A Typical Neurological Presentations in the ICU: Limbic Encephalitis

Common neurological emergencies include overdose or withdrawal from illegal substance abuse, adverse effects of prescription medications, seizures, metabolic encephalopathy, infections and cerebrovascular accidents. Following a thorough clinical and radiologic assessment, a small group of patients escape definitive diagnosis and autoimmune encephalitides should be considered. Of these, limbic encephalitis (LE) is the most common and may result from paraneoplastic or nonparaneoplastic sources. Common to both is the production of antibodies targeting epitopes in the brain parenchyma thought to be responsible for the clinical manifestations. Paraneoplastic Anti-N-methyl D-aspartate receptor (NMDAR) encephalitis is a common cause of LE and has gained awareness in neurological and psychiatric literature. Paraneoplastic and nonparaneoplastic anti NMDAR encephalitis typically presents in young, previously healthy females with subacute onset of psychiatric symptoms, respiratory insufficiency, orofacial dyskinesias, autonomic instability and seizures. Paraneoplastic LE is induced by antibody production against NMDAR with occult ovarian teratoma being the most common inciting tumor. LE has also been described in association with other tumors and also without tumors. The latter are known as nonparaneoplastic or primary autoimmune disease. Diagnosis requires both clinical suspicion along with prompt serum and cerebrospinal fluid analysis for antibody detection. Immunotherapy to remove and suppress these antibodies along with resection of an identified tumor is the therapy of choice. This article will review the clinical presentation and management of LE in patients who present to the medical intensive care unit.