Limbic encephalitis: Clinical spectrum and long-term outcome from a developing country perspective

INTRODUCTION: Limbic encephalitis (LE) is characterized by rapidly progressive short-term memory loss, psychiatric symptoms and seizures. We describe the clinical spectrum, underlying etiology and long-term follow-up of patients with LE from India. MATERIALS AND METHODS: This prospective study included patients during the period of January 2009 and December 2011 with the clinical features consistent with LE with one or more of the following: (1) Magnetic resonance imaging (MRI) evidence of temporal lobe involvement; (2) cerebrospinal fluid inflammatory abnormalities, or (3) detection of antineuronal antibodies. Patients with metastasis, infection, metabolic and nutritional deficits, stroke, were excluded. RESULTS: There were 16 patients (9 females), mean age of presentation was 36.6 years (range 15-69 years). The mean duration of symptoms before presentation was 11 months (range 5 days-2 years). The most common symptom at presentation was short-term memory impairment in 7 patients followed by seizures in 5 and behavioral changes in three. Nine patients had seizures, 11 had change in behavior, language involvement in eight, cerebellar features in 3 and autonomic dysfunction in two. Four patients had associated malignancy, 3 of four presented with neurological symptoms and on investigations found to be have malignancy. Antineuronal antibody testing was done in 6 of 12 non paraneoplastic and two paraneoplastic patients, one positive for N-methyl-D-aspartate and one for anti-Hu antibody. MRI brain showed typical fluid attenuated inversion recovery or T2 bilateral temporal lobe hyperintensities in 50% of patients. At a mean follow-up of 21 months (3-36 months), 10 patients improved, 4 patients remained same and two patients expired. CONCLUSION: Early recognition of LE is important based upon clinical, MRI data in the absence of antineuronal surface antibody screen in developing nations. Early institution of immunotherapy will help in improvement in outcome of these patients in long-term.