Post infectious encephalitis at Covid19: About one pediatric observation and review of the literature.

We report the case of a 7-years-old female living in Senegal who never traveled and has no particular personal or family medical history, with a good psychomotor development. In late March, she complained about having a cough, headaches and fever and was diagnosed Covid19 through the use of an RT-PCR for SARS-CoV-2 using a nasopharyngeal swab. On day 6 during her hospitalization, she presented 4 episodes of generalized tonic-clonic seizures per day lasting about 1 minute. Her blood test showed a CRP at 12 mg/L. The lumbar puncture showed a clear cerebral spinal fluid with a sterile culture, normal glycorachia and a slight hyperproteinorachia at 0.76 g/L. The study of SARS-CoV-2 in CSF has not been conducted. She was treated with injectable diazepam then with sodium valproate which partially reduced the seizures. The brain MRI was normal. After 11 days of hospitalization and two negative RT-PCR tests for SARS-CoV-2, at 48-hour intervals, the patient was declared cured. Three days post-recovery, she was admitted in neurology for a gait and behavior disorder, a neurological examination found a confusional syndrome and osteotendinous hyperreflex. The electroencephalogram showed an overall slowing of the pattern with the presence of diffuse pseudoperiodic complexes predominating in fronto-temporal area (see Fig. 1 ). Carbamazepine was added to sodium valproate, which led to a significant decrease in seizures: one seizure per month and the behavioral and walking disorders disappeared over the follow-up period of 2 months.

Fig. 1

Overall slowing of the pattern with the presence of diffuse pseudoperiodic complexes predominating in fronto temporal.

A recent study claims that SARS-CoV and SARS-CoV-2 have similar genomic sequences especially at the binding receptors level. This can lead to SARS-CoV and SARS-CoV-2 sharing the ACE2 receptor, which could explain why SARS-CoV and SARS-CoV-2 are able to invade the same locus in the human brain [1]. Our literature search identified 9 cases of encephalitis worldwide [2], [3], [4], [5], [6], [7], [8], [9]. The average age found is 45.2 years with extremes ranging at 11 and 72 years and with a female predominance (sex ratio: 3/1). Our patient is the second from a pediatric population. Clinically 4/9 patients had generalized clinical tonic seizures while the rest was characterized with the disturbance of consciousness associated with stiff neck or behavioral disorders, one patient had cerebellar syndrome and diffuse myoclonus [9]. Although the subject presented several episodes of generalized tonic clinical seizures and behavioral disturbances. The electroencephalogram performed in 4/9 patients showed either irregular wave peaks superimposed on a slowed theta background or generalized slowing patterns or frontal intermittent delta activity. Our patient's pattern showed an overall slowing with the presence of diffuse pseudoperiodic complexes predominating in fronto-temporal area. Of the 9 patients reported as having encephalitis, CSF pleocytosis was reported in 5/9 cases, elevated CSF protein in 4/9 cases, at an average of 0.86 g/L. The CSF RT-PCR test was run on 6/9 cases and came back positive in 2/6 cases. Regarding the subject, the CSF was clear and presented a slight hyperproteinorrachia at 0.76 g/L; the CSF RT-PCR was not tested. Although the definitive diagnosis of viral encephalitis largely depends on virus isolation, this is difficult for COVID-19 because SARS-CoV-2 dissemination is transient and its CSF titer may be extremely low. The cerebral MRI of the subject was normal as well as 8/9 of the reported encephalitis cases. 1/7 case presented a hyper signal in the right temporal lobe [7]. However, Grimaldi et al., are the first to use Brain 18F-FDG-PET that showed diffuse cortical hypometabolism, associated with putaminal and cerebellum hypermetabolism, compatible with encephalitis. They advice that the mismatch between the abnormalities found on brain PET and the normality of MRI also highlights the potential of PET as an early biomarker [9]. Seizures were treated in all patients with diazepam or clonazepam injection in combination with sodium valproate. The outcome was favorable in 8/9 patients. The subject was put on valproate followed by carbamazepine and the frequency of her seizures worsened considerably, yet the behavioral and walking disorders disappeared.

Disclosure of interest

The authors declare that they have no competing interest.