Lumbar Puncture

What is a Lumbar Puncture?

A lumbar puncture (also called a spinal tap) is a procedure where a doctor places a thin needle into the lower back to collect cerebrospinal fluid (CSF) — the fluid that surrounds your brain and spinal cord. This fluid can be tested to look for infections, bleeding, or other problems. Sometimes, a lumbar puncture is also used to give medicines directly into the spinal fluid.

How do you prepare for a Lumbar Puncture?

• Tell your doctor about all medicines you take, especially blood thinners or medicines that affect clotting.
• Share any medical conditions such as bleeding disorders or spine problems.
• You may be asked to fast (avoid food or drink) for a few hours before, but often you can eat and drink normally.
• Arrange for someone to drive you home afterward, since you may feel tired or sore.

Why is a Lumbar Puncture performed?

A lumbar puncture may be done to:

• Diagnose infections such as meningitis or encephalitis.
• Check for bleeding around the brain or spinal cord.
• Look for diseases like multiple sclerosis or certain cancers.
• Measure pressure inside the spinal canal.
• Give medicines such as chemotherapy, antibiotics, or anesthesia.

What can you expect during a Lumbar Puncture?

• The procedure is usually done in a hospital or ambulatory surgery center and takes about 30–45 minutes.
• You will lie on your stomach, or the doctor may have you lie on your side with knees pulled up to your chest.
• The doctor cleans your lower back and gives numbing medicine.
• A thin needle is placed between the bones in your lower spine to collect spinal fluid.
• You may feel pressure, but sharp pain is uncommon.
• Once enough fluid is collected, the needle is removed, and a small bandage is placed.

What is the follow-up like for a Lumbar Puncture?

• You’ll usually rest flat for a short time afterward.
• Some people get a headache after the procedure; drinking fluids, resting, and caffeine can help.
• You may feel mild soreness in your back for a day or two.
• Your doctor will explain the results once the spinal fluid is tested.

What are the potential risks for a Lumbar Puncture?

Most people do well, but possible risks include:

• Headache (the most common side effect).
• Back pain or soreness at the injection site.
• Bleeding or infection (rare).
• Nerve irritation causing tingling or pain in the legs (usually temporary).

Are there related tests to a Lumbar Puncture?

• Blood tests may be done at the same time to help interpret results.
• Brain imaging (CT or MRI scans) may be done before a lumbar puncture if there’s concern about swelling or pressure in the brain.
• Other neurological exams may be combined with the procedure depending on your condition.