A common low back pain hiding tuberculous sacro-iliitis
Key Clinical Message: An early diagnosis of tuberculous sacro-iliitis requires a high index of clinical suspicion.
Isolated tuberculosis of the sacrum is rarely reported in the literature [1]. It usually presents as vague back pain [1]. We report the case of a 61-year-old healthy female with a history of low back pain lasting for 2 years with no radicular irradiation. Her pain increased while efforts and decreased at rest with no night awakeness and no relief under paracetamol. She did not report constitutional symptoms. A plain radiograph of the pelvis showed widening of the left sacroiliac joint space with erosions of the subchondral bone (figure1). Magnetic resonance imaging confirmed the left sacro-iliitis and showed a collection in the left sacro-iliac joint and in the left iliopsoas muscle with an extension to the sacral spinal canal (figure 2 and 3). A fistula was born from an opening inside the sacral spinal canal, along the first sacral nerve root, to an outside opening in the left gluteal area, resulting in an abscess measuring 3.8 x 14.4cm. Considering these aspects, the most likely diagnosis was tuberculous sacro-iliitis. Percutaneous drainage of the abscess was performed. Smears of the aspirated material did not reveal acid fast bacilli, the culture on Lowenstein–Jensen medium was negative but PCR performed on the specimen was positive for Mycobacterium tuberculosis.
Acknowledgements: None.
Conflict of interest: None.
Draft manuscript prepared by Ben Ayed H and Miladi S. Improvements to draft made by the other co-authors.