Lower-dose intravenous immunoglobulin therapy for geriatric inflammatory bowel disease accompanied by COVID-19 multisystem inflammatory syndrome: A case report.

RATIONALE: This article presents a complex case of refractory severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related inflammatory bowel disease (IBD) and outlines its diagnostic and therapeutic challenges. Considering inadequate responses to conventional and steroid treatments, the potential efficacy of intravenous immunoglobulin is explored.

PATIENT CONCERNS: The patient, an elderly individual, experienced short-term fever and sore throat after encountering the coronavirus disease 2019 pandemic. Despite receiving a 3-dose inactivated SARS-CoV-2 vaccine, the patient tested positive for the viral antigen and developed worsening symptoms, including diarrhea and recurrent fever. Initial antibiotic treatment for bacterial enteritis proved ineffective.

DIAGNOSES: Further evaluation, including endoscopy and pathology, confirmed the diagnosis of IBD with concurrent multisystem inflammatory syndrome (MIS) in adults, as evidenced by tachycardia and elevated inflammatory markers.

INTERVENTIONS: Following unsuccessful treatment with mesalazine, probiotics, corticosteroids, and supportive care, the patient underwent lower-dose intravenous immunoglobulin therapy.

OUTCOMES: The patient experienced symptom improvement, with resolution of fever, diarrhea, and inflammation. At the 30-day follow-up, the patient remained afebrile, without diarrhea, and exhibited favorable mental status.

LESSONS: Elderly individuals infected with SARS-CoV-2 may develop severe systemic inflammatory responses. The patients in this report predominantly presented with IBD following SARS-CoV-2 infection, accompanied by MIS. Favorable clinical outcomes were achieved following lower-dose intravenous immunoglobulin immunotherapy, which demonstrated superior efficacy compared to glucocorticoids in managing such conditions. Future research should prioritize investigating immunotherapy application strategies in IBD and MIS. Notably, the significant clinical improvement observed with lower-dose intravenous immunoglobulin administration could optimize the utilization of this limited medical resource.