Brain & Nervous System Health Center

How It Feels continued...

During the procedure, the needle may touch one of your spinal nerves and cause a tingling feeling, like a light electrical shock, running down one of your legs. The needle will not touch or damage the spinal cord.

Some people (10% to 25%) develop a headache after having a lumbar puncture. Of those who do get headaches, only about half report that they are severe. These headaches last 24 to 48 hours and go away on their own. Pain medicine does not help control the headache, but lying flat in bed for several hours after the procedure may help the headache.

You may feel tired and have a mild backache the day after the procedure. Some people have trouble sleeping for 1 to 2 days.

Risks

A lumbar puncture is generally a safe procedure. In some cases, a leak of cerebrospinal fluid (CSF) may develop after a lumbar puncture. Symptoms of this problem are a headache that does not go away after 1 to 2 days. A CSF leak can be treated with a blood "patch," in which the person's own blood is injected into the area where the leak is occurring in order to seal the leak.

About 1 in 1,000 people who have a lumbar puncture have a minor nerve injury. This heals on its own with time. There is also a small chance of infection of the CSF (meningitis), bleeding inside the spinal canal, or damage to the cartilage between the vertebrae. Your doctor will talk with you about these risks.

People who have bleeding problems and those who are taking blood-thinning medicine (such as warfarin or heparin) have a higher chance of bleeding after the procedure. A lumbar puncture may not be done unless it is needed for a life-threatening illness.

A lumbar puncture may cause serious problems for people who have high pressure in the brain caused by a tumor, a pocket of infection in the brain (abscess), or major bleeding inside the brain. Your doctor will check your nervous system, spinal cord and brain before doing a lumbar puncture. In some cases, a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan may be done before the lumbar puncture to know that it is safe to do the puncture.

After the procedure

Call your doctor immediately if you have:

• Chills or a fever.
• A stiff neck. This may be a sign of a developing infection.
• Any drainage or bleeding from the puncture site.
• A severe headache.
• Any numbness or loss of strength below the puncture site.

Results

A lumbar puncture (also called a spinal tap) is a procedure to collect and look at the fluid (cerebrospinal fluid, or CSF) surrounding the brain and spinal cord. Many different tests can be done on the CSF. Some results will be ready right away, some will take a few hours after the procedure, and others will take several weeks.