What is a lumbar puncture?
A lumbar puncture (LP), also called a spinal tap, is a simple diagnostic test performed at Northern Westchester Hospital Center, Mount Kisco, NY.
Why am I having a lumbar puncture?
Your neurologist will explain the precise reason for the test in your particular case. A lumbar puncture can be very helpful in the diagnosis of bacterial, fungal, mycobacterial, and viral CNS infections and, in certain settings, for help in the diagnosis of subarachnoid hemorrhage, CNS malignancies, demyelinating diseases, multiple sclerosis, dementias, Alzheimer's disease, and Guillain-Barré syndrome. Other reasons are described at the end of this section.
May I eat before the lumbar puncture?
What about my taking my medications?
Unless your doctor indicates otherwise, you may have a light breakfast before the procedure. Take all medications as usual, including aspirin, Plavix and Aggrenox. Aspirin has not been shown to increase the risk of serious bleeding following LP.
The test cannot be done while on warfarin/Coumadin. Special arrangements will be made for patients taking warfarin.
How is the lumbar puncture performed?
After registering you will wait in a special lounge until a nurse brings you to the Procedure Room where the doctor will perform the test. The nurse will briefly review your medical history, have you change into a hospital gown, and check your blood pressure, pulse and temperature.
To perform the test, the doctor will clean the lower part of your back with an antiseptic solution and give you a local anesthetic to numb the area. This makes the procedure less uncomfortable. A small needle is inserted through the numbed area to puncture the dural sac that contains cerebrospinal fluid (CSF). The fluid is collected in several tubes. Once in place, the spinal needle causes minimal, if any, discomfort. The needle is withdrawn.
Usually the amount of fluid collected is 10 - 25 cc from the total amount of ca. 150 cc in the central nervous. Do not worry about loosing the fluid. Daily turnover of CSF is about 450 cc, so the amount removed is quickly replaced.
The procedure itself usually takes less then 15 minutes. Venous blood is sometimes collected by a nurse before or after the LP. You will remain in a waiting area for one or two hours.
Are there any limitations after the lumbar puncture?
You must arrange for someone to take you home after the procedure. At home you should lay flat for several hours and drink plenty of fluids. You can return to work and drive the next day. You will not be discharged from the hospital unless someone meets you there to bring you home.
Are there any complications from the lumbar puncture?
Rarely, a patient may experience some tingling in the leg during the procedure, but this resolves as soon as the needle is moved. Sometimes patients develop a headache (or, rarely, nausea, vomiting, stiff neck, backache) within the first few days after the lumbar puncture.
Should these develop, you should rest flat in bed, drink plenty of fluids, and take a mild pain medication. If the headache is severe, or if it is associated with vomiting, fever of any other unusual symptoms, you should call your doctor.
LP is a relatively safe procedure, but minor and major complications have been described, such as infection, bleeding, cerebral herniation, as well as minor symptoms such as radiating pain in the legs or numbness.
Post-spinal syndrome with one or several of the symptoms mentioned is fairly common and affects about 10% of the patients. It is a normal effect of low pressure of cerebrospinal fluid. Fever is not a normal consequence of the procedure and should be reported.
Instructions for care following the lumbar puncture
To minimize any problems after the procedure, please follow these recommendations carefully:
1. Return home immediately. You need someone to bring you home.
2. Lie flat in bed (one pillow is permissible) for at least 3- 4 hours.
3. Drink plenty of fluids, at least 6 to 8 oz glasses over the remainder of the day.
4. No driving until the next day. NO lifting, straining or exertion, or sexual activity for 24 hours.
5. If you develop a soreness in your lower back at the site of the spinal tap, please, have someone check the area for redness or swelling; if either are present, call the office. If there is no redness or swelling, you can use an ice pack and take two (2) Tylenol tablets to reduce your discomfort.
6. If you should develop a headache, nausea, neck/back pain/cramps the following recommendations may be helpful:
- Lie in bed for another 1-2 days and drink plenty of fluids as in #3 above.
- Avoid straining.
- If you have a lumbar corset or girdle, apply this as tightly as comfortable.
- You may use Tylenol for pain. If you have been given other pain medicine, you may use it as prescribed.
- If you develop any fever over 99.8 degrees, any vomiting, or any unusual problem, or if the pain is very severe, please contact the office.
- In very few patients with severe and persisting postspinal syndrome, the procedure of “blood patch” is done in the hospital, again as outpatient. Patient’s venous blood is injected over the site of the lumbar puncture, to black the leakage of cerebrospinal fluid by “patching” the small hole in the dural sac.
- Headaches will invariably resolve in each and every patient.
When will I receive the results of the test?
Generally it takes 3-4 weeks for results of specialized tests such as Lyme, multiple sclerosis and Alzheimer proteins. Results regarding acute infection will be available within a few hours; however, such indication is usually for hospital in-patients, not for elective procedures. Please, call the office for your results, if you have not received a message in three weeks.
Other reasons for doing lumbar puncture
Cisternographyis the injection of a radio-labeled isotope in the lower back by the method of an LP. The needle is placed in the subarachnoid space of the lumbar cistern well below the spinal cord; the distribution of the marked or tagged CSF can now be visualized as it flows fairly slowly through the brain. Imaging in the Nuclear Radiology Department is done at set time periods following the injection, usually at 4, 24, 48, and 72 hours. After collecting the CSF, a small amount of a radioactive tracer solution (Indium-111) is injected into the space of the spinal fluid. Radiographic imaging will be done a few hours later. Possible need for additional brain images will be reported to the patient by the radiology department. Such imaging will be done the next day or thereafter. This procedure is called "Lumbar Puncture with Cisternogram" and it is done to evaluate the diagnosis of Pseudotumor Cerebri (see more about this condition on my website above).