Invasive Pneumococcal Disease Presenting with Abdominal Pain, Vomiting and Diarrhoea in A Patient with Multiple Myeloma.

Background: Case report: We report a 40-year-old woman with smouldering IgG lambda multiple myeloma presenting with abdominal pain, diarrhoea, vomiting, and hypotension. Laboratory tests revealed macrocytic anaemia, leukopenia with absolute neutropenia, acute kidney injury, elevated inflammatory markers, and compensated metabolic acidosis. A computed tomography (CT) scan of the abdomen and pelvis showed partially loculated ascites, peritoneal fat stranding, and thickening of duodenum, descending, and sigmoid colon walls. Blood cultures were positive for Conclusion: This case highlights a rare and severe gastrointestinal manifestation of invasive pneumococcal disease in a high-risk host. Spontaneous pneumococcal peritonitis complicated by multiple intra-abdominal abscesses is exceptionally uncommon in multiple myeloma. Early recognition, multidisciplinary management, and minimally invasive source control were crucial to a favourable outcome. Preventive strategies, particularly pneumococcal vaccination, remain essential to reduce morbidity in immunocompromised patients. LEARNING POINTS: Atypical invasive pneumococcal disease involving the peritoneum and gastrointestinal tract is rare in adults, but immunocompromised patients, such as those with multiple myeloma, are at increased risk of morbidity and mortality.Timely, targeted antibiotic therapy combined with effective source control through image-guided drainage of intra-abdominal abscesses is crucial for recovery and minimizes the need for surgery.Prompt recognition, integrated multidisciplinary management, and vaccination are essential to improve outcomes and prevent recurrence in vulnerable patients.