ESPE Abstracts

Background: Secondary pseudohypoaldosteronism presents with hyponatremia and hyperkalemia due to a transient aldosterone resistance.

Objective and hypotheses: We recommend a check of urea and electrolytes in all infants with urinary tract infection, dehydration and failure to thrive.

Method: A 5 month old presented with a day’s history of poor feeding and two episodes of vomiting. He was afebrile with normal observations. His urine examination showed UTI and he was to be sent home on oral antibiotics. Before discharge he vomited and hence started on IV antibiotics. An incidental gas showed a sodium of 124 mEq/l and potassium of 8.6 mEq/l. ECG showed tall tented T waves. His aldosterone level was 2500 pmol/l, renin was 19 nmol/l per h, cortisol was1500 nmol/l and 17OHP was normal. His electrolytes normalised with saline, calcium and salbutamol. Investigations revealed bilateral hydronephrosis and posterior urethral valves. All electrolyte abnormalities resolved after surgery. An 8 week old presented with a 2 week history of vomiting and diarrhoea. He was clinically dehydrated with a sodium of110 mEq/l and a potassium of 8 mEq/l. Electrolytes normalised after 40 h of rehydration. He received IV antibiotics. His aldosterone was markedly raised at 47000 pmol/l (normal<850) and renin 102 nmol/l per h. His 17OHP was within the normal range and his cortisol was raised. Investigations showed UTI and bilateral hydronephrosis. His electrolyte abnormalities resolved with resolution of the infection.

Results and conclusion: In both cases secondary pseudohypoaldosteronism was discovered by chance. In the first case, the presentation was subtle and could have been missed whilst the infant was showing cardiac manifestations of hyperkalemia. We recommend that all children presenting with hyperkalemia and hyponatremia be evaluated by renal ultrasound and urine culture. Finally these are good examples that hormonal change is transient and can be corrected when the obstruction is relieved and infection is controlled.