Nephrocalcinosis in a young male with anorexia nervosa

Nephrocalcinosis (NC) has been described as a long-term complication of anorexia nervosa (AN). This is the first report of this complication in an adolescent male patient. We describe the case of a 12-year-old male with AN who presented with acute food restriction and excessive exercising leading to three inpatient admissions. The patient experienced an isolated episode of dysuria and hematuria while on calcium and vitamin D supplementation. Investigations revealed hypophosphatemia, hypercalciuria and mild NC. Follow-up confirmed the presence of NC and possible nephrolithiasis (NL). We discuss the pathophysiology and risk factors of NC and NL in the context of an early presentation of AN. We suggest fluid intake should be liberalized under observation and calcium and vitamin D supplementation should be initiated with caution in patients presenting with AN and risk factors for NC and NL.