Hyperammonemic coma in a post-partum patient with undiagnosed urea cycle defect
A 33-year-old primigravida, four days post-cesarean section, was referred to us with 2 days history of altered sensorium progressing to coma. A pre-admission MRI brain with cerebral venography was unremarkable. The peripartum period was uneventful. She had past history of self-limiting episodes (3 in the last 5 years) of altered behavior and confusional state. In the intensive care unit (ICU), she was found to be in grade IV encephalopathy (Glagow Coma Scale (E1V1M2), pupils were bilateral mid dilated and reactive to light. Bilateral plantars were extensor, and deep tendon reflexes were absent. Neck rigidity was absent, and there was generalized hypotonia. She was hemodynamically stable. The trachea was intubated for airway protection. Her blood investigations showed a serum ammonia 286 mmol/L and serum urea of 13 mg/dL. Arterial blood gases showed well compensated respiratory alkalosis. Rest of the investigations including liver function tests and blood glucose levels were normal.\nPlasma amino acid levels and urine orotic acid levels were sent. A protein-free nasogastric feed was started. Anti-ammonia measures were instituted in the form of lactulose (30 ml q4h) and tablet rifaximine (300 mg twice-daily) through nasogastric tube.\nThe next day, ammonia levels rose to 300 mmol/L, despite passage of good amount of loose stools. Decision of instituting hemodialysis was taken. On day 3, we received the report of amino acid levels with citrulline levels of 933 (normal <70) micromol/L, glycine 970 (normal <505) micromol/L and phenyalanine 181 (normal <120) micromol/L. Urinary orotic acid – result value 31.20, reference range in % 0.30, elevation factor 104.00. Ammonia levels after a second cycle of hemodialysis was 160 mmol/L.Serum ammonia level showed a progressive decline [] over the next 3 days through 3 cycles of hemodialysis. She was extubated on day 5. Ammonia levels stayed below 50 mmol/L with no further dialysis required. She could be transferred out of ICU on day 7 and discharged on day 9 of hospitalization in a stable condition.