Persistent hyperkalaemia in vitamin B₁₂ unresponsive methylmalonic acidaemia

Abstract

Persistent hyperkalaemia was found in a patient with vitamin B12 unresponsive methylmalonic acidaemia associated with hyperuricaemia. At 3 years and 8 months of age, a serum potassium level of 6.8 mmol L-1 was found when blood gas measurement was normal. One year later azotaemia was noted. At the age of 5 years, renal function studies disclosed hyperaldosteronism, decreased creatinine clearance, reduction of the reabsorption of sodium at distal diluting segments and inadequate concentration of urine at the collecting ducts. The reduction of the reabsorption of sodium, which may have resulted in decreased potassium excretion, and the decrease in glomerular filtration rate, together with the superimposed excess intake of potassium, appeared to be responsible for the hyperkalaemia. Dietary potassium restriction was effective in suppressing the hyperkalaemia.

Renal Involvement in Methylmalonic Aciduria

“…Hyperkalemia is not a common feature of MMA and has been reported in case reports. 26 , 27 , 28 Among our patients, hyperkalemia was observed only during metabolic decompensation and usually corrected once the metabolic crisis had resolved.…”