Anti-Kelch-like protein 11 antibody encephalitis presenting with progressive cognitive deficits in an older woman: a case report and literature review.

backgroundAnti-Kelch-like protein 11 (KLHL11) antibody encephalitis is very rare,with a much lower incidence in female patients,and has not been reported to cause progressive cognitive impairment.We report a case of a 65-year-old woman who presented with progressive cognitive impairment. CASE PRESENTATION: A 65-year-old woman presented with progressive cognitive impairment and pathological hypersomnia (>15 hours/day) for six months.On admission, neurological examination revealed severe cognitive impairment (MMSE 8/30; MoCA 9/30).The contrast-enhanced brain MRI scan showed a subcortical patchy intensifying lesion in her left frontal lobe,and the cell-based assay (CBA) showed positive anti-KLHL11 antibodies in both her serum (1:320)and CSF(1:32). This patient was diagnosed with anti-Kelch-like protein 11 (KLHL11) antibody encephalitis and received intravenous methylprednisolone at a daily dose of 1 g for 5 days with slight symptomatic relief.The patient was discharged without receiving further treatment. At the 13-month follow-up after discharge, she was still alive but slept for more than 20 hours a day and did not recognise anyone.We also conducted a literature review of reported female patients with positive anti-KLHL11 antibodies to summarize the characteristics of the disease and improve clinicians' understanding of this illness in female patients.

conclusionThis case broadens the clinical and radiological spectrum of anti-KLHL11 encephalitis in women. The literature review revealed that female patients may present with more diverse symptoms. Clinicians should remain alert to this diagnosis in female patients, particularly when opsoclonus-myoclonus is presented, and should concurrently assess for underlying ovarian teratomas or malignancy.