Unremitting diarrhoea in a girl diagnosed anti-N-methyl-D-aspartate-receptor encephalitis: A case report

BACKGROUND: Asymptomatic cytomegalovirus (CMV) infection is common in children; in contrast, in children with a weakened immune system, invasive CMV can occur. This is the first case report of a severe manifestation of CMV esophago-enterocolitis in a girl diagnosed with anti-N-methyl-D-aspartate-receptor (anti-NMDAR) encephalitis who received only a moderate dose of corticosteroid therapy. CASE SUMMARY: A 12-year-old-Thai girl presented with acute behavioural change and headache for 6 d. Electroencephalogram and positivity for NMDAR autoantibodies were compatible with anti-NMDAR encephalitis. Hence, she received pulse methylprednisolone 10 mg/kg per day for 4 d and continued with prednisolone 1.2 mg/kg per day. On day 42 of corticosteroid therapy, she developed unremitting vomiting and diarrhoea. Endoscopy showed multiple ulcers and erythaematous mucosa along the gastrointestinal tract. Tissue CMV viral load and viral-infected cells confirmed CMV esophago-enterocolitis. Therefore, the patient received ganciclovir 5 mg/kg per dose every 12 h for 3 wk and then 5 mg/kg per dose once daily for 3 wk. Unremitting diarrhoea slowly improved from stool output 1-4 L per day to 1-2 L per day after 3 wk of treatment. Pulse methylprednisolone 20 mg/kg for 5 d was initiated and continued with prednisolone 1 mg/kg per day. After this repeated pulse methylprednisolone treatment, surprisingly, diarrhoea subsided. Immunologic work-up was performed to rule out underlying immune deficiency with unremarkable results. CONCLUSION: Unremitting diarrhoea from CMV esophago-enterocolitis subsided with antiviral and methylprednisolone therapy, implying the immune and NMDAR dysregulation in anti-NMDAR encephalitis.