Lumbar Puncture Overview
A lumbar puncture is an important clinical test that can identify evidence of infection, inflammation, and cancer. These conditions can cause memory, thinking, and behavioral changes similar to frontotemproal dementia (FTD) and other neurodegenerative diseases. Your doctor may decide that a lumbar puncture is needed to best diagnose your illness.
Lumbar punctures are also important for research. Currently, there are research tests which can help diagnose Alzheimer’s disease by measuring proteins that accumulate in plaques (amyloid-beta) and tangles (Tau). Lumbar punctures can also be used to develop new tests that can better diagnose FTD and other neurodegenerative diseases. These new tests are very important for the development of new treatments that aim to slow or stop the neurodegenerative process in FTD and related conditions.
During a lumbar puncture, your doctor will remove a small amount of the fluid, called cerebrospinal fluid (CSF), that naturally bathes your brain and your spinal cord. Your body will automatically replace this fluid over 1-2 hours.
What do LPs Cost?
If your doctor feels a clinical LP is needed to exclude inflammatory or other diseases that can mimic FTD and related disorders, the procedure and tests are usually billed to your insurance. During a clinical LP additional CSF can be collected for research for interested participants, or in some instances LPs can be performed solely for research purposes. Research LPs and research testing of CSF has no cost to patients.
If you have questions about the need for a clinical LP, please talk to your neurologist.
What Happens During the Lumbar Puncture Procedure?
During the lumbar puncture, you will either be lying on your side or sitting up with your head resting on a pillow (see images to the right).
Once you are in the correct position, your doctor will press on your lower back with their hands. This part may feel like a very firm massage. Once the doctor finds the correct spot, the area will be sterilized. Your doctor will then use a small needle to numb the area with lidocaine. This can feel like a quick pinch and then a tingly feeling for ~60 seconds (like the feeling when you receive numbing medication at the dentist). Once the area is numb, your doctor will place a thin needle in the lower back to collect a small amount of your CSF. Your doctor will talk with you throughout the procedure. There will be staff in the room with you during the lumbar puncture to make sure you are comfortable.
The lumbar puncture takes about 30 minutes. This includes the time spent getting in the correct position, setting up, and cleaning up.
What are the risks?
Most people who undergo an LP have no side effects. However, there are three main risks to be aware of:
- Headache (about 10-15% of people who get an LP have a headache afterwards)
- Bleeding (<1% of people)
- Infection (<1% of people)
Headaches are the most common risk after an LP. The typical headache is better with laying down and worse with sitting up. It is thought that the symptom is caused by a small, ongoing leak of CSF inside the body. We take several steps to lower the risk of headache, including using a thin needle, planning time for patients to lie flat for about 1 hour after the LP, and recommending that you refrain from intense exercise and heaving lifting for 48 hours after the LP. If you do have a headache after your LP, it typically resolves on its own within 1-2 weeks. However, we encourage you to reach out to your neurologist if you notice a headache, so that they can make a treatment plan for you.
Bleeding is also a risk (affecting less than 1% of people). To decrease the risk of bleeding, we typically ask subjects to stop blood thinning medications 10 days before, and 2 days after, the LP. If you are on a blood thinning medication, please talk with your doctor to see if it is safe for you to stop.
Any time we use a needle to puncture the skin, there is a risk of infection. To prevent an infection during a lumbar puncture, the procedure is done using a sterile method.
CSF is an important “window to the brain” and can provide critical information about the biology of FTD, Alzheimer’s disease and other neurodegenerative diseases. Researchers can use this information to develop new tests that can lead to new discoveries and help improve treatment trials for new therapies to slow or stop the progression of FTD, AD and related disorders.
CSF from both patients and healthy family members and volunteers are critical to accelerate discoveries for FTD and related disorders.
If you are interested in research participation, please contact us at: 215-662-6138.