Simultaneous double hemodialysis for the control of refractory hyperammonemia

In adults, hyperammonemia is generally associated with hepatic dysfunction or as a complication of urinary diversions when infected or obstructed. Hyperammonemia has also rarely been reported in association with multiple myeloma. With modest elevations, hyperammonemia often leads to encephalopathy. However, when ammonia reaches extreme levels cerebral edema and herniation may occur leading to coma, seizures, or death.

We describe a 72-year-old Caucasian male with a history of end-stage renal disease (ESRD) and multiple myeloma who developed profound encephalopathy and eventual obtundation. He was found to have severe hyperammonemia that was not due to any identified hepatic impairment. His hyperammonemia proved to be refractory to medical therapy with cathartics and antibiotics, prolonged high-flux hemodialysis, and even continuous venovenous hemodialysis (CVVHD). This metabolic derangement as well as encephalopathy was eventually reversed with simultaneous CVVHD and extended daily hemodialysis (EDD). A more durable response was achieved after vincristine and dexamethasone were administered, which allowed the patient to resume his previous intermittent hemodialysis (IHD) schedule. The patient regained his full sensorium and was eventually discharged to home.

Simultaneous double hemodialysis may be used as an important adjunct in treating refractory hyperammonemia.