Patients with autoimmune encephalitis (AE) frequently develop life-threatening illnesses and often require intensive care unit (ICU) admission—which typically portends a poor prognosis. We report the clinical characteristics, complications, and outcomes of patients with AE admitted to the neurologic ICU.

We performed a retrospective cohort study using both an institutional database analysis and provider referrals to identify all patients with AE treated at a single-tertiary center between 2005 and 2017 in the neurologic ICU.

Thirty-one patients with AE were identified, 52% (16/31) of whom developed critical illness requiring admission to the ICU. Of those, 10 patients were female, 6 were male, average 39 years of age. Criteria for admission was status epilepticus (75%), respiratory failure (18.75%), and encephalopathy (6.25%). The average length of stay was 22 days (range 2-92) and 62.5% required between 2 and 149 days of mechanical ventilation. Of the ICU-managed AE patients, average time from symptoms to diagnosis was 243 days, compared to 160 days in those not requiring ICU admission. 62.5% of patients developed pneumonia, 43% developed urinary-tract infections (UTI), and 31.25% developed venous thromboembolism (VTE).  Of the AE patients admitted to the ICU, 81.25% of patients developed a reaction to antiepileptic drugs (AEDs), including rash, liver failure, ileus and hyperammonemia. Upon ICU discharge, 62.5% of patients required prolonged mechanical ventilation and 68% required nutritional support. Mortality was 6.25% after one year.

Patients requiring neurologic ICU care were primarily admitted for status epilepticus followed by respiratory failure and encephalopathy. There was significant heterogeneity in the intensive-care length of stay and ventilatory requirements. Complication rates of pneumonia, UTIs, and VTEs require further investigation and comparison to other critically-ill patients. Most importantly, the large number of patients with an adverse reaction to AEDs deserves further attention, as many adverse effects appeared to be immunologically-mediated on review.