Anti-N-methyl-d-aspartate receptor encephalitis and positive human herpesvirus-7 deoxyribonucleic acid in cerebrospinal fluid: a case report

BACKGROUND: Anti-N-methyl-d-aspartate receptor encephalitis is a neuroautoimmune syndrome typically presenting with seizures, psychiatric symptoms, and autonomic dysfunction. Human herpesvirus-7 is often found with human herpesvirus-6 and infects leukocytes such as T-cells, monocytes–macrophages, epithelial cells, and central nervous system cells. The pathogenicity of human herpesvirus-7 is unclear. Cases of anti-N-methyl-d-aspartate receptor encephalitis with human herpesvirus-7 present in cerebrospinal fluid have been documented, but the clinical significance of this finding remains unclear. CASE PRESENTATION: An 11-year-old Caucasian boy was admitted to hospital after a generalized tonic–clonic seizure. Generalized tonic seizures repeated three more times during the day of hospitalization. Blood tests showed minor ongoing inflammation, while brain computed tomography yielded normal results. Brain magnetic resonance imaging showed hyperintense focal alterations in both temporal lobes, hippocampi, and at the base of the right frontal lobe. Positive anti-N-methyl-d-aspartate receptor antibodies were found in both serum and cerebrospinal fluid. Positive novel coronavirus 2 (severe acute respiratory syndrome coronavirus 2) immunoglobulin G antibodies were found in serum. Polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2 was negative. Furthermore, positive human herpesvirus-7 deoxyribonucleic acid was found in cerebrospinal fluid. The patient was treated with acyclovir, human immunoglobulin, and methylprednisolone. The seizures did not repeat, and no psychiatric symptoms were present. The patient made a full recovery. CONCLUSIONS: We present a pediatric case of anti-N-methyl-d-aspartate receptor encephalitis with atypical clinical presentation. The role of human herpesvirus-7 in neurological disorders remains unclear in immunocompetent patients.