Hidden Fire: Recurrent Neuropsychiatric Manifestations in a Patient with Voltage Gated Potassium Channel Autoimmune Encephalitis
Recently, voltage gated potassium channel (VGKC) antibodies have been increasingly recognized as an underlying aetiology of cases of autoimmune encephalitis, with diverse clinical presentations that are usually responsive to immunosuppresive therapy.
Antibodies against VGKC and its bound protein complexes, including Lgi1 and Caspr2 have been shown to have varied clinical presentations, including psychosis, dementia, memory impairment, multimodal hallucinations, seizures, extrapyramidal features and autonomic dysfunction. It has been recognized that symptomatic profile depends on the antibody profile (Lgi1+, Caspr2+ or VKGC+ with Lg1-/Caspr2-).
Such presenting symptoms might triage patients into the wrong department and delay treatment, which is detrimental since patient’s with VGKC encephalitis are unlikely to improve spontaneously nor when optimal treatment such as steroids, plasma exchange (PLEX) or intravenous immunoglobulin (IVIG) is withheld.
Here we present the case of a 16-year-old, previously healthy male that presented with disorganized thinking, persecutory/grandiose delusions and auditory hallucinations. Workup was originally negative, but with his atypical presentation and elevated leukocytes in his cerebrospinal fluid, a diagnosis of autoimmune encephalitis was entertained.
Once infectious aetiology was ruled out, patient was started on IVIG therapy with subsequent symptom resolution. VGKC antibody was eventually found to be positive. While chronic immunosuppressive therapy was considered, patient presented with 2 subsequent similar episodes that were equally responsive to IVIG.
Our case calls for a higher index of suspicion of VGKC encephalitis in working up patients with psychiatric symptoms and atypical presentations since patients otherwise managed with anti-psychotics only will have recurrence of symptoms and ultimately might require re-hospitalizations.