Merck Manual

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Epidural Abscess in the Spine


Michael Rubin

, MDCM, New York Presbyterian Hospital-Cornell Medical Center

Reviewed/Revised Feb 2023

A spinal epidural abscess is an accumulation of pus in the space between the spine and outer layer (dura mater) of tissue covering the spinal cord (epidural space). These abscesses can put pressure on (compress) the spinal cord.

  • Epidural abscesses are often caused by bacteria from another infection in the body.

  • They may cause back pain, which may become severe, and weakness or partial paralysis of the legs, loss of bladder and bowel control, fever, and other serious symptoms.

  • Doctors use magnetic resonance imaging (MRI) to diagnose an epidural abscess in the spinal cord or, if MRI, is unavailable, myelography followed by computed tomography.

  • Doctors treat abscesses with antibiotics, and if the abscess is causing serious problems, they drain it immediately.

The bacteria that usually cause these abscesses are Staphylococcus aureus (60%), Escherichia coli or other gram-negative bacteria (15%), or streptococci (10%). Occasionally, the abscess is caused by tuberculosis that affects the spine (Pott disease) or injection drug use. In about one third of people, the cause cannot be determined.

Symptoms of Spinal Epidural Abscess

Symptoms of a spinal epidural abscess begin with back pain. The back over the abscess is tender to the touch. Pain may become severe and is worsened by lying down. Fever is common.

Diagnosis of Spinal Epidural Abscess

  • Magnetic resonance imaging (MRI)

Doctors may suspect a spinal epidural abscess if people have significant, unexplained back pain, particularly when the spine is tender to the touch or when they have a fever or have had a recent infection or dental procedure.

Spinal epidural abscess is diagnosed using MRI. If MRI is not available, myelography Myelography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more Myelography followed by computed tomography (CT) may be used. Samples of blood and, when possible, samples from the infected areas are taken and sent to a laboratory to be grown (cultured) so that the bacteria causing the abscess can be identified. Examination of the blood sample often detects evidence suggesting infection, such as an elevated white blood cell count.

Treatment of Spinal Epidural Abscess

  • Antibiotics

  • If abscesses compress the spinal cord, immediate drainage

Rapid treatment of epidural abscesses is necessary to prevent or minimize problems.

Antibiotics may be sufficient. But if abscesses compress the spinal cord, causing weakness or paralysis in the legs, incontinence, or other serious problems, they are surgically drained immediately. A sample of pus from the abscess is sent to a laboratory to be analyzed and cultured to help identify the bacteria causing the abscess.

Antibiotics to treat the bacteria that are usually involved are given without waiting for test results. They are changed as needed when results of testing are available.

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