By: Derville O'Shea, Brian Sweeney, Alex Dudley, Niamh Bermingham, Simon Cronin, Noel Fanning
A 19-year-old woman had a 1-week history of gradual onset headache, vomiting, double vision and unsteadiness. She had been previously well. She had no sick contacts and her last foreign travel had been to Nepal over 5 years before. She was febrile at 38.4°C but systemic examination was otherwise normal. She had an ataxic gait, left sixth and seventh cranial nerve palsies, brisk lower limb reflexes and right ankle clonus.Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis with 24 cells/µL (≤5), protein was raised to 1.01 g/L (0.15–0.45) and glucose was 3.0 mmol/L (plasma 5.1). Viral and bacterial tests, including TB stains and culture, were negative. There were no oligoclonal bands. Routine bloods, inflammatory markers, infective serology, vasculitis screen and serum angiotensin-converting enzyme (ACE) were normal.MR scan of brain showed extensive leptomeningeal enhancement; as well as patchy white matter signal abnormality and curvilinear enhancement mainly affecting the pons and cerebellum but also in the right frontal lobe (figure 1). MR scan of spine showed a short segment of right-sided T2 high signal and patchy enhancement in the thoracic cord.Figure 1 MR scan of brain at initial presentation showing (A) punctate FLAIR hyperintensities in the pons and cerebellum arrows , (B, C) axial and coronal post-contrast T1 with small (<3 mm) punctate and curvilinear pontine enhancements and diffuse leptomeningeal enhancement along the cerebellar folia arrowheads and (D) right frontal parenchymal FLAIR hyperintensity.The radiological differential diagnoses included acute demyelinating encephalomyelitis (ADEM) and sarcoidosis. However, the posterior fossa abnormalities resembled chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS). Given the subacute onset over days and fever, we first considered an infective rhombencephalitis, including bacterial causes such as tuberculosis, listeria and Lyme disease and viral causes such as herpes simplex virus 1 and 2, SARS-CoV2, Epstein-Barr virus and cytomegalovirus. Other differentials included sarcoidosis, Bickerstaff’s encephalitis, …
