Unremitting diarrhoea in a girl diagnosed anti-N-methyl-D-aspartatereceptor 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 esophagoenterocolitis in a girl diagnosed with anti-N-methyl-D-aspartate-receptor(antiNMDAR)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.