Tuberculous spondylitis with bilateral psoas abscesses presenting with renal colic

Clinical History

The patient was admitted with symptoms of left sided renal colic and haematuria. A routine unenhanced helical CT abdomen was performed which yielded an unsuspecting find.

Imaging Findings

The patient presented with symptoms of renal colic on the left side. This was accompanied by microscopic haematuria. No other physical findings were present. A routine unenhanced helical CT abdomen was performed as per departmental protocol. The CT revealed a 2mm calculus at the left vesicouereteric junction, with mild hydroureter above this and very mild left sided hydronephrosis. No renal calculi was identified on the right side. Of greater importance however was the presence of bilateral psoas abscesses which originated from an infective discitis / vertebral body osteomyelitis centered on the L2/3 disc and involving the inferior portion of L2 and most of the L3 vertebral body. The L3 vertebral body was comminuted with posterior displacement towards the spinal canal. A subsequent spinal MRI revealed diffuse high signal of the L2 and L3 vertebrae on STIR imaging with expansion and some enroachment into the spinal canal. The bilateral psoas abscesses were drained and microbiological specimens confirmed the presence of tuberculosis.

Discussion

Tuberculous spondylitis also known by its eponymous name, Pott disease, is destruction of the vertebral body and intervertebral disk by mycobacterium tuberculosis. The clinical onset is insidious and it presents as back pain, stiffness and local tenderness, fever and malaise. The commonest site of involvement appears to be the thoracic and lumbar vertebrae with a predilection for the anterior part adjacent to the superior and inferior endplates. Since the anterior parts of the vertebrae are most affected, a gibbus deformity will appear. The bony destruction of the vertebral body tends to be of the fragmentary type followed by lytic destruction. Other manifestations include paraspinal masses, epidural abscesses, psoas abscesses and collapse of the intervertebral disk spaces. The abscesses may track widely and become calcified which differentiates it from a non-tuberculous which rarely clacifies. Differentiating between tuberculous and pyogenic infections is difficult with both sharing many similar imaging characteristics. However, tuberculous infections may be suggested by the presence of associated lesions elsewhere in other organs e.g lung, urinary tract, tendency of tuberculosis to be multifocal in the spine and tendency to result in a gibbus deformity. Recent MRI work suggest that tuberculous infections cause a local and heterogeneous enhancement of the vertebral body compared with diffuse and homogeneous enhancement in pyogenic spondylitis. Treatment of the psoas collections would involve a combination of medical therapy and drainage of the abscess. As demonstrated in this case, percutaneous drainage represents an efficient and attractive alternative to surgical drainage as a supplement to medical therapy in the management of patients with large tuberculous psoas abscesses.

Differential Diagnosis List

Final Diagnosis

Tuberculous spondylitis with psoas abscesses.

URL:	https://www.eurorad.org/case/5650
DOI:	10.1594/EURORAD/CASE.5650
ISSN:	1563-4086