Epidural abscess CT
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Epidural abscess Microchapters |
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Epidural abscess CT On the Web |
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American Roentgen Ray Society Images of Epidural abscess CT |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
An epidural abscess is a rare suppurative infection of the central nervous system, a collection of pus localised in the epidural space lying outside the dura mater, which accounts for less than 2% of focal CNS infections. [1] It may occur in two different places: intracranially or in the spinal canal. Because the initial symptoms and clinical characteristics are not always identical, and are similar to the ones in other diseases, along with the fact that they are both rare conditions, the final diagnosis might be delayed in time. This late diagnosis comes at great cost to the patient, since it is usually accompanied by a bad prognosis and severe complications with a potential fatal outcome. The diagnosis of epidural abscess should be first suspected from the clinical findings, being posteriorly supported by laboratory tests and imaging studies, however it can only be confirmed after surgical drainage and proper study of the collected material. According to the location of the collection, the abscess may have different origins, different organisms involved, symptoms, evolutions, complications and therapeutical techniques. [2][3]
CT Scan
Despite being an important and valuable imaging study and considered the imaging study of choice until very recently, the CT scan is now secondary, compared to the MRI. It's a non-invasive procedure, which allows for study of intracranial and spinal abscesses, however its sensitivity is limited by signal artifacts caused by the bone [4]
Intracranial Epidural Abscess
In this location the CT scan may be used, in case an MRI isn't available, or to perform an image study of the bone. The appearance of an epidural abscess on a CT scan is similar to crescent-shaped hypodense extraaxial lesion or a lens. [5]
Spinal Epidural Abscess
In this location the CT scan may be used if an MRI isn't available. It is helpful to produce high-resolution axial tomograms of the spine, being able to detect a possible encroachment of the spinal canal, as well as air in the pus collection. Due to its insufficient capacity to differentiate densities of soft tissues, particularly in the cervical region, it isn't always reliable to delineate the spinal cord, nor contained lesions nor the epidural space. [6] It may be used to guide percutaneous drainage, alternatively to surgical drainage. [7]
References
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Danner, R. L.; Hartman, B. J. (1987). "Update of Spinal Epidural Abscess: 35 Cases and Review of the Literature". Clinical Infectious Diseases. 9 (2): 265–274. doi:10.1093/clinids/9.2.265. ISSN 1058-4838.
- ↑ Darouiche, Rabih O. (2006). "Spinal Epidural Abscess". New England Journal of Medicine. 355 (19): 2012–2020. doi:10.1056/NEJMra055111. ISSN 0028-4793.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Grewal, S. (2006). "Epidural abscesses". British Journal of Anaesthesia. 96 (3): 292–302. doi:10.1093/bja/ael006. ISSN 0007-0912.
- ↑ Lyu RK, Chen CJ, Tang LM, Chen ST (2002). "Spinal epidural abscess successfully treated with percutaneous, computed tomography-guided, needle aspiration and parenteral antibiotic therapy: case report and review of the literature". Neurosurgery. 51 (2): 509–12, discussion 512. PMID 12182793.