Crystal clear

Extravertebral low back pain: a scoping review

BACKGROUND

Low back pain (LBP) is one of the most common reasons for consultation in general practice. Currently, LBP is categorised into specific and non-specific causes. However, extravertebral causes, such as abdominal aortic aneurysm or pancreatitis, are not being considered.

METHODS

A systematic literature search was performed across MEDLINE, Embase, and the Cochrane library, complemented by a handsearch. Studies conducted between 1 January 2001 and 31 December 2020, where LBP was the main symptom, were included.

RESULTS

The literature search identified 6040 studies, from which duplicates were removed, leaving 4105 studies for title and abstract screening. Subsequently, 265 publications were selected for inclusion, with an additional 197 publications identified through the handsearch. The majority of the studies were case reports and case series, predominantly originating from specialised care settings. A clear distinction between vertebral or rare causes of LBP was not always possible. A range of diseases were identified as potential extravertebral causes of LBP, encompassing gynaecological, urological, vascular, systemic, and gastrointestinal diseases. Notably, guidelines exhibited inconsistencies in addressing extravertebral causes.

DISCUSSION

Prior to this review, there has been no systematic investigation into extravertebral causes of LBP. Although these causes are rare, the absence of robust and reliable epidemiological data hinders a comprehensive understanding, as well as the lack of standardised protocols, which contributes to a lack of accurate description of indicative symptoms. While there are certain disease-specific characteristics, such as non-mechanical or cyclical LBP, and atypical accompanying symptoms like fever, abdominal pain, or leg swelling, that may suggest extravertebral causes, it is important to recognise that these features are not universally present in every patient.

CONCLUSION

The differential diagnosis of extravertebral LBP is extensive with relatively low prevalence rates dependent on the clinical setting. Clinicians should maintain a high index of suspicion for extravertebral aetiologies, especially in patients presenting with atypical accompanying symptoms.

Gout in the Spine: Imaging, Diagnosis, and Outcomes

Gout is characterized by the deposition of monosodium urate crystals and by acute and chronic inflammation in response to crystals so deposited. Multiple case reports and series describe the deposition of monosodium urate in the spine as a rare manifestation of gout, but the actual prevalence of spinal involvement is unknown and likely to be higher than generally anticipated. Here we review the characteristics of 131 previously reported cases of spinal involvement in gout. We focus in particular on the use of imaging modalities and the extent to which they correlate with presenting symptoms and tissue diagnoses. The recent innovation of using dual-energy computerized tomography to identify urate crystal deposition holds promise for reducing the need for surgical intervention and for establishing a true prevalence rate for spinal gout.

Spinal gout mimicking paraspinal abscess: A case report

Gout is usually thought of as a peripheral joint disease. However, case reports are available describing gouty lesions in the spine. We report a case of a 51 year old African American woman with no previous history of gout who presented with lower back pain and fever and was found to have multiple small fluid collections in the paraspinal muscles at the L3 to L5 levels on the MRI. She was empirically treated with antibiotics, since the fluid was not accessible for drainage initially. Unsuccessful antibiotic therapy and an episode of peripheral gout during this hospitalization prompted the diagnosis of axial gout as the cause for the paraspinal lesions in this patient. CT guided aspiration of the paraspinal lesions confirmed monosodium urate (gout) crystals under polarized microscopy.