(775) Double Jeopardy: Cerebral Edema in a Pregnant Patient With Acetaminophen Overdose

Introduction: Acetaminophen (APAP) toxicity is a common cause of acute liver failure (ALF). An unusual complication of APAP toxicity is cerebral edema. Pregnant patients with APAP ALF may have a higher risk of cerebral edema.

Description: A 23-year-old female at 17 weeks gestation presented with altered mental status. Per family she had been taking multiple daily doses of APAP for abdominal pain for several weeks. There were no other prescription or non-prescription drug used. Initial evaluation was notable for somnolence yet she was able to respond to voice. She could not maintain attention. Heart rate was 110 bpm, blood pressure 129/93 mmHg, and respirations normal. Fetal heart tones were normal. Laboratory work up was notable for AST and ALT of 1068 and 880 units/liter, respectively, total bilirubin of 3.4 mg/dL, serum creatinine of 1.7 mg/dL, INR of 1.7, and an APAP level of 118 ug/mL (unknown last dose). She was admitted for management of ALF due to APAP toxicity and started on IV N-acetylcysteine (NAC) therapy.

Over the next 48 hours her liver enzymes gradually improved. Her APAP level decreased, during which she remained on NAC. Despite improvement in metabolic parameters her encephalopathy persisted. Head CT showed cerebral edema. MRI confirmed cerebral swelling with no vascular thrombosis. EEG was notable for generalized slowing. She was treated supportively and with NAC, with mental status slowly improving in the subsequent days. Repeat MRI three days later showed resolution of cerebral edema.

Discussion: ALF is a syndrome characterized by new onset encephalopathy and coagulopathy. APAP toxicity is a major cause of ALF; with most patients recovering with early NAC treatment. Encephalopathy with APAP induced ALF is caused by cerebral edema, particularly in patients who have more severe ALF. Management strategies include monitoring and treating elevated intracranial pressures such as elevating head of the bed, sedation, and hyperosmolar therapy. While our patient did not have severe ALF, pregnancy results in physiologic changes in cerebral vascular permeability as seen in disorders such as eclampsia. Cerebral edema may occur with milder degrees of APAP toxicity in pregnancy.