Encephalitis associated with anti-mGluR5 antibodies.

A 30-year-old woman had 5 days of visual hallucinations, nystagmus, memory impairment and mutism. On examination, she was disorientated with reduced attention span, gaze-evoked nystagmus, paratonia and abnormal frontal reflexes. Cerebrospinal fluid (CSF) showed 80 cells, protein 0.41 g/L and glucose 3.2 mmol/L (plasma glucose 5.0 mmol/L). MR scan of the brain showed involvement of limbic and extra-limbic regions and brainstem. Commercial cell-based assays were negative, but tissue-based assays showed neuropil staining, and cell-based assays for anti-metabotropic glutamate receptor 5 (mGluR5) antibodies were positive in serum and CSF. Six months later, she was diagnosed with Hodgkin's lymphoma. This case emphasises the broader clinical spectrum of anti-mGluR5 encephalitis, challenging its initial characterisation as Ophelia syndrome. It underscores the significance of interpreting commercial cell-based assays and advocates for tissue-based assay testing followed by cell-based assay testing in serum and CSF for diagnosing rare autoimmune encephalitis.

Neurocysticercosis: diagnosis via metagenomic next-generation sequencing.

A 68-year-old Brazilian woman had 3 months of progressive fatigue, difficulty walking and 18 kg weight loss. On examination, there was gait apraxia and executive dysfunction. MR scan of brain showed communicating hydrocephalus and a cerebrospinal fluid showed 105 white cells/µL (≤5), predominantly lymphocytes, protein of 1.35 g/L (0.15-0.45) and the glucose content of 0.06 mmol/L (3.3-4.4). We suspected an infective cause and used of metagenomic next-generation sequencing to diagnose neurocysticercosis. This case highlights the challenge of diagnosing chronic meningitis and the relevance of genetic approaches in diagnosing neurological infections.