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What is a lumbar puncture?
- Your spine ("backbone") is made of vertebrae (VER-te-bray), your spinal cord, and cerebrospinal (ser-ee-broh-SPEYE-nal) fluid. The vertebrae are small bones that are stacked on one another to make your spine. Your vertebrae stretch from your neck to your tailbone. The spinal canal is a space that passes through the center of the vertebrae. The spinal cord is inside the spinal canal and is surrounded by cerebrospinal fluid. Cerebrospinal fluid (CSF) bathes, cushions, and protects the brain and spinal cord. The spinal cord carries messages between your brain and your body.
- A lumbar puncture test is also called an LP or a spinal tap. During an LP, a needle is inserted into your lower spine. A small amount of CSF fluid is then taken from your spinal canal. The CSF fluid may be sent to a lab for testing. Sometimes the CSF is taken to decrease pressure caused by certain medical problems. Pressure within the spinal canal can also be measured during an LP.
Why do I need a lumbar puncture?
You may need an LP to check for one or more of the following:
- Infection, such as meningitis (men-in-JEYE-tis), or inflammation (swelling) of the brain.
- Bleeding in the brain, such as from a head injury.
- Increased pressure that may be causing certain kinds of headaches.
- A tumor (lump or mass) in the area of the spine or brain.
- Some diseases of the nervous system, such as multiple sclerosis or epilepsy (seizures).
- An LP may also be done as part of another test, such as a test that needs dye put into the CSF.
- Some medicines can be given into the spine during an LP. Examples include anesthesia (an-es-THEE-zah) medicine, antibiotics (an-ti-bi-AH-tiks), and cancer-treating medicine (chemotherapy).
What happens during a lumbar puncture?
The actual LP usually takes about 20 to 30 minutes, but it may take longer. You will need to be able to lay flat or nearly flat after the test. If you are sent home right after the test, another adult will need to drive you home. You may need other tests besides the LP. These tests may include blood tests, x-rays, or a CT ("cat") scan.
- Informed consent: The risks and benefits of an LP should be explained to you in words that you know. You should be told what tests, treatments, or procedures may be needed to learn about and treat your health condition. You may be asked to sign a consent form. A consent form is a legal piece of paper that tells you exactly what will be done. Before giving your consent, make sure that all of your questions have been answered.
- Before the LP:
- Eat a normal diet before the lumbar puncture.
- Continue taking your usual medicines unless caregivers tell you not to.
- You will be asked to put on a hospital gown. Put your gown on so that it opens in the back.
- Go to the bathroom before the LP so that you are not uncomfortable during the test.
- Caregivers may take your vital signs before, during, and after the LP. This includes checking your temperature, blood pressure, heart rate, and breathing. Caregivers may listen to your heart and lungs by using a stethoscope (STETH-oh-skohp). Your vital signs may be taken so that caregivers can see how you are doing.
- During the LP:
- You will need to lie on your side with your knees curled up against your chest. Try to get your knees as close to your chin as possible. Your caregiver may want you to sit on the side of a bed or table and bend way forward instead. Caregivers will help you tuck your head toward your chest. This helps round your back and widens the space between the vertebrae so that the LP can be done. Tell your caregiver if you are unable to bend your legs or back. Your caregiver will need to give you special instructions about how to position yourself during your LP.
- Your lower back will be washed with soap to clean the skin of germs. Let your caregiver know if you are allergic (al-ER-jik) to iodine or any medical cleansing solution. You may be given one or more shots of numbing medicine under the skin. This medicine may sting or burn at first, but it will help decrease pain during the test. Tell your caregiver if you are allergic to lidocaine or any dental or numbing medicine.
- It is important to hold very still during the LP so that the needle does not move. If you cannot hold still, your caregiver may not be able to complete the test. Try to relax as much as possible. This may make the LP easier for your caregiver to do.
- Keep your back as rounded as possible during the test. Your caregiver will carefully put a needle into a space between your vertebrae in the lower back. You may feel some pushing or discomfort as the needle enters your back. Tell your caregiver if you have pain that does not stop within a few seconds. Your caregiver may need to insert the needle more than once.
- Your caregiver may take readings of your CSF pressure. Before the pressure is taken, you may be asked to relax or stretch your legs. A sample of your CSF is then taken. The sample may be sent to a lab for tests. A small bandage is put on your back after the needle is taken out.
- Tell a caregiver if you have any of the following symptoms during or right after your LP test:
- Headache or back pain.
- New or worsening tingling or numbness (loss of feeling) below your waist.
- New problems with moving your legs or feet.
What happens after a lumbar puncture?
- Caregivers will check the LP site to make sure it is not bleeding too much, leaking fluid, or swelling. You may also be asked to wiggle your toes.
- You will be asked to lie flat or nearly flat for two to eight hours after the LP. If you are sent home after your LP, lie flat or recline as much as possible on your way home. For 24 hours after the LP, rest as much as possible. This helps decrease the chance of having a "spinal headache". Do not do any hard activity (such as sports or heavy lifting) for 48 hours after your LP.
Care for a spinal headache:
A spinal headache can happen during the first few hours to several days after your LP. Spinal headaches may happen because you have less CSF for a short time after the test. The discomfort of a spinal headache can range from mild to severe (very bad). The headache may get worse when you sit or stand. You may have neck pain or back pain as well. Things that may decrease the pain of a spinal headache include the following.
- If you get a headache, lie down until your headache is better. Tell your caregiver if your headache is very bad and it does not get better after you lie down for a while.
- Over-the-counter medicines, such as acetaminophen (a-seet-a-MIN-oh-fen) or ibuprofen (eye-bu-PROH-fen), may decrease your pain. Ask your caregiver which over-the-counter pain reliever is right for you. Your caregiver may suggest that you increase your intake of caffeine or take caffeine tablets. Extra caffeine may decrease the pain of a spinal headache. Examples of things that have caffeine include coffee, some sodas, some teas, and some energy drinks. Do not increase your caffeine intake or take caffeine pills unless your caregiver tells you to do so.
- You may be asked to drink more liquids for the first 12 to 24 hours following your LP. This may help decrease your chance of having a spinal headache. For most people, good liquids to drink include water, milk, and juices. Do not drink alcohol. Tell your caregiver if you cannot drink more liquids because of another medical condition (such as heart failure).
What is a blood patch?
A blood patch may be used to help a spinal headache that is very bad or does not go away. This is also called an epidural (ep-i-DU-ral) blood patch. A blood patch may be done in the days or weeks following an LP. To place a blood patch, caregivers first draw some blood from you. This blood is injected with a needle into your back over the LP site. You will need to lay flat for about an hour after this is done. You may need IV fluids also.
There is a risk of an allergic reaction to the numbing medicine used during the LP. Other problems are rare, such as bleeding, infection, injury to a disk in your spine, or leakage of the spinal fluid. There is a very small chance that your brain or spinal cord could be injured. The risk of problems is increased if you move during the LP test. If you do not have an LP test, your caregivers may not be able to find or treat your illness. Talk with your caregiver if you are worried or have questions about your medicine or care.
You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.