Lumbar Puncture

About this Procedure

What is a Lumbar Puncture (LP)?
It’s a bedside procedure done to collect a sample of cerebrospinal fluid (CSF). A needle is inserted into your lower spine and CSF is withdrawn. You are conscious throughout the procedure and given local anesthetic.

Who does this procedure? Where is it done?
A Neurology doctor does this procedure in our outpatient Neurology Clinic.

Why is this done?
A lumbar puncture is done to examine the contents of your spinal fluid (similar to a blood test). The analysis of the fluid is used to confirm a diagnosis or detect infection, inflammation, increased intracranial pressure and other reasons. A common reason for lumbar puncture is to diagnose meningitis to measure your cerebrospinal fluid (CSF) pressure level, to check for markers of multiple sclerosis or dementia.

Are there any risks or side effects associated with this test?
The risks of this procedure are limited and will be explained to you before you agree to undergo the procedure. The most common side effect is a headache. If you are a person who gets bad headaches or migraines, you may be more prone to having a headache after a lumbar puncture. Usually the type of headache you get after the LP is affected by position. The headache is worse when you sit up or stand. It should improve when you lie flat. In most cases the headache is self limiting and will disappear after a few days. In the meantime, taking Tylenol may help, as well as caffeine drinks and beverages may reduce the headache.

You may also feel sore in your lower back where the needle was inserted. This discomfort is minimal and should not last more than a couple of days. The physician will discuss any other potential risks and side effects with you at the time of your procedure.

Before the Test

What do I need to have done before the test?

Your doctor will need to have bloodwork done before the test: PT/PTT and platelets (CBC). You will need to have the results of the bloodwork sent to us before you can have the test. This is to prevent bleeding during the test.

What medications should I stop taking before the test?

If you are taking blood thinners you will need to stop them before the test. This should be done with the help of your treating physician in case you need to switch to another blood thinner like Lovenox. Let your treating physician know that you are going to have this test done and that you need to hold these medications.

• Plavix: hold for 5 days prior to LP
• Warfarin: Patients must hold warfarin for at least 5 days and have a STAT INR the day of the procedure of 1.3 or below
• Eliquis, apixaban, dabigatran should be held for 3 days prior to the LP

Can I eat and drink liquids before this test?
Fasting is not necessary and you may take your medications as directed.

During the Test

How long does it take?
From beginning to end, it should take about one half hour. The time needed to withdraw the sample is actually quite short, most of the time is taken up with preparations, such as disinfecting the puncture site (the area where the needle will go in) and giving you a local anesthetic.

What happens during the test?
You will be asked to lie or sit in a fetal position with your knees curled up to your stomach and your chin tucked into your chest. In this position, the space between the vertebrae of your lower spine is increased and a thin needle can be threaded into your spinal canal. Though everybody’s anatomy is a little bit different, usually the puncture site is found between the L3-L4 and L4-L5 interspaces.

After the site is found, the puncture area is cleaned with an antiseptic and the surrounding area is draped with sterile towels. A local anesthetic is used to numb or ‘freeze the area’ of the puncture site. Next a spinal needle is inserted into your lower back. The needle goes into a space below where the spinal cord ends. The doctor will collect some of the fluid to send to the laboratory. A small sterile dressing will be placed over the puncture site to protect you from infection.

What happens after the test?
You will be asked to lie flat for approximately 10-15 minutes to prevent headache. Headaches may occur due to the changes in your spinal fluid level. You should continue to rest until the next morning. You will need someone to accompany or drive you back home.

When and how will I receive the results?
The time to get the results depends on the type of analysis requested by your doctor and on the urgency of the request (which is also determined by your doctor). Results will be sent to your doctor.

What if I have a headache after the test?
It is common to develop a headache after a lumbar puncture. If you have a headache you should lie down, remain hydrated and drink caffeinated beverages (for example, soda, coffee, or tea). You may also take Tylenol. The headache typically lasts for less than 72 hours. If your headache is not improving after 48 hours, please call us back at 617-726-7421 during regular business hours. If you need to reach a physician urgently over the weekend or during non-business hours regarding a problem related to your lumbar puncture, you can call the pager operator at 617-726-2000 and ask that the physician who performed your lumbar puncture be paged.