Autoimmune encephalitis associated with anti-recoverin antibodies

Autoimmune encephalitis (AE) is a spectrum of autoimmune disorders manifesting by epilepsy, loss of consciousness, and neuropsychiatric symptoms. Anti-recoverin antibodies are intracellular antibodies and a well-known marker of paraneoplastic retinopathy. However, they have rarely been associated with neurological and psychiatric diseases with or without cancer. To date, there have been only a few identified cases of anti-recoverin antibody-associated limbic AE.

A 33-year-old North-African female with a family history of cancer and no relevant medical history presented to the neurology department of the Military Hospital of Tunis, Tunisia, with a 3-month history of temporal epilepsy, insomnia, and mild cognitive impairment. The episodes lasted 3-4 minutes. Scalp electroencephalogram showed bilateral epileptiform spikes and spike waves in the temporal regions. Brain magnetic resonance imaging showed bilateral hippocampal and thalamic hyperintense lesions on T2-weighted imaging with hypointensities in the same regions on T1-weighted imaging and no contrast enhancement. Anti-recoverin antibodies were strongly positive (3+) in blood and cerebrospinal fluid (CSF). The patient met the criteria for definite limbic AE after exclusion of alternative etiologies. The extended cancer work-up was unremarkable. The patient received 1 g daily of intravenous methylprednisolone for 5 days, along with 1000 mg/day of oral levetiracetam followed by 0.4 g/kg/day of intravenous immunoglobulin (IVIG) for 5 days. Levetiracetam was replaced by lamotrigine (100 mg/day) orally. During the 2-year follow-up, the patient's condition improved clinically and radiologically. Anti-recoverin antibody positivity persisted (1+) to date with minimal symptoms.

Our case illustrated the value of testing anti-recoverin antibodies in CSF and provides insights into management and prognosis through a longitudinal 2-year follow-up. Anti-recoverin antibody-related AE is a rare but treatable cause of adult subacute encephalopathy and epilepsy. Prompt and optimized management associating appropriate anti-epileptic drugs and immunotherapies is essential to alleviate sequelae.