Epidural AbscessThe spinal cord and the roots of nerves that lead from the spinal cord are covered in a membrane called the dura. Epidural abscesses are infections that form in the space around the dura. These may press on the spinal cord or nerve roots so much that mental skills, the ability to feel sensations (such as heat and cold or pain) and the ability to move in a coordinated way are affected.
- A "pins and needles" feeling
- Back pain and tenderness when touched
- Weakness in a cauda equina, paraplegic (two limb) or quadriplegic (four limb) pattern
- Weakness that gets worse over a period of hours or days before suddenly worsening to the point of paralysis in two limbs (an arm and a leg) or all four (both arms and both legs)
- Motor control symptoms that vary depending on the location of the abscess
Causes and Risk Factors
Usually the patient has an infection that has spread to the spinal area, but about a third of the cases develop without any known cause. These types of infections are usually caused by Staphylococcus aureus, followed by Escherichia coli and mixed anaerobes. Rarely, a tuberculous abscess develops with Pott's disease of the thoracic spine.
As with all infections, the white blood cell count may be higher than normal, indicating the presence of an infection. A magnetic resonance image (MRI) is performed to find the location of the abscess and where the pressure on the spinal cord is building up. Contrast dye may be injected into the space around the dura to help locate the abscess, but care must be taken to be sure that the injection does not disturb the abscess and cause it to spread.
If the symptoms become severe, surgery is necessary to drain the abscess and relieve the pressure on the spinal cord. The fluid drained from the spinal cord can be used to identify the cause of the infection. Antibiotics may be effective, but if the patient is experiencing a loss of functioning (such as problems moving, paralysis, numbness or a loss of the ability to feel sensations), surgery is essential to prevent permanent damage.