Bilateral tuberculous psoas abscesses in an immunocompetent patient: a case report and review of the literature

Abstract

Psoas abscess is a rare infection historically associated with tuberculosis (TB), although non-tuberculous bacterial causes, particularly Staphylococcus aureus, have become increasingly common. This type of abscess can be either primary or secondary, and its diagnosis remains challenging due to the non-specific nature of clinical signs. Imaging and microbiological analyses are essential for establishing the diagnosis. We report the case of a 22-year-old patient with no significant medical history, who presented with persistent mechanical low back pain for 18 months. Initial computed tomography revealed a non-compressive disc protrusion, leading to treatment with non-steroidal anti-inflammatory drugs, without improvement. Further investigations revealed an extrapulmonary spinal localization of TB in an immunocompetent patient, with bilateral psoas abscesses caused by Mycobacterium tuberculosis, confirmed by the Ziehl-Neelsen staining, auramine staining, culture on Löwenstein-Jensen medium and GeneXpert PCR. Anti-TB treatment was initiated, resulting in favourable clinical evolution.

Keywords: immunocompetent; psoas abscess; tuberculosis.

Fig. 1.. Lumbar CT scan in parenchymal window in axial section showing a harmonious global disc protrusion at the L1–L2, L3–L4 and L4–L5 levels, non-conflicting.

Fig. 2.. Evidence of infectious spondylodiscitis suggestive of tuberculosis, with an L1–L2 discal abscess extending into adjacent foraminal and paravertebral spaces and infiltrating the right and left psoas muscles.

Fig. 3.. Presence of AFB from the M. tuberculosis complex in the Ziehl–Neelsen staining.