COVID-19 and herpesvirus encephalitis

The SARS-CoV-2 virus, which causes COVID-19, could give rise to damage the nervous system. Many studies have been conducted on this topic, but few have focused specifically on encephalitis. The effect of SARS-CoV-2 on the clinical expression of other neurotropic viruses, such as Herpesviridae, is unknown. We describe the cases of two young men (39 and 18 years old) in whom SARS-CoV-2 had been detected -reverse transcription polymerase chain reaction (RT-PCR)-, and with a clinical diagnosis and cerebrospinal fluid (CSF) analysis consistent with encephalitis. The first patient had a positive PCR for varicella zoster virus in CSF, while the second had a positive PCR for herpes simplex virus types 1 and 2. The first patient, who was recently diagnosed with human immunodeficiency virus, presented with fever, headache, vomiting, cough, inappropriate behaviour and epileptic seizures; the second was seen to have fever, headache, myalgia and exanthema. Both offered the same laboratory findings (lymphopenia and high interleukin 6). CSF showed pleocytosis with a predominance of monomorphonuclear cells, hyperproteinorrachia and normal glycorrhachia. A cranial CT scan showed only mild diffuse cerebral oedema in the first case. Both cases were treated with corticosteroids, antibiotics and acyclovir. The second progressed favourably, while the first did not. Little is known about co-infection of SARS-CoV-2 with neurotropic viruses, such as Herpesviridae, and we have only limited evidence of direct neurological involvement of SARS-CoV-2, due to the technical difficulty of detecting it in the nervous system, thus making it important to take co-infection into account in order to be able to establish an early diagnosis and treatment to improve prognosis.