Disseminated Macrolide-Resistant Mycobacterium intracellulare Infection in a Child with Autoimmune Lymphoproliferative Disorder: A Case Report and Literature Review.

A 4-year-old girl, previously treated with prednisolone and cyclosporin A due to autoimmune lymphoproliferative syndrome, presented with acute fever, progressive pancytopenia, intermittent abdominal pain, and acute episode of hematemesis. Esophagogastroduodenoscopy revealed diffuse erythematous gastric mucosa and blunt duodenal villi. Histopathology of the duodenal mucosa was notable for numerous acid-fast bacilli within foamy macrophages in the lamina propria, and nontuberculous Mycobacterium DNA was detected by polymerase chain reaction of duodenal tissue. Azithromycin, rifampicin, and ethambutol were started while waiting for species identification and drug susceptibility testing. Macrolide-resistant Mycobacterium intracellulare was demonstrated from blood culture, indicating disseminated infection. The patient died of overwhelming infection, despite receiving newly adjusted regimen (rifampicin, ethambutol, clofazimine, and amikacin). This case highlights the importance of considering disseminated Mycobacterium avium complex (MAC) in the differential diagnosis of immunocompromised, non-HIV patients presenting with gastrointestinal manifestations. Early identification of macrolide-resistant MAC is crucial for guiding appropriate treatment and potentially improve patient outcomes.