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Lumbar Epidural Abscess

What is a Lumbar Epidural Abscess?

An epidural abscess is a collection of fluid which contains bacteria. This bacterial epidural abscess is located outside of the lining of the spinal cord (dura). As the abscess enlarges and swells, it can potentially place pressure on the spinal cord, cauda equina or spinal nerves, depending on its location.

What causes a Lumbar Epidural Abscess?

An epidural abscess can happen due for the following reasons:

  1. Following a spine surgery where bacteria entered the spine.
  2. Depressed immune system, such as HIV disease, patients on chemotherapy, etc.
  3. Diabetes Mellitus, especially when poorly controlled.
  4. Presence of a bacterial infection such as a Urinary Tract Infection or Lung Infection.
  5. Spread from another spine abscess
  6. Spread from an infection in spinal bones (vertebral osteomyelitis)
  7. No reason at all. Some patients get an epidural abscess without any apparent risk factors

What are the symptoms of a Lumbar Epidural Abscess?

The following are possible symptoms of an epidural abscess in the spine:

  1. Feeling ill with fevers, chills, sweats, fatigue, nausea, lack of appetite
  2. Unusual sensations in the legs
  3. Weakness in the legs
  4. Difficulty with gait
  5. Pain in the spine at the level of the epidural abscess
  6. Headaches
  7. Severe low-back pain and muscle spasms
  8. Inability to control bowel or bladder function

How do Spine Specialists make the diagnoses of a Lumbar Epidural Abscess?

Spine specialists use the information from the patient history, examination and special spine tests to make the diagnosis of an epidural abscess.

  1. History

A patient with a recent history of fevers, chills, sweats and severe low-back pain causing numbness and weakness in the legs may have an epidural abscess which is compressing the spinal cord, cauda equina or spinal nerves.

      2. Examination

Here are some examination techniques the doctor may be performing:

  1. Palpation (touch and pressure) over the spine
  2. Sensation testing (sensory) of the legs
  3. Strength testing (motor) of the legs
  4. Reflex testing of the legs
  5. Kernig’s Sign
  6. Ankle Clonus Test
  7. Babinski’s Sign
  8. Valsalva test

      3. Imaging

The diagnosis is often made with the help of imaging studies and laboratory tests:

A. X-Rays

X-Rays are generally not useful when looking for an epidural abscess.

B. MRI scans

MRI scans can show an epidural abscess quite clearly and are the test of choice. The size of the abscess and its potential to cause compression of the spinal cord, cauda equina or spinal nerves can be seen. Often intravenous contrast dye is given to be able to visualize the abscess better.

C. CT Scans

CT scans can show some epidural abscesses but MRI is typically preferred.

D. Laboratory Studies

Typically blood cells are evaluated for the presence of infection with a:

  1. Complete blood count with differential (CBC)

A Complete Blood Count (CBC) counts the cells in the blood stream. When an infection is present, the number of White Blood Cells (WBC) will increase as they try to fight the infection. Some specific types of WBC’s can also be specifically elevated (Neutrophils) making an infection even more likely.

      2. C-Reactive Protein Count (CRP)

The CRP count is a measure of an inflammatory protein which increases when a severe inflammation or infection is present.

      3. Erythrocyte Sedimentation Rate (ESR)

The ESR is another measure which increases with a severe inflammation or infection.

How is a Lumbar Epidural Abscess treated?

The treatment of an epidural abscess must occur quickly after recognizing the diagnosis. The main fear is that the abscess gets larger and begins to compress the spinal cord or cauda equina if not treated. There are two main treatments:

  1. Intravenous Antibiotics

Antibiotics given intravenously are typically given first. The most common bacteria causing an epidural abscess are called “Staphylococcus Aureus”. Sometimes antibiotics alone can cure an epidural abscess.

      2. Surgical Care

An epidural abscess which is either causing compression of the spinal cord, cauda equina or spinal nerves, or one which does not respond to antibiotics is often treated with surgery. Typically the spine is opened and the infection washed out and removed. This is called a Lumbar Laminectomy Decompression.