Encephalitis associated with Covid-19 and thunderclap headache: an unusual relationship

Abstract

The Covid-19 is characterized by respiratory symptoms, however this virus frequently damages the nervous system, although the exact mechanism involved is still unclear. Headache is the most common neurological symptom and has a great heterogeneity, including thunderclap headache which should be considered a red flag on emergency departments.
Case report: female, 51 years-old, with thunderclap headache started seven days ago that evolved to mental confusion, inattention and language plus memory disturbance at the day of admission.  General physical examination was normal except by the presence of borderline pyrexia (37.7°C). Neurological examination showed no particularities, except for mental and cognitive alterations. Computed angiotomography of the brain excluded bleeding but showed one aneurysm. Cerebrospinal fluid (CSF) had no xanthochromia, but evidenced a lymphomonocytic pleocytosis with discrete hyperproteinorraquia. Due to hospital protocol the patient underwent computed tomography of thorax and we found ground-glass opacities suggesting viral infection. Then, RT-PCR for SARS-CoV-2 with nasopharyngeal swab and in CSF was performed with both positives. Therefore the diagnosis was encephalitis associated with COVID-19. We opted for supportive care only. Patient evolved with many complications, need of ventilatory support and renal replacement therapy, but she was discharged after 35 days with no symptoms and at follow-up, two months later, the only finding was mild inattention.
Discussion: when faced with a case with thunderclap headache, especially with other neurological findings, the first step is excluded subarachnoid hemorrhage, but health professionals should keep in mind the differential diagnoses, mainly infectious and highly contagious diseases such as COVID-19.