Primary hyperaldosteronism with normokalaemia secondary to an adrenal adenoma (Conn's syndrome) in a 12 year-old boy.

A 12-1/2 year-old boy presented to the Accident Department following an episode of dizziness and was found to be hypertensive. Investigations revealed primary hyperaldosteronism secondary to an adrenal adenoma (Conn's syndrome). He had normal electrolytes during the period of investigation and potassium concentrations were > or = 4.2 mmol/l on all but one occasion. The hypertension resolved following excision of the adrenal tumour. Normokalaemia with potassium >4.0 mmol/l is very unusual in patients with Conn's syndrome and has not been described in childhood before. Primary hyperaldosteronism needs to be considered in hypertensive children even when potassium concentrations are well within the laboratory reference range.