There is no single test to diagnose Multiple Sclerosis – it is a clinical diagnosis, meaning that the diagnosis comes about as a result of multiple tests and symptom analysis. When I was diagnosed an MRI, a lumbar puncture, and paralysis in my right arm and on the right side of my face were all taken into account. Although it took years to get to this point, you could say that I was fortunate to have such a clear case – many individuals have a very difficult time receiving a diagnosis while others may be incorrectly diagnosed with MS. The lumbar puncture, or a crude version of it, was developed in 1889 to relieve intracranial pressure for tuberculous meningitis. It has been somewhat refined over the years as many different uses for it were discovered, but the basics remain the same.
The brain and spinal cord are surrounded in spinal fluid which contains glucose (sugar), proteins (antibodies or immunoglobulins), white blood cells, and other substances that are also found in the blood.
What do lumbar punctures tell us? When CSF is analyzed, the protein, glucose, and cell count are measured and an MS Panel is done which measures and compares the CSF and serum protein levels and immune system activity. Oligoclonal bands may indicate an elevated immunoglobulin G (IgG) index which suggests an increased production of IgG within the central nervous system.
When your cerebrospinal fluid (CSF) is examined in the process of a Multiple Sclerosis diagnosis, the doctor is looking for:
- a large number of immunoglobulins (antibodies / proteins)
- certain proteins created by the breakdown of myelin
- oligoclonal bands (a pattern of immunoglobulins)
All of this was present in my lumbar puncture, yielding a positive diagnosis of MS. For many individuals it is not that simple. Over 90% of us with MS have oligoclonal bands in their CSF, but up to 10% of individuals with MS never have these CSF abnormalities.
What To Expect
You will lie very still in the fetal position on your left side with your shirt off (sometimes patients will lie on their right side). An alternate position is to sit on a stool with your head and shoulders bent forward. The doctor will spread antiseptic on your back and then give you an injection of a local anaesthetic along the path the needle will take. When you are numb, the doctor will insert a needle between the L3/L4 or L4/L5 vertebrae until the ligamentum flavum is reached, then through that until it is past the dura mater. The stylet is then removed from the spinal needle and CSF begins to drip from the needle. As the needle is inserted, you might feel an electric shock go through your leg as the needle comes into contact with the spinal nerve root. This happens all the time and is no cause for concern. At this time, your doctor may measure the opening pressure of your cerebrospinal fluid using a column manometer. After several vials of CSF are collected, the spinal needle will be withdrawn while pressure is placed on the puncture site.
After the lumbar puncture is complete, you will probably have some blood drawn for tests. My neurologist took 5 vials of spinal fluid and 7 vials of blood. Antibodies in both will be compared against each other, but other tests will also be done on your blood to rule out diseases that mimic Multiple Sclerosis such as Lyme Disease. Your blood may also be tested for HIV, genetic disorders, lupus, rheumatoid arthritis and scleroderma.
Lumbar Puncture Risks
- Headache And Nausea – Headache and nausea are common. Drink plenty of fluids and use an analgesic.
- CSF Leak – Occasionally spinal fluid may continue to drip out, causing a headache when you sit up. Bedrest is most commonly used to treat this, although an epidural blood patch is sometimes used (your own blood is injected into the leak site to form a clot)
- Bloody Tap – Occasionally a small blood vessel is pierced during the procedure, causing a “bloody tap.” No treatment is needed.
- Infection – The risk of infection is extremely low.
- Spinal Or Epidural Bleeding – These are extremely rare.
- Adhesive Arachnoiditis – This is extremely rare.
- Trauma – Trauma to the spinal cord or spinal nerve roots can cause weakness, loss of sensation, or paraplegia. This is extremely rare.
- Perforation Of Abnormal Dural Arterio-Venous Malformations – this can cause epidural hemorrhage but it is exceedingly rare.
To lessen the risk, LP can now be done using an x-ray technique called fluoroscopy which aids the doctor in guiding the needle. This makes the procedure faster and less stressful. This was not an option for my spinal tap, but it may be for yours. Check to see if it’s possible.
So you’ve had your lumbar puncture and your MRI and are waiting for a diagnosis. What do your results mean?
- Negative – You don’t have MS. It is possible for the doctor to give this diagnosis only when another definite diagnosis is made that can account for your symptoms.
- Possible – This means that you may have symptoms that look like MS, but your tests are normal. No other diagnosis which accounts for the symptoms has been confirmed.
- Probable – Many people fall into this category when they are first seen by a neurologist. You may have symptoms that look like MS and have had two separate episodes separated by at least a month, but normal findings on an MRI. You could also have an MRI that showed only one lesion in your brain or spine. In this case, your doctor will probably recommend repeating the MRI after a certain period of time (for instance, 3 months) to see if any other lesions appear. Depending on how certain your doctor is that you really do have MS, he may recommend that you consider starting an early therapy.
- Definite – Your case fits the diagnostic criteria above. You have had at least two attacks, separated in time, plus at least two areas of demyelination. Believe it or not, many people are relieved to receive a definite diagnosis of MS. I was. I knew what was wrong with me and I knew what I had to do next, rather than continuing to wonder what was causing my problems and worrying that it was something that I was doing.
What was your lumbar puncture experience like?