Objective:

To describe a patient with intermittent confusion and refractory subclinical seizures diagnosed with anti-leucine-rich-glioma-inactivated 1 (LGI-1) encephalitis. 

Background:

LGI-1 encephalitis is a rare autoimmune encephalitis characterized by behavioral disturbances and confusion associated with brief faciobrachial dystonic seizures with poor response to multiple antiseizure medications (ASMs). The mainstay of treatment includes prompt initiation of glucocorticoids or Intravenous Immunoglobulin (IVIG) prior to confirmatory serum and cerebrospinal fluid (CSF) antibody testing. Most patients show significant clinical improvement with steroids or IVIG, but cognitive deficits may persist with possibility of relapse. Severe hyponatremia, a common medical complication, can be life-threatening.

Design/Methods:

Case report and literature review. 

Results:

A 67-year-old hypertensive male with right frontal meningioma and newly diagnosed epilepsy on Levetiracetam presented with several weeks of intermittent confusion and cognitive difficulties. He was found to have multiple focal seizures during an outpatient electroencephalography (EEG) and was admitted to hospital, he was afebrile with no history of recent travel, normal metabolic panel except for mild hyponatremia (133 mmol/L). Long-term monitoring (LTM) demonstrated persistent nonconvulsive status epilepticus with over 100 subclinical seizures with bitemporal sharp waves, that was refractory to several ASMs during hospital stay. Initial CSF studies were negative for infectious processes. A brain MRI showed bitemporal FLAIR hyperintensities raising concern for an autoimmune etiology. Patient showed clinical improvement with IV methylprednisolone. His hospital course was complicated by transient hyperammonemia and persistent hyponatremia. Serum and CSF autoimmune panel came back positive for LGI-1 antibodies. Given good clinical response to steroids, IVIG was deferred, and patient was discharged on a prednisone taper. 

Conclusions:

It is critical to consider possible autoimmune encephalitis in patients with subacute onset of memory deficits, unexplained seizures, CSF pleocytosis or MRI features suggestive of encephalitis and reasonable exclusion of alternative etiologies. Prompt empiric treatment based on clinical features can improve outcomes and prevent serious sequala.