Renal tubular dysfunction and lactic acidosis: Questions

Excerpt

A 10-year-old girl presented with a 3-week history of lethargy and weight loss with associated polyuria and polydypsia. There was no significant past medical or family history. On examination she was appropriately grown for age, with no organomegaly or lymphadenopathy, but was noted to be peripherally mottled. Serum electrolyte and venous blood gas levels indicated marked metabolic acidosis (pH 7.29, bicarbonate 12 mmol/L) and hypokalaemia (potassium 1.8 mmol/L). Lactic acid was also elevated (6.4 mmol/L; normal <2 mmol/L). Urinary potassium was 9.9 mmol/L and urinary pH was 6.0 on admission. Calcium, magnesium and phosphate levels were within normal limits, and the results of a full blood examination were normal. …