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We describe the use of sodium resonium in a patient with pseudohypoaldosteronism (PHA). PHA is a rare but serious abnormality characterised by raised plasma aldosterone, but mineralocorticoid resistance causing hyperkalaemia and hyponatraemia. Severe recessive type 1 PHA is due to defective epithelial amiloride sensitive sodium channels (ENaC).1
Our patient presented aged 14 days with hyponatraemia (130 mmol/l) and hyperkalaemia (9.4 mmol/l). He made no response to hydrocortisone or fludrocortisone. His plasma aldosterone level during crisis was extremely high (3820 pmol/l), confirming a diagnosis of PHA. Our patient’s sibling died neonatally with a presumptive diagnosis of PHA, suggesting autosomal recessive inheritance compatible with an ENaC defect.
Our patient was managed on intermittent rectal calcium resonium when hyperkalaemic, and daily solution G (a preparation containing high levels of sodium (1.3 mmol/ml)). The sodium requirement was 45 mmol/kg/day. Due to its unpalatability, solution G was given via gastrostomy. Despite this he had episodes of sudden collapse, precipitated by minor infections, with hyponatraemia and life threatening hyperkalaemia, including a cardiac arrest. Discharge proved impossible.
After 18 months we changed his treatment to sodium resonium 0.25 g/kg twice daily via gastrostomy on advice from Professor Dillon (Great Ormond Street Hospital). Our patient improved and the electrolytes became tightly controlled (see fig 1). Our patient was so much better that after two years inpatient stay, we managed to discharge him home on treatment. The sodium requirement is 19 mmol/kg/day, and he has had no further electrolyte decompensation.
We have treated six patients with recessive PHA in the past 10 years, previously treating them with calcium resonium rectally at times of hyperkalaemic crisis. This treatment has not controlled electrolytes, and two of our patients died. Our experience with recessive PHA is that the defect does not improve with age; one of our patients died at the age of 21 years, and the survivors remain on vast daily intakes of sodium. Sodium resonium has improved our current patient’s quality of life and allowed his discharge. Although use of sodium resonium in PHA was first described in 1984,2 it is not widespread. This case should prompt greater use of sodium resonium in PHA.
We must acknowledge the huge number of nurses and doctors that contributed to a successful outcome in this case.