Type 4 Renal Tubular Acidosis (Sub-type 2) Associated with Idiopathic Interistitial Nephritis

ABSTRACT. An 18-month-old girl presenting with anorexia and failure to thrive, was referred for adenoidectomy. Arterial hypertension was discovered on physical examination. Laboratory results revealed hyperkalaemic, hyperchloraemic, metabolic acidosis, with slight azotemia. Urinary aldosterone excretion and plasma renin were decreased. Renal biopsy showed idiopathic interstitial nephritis. The diagnosis of type 4 renal tubular acidosis, sub-type 2, i.e. primary hyporeninaemic secondary hypoaldosteronism was proposed. According to our knowledge, this disease has not previously been reported in young children, but is well known in azotaemic adults. We therefore propose the inclusion of this uncommon renal disease in the differential diagnosis of failure to thrive in childhood.     

Adrenocortical insufficiency with normal serum cortisol levels and hyporeninaemia in a patient with acquired immunodeficiency syndrome (AIDS).

The acquired immunodeficiency syndrome (AIDS) has been associated with abnormalities of adrenocortical function, and hypoaldosteronism due to hyporeninaemic hypoaldosteronism (HHA). We here report the case of a woman with AIDS associated with orthostatic hypotension, persistent hyponatraemia and hyperkalaemia, in whom basal serum cortisol levels were normal and serum renin activity was low. Subsequent post-mortem examination revealed almost complete adrenocortical destruction. A possible explanation of this apparently contradictory combination of findings is discussed, together with the therapeutic implications for similar cases.