How to Get Through a Spinal Tap to Confirm an MS Diagnosis

In many if not most cases, neurologists can diagnose multiple sclerosis (MS) on the basis of symptoms, along with an MRI scan of the brain and spinal cord. But when results aren’t conclusive, they might turn to a spinal tap, also known as a lumbar puncture.

Read on to learn what a spinal tap entails, what it can and can’t reveal, and whether it poses any risks.

A spinal tap involves the removal of a sample of cerebrospinal fluid — the fluid that surrounds the brain and spinal cord.

A neurologist cannot 100 percent confirm or rule out MS by analyzing these fluids, says Barbara Giesser, MD, a multiple sclerosis specialist with Pacific Neuroscience Institute and a professor emeritus of clinical neurology at the David Geffen UCLA School of Medicine.

Even if spinal tap results are negative for MS, she notes, about 10 percent of people with MS have normal spinal fluid. “And other things [besides MS] can cause a positive result,” she says.

Despite these flaws, a spinal tap can be an important tool for MS diagnosis.

• White Blood Cell Count White blood cells are part of your immune system. In MS, the total number of white blood cells is up to seven times higher than normal.

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   Levels of monocytes, basophils, and neutrophils (types of white blood cells) are also higher than normal.

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• Immunoglobulin G (IgG) Index Immunoglobulins are antibodies produced by plasma cells.

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   IgG is the most common type of immunoglobulin in the human body.

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  High IgG levels can signal MS or simply inflammation or trauma. So, to distinguish between the two, researchers calculate a so-called IgG index. A high IgG index can signal MS in about 90 percent of people with the condition.

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• Neurofilaments Neurofilaments and neurofilament proteins help create the structure that supports your neurons (nerve cells).

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   If fragments of these structures are in your spinal fluid, that could mean your myelin — the protein that covers and protects your neurons — has been damaged, as is the case in MS.

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• Oligoclonal Bands These are also called bands of immunoglobulins. When these are higher than normal, they signal a high level of inflammation in the body. This inflammation could result from damage to the myelin sheath, which would indicate MS.

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  About 85 percent of people with MS show oligoclonal bands in their spinal fluid.

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  Sometimes, testing does not reveal oligoclonal bands, especially in the early stages of the illness, but they appear later as the disease progresses.

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Before you have a spinal tap, your doctor will order blood tests to check for any bleeding or clotting disorders. If you’re taking blood thinners or painkillers such as ibuprofen and aspirin, tell your doctor. You will probably have to stop taking them before the procedure.

Spinal taps most commonly take place at an outpatient facility. You’ll be asked to put on a hospital gown and either lie on your side with your knees drawn up or sit leaning forward on a stable surface. These positions flex your back and widen the spaces between your vertebrae, making it easier to insert a needle.

Your back will be washed and covered with a sterile sheet, and a local anesthetic will be injected into your lower back to numb the puncture site. Typically, this is the only painful part of the procedure. “Spinal taps are usually uncomfortable but seldom extremely painful,” notes Dr. Giesser.

When the needle used to remove spinal fluid is inserted through your spinal membrane and into the spinal canal, you may feel pressure in your back, but this part of the procedure is usually painless. Some people may feel some burning and nerve twinges when the needle is inserted. You may be asked to shift your position slightly to help the doctor correctly position the needle. A small amount of cerebrospinal fluid is then collected in a sterile container and sent to a lab for analysis.

When the needle is removed, a bandage is put on the entry site, and you’ll lie down for a while before leaving the medical facility. From start to finish, a spinal tap takes about a half hour.

A spinal tap using fluoroscopy — a type of medical imaging using a continuous X-ray image — may be recommended in some cases, Giesser says. Reasons include:

• If you’re overweight
• If you have degenerative bone disease
• If you have a spinal deformity, such as scoliosis or kyphosis

Like any invasive procedure, a spinal tap comes with certain risks, and doctors have to weigh those risks against the potential benefits.

Some people develop a headache — called a “spinal headache” — after a spinal tap. Spinal headaches usually start within a day or two after a lumbar puncture but can occur several days later. They are thought to result from an internal leak at the puncture site, which is believed to cause pressure changes in the cerebrospinal fluid that can be sensed by the dura mater, the tough membrane that surrounds the spinal cord.

You’ll know it’s a spinal headache if the pain goes away when you lie down but reappears when you sit or stand.

Home remedies for a mild spinal headache include:

• Lying down in a comfortable position
• Drinking liquids
• Taking an over-the-counter analgesic, such as acetaminophen (Tylenol)
• Studies have shown that caffeine can also be helpful.

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Let your doctor know if you develop a headache following a spinal tap, particularly if your pain or any other symptoms, such as nausea, are severe or get progressively worse.

According to Orhun Kantarci, MD, a professor of neurology at Mayo Clinic in Rochester, Minnesota, spinal headaches usually last no longer than three days, and they usually go away on their own.

Other potential complications of a spinal tap include infection and bleeding, but both are rare. Contact your physician immediately if you experience signs of infection such as fever, severe neck stiffness, and pain or redness at the puncture site.

• A spinal tap can help confirm a diagnosis of MS, particularly when an analysis of symptoms and a neurological exam and MRI scan haven’t been conclusive. But a spinal tap cannot categorically confirm or rule out MS. Additional tests will be needed.
• The procedure itself lasts around 30 minutes, and although uncomfortable, it’s rarely very painful. Severe side effects of spinal taps are rare, and the most common side effect is a headache, which usually goes away after a couple of days.
• If you experience signs of infection after your spinal tap or your headache doesn’t go away or worsens, contact your healthcare professional right away.