Anti-N-Methyl-D-Aspartate Receptor Encephalitis Complicated by Autoimmune Enteropathy and Pulmonary Embolism: A Rare Case

Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is an autoimmune disorder affecting the N-methyl-D-aspartate receptors in the central and peripheral nervous systems. Gastrointestinal (GI) complications are rarely manifested in this disease. Autoimmune dysregulation of the GI tract is considered a potential cause. We present a challenging case of a 38-year-old male with a history of newly diagnosed epilepsy. He was admitted for three weeks of confusion, hallucinations, and bizarre behavior, and was later diagnosed with anti-NMDA encephalitis from a cerebrospinal fluid (CSF) immunological study. He was treated with a five days course of intravenous immunoglobulin (IVIG) and high-dose steroids. His course was further complicated with GI obstruction and upper GI bleed. His laboratory workup showed lactic acidosis and there was a concern for ischemic bowel injury. Computed tomography (CT) of the abdomen with contrast showed diffuse moderate to pronounced dilated small intestine swirling the mesenteric vessels, concerning for intestinal vascular compromise. The patient also became tachypneic and hypoxic, requiring 6 L of oxygen with a venti-mask. CT of the chest, abdomen, and pelvis with contrast revealed saddle pulmonary embolism (PE) extending to the right and left pulmonary arteries with right heart strain. He underwent emergent explorative laparotomy and emergent catheter-directed thrombectomy. Neither necrotic bowel nor any evidence of perforation or volvulus was noted during the laparotomy; however, the small bowel and the colon were reported to be significantly dilated, hyperemic, and engorged with blood without any evidence of ischemic bowel. He had a complicated 29-day admission course and recovered functional capacity to be safely discharged to a skilled nursing facility for further care. Physicians should keep in mind the gut-brain axis and autonomic effects on gut receptors of any patient presenting with psychosis and seizure disorder to provide timely care and improve morbidity and mortality in this patient population.