A Probable Case of Postpartum Sacroiliac Joint Tuberculosis: The Diagnostic Value of Imaging in a High-Endemic Setting.

Tuberculous sacroiliitis is a rare form of osteoarticular tuberculosis and is particularly uncommon in the postpartum period. Its presentation is often nonspecific and can mimic more common postpartum musculoskeletal or infectious conditions, leading to delayed diagnosis, especially in high tuberculosis-endemic regions. We report the case of a 24-year-old woman presenting 10 days postpartum with severe, debilitating right-sided lower back pain and markedly elevated inflammatory markers. Initial evaluation revealed retained products of conception (RPOC), which were managed surgically and with broad-spectrum antibiotics, resulting in biochemical improvement but no clinical relief. A comprehensive rheumatologic work-up was negative. Magnetic resonance imaging of the sacroiliac joint demonstrated unilateral joint effusion, bone marrow edema, joint space widening, and adjacent soft tissue inflammation, features highly suggestive of infectious sacroiliitis. In the context of a tuberculosis-endemic setting, lack of response to conventional antibiotics, negative blood cultures, and characteristic MRI findings, a diagnosis of presumed tuberculous sacroiliitis was made. The patient was started on empirical anti-tuberculous therapy with a standard four-drug regimen, followed by continuation therapy. She showed marked clinical improvement with resolution of pain and restoration of mobility. Follow-up MRI at 7 months demonstrated significant regression of inflammatory changes, confirming an excellent treatment response and no evidence of ongoing infection. This case highlights the importance of maintaining a high index of suspicion for tuberculous sacroiliitis in postpartum women from tuberculosis-endemic regions presenting with severe, refractory lower back pain. Early MRI plays a pivotal role in diagnosis when routine investigations are inconclusive. Prompt initiation of empirical anti-tuberculous therapy, even in the absence of microbiological confirmation, can lead to excellent outcomes and prevent long-term joint damage.