- What is a lumbar puncture?
- Why is this test done?
- What conditions may interfere with getting a LP?
- What are the risks of an LP?
- What about "spinal headaches"?
- What if I develop a spinal headache?
- Should somebody come with me for this test?
- I am very nervous; can you give me an injection to relax me for the test?
- How long will the procedure take?
- What happens during the test?
- What if I move during the test?
- Are there any restrictions after the test?
- What symptoms should prompt the patient to call our office back immediately?
- When should I expect to hear results of my LP?
What is a lumbar puncture?
It is a type of diagnostic test during which a medical professional collects a sample of the fluid that surrounds the brain and spinal cord. This fluid is removed by using a carefully inserted needle into the lower back where the spinal cord ends. Fluid is withdrawn from this area to avoid the needle directly hitting the spinal cord.
Why is this test done?
A LP provides information that may assist your physician with obtaining a correct diagnosis for your condition. In evaluation for MS and related disorders, spinal fluid analysis may be useful to document the presence or absence of inflammation using tests known as oligoclonal bands and IgG index. These tests require comparison with blood drawn on the same day as the test. Spinal fluid analysis may also help evaluate for infections, degeneration, or other disorders. Studies of spinal fluid may include a test for cells, proteins, infections or other abnormalities. On occasion, we are not able to obtain an adequate amount of spinal fluid for all studies necessary and the test may need to be repeated.
What conditions may interfere with getting a LP?
Recent low back surgery, congenital malformations of the spine, and infection or inflammation of the skin of the low back may interfere with the safe performance of a LP. Let your physician know before the scheduled procedure date if you have any of these issues, so that a determination can be made. We also prefer not to do a LP in the first few weeks after a new low back tattoo.
What are the risks of an LP?
Most people feel some discomfort during the LP and many have some aching-type low back pain for several days following the procedure. A spinal headache may occur. See the next section for a description of this. The risk of infection, bleeding, or bruising is about the same as a blood draw. Injury to a nerve root is another rare possibility. Bleeding into the spinal canal is an extremely rare occurrence unless someone is on blood thinners or has a bleeding disorder. Allergic reactions to the skin cleanser or numbing medicine may occur but are also quite rare.
What about "spinal headaches"?
Spinal headaches, also known as post dural puncture headaches, may arise after a LP. They are markedly worse when a patient is in the upright position and usually resolve quickly when the patient is in a flat position. They may be quite severe and, at times, are associated with other symptoms such as stiff neck, tingling, ringing in the ears, blurred double vision, and nausea. The risk of a spinal headache is greatly decreased by using needles of smaller thickness and by using "atraumatic" type needles. By using these types of needles, the risk of a spinal headache is around 3%. If you experience a spinal headache, see the instructions below.
What if I develop a spinal headache?
Headaches due to a LP can be severe. They occur when the head is elevated, such as when sitting or standing, and usually markedly decrease or resolve if you lie flat (head and hips at the same level). They do not respond to pain pills! If you get a headache, you should lie flat for 24 hours. You can get up to use the bathroom. Remain on your side to eat and drink during this time, if it can be safely done. Increasing your fluid and caffeine intake at this time may be helpful. If your headache is severe despite remaining flat overnight or continues for more than 24 hours, please call our office for instructions. We may ask that you continue bed rest but may also need you to come to the office or hospital for treatments which may include intravenous fluids and/or caffeine or a procedure known as an epidural blood patch. An epidural blood patch is performed by injecting some of your own blood near the same area where the LP was done.
Should somebody come with me for this test?
Yes, we ask that you have an adult with you to drive you home. The health professional doing the test may allow them to sit with you through the procedure if you wish. Children under age 18 will not be allowed in the room during the test. If they must come along, you will need to have someone supervise them and attend to their needs in the lobby.
I am very nervous; can you give me an injection to relax me for the test?
We do not administer systemic medications to LP patients. If you normally take medications for anxiety, we do not restrict your taking them but ask that you arrive at our office able to understand the risks and benefits of this test and to sign your consent form.
How long will the procedure take?
The duration of an LP varies from 15-45 minutes, depending upon the amount of sample your doctor needs and the rate of fluid flow through the needle. An additional hour of recovery time may be required if you have a large amount of fluid removed or have symptoms after the test.
What happens during the test?
After you register at the front desk, you'll be taken back to the room where the test will be performed. We suggest emptying your bladder to remain comfortable. You'll be asked to sign a consent form for the LP procedure. Patients are usually lying on their side with their knees pulled up toward their chest. Occasionally, the test is done with the patient sitting up and flexed forward over a table. The health professional will press over your hips and back to identify and mark the proper location for the needle to be inserted. The skin of your low back will be cleaned with a soap (Providine-iodine is usually used; let us know if you're allergic.) that usually feels cold. A sterile drape will be placed over your lower back. You will then usually be given a local numbing medicine (Xylocaine) through a small needle.
Most patients experience stinging or burning when this medication is first injected. This medicine should block most of the sharp feeling a needle will cause; however, it will not take away all sensation. Most patients continue to feel some pressure and sensations in their low back. You'll be awake and able to talk and interact with us throughout the test. The spinal needle will then be inserted through your skin. The needle will be passed between the bones and other structures that surround the spinal cord. It will then enter the sack that contains the spinal fluid.
You should let us know if you feel any abnormal sensation or pain. On some occasions, as the needle is being adjusted, patients may experience a shooting or sharp-type pain. If this happens, you should let us know and the needle position may be adjusted. If indicated by your symptoms, we will attach a tube to the needle to measure the pressure of your spinal fluid. Otherwise, the fluid is allowed to drip into collection tubes and will be sent to laboratory. Once fluid collection is complete, the needle is removed, the skin cleaned of soap, and a small bandage applied. If needed, a blood sample will be obtained by our medical assistant prior to your departure from the office.
What if I move during the test?
We prefer that patients are still during the test; however, we realize that individuals may have abnormal involuntary movements such as coughing, sneezing, or even muscle spasms during the test. These movements usually do not cause any difficulty. If you have frequent major spasms or other abnormal uncontrolled major movements, discuss these with your physician prior to the test.
Are there any restrictions after the test?
We suggest that you not drive for the rest of the day. You do not have to stay flat unless you develop a headache. If you were on blood thinners or anticoagulants, ask your physician for instructions on when and how to restart them. We prefer that you avoid strenuous or vigorous activity for 2 days after the test and avoid lifting more than 20 pounds for the next 2 days. You may remove your bandage in 4 hours. If bleeding or oozing continue from the puncture site after bandage removal, contact our office. Any remaining soap residue should be washed off, as well. You may resume your other normal activities the next day as long as you do not have a headache. It is normal to have some pain, soreness, or aching in the low back for a few days after a LP. You may use over-the-counter pain medicines for low back pain unless restricted by your doctor.
What symptoms should prompt the patient to call our office back immediately?
We ask that you call us if you develop severe pain in the low back or neck, new neck stiffness, severe headache that does not improve when lying down, fever, or new confusion/trouble thinking clearly. We also ask that you notify us immediately if you develop new numbness, tingling, or weakness of the legs or feet, new difficulty with bowel or bladder control, or any redness, pus, or drainage from the LP site.
When should I expect to hear results of my LP?
Most tests we obtain during the spinal tap have results available within 14 days. You should discuss with your physician how and when results will be communicated. If you have not received results within 14 days, please contact the physician who ordered your LP.