile fulminant disease. 
Conclusion: Diffuse cortical-predominant nephrocalcinosis on ultrasound in infants with severe unexplained AKI should prompt urgent suspicion of PH1. Early radiologic recognition accelerates metabolic evaluation, renal biopsy confirmation, and multidisciplinary management, including potential RNAi therapy.