SHM Converge Scientific Abstract ePoster Gallery-Breaking the Mold: When Back Pain Reveals a Tuberculous Surprise

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This case highlights an uncommon cause of low back pain: Mycobacterium avium complex (MAC) osteomyelitis. Low back pain is common, but rare causes like bone infection can be missed or misdiagnosed. Osteomyelitis is usually caused by <em>Staphylococcus aureus</em>, while MAC-related osteomyelitis is exceptionally rare and more often seen in immunocompromised patients.

The patient was a 69-year-old man with rheumatoid arthritis on methotrexate who presented with acute worsening of chronic lumbar pain. CT of the lumbar spine showed an L3 compression fracture and abnormal lucency at L2-L3, raising concern for discitis, osteomyelitis, or malignancy. MRI supported discitis/osteomyelitis of L2 and L3 and revealed two small anterior left psoas abscesses. He was initially treated with ceftriaxone and vancomycin for presumed MRSA infection.

Further evaluation was prompted by a positive PPD test before starting Remicade. Although QuantiFERON gold and blood cultures were unremarkable, surgery with laminectomy and abscess drainage was performed. Culture of the abscess grew <em>Mycobacterium intracellular</em> (a subset of acid-fast bacilli). Chest CT then revealed suspicious cavitary lesions in the left lung, and bronchoalveolar lavage from the left upper lobe was positive for AFB growth, supporting MAC infection.

Treatment was changed to clarithromycin, ethambutol, rifabutin, and amikacin, with a planned duration of approximately 1 to 18 months. The case emphasizes that rare diagnoses require broad workup and should be considered in patients with rheumatoid arthritis, immunosuppression, or a positive PPD, since delayed recognition can postpone appropriate therapy.

Asset Subtitle

Taylor Karns

Meta Tag

Author List Camila Villacreses, Khoa Tran, MMrhaf Alsamman, Michael Sabina, Taylor Karns, Zoya Khan

Category Clinical Vignettes

Concept Osteomyelitis

Concept Mycobacterium avium complex

Concept Diagnostic Workup

Concept Back Pain

Concept Immunocompromised State

Distinguished Non-Finalist

Presenter Organization Lakeland Regional Hospital

Presenting Author Taylor Karns

Track Adult

Keywords

Mycobacterium avium complex

MAC osteomyelitis

low back pain

discitis

osteomyelitis

rheumatoid arthritis

immunosuppression

psoas abscess

acid-fast bacilli

clarithromycin ethambutol rifabutin amikacin

Osteomyelitis

Mycobacterium avium complex

Diagnostic Workup

Back Pain

Immunocompromised State