ESPE Abstracts

From time to time pediatric endocrinologists may be confronted with paradoxical constellations. Here, we report on a 13-year-old boy with type-1 diabetes. He had polyuria and polydipsia for the previous 2 weeks. Three days before presentation, he got increasingly exhausted and developed recurrent vomiting. At presentation his weight was 41,4 kg (P 25-50) and his height was 154 cm (P 25-50). Initial labs were HbA1c 10.2%, glucose 530 mg/dl, pH 7.15, base excess - 21.1 mmol/l, bicarbonate 9.8 mmol/l, Na 131 mmol/l, K 2.4 mmol/l. Type-1 diabetes was diagnosed and the boy treated with i.v. insulin, fluid and electrolyte substitution. However, despite a high potassium substitution of up to 6 mmol/kg body weight/24h, therapy-resistant hypokalemia with hypokalemic metabolic alkalosis persisted after regression of ketoacidosis: pH 7.48, base excess 10.8 mmol/l, bicarbonate 33.7 mmol/l, Na 136 mmol/l, K 2.7 mmol/l. Further lab diagnostics showed a plasma renin of >300ng/l and a serum aldosterone of 141.1 ng/dl. The constellation of therapy-resistant hypokalemic alkalosis and secondary hyperaldosteronism with normal blood pressures made us think of the additional presence of Bartter’s syndrome. Bartter’s syndrome is a clinically and genetically heterogeneous renal salt loss disorder with hypokalemic metabolic alkalosis and secondary hyperaldosteronism. Bartter`s syndrome type 3 is caused by pathogenic changes in the CLCNKB gene and is inherited as an autosomal recessive trait. Analysis by next generation sequencing showed a complete deletion of the CLCNKB gene in the homozygous state, which was confirmed by multiplex ligation-dependent probe amplification analysis. To the best of our knowledge, we describe the first case of persisting hypokalaemia and alkalosis after regression of diabetic ketoacidosis due to a previously undiagnosed Bartter`s syndrome. During the course of long-term therapy with spironolactone and potassium substitution, the potassium levels normalized.