Objective:To determine risk factors associated with clinical relapses and development of chronic epilepsy in patients with anti-leucine-rich glioma-inactivated 1 (LGI1) IgG encephalitis.Methods:Patients with seizures related to LGI1-antibody encephalitis with ≥ 24 months of follow-up from disease onset were identified in the Mayo Clinic electronic medical record and Neuroimmunology lab records. Charts were reviewed to determine clinical factors, seizure types, imaging, treatment, occurrence of relapse, and outcome. Binary logistic regression analysis was performed to identify predictors of the development of chronic epilepsy. Univariate Cox proportional hazards regression was used to examine the influence of baseline characteristics on relapse risk.Results:Forty-nine patients with LGI1-antibody encephalitis and acute symptomatic seizures were identified. Almost all patients (n=48, 98%) were treated with immunotherapy. Eight had definite, and two had possible chronic epilepsy at last follow-up (10/49, 20.4%). Female sex (P=0.048) and younger age at disease onset (P=0.02) were associated with development of chronic epilepsy. Relapses occurred in 20 (40.8%), with a median time to first relapse of 7.5 months (range 3-94 months). Initial treatment with chronic steroid sparing immunotherapy was associated with reduced risk of relapse (hazards ratio=0.28, 95% CI 0.11-0.73, P=0.009).Conclusions:Chronic epilepsy occurred in 20.4% of our patients with LGI1-antibody encephalitis despite aggressive immunotherapy. Risk factors for chronic epilepsy were female sex and earlier age of onset. Relapses occurred in 40.8% of patients with prolonged follow-up, and chronic steroid sparing immunotherapy was associated with a lower relapse rate.

Digital subtraction myelography is a valuable diagnostic technique to detect the exact location of CSF leaks in the spine to facilitate appropriate diagnosis and treatment of spontaneous spinal CSF leaks. Digital subtraction myelography is an excellent diagnostic tool for assessment of various types of CSF leaks, and lateral decubitus digital subtraction myelography is increasingly being used to diagnose CSF-venous fistulas. Lateral decubitus digital subtraction myelography differs from typical CT and fluoroscopy-guided myelograms in many ways, including equipment, supplies, and injection and image-acquisition techniques. Operators should be familiar with techniques, common pitfalls, and artifacts to improve diagnostic yield and prevent nondiagnostic examinations.

In contrast to previously reported cases, our study demonstrates that BHAG can be associated with MRI signal abnormalities of the herniated and adjacent brain. Symptoms are typically absent, though may be present in a small subset of patients, regardless of the presence of signal change or encephalomalacia of the involved brain. Indirect evidence of intracranial hypertension is present in a majority of patients but completely lacking in others.

Although autoimmune epilepsy (AE) is a relatively new concept in the radiology literature, evidence for immunological mechanisms in epilepsy has increased in the last several years. 1-9 AE was originally described in the context of more generalized autoimmune encephalopathy, predominately as a paraneoplastic phenomenon targeting the limbic system. Certain tumors expressing neuronal proteins were found to provoke a cell-mediated neurological disorder as a byproduct of an attack on cancer cells. The classically described paraneoplastic limbic encephalitis (LE) reflects involvement of limbic structures including the anteromedial temporal lobe, hippocampus and amygdala and is clinically characterized by the subacute onset of temporal lobe seizures, anterograde memory impairment and psychiatric symptoms. Similar to other paraneoplastic syndromes, neurologic symptoms can present well before a cancer is detectable. Antibodies traditionally considered paraneoplastic include anti-Hu (ANNA-1) and anti CRMP-5 antibodies, usually found in conjunction with small cell lung carcinoma (SCLC), and anti-N-methyl-Daspartate (NMDA) receptor antibodies which are often associated with ovarian teratoma.

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