Fanconi Syndrome in Severe Burns: A Case Report

Introduction: Fanconi's syndrome is a disorder of generalised proximal tubular dysfunction. It may be inherited or acquired due to drugs, heavy metals, dysproteinaemia, or autoimmune disease (Sjogren’s syndrome). We report a rare case of Fanconi's syndrome due to severe burns. Case Description: A 30-year-old man was admitted for 70% body surface area burns, requiring multiple escharotomies, debridements, and skin grafts. Initial renal function was normal. He developed oliguric acute kidney injury requiring continuous kidney replacement therapy from days +4 to +7 after admission. Kidney function recovered thereafter. 3 weeks post-burn, he developed persistent hypokalemia, hypophosphatemia, hypomagnesemia, and metabolic acidosis. Urinary studies found inappropriate urinary losses of potassium, elevated fractional excretion of phosphate and magnesium, a positive urine anion gap, glycosuria, and tubular proteinuria consistent with Fanconi’s syndrome (Table 1). Extensive investigations were performed to exclude other causes of Fanconi’s syndrome. Serum protein electrophoresis, vitamin D, and computed tomography of the abdomen was normal. No causative drugs, heavy metal exposure, family history, or autoimmune disease was identified. Over the next 2 months, he persistently required high-dose electrolyte replacements. Amiloride was added with reduction of electrolyte requirements, but its dose was limited by hypotension. Electrolyte replacements were weaned as he recovered and skin re-epithelized. He was discharged after a 7 month stay with normal electrolytes and no replacements. Discussion: While many mechanisms may cause electrolyte imbalances in burns victims, Fanconi’s syndrome is rarely reported. We are only aware of one case series (Lindquist 1987, AJKD). This patient has proximal tubular dysfunction without other secondary causes, which resolved as his burns recovered. Physicians should consider Fanconi’s syndrome should a burns victim manifest persistent electrolyte dysfunction requiring high-dose replacement.Table 1