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Lumbar Puncture
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.
|
Appearance: |
CSF is normally clear and colorless. |
|---|---|
|
Pressure: |
Normal CSF pressure in the lower back for an adult ranges from 50–180 millimeters (mm) water. For children, the normal opening pressure range is 10–100 mm water. |
|
Protein: |
The normal protein content of CSF in an adult's lower back (lumbar) region is 15–45 milligrams per deciliter (mg/dL) or less. Older adults and children may have higher values (up to 70 mg/dL) that are still in the normal range. |
|
Glucose: |
The normal range for glucose content in the CSF is at least 40%–80% of the blood glucose level. The levels may be slightly increased if the person has just eaten. |
|
Cell counts: |
Normal CSF contains no red blood cells (RBCs). The white blood cell (WBC) count for adults is 0–10 WBCs per cubic millimeter (mm3). Children may normally have a higher WBC count. No neutrophils are present. Lymphocytes or monocytes are 0–4 per mm3. |
|
Other results: |
No infectious organisms (such as bacteria, fungi, or a virus) are found in the CSF sample. No tumor cells are present. |
|
Appearance: |
Blood in the CSF can result from bleeding (hemorrhage) in or around the spinal cord or brain, but it may also be caused by tiny blood vessel poked during the spinal tap. If a brain hemorrhage has occurred, the color of the CSF may change from red to yellow to brown over several days. Bleeding caused by the lumbar puncture itself will show more red blood cells in the first sample collected than in later samples. Cloudy CSF may mean an infection (such as meningitis or a brain abscess) is present. |
|---|---|
|
Pressure: |
High CSF pressure may occur as a result of swelling (edema) or bleeding (hemorrhage) in the brain, infection (such as meningitis), stroke, or other circulatory problems. Below-normal pressure may mean a blocked spinal canal. |
|
Protein: |
A high level of protein may be caused by bleeding in the CSF, a tumor or spread of a cancer from another area of the body, diabetes, infection, injury, Guillain-Barré syndrome, severe hypothyroidism, or other nerve diseases. An increase in antibodies (immunoglobulins) may be caused by inflammation in people who have multiple sclerosis, immune system disorders, or other bacterial and viral diseases. |
|
Glucose: |
Low glucose levels in the CSF are abnormal and may be caused by bacterial meningitis. Viral meningitis does not often cause low glucose levels in the CSF. Brain hemorrhage may also cause low glucose levels several days after bleeding begins. Higher-than-normal glucose levels are often caused by diabetes. |
|
Cell counts: |
Red blood cells (RBCs) in the CSF means bleeding. High levels of white blood cells (WBCs) mean meningitis. Tumor cells and abnormal levels of white blood cells mean cancer. |
|
Other results: |
Antibodies, bacteria, or other organisms in the CSF means that an infection (such as syphilis) or disease is present. Bacterial markers (bacterial antigens) that show up mean meningitis. Cultures or stains of the CSF may also help show the cause of meningitis or encephalitis. |
Your doctor may order other special tests on the CSF fluid depending on your symptoms and medical history.
WebMD Medical Reference from Healthwise
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