Fulminant thymomatous AMPAR-antibody limbic encephalitis with hypertonic coma, bruxism, an isoelectric electroencephalogram and temporal cortical atrophy, with recovery

Anti-Alpha-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid Receptor Encephalitis: A Review

Anti-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis, a rare subtype of autoimmune encephalitis, was first reported by Lai et al. The AMPAR antibodies target against extracellular epitopes of the GluA1 or GluA2 subunits of the receptor. AMPARs are expressed throughout the central nervous system, especially in the hippocampus and other limbic regions. Anti-AMPAR encephalitis was more common in middle-aged women and most patients had an acute or subacute onset. Limbic encephalitis, a classic syndrome of anti-AMPAR encephalitis, was clinically characterized by a subacute disturbance of short-term memory loss, confusion, abnormal behavior and seizure. Magnetic resonance imaging often showed T2/fluid-attenuated inversion-recovery hyperintensities in the bilateral medial temporal lobe. For suspected patients, paired serum and cerebrospinal fluid (CSF) testing with cell-based assay were recommended. CSF specimen was preferred given its higher sensitivity. Most patients with anti-AMPAR encephalitis were complicated with tumors, such as thymoma, small cell lung cancer, breast cancer, and ovarian cancer. First-line treatments included high-dose steroids, intravenous immunoglobulin and plasma exchange. Second-line treatments, including rituximab and cyclophosphamide, can be initiated in patients who were non-reactive to first-line treatment. Most patients with anti-AMPAR encephalitis showed a partial neurologic response to immunotherapy.

Bruxism in Acute Neurologic Illness

PURPOSE OF REVIEW

While traditionally encountered in ambulatory settings, bruxism occurs in patients with a variety of acute neurologic illnesses including encephalitis, intracerebral hemorrhage, traumatic brain injury, hypoxic-ischemic encephalopathy, and acute ischemic stroke. Untreated bruxism in acute neurologic illness can lead to tooth loss, difficulty in mouth care resulting in recurrent aspiration pneumonia, endotracheal tube dislodgement, and even tongue laceration or amputation. Inpatient clinicians should be aware of the etiologies and management strategies for bruxism secondary to acute neurologic illness.

RECENT FINDINGS

Management strategies for bruxism are varied and include pharmacologic and non-pharmacologic therapies in addition to onabotulinumtoxinA (BoNT-A). Bruxism impacts patients with a variety of acute neurologic illnesses, and emerging evidence suggests successful and safe treatment strategies.

A case of anti-VGKC antibody encephalitis and prolonged encephalopathy despite spontaneous resolution of imaging abnormalities

Anti-voltage-gated potassium channel (anti-VGKC) antibody encephalitis is a common form of autoimmune encephalitis (AE). AE is usually associated with autoimmune diseases or paraneoplastic phenomena such as seen in small cell lung cancer. Clinical presentation can include memory impairment, seizures, and psychiatric symptoms. We report a case of a 72-year-old male with non-small lung cancer in remission who presented with erosive gastritis and acute severe encephalopathy. Anti-VGKC antibody limbic encephalitis was diagnosed. Spontaneous resolution of encephalitis-associated changes on brain Magnetic Resonance (MR) with concomitant decreased circulating antibody levels were observed despite lack of overall cognitive improvement.

Abbreviations

AE: autoimmune encephalitis; AMPAR: antibody limbic encephalitis - anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor encephalitis; Anti-VGKC encephalitis: anti-Voltage-gated potassium channel antibody encephalitis; CRP: c-reactive protein; CT: computed tomography; EEG: electroencephalography; ESR: erythrocyte sedimentation rate; GCS: Glasgow Coma Scale; MRImaging: Magnetic resonance imaging; NMDA-R encephalitis: Anti-N-methyl D-aspartate receptor encephalitis; PCR: polymerase chain reaction.