Why do I need a lumbar puncture to diagnose MS?

Ryan Jones from MS-UK’s helpline explains what a lumbar puncture is and why it is needed

It is over 40 years since the release of the original Spinal Tap movie, and the spoof band are back in the news with the release of their new mockumentary. It has prompted us to ‘turn it up to 11’ (a famous quote from the original movie!) and write a guide to the multiple sclerosis (MS) spinal tap.

The spinal tap, or to give it is proper name, the lumbar puncture, is one of the diagnostic tests that is used in diagnosing multiple sclerosis. It is also occasionally used in monitoring MS activity and progression. A lumbar puncture is also sometimes used during MS research trials.

What is a lumbar puncture?

A lumbar puncture is a procedure where a small amount of cerebrospinal fluid (CSF) is collected for testing. CSF is a clear liquid that surrounds and protects your brain and spinal cord. A thin, hollow needle is inserted into the lower back, between the vertebrae, to access the spinal canal and retrieve a sample of the fluid.

Why is a lumbar puncture needed for MS?

While a magnetic resonance imaging (MRI) scan is the main diagnostic tool for MS, a lumbar puncture provides additional information and evidence that can help confirm (or rule out) a diagnosis. Analysing the CSF helps neurologists differentiate MS from other conditions that have similar symptoms.

What is the neurology team looking for in your CSF?

The lumbar procedure is looking for evidence of abnormalities in your CSF. These include

• White blood cells (WBCs). WBCs are part of your immune system there to fight off infection. If you have MS, then the number of white cells in your CSF is usually up to seven times higher than would normally be found in a healthy individual. If the count is even higher than this, it is probably due to an infection of some sort and not MS
• Neurofilaments. These are fragments of the structural support that normally surrounds your nerve fibres (axons). If neurofilaments are found in the CSF, then this is evidence that your myelin (protection surrounding nerves) is under attack and helps identify if you have a demyelinating condition (such as MS).
• Oligoclonal bands (OCB) are proteins that indicate inflammation in the CNS. In MS, antibodies cross the blood-brain barrier and attack the myelin surrounding your nerves. As a result, the level of antibodies in the CSF of someone with MS is higher than it should be.

What should I expect before the lumbar puncture?

Before your lumbar puncture, your neurologist, MS nurse, or other member of your MS team should discuss the procedure with you in detail. They will likely gather a little more about your medical history and any medications you are taking. If you are taking blood thinning medications, they may ask you to stop them a few days beforehand. They should talk to you about risks surrounding the procedure and ask you to sign a consent form. You should have opportunity to ask questions and express any concerns that you have. Generally, you can eat and drink as you would normally before the procedure and you don’t need to fast.

What to expect during the lumbar puncture

The procedure usually happens in an outpatient clinic. You will need to change into a hospital gown, and the procedure is performed while you are awake

• You will need to be lying on your side with your knees curled up to your chest. This position helps open up the spaces between your vertebrae.
• Your lower back will be cleaned and then a local anaesthetic injection will be given.
• Sample collection. The doctor will insert a needle into your lower back. You may feel some pressure or mild pain, but due to the anaesthetic injection, you shouldn’t feel any severe pain. The CSF will be gathered in a small collection tube.
• Completion. Once enough CSF has been collected (approximately 10 ml), the needle is removed, a dressing will be applied, and you are left to recover.

What to expect after the procedure

• Immediate recovery. You will be asked to lie flat for a while. This is to help reduce the risk of a post-procedure headache (one of the potential side effects of the procedure).
• You will be encouraged to drink plenty of fluids to help your body with the spinal fluid that was removed and importantly help prevent a potential post procedure headache.
• Common side effects. The most common side effect is the headache we’ve already mentioned, which can often be relieved by lying down and resting. Other side effects can include back pain and minor bruising at the injection site.
• Follow-up. Your MS team will provide instructions on when you can resume normal activities. It is often advised that you avoid strenuous exercise for at least 24 hours.
• When to seek help. While serious complications are rare, you should contact your MS team or call 111 if you experience a worsening or persistent headache, fever, numbness, confusion, or visual symptoms.

If you need to know more about the whole diagnosis process MS-UK have further reading and support options for you.

We have well sourced information (both online and physical booklets), blogs and real-life stories, MS news stories, and we have support from our helpline and our peer support groups.

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