From the Guidelines
The best screening test for an epidural abscess is magnetic resonance imaging (MRI) with gadolinium contrast, which is also considered the gold standard for diagnosis. This recommendation is based on the highest quality and most recent evidence available, specifically from the study published in the Journal of the American College of Radiology in 2021 1. MRI provides excellent visualization of the spinal cord, epidural space, and surrounding tissues, with a sensitivity of 96% and a specificity of 94% for the evaluation of patients with suspected spine infection 1. The gadolinium enhancement helps distinguish abscesses from other pathologies by highlighting areas of inflammation and infection.
Key Points:
- MRI with gadolinium contrast is the preferred imaging modality for diagnosing epidural abscesses due to its high sensitivity and specificity.
- The use of IV contrast in MRI helps to identify abnormal epidural fluid collections, define their size and extent, and determine the presence of spinal cord and/or cauda equina compression 1.
- When MRI is unavailable or contraindicated, computed tomography (CT) with contrast can serve as an alternative, though it is less sensitive, with a sensitivity of 79% and a specificity of 100% for spine infection, but low sensitivity (6%) for the identification of epidural abscess 1.
- Blood tests, including complete blood count, C-reactive protein, and erythrocyte sedimentation rate, should be obtained to assess for systemic inflammation, and blood cultures should be collected before antibiotic administration to identify the causative organism.
Diagnostic Approach:
The diagnostic approach for an epidural abscess should prioritize MRI with gadolinium contrast as the initial imaging modality. If MRI is not available or contraindicated, CT with contrast may be used as an alternative. Blood tests and blood cultures should be obtained to support the diagnosis and guide treatment. Early diagnosis is critical to prevent irreversible neurological damage, including paralysis, which can result from untreated epidural abscesses.
From the Research
Screening Test for Epidural Abscess
- The best screening test for an epidural abscess is not explicitly stated, but laboratory findings such as systemic leukocytosis and elevated inflammatory markers, including an elevated erythrocyte sedimentation rate (ESR), can aid in the diagnosis 2.
- A detailed history-taking to identify risk factors, such as intravenous drug use, alcohol abuse, diabetes, and immunocompromising conditions, can also help in recognizing spinal epidural abscesses 2.
Gold Standard for Diagnosing Epidural Abscess
- The gold standard for diagnosing an epidural abscess is Magnetic Resonance Imaging (MRI) with gadolinium contrast 2, 3.
- Computed Tomography (CT) with myelography can be considered if MRI is contraindicated 2.
- Unenhanced MRI can also be useful, with paraspinal edema being a highly sensitive feature of lumbar spinal epidural abscess 4.
Key Features of Epidural Abscess
- Classic symptoms include fever, back pain, and neurological changes, although these symptoms may not always be present 2.
- Laboratory findings, such as leukocytosis and elevated ESR, can aid in the diagnosis 2.
- Imaging features, such as paraspinal edema and abnormal disk signal, can also be suggestive of epidural abscess 4.
Importance of Prompt Diagnosis and Treatment
- Prompt diagnosis and treatment of epidural abscess are crucial to prevent devastating neurological sequelae and improve patient outcomes 2, 3, 5, 6.
- Early surgical drainage and appropriate antibiotics may yield a favorable outcome 3.
- Long-term antibiotic therapy is also essential postoperatively 5, 6.