A case of limbic encephalitis associated with asymptomatic COVID-19 infection

Since the emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), millions have been diagnosed with COVID-19. The major clinical manifestations of SARS-CoV-2 infection are pulmonary, however reports of COVID-19-associated central nervous system complications emerged.1 2 We report a case of encephalitis in a pulmonologically asymptomatic patient with COVID-19. A 66-year-old female presented in mid-March 2020, with a few hours history of confusion. She was completely well until the day of admission. There was no medical, infectious or behavioural prodrome. There was no alcohol or nutritional history. She had travelled to Spain, the USA and Mexico in the 3 months prior, but had been home for 19 days. She suddenly complained that her head ‘felt funny’. She carried on normal tasks but, within an hour, became confused, amnestic and was unaware of why social distancing measures were being observed. On admission, her temperature was 37.9°C. Other observations were normal. She was lymphopaenic at 0.4×109/L (0.8–3.1). Full blood count was otherwise normal. C-reactive protein (CRP) was 14.5 mg/L (0–5). Routine blood tests, including renal function, liver function and clotting, were normal. A brain CT was unremarkable. Six hours after admission, she had a single, spontaneously resolving, generalised tonic-clonic seizure. Her postictal Glasgow Coma Scale (GCS) was 6/15 (E1/V1/M4). This remained unchanged for 48 hours. Postictal neurological examination showed equal, reactive pupils, no response to visual menace, no vestibulo-ocular reflex, normal tone bilaterally, symmetrical brisk reflexes and extensor plantars. She remained febrile (37.9°C) for 48 hours. Oxygen saturation dropped to 93% on air only once during her 4-week admission. She never developed breathlessness, cough or tachypnoea. An MRI of the brain on day 2 showed non-enhancing, symmetrical T2 and FLAIR …