Voltage‐gated potassium channel complex (VGKC) antibody encephalitis in a Filipino adult: A reversible cause of early‐onset neurocognitive disorder

• Published in: Clinical & experimental neuroimmunology 2021-02, Vol.12 (1), p.72-75
• Main Authors: Ocampo, Ferron F., Saniel, Edmundo G., Martinez, Ma. Socorro C.
• Format: Article
• Language: English
• Subjects: Antibodies; Antigens; autoimmune encephalitis; Azathioprine; Case reports; Cell surface; Central nervous system; Cerebrospinal fluid; Cognition; EEG; Encephalitis; Hyponatremia; Immunosuppressive agents; Intravenous administration; Magnetic resonance imaging; memory loss; Potassium; Potassium channels; Potassium channels (voltage-gated); Seizures; Steroid hormones; Surface antigens; VGKC antibody encephalitis
• ISSN: 1759-1961; 1759-1961
• DOI: 10.1111/cen3.12609

Background Voltage‐gated potassium channels (VGKCs) are cell‐surface proteins with several functions in the central nervous system. VGKC antibody encephalitis is caused by antibodies against the cell‐surface antigens that are part of the VGKC complex, which are highly concentrated in the limbic lobes and the hippocampus. Case Presentation We report a case of a 46‐year‐old Filipino female who presented with subacute onset of memory loss, behavioral changes, and focal motor seizures. On cranial magnetic resonance imaging, there were increased signal intensities on both medial temporal lobes but no intracranial tumor, restricted diffusion, or meningeal enhancement. Electroencephalography showed focal slowing on bilateral frontotemporal regions and blood test revealed hyponatremia. Cerebrospinal fluid analysis revealed high titers for antibodies against VGKC complex. Pulse intravenous steroid therapy was administered and oral steroids and azathioprine were continued as outpatient. The patient showed significant response with marked improvement of memory without any recurrence of seizure episodes. Conclusion This case highlights VGKC antibody encephalitis as an important diagnostic consideration in patients presenting with subacute onset of memory loss, behavioral changes, and seizures. With prompt initiation of immunosuppressive therapy, neurocognitive changes can be potentially reversed. A case of a 46‐year‐old Filipino female with subacute onset of memory loss, behavioral changes, seizures, and hyponatremia. Workup showed elevated titers of antibodies against voltage‐gated potassium channel complex. Intravenous steroid therapy was administered that reversed the neurocognitive disorders.