Persistent acidosis at presentation in a patient with type 1 diabetes: Concomitant diagnosis of type 1 distal renal tubular acidosis

We present a rare case of a 7-year-old boy who was diagnosed with type 1 diabetes mellitus and type 1 distal renal tubular acidosis concomitantly. The proband presented with history of polyuria, polydipsia and lethargy. He was found to be severely dehydrated. Initial pH value was 7.025 with bicarbonate level of 5.3 mmol/L, and serum glucose of 23 mmol/L. Despite adequate rehydration and insulin therapy (0.1 U/kg/hr), he continued to have persistent metabolic acidosis with normal bicarbonate. Other causes for acidosis were thought off, and with further inquiry, the parents revealed that the father and two other siblings are treated for renal tubular acidosis. Our patient had urine pH of 8, serum potassium 2.9 - 3.7 (3.5 - 5.4 mmol/L), chloride 110 - 116 (98 - 110 mmol/L). The diagnosis of type 1 renal tubular acidosis was made, and the acidosis was corrected with oral sodium bicarbonate and potassium chloride. The patient was discharged on subcutaneous multiple daily insulin injections.