Autosomal recessive pseudohypoaldosteronism: a rare cause of life-threatening electrolyte imbalance

K Tharian; J T Warner; J Gregory

A well-term baby born to consanguineous healthy Yemenese parents was observed in the hospital as parents had lost previous three babies (both male and female) within 10 days of age (in Yemen). These babies who were initially well were reported to have developed a rash and then collapsed and died. Post-mortems were not done. This baby who appeared well at birth, also developed a facial rash on day seven and was found to have hyponatremia and severe hyperkalemia, albeit a normal hemodynamic status. Further investigations revealed normal cortisol of 322 nmol/l and 17-OH progesterone 1.3 nmol/l but markedly elevated plasma renin activity of 480 pmol/l and aldosterone of 29 000 nmol/l consistent with a diagnosis of pseudohypoaldosteronism.

The baby was aggressively treated with i.v. sodium and sodium resonium rectally resulting in improvement in electrolyte balance and facilitation of an early discharge home on very high doses of oral sodium supplements and continued sodium resonium rectally with regular monitoring of electrolytes at home. She remains well at 6 months of age with acceptable electrolytes (see Table).


Age (days)	5	7	8	9	11	16	35	93	182
Serum Na⁺ (mmol/l)	139	127	128	130	139	136	139	134	133
Serum K⁺ (mmol/l)	5.5	9.4	7.2	8.1	6.8	6.3	5.6	6.3	6.0
Oral NaCl (mmol/kg per day)		4–7	10–20	28	24	15	20	20	24

Genetics investigations have demonstrated four variants in the SCNN1 gene (coding for epithelial sodium channel) of which three are thought to be polymorphisms but one of which is likely to be functionally important. Further investigations into this are underway.

Conclusion: Our case highlights the importance of instituting early and continued use of potassium chelator (sodium resonium) along with aggressive electrolyte management in cases of pseudohypoaldosteronism.

Endocrine Abstracts

P14