Lumbar Puncture

Spinal Tap

Why It Is Done

A lumbar puncture is done to:

• Find a cause for symptoms possibly caused by an infection (such as meningitis), inflammation, cancer, or bleeding in the area around the brain or spinal cord (such as subarachnoid hemorrhage).
• Diagnose certain diseases of the brain and spinal cord, such as multiple sclerosis or Guillain-Barré syndrome.
• Measure the pressure of cerebrospinal fluid (CSF) in the space surrounding the spinal cord. If the pressure is high, it may be causing certain symptoms.

A lumbar puncture may also be done to:

• Put anesthetics or medicines into the CSF. Medicines may be injected to treat leukemia and other types of cancer of the central nervous system.
• Put a dye in the CSF that makes the spinal cord and fluid clearer on X-ray pictures (myelogram). This may be done to see whether a disc or a cancer is bulging into the spinal canal.

In rare cases, a lumbar puncture may be used to lower the pressure in the brain caused by too much CSF.

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Author:	Caroline Rea, RN, BS, MS	Last Updated: September 12, 2008
Medical Review:	Anne C. Poinier, MD - Internal Medicine Joseph O'Donnell, MD - Hematology/Oncology
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