Transient renal tubulopathy: a case report

A five-year-old boy was evaluated for fever, abdominal pain, vomiting, and diarrhea lasting two days. Chest radiograph revealed a left bronchopneumonia. Metabolic work-up demonstrated phosphaturia, glucosuria, calciuria, proteinuria, profound hypophosphatemia, hypouricemia, borderline hypomagnesemia, and normoglycemia. Creatine phosphokinase values were elevated, a finding consistent with rhabdomyolysis. Serum pH was normal and urine pH was 5. Serum urea and creatinine levels were normal. The child was treated with ceftriaxone and azithromycin. Oral phosphate was administered, followed by a rapid normalization of its serum level. Re-evaluation one and three months after discharge, while being off any therapy, showed the resolution of all metabolic abnormalities. We believe that the metabolic disturbances in this child were due to an acute and transient tubular dysfunction, possibly secondary to inflammatory/infectious induced tubulointerstitial nephritis (TIN). TIN presenting with an isolated tubular functional impairment, in the absence of any evidence of functional glomerular impairment, does not appear to have been described before.