(Cerebrospinal Fluid Analysis; Cerebrospinal Fluid Tap; Spinal Tap)
In this procedure, the doctor samples the cerebrospinal fluid (CSF) from your lower back. CSF is the fluid the brain and spinal cord sit in. It provides protection and nutrition to the brain and nerve cells. This fluid also helps to remove waste products from the brain.
Lumbar Puncture Method
Reasons for Procedure
A lumbar puncture may be done when the following conditions are suspected:
- Brain infection, or infection of the layers around the brain
- Multiple sclerosis (MS)
- Any disorder affecting the nervous system
- Certain types of cancer
- Bleeding in the brain or spinal cord
- Excess CSF in the brain
The procedure may also be done to:
If you are planning to have a lumbar puncture, your doctor will review a list of possible complications, which may include:
What to Expect
Prior to Procedure
Prior to the procedure, your doctor will likely do the following:
- CT scan of the head—a type of x-ray that uses a computer to make pictures
- Clean the site where the needle will be inserted
Local anesthesia—just a small area is numbed; given as an injection
Description of Procedure
You will lie on your side with your knees drawn up to your abdomen. Sometimes, the procedure is done while you sit on the edge of the bed. A needle will be inserted into the spinal canal through the lower back. The doctor will take a sample of CSF through the needle. The pressure of the CSF will be measured. If you have discomfort, the needle may need to be repositioned. It may take several minutes for the doctor to collect all the fluid he needs. Once the doctor is done, the needle will be taken out, and a dressing will be placed.
Immediately After Procedure
You will lie down for 10-15 minutes. Unless you have a severe headache, you will be able to go home.
How Long Will It Take?
About 30-45 minutes from setup to completion
Will It Hurt?
Discomfort is minimal to moderate. The anesthetic will sting when first injected.
When you return home after the procedure, do the following to help ensure a smooth recovery:
- Drink extra fluids for the next 24 hours.
- Rest and remain quiet for at least 24 hours.
- Be sure to follow your doctor's instructions.
Call Your Doctor
After arriving home, contact your doctor if any of the following occurs:
- Severe headache or headache lasting for more than 24 hours
- Nausea or vomiting
- Signs of infection, including fever and chills
- Redness, swelling, increasing pain, bleeding, or discharge from the lumbar puncture site
- Numbness, tingling, or pain in your lower back or legs
- Problems with urination or defecation
- A stiff neck
- Pain that you cannot control with the medicines you have been given
- Cough, shortness of breath, or chest pain
In case of an emergency, call 911.
American Academy of Family Physicians
National Library of Medicine
About Kids Health
Adams RD, Victor M, Ropper AH. Disturbances of cerebrospinal fluid and its circulation, including hydrocephalus and meningeal reactions. In: Adams RD, Victor M, Ropper AH. Pinciples of neurology. San Francisco: McGraw-Hill; 1997:623-641.
Lumbar puncture (LP). DynaMed website. Available at http://www.ebscohost.com/dynamed/what.php. Updated August 19, 2009. Accessed October 9, 2009.
Lumbar puncture. Journal of American Medical Association website. Available at: http://jama.ama-assn.org/cgi/reprint/296/16/2050.pdf. Updated July 2008. Accessed July 22, 2008.
Lumbar puncture test. The University of Iowa website. Available at: http://www.uihealthcare.com/topics/brainnervoussystem/lumbarpuncturetest.html. Published 2005. Accessed September 22, 2009.
The PDR Family Guide Encyclopedia of Medical Care. New York, NY: Three Rivers Press; 1997.
Last reviewed October 2009 by
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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