A case of refractory seizure with cognitive impairment due to anti-GABA encephalitis

Abstract

A 57-year-old man presented with first episode of loss of consciousness at work in February 2014. He experienced no symptoms prior to this syncope event. He was witnessed by his colleagues to have tonic rigidity over his upper limbs, with a bite mark evident over the lateral aspect of his tongue. He had experienced a right-sided temporal headache characterised as dull and persistent for 3 weeks prior to this incident without any precipitating factors or aura identified.He enjoyed good past health and had been educated to high school level. He was currently working as an accountant. He did not smoke or drink, had no recent travel history, and was not on any long-term medication or taking herbs. He could not recall any febrile convulsion during childhood or significant family history of neurological diseases.He was fully oriented and remained afebrile on admission. Routine blood tests (electrolytes, glucose, and inflammatory markers), physical examination, and initial computed tomographic (CT) brain were unremarkable. The patient refused lumbar puncture and was discharged against medical advice.Three days after discharge, he was admitted to a private hospital with generalised tonic-clonic convulsion. Electroencephalography was normal and magnetic resonance imaging (MRI)/magnetic resonance angiography brain showed no mass lesion or infarct. He was discharged with a prescription of levetiracetam in view of the second episode of seizure.He was again admitted to us in early March 2014 with breakthrough seizure and post-ictal drowsiness, despite good drug compliance and no identifiable precipitating factors. His seizure was initially controlled with levetiracetam with the addition of phenytoin, but he remained disoriented with confused speech. His Mini-Mental State Examination (MMSE) score was 14/30: his main deficit was delayed recall with failure to perform serial sevens and to copy a polygon. He developed a low-grade fever of 37.8°C with negative septic workup. Lumbar puncture did not reveal any evidence of central nervous system infection (white cell count, <1/mm 3 , protein level not elevated, and negative culture result). Electroencephalography showed right temporal spikes only. He was prescribed empirical Augmentin (Sandoz, Australia) 1.2 g every 8 hours intravenously and his fever settled. One week after admission, he experienced multiple episodes of generalised tonic-clonic seizure without progression to status epilepticus. Doses of both phenytoin and levetiracetam were increased along with the addition of valproic acid. His seizures abated but cognition was not improved. Electroencephalography was repeated and demonstrated left temporal polyspikes over F7/T3/T5 in addition to bitemporal sharp waves (Fig 1). Brain MRI was also repeated and showed no abnormality (Fig 2). Blood tests were unremarkable with normal electrolytes, negative tumour markers (alphafetoprotein/carcinoembryonic antigen/prostatespecific antigen), negative autoimmune markers (antinuclear antibodies/rheumatoid factor), normal thyroid functio...

Autoimmune Encephalitis Associated with Anti-gamma-aminobutyric Acid B Receptor Antibodies Mimicking Syncope

“…An interesting commonality between these three cases and our pa-tient's case is that immunotherapy was initiated after nonseizure limbic symptoms emerged. In two patients, followup MRI scans revealed emergent abnormalities (5,6), but the third patient, like ours, exhibited no abnormal findings in follow-up MRI scans (7). As mentioned earlier, some case reports showed abnormalities in PET or SPECT images (7-9), but our patient exhibited no abnormalities in ASL perfusion MRI or perfusion SPECT images.…”

“…Intern Med 59: 843-847, 2020 DOI: 10.2169/internalmedicine.3652-19 In recent case series studies, approximately one third (27-44%) of patients with GABABR-AE had normal brain MRI findings, most of which were probably obtained in the disease's early phase (1-4). Interestingly, a few case studies concerning patients with GABABR-AE reported that normal MRI findings were observed in early-phase GABABR-AE but that MRI abnormalities were observed during symptom progression (5,6). This suggests that the emergence of MRI abnormalities tends to accompany clinical progression in GABABR-AE.…”