Getting a correct diagnosis of multiple sclerosis (MS) can be a challenge.
No single test can determine a diagnosis conclusively, and not everyone has all of the common symptoms of MS, such as numbness, tingling, pain, fatigue, and heat sensitivity. And to complicate matters, the symptoms you do have may resemble those of some other condition.
To figure out what’s causing possible MS symptoms, doctors look at your medical history, the results of a neurological exam, and an MRI — and sometimes do a spinal tap (also called a lumbar puncture), says Jack Burks, MD, a neurologist and chief medical officer for the Multiple Sclerosis Association of America. "The diagnosis can also require eliminating the possible MS mimicker diseases," he says. That leads to an MS diagnosis by exclusion.
Here are some of the conditions that are sometimes mistaken for multiple sclerosis:
Lyme disease is a bacterial infection transmitted through a tick bite. Early symptoms include fatigue, fever, headaches, and muscle and joint aches. Later symptoms can include numbness and tingling in the hands and feet, as well as cognitive problems such as short-term memory loss and speech issues. If you live in an area that’s known to have Lyme disease or have recently traveled to one, your doctor will want to rule out the possibility, Dr. Burks says.
A migraine is a type of headache that can cause intense pain; throbbing; sensitivity to light, sounds, or smells; nausea and vomiting; blurred vision; and lightheadedness and fainting. A study published online in Neurology in August 2016 found that a migraine was the most common correct diagnosis in study subjects who had definitely or probably been misdiagnosed with MS, occurring in 22 percent of them. That said, headaches — and migraines in particular — do commonly occur with MS, shows a study published in Neurological Sciences in April 2011. And according to a study published in the Journal of Headache Pain in October 2010, they are also significantly associated with other types of pain, as well as with depression.
Migraines can be difficult to diagnose, and doctors use some of the same tools to diagnose the headaches as they do for MS, including taking a medical history and performing a thorough neurological examination.
Conversion and psychogenic disorders are conditions in which psychological stress is converted into a physical problem — such as blindness or paralysis — for which no medical cause can be found. In the Neurology study on MS misdiagnosis, 11 percent of subjects definitely or probably misdiagnosed with MS actually had a conversion or psychogenic disorder.
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease that, like multiple sclerosis, attacks the myelin sheaths — the protective covering of the nerve fibers — of the optic nerves and spinal cord. But unlike MS, it usually spares the brain in its early stages. Symptoms of NMOSD — which include sudden vision loss or pain in one or both eyes, numbness or loss of sensation in the arms and legs, difficulty controlling the bladder and bowels, and uncontrollable vomiting and hiccups — tend to be more severe than symptoms of MS. Treatments for MS are ineffective for and can even worsen NMOSD, so getting an accurate diagnosis is extremely important. A blood test known as the NMO IgG antibody test can help to differentiate between MS and NMOSD.
Lupus is a chronic, autoimmune disorder that, like MS, affects more women than men. It can cause muscle pain, joint swelling, fatigue, and headaches. The hallmark symptom of lupus is a butterfly-shaped rash covering the cheeks and bridge of the nose, but only about half of people with lupus develop this rash. There is no single diagnostic test for lupus, and because its symptoms are similar to those of many other conditions, it is sometimes called “the great imitator.”
Rheumatologists (physicians specializing in diseases of the muscles and joints) typically diagnose lupus based on a number of laboratory tests and the number of symptoms characteristic of lupus that a person has.
A stroke occurs when a portion of the brain stops receiving a steady supply of blood, and consequently doesn't get the oxygen and nutrients it needs to survive. Symptoms of a stroke include loss of vision; loss of feeling in the limbs, usually on one side of the body; difficulty walking; and difficulty speaking — all of which can also be signs of an MS flare. The age of the person experiencing the symptoms may help to pin down the correct diagnosis. "While MS can occur in 70-year-olds, if the person is older, you tend to think of stroke, not MS," Burks says. A stroke requires immediate attention; if you think you’re experiencing a stroke, call 911.
Fibromyalgia and MS have some similar symptoms, including headaches, joint and muscle pain, numbness and tingling of extremities, memory problems, and fatigue. Like MS, fibromyalgia is more common in women than in men. But unlike MS, fibromyalgia does not show up as brain lesions on an MRI.
Sjögren’s syndrome is another autoimmune disorder, and the symptoms of many autoimmune disorders overlap, Burks says. Sjögren’s causes fatigue and musculoskeletal pain and is more common in women than in men. But the telltale signs are dry eyes and dry mouth, which are not associated with MS.
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Vasculitis is an inflammation of the blood vessels that can mimic MS, says Kathleen Costello, an adult nurse practitioner and at The Johns Hopkins MS Center in Baltimore and vice president of healthcare access at the National Multiple Sclerosis Society. Depending on the type of vasculitis, symptoms can include joint pain, blurred vision, and numbness, tingling, and weakness in the limbs.
Myasthenia gravis is a chronic autoimmune disease that causes muscle weakness that typically comes and goes, but tends to progress over time. The weakness is caused by a defect in the transmission of nerve impulses to muscles. In many people, the first signs of myasthenia gravis are drooping eyelids and double vision. Like MS, it can also cause difficulty with walking, speaking, chewing, and swallowing. If a doctor suspects myasthenia gravis, a number of tests can help to confirm or rule out the diagnosis.
Sarcoidosis is another inflammatory autoimmune disease that shares some symptoms with MS, including fatigue and decreased vision. But sarcoidosis most commonly affects the lungs, lymph nodes, and skin, causing a cough or wheezing, swollen lymph nodes, and lumps, sores, or areas of discoloration on the skin.
Vitamin B12 deficiency can cause MS-like symptoms such as fatigue, mental confusion, and numbness and tingling in the hands and feet. That's because vitamin B12 plays a role in the metabolism of fatty acids needed to maintain the myelin sheath. Vitamin B12 deficiency can be identified with a simple blood test.
Acute disseminated encephalomyelitis (ADEM) is a severe inflammatory attack affecting the brain and spinal cord. Symptoms include fever, fatigue, headache, nausea, vomiting, vision loss, and difficulty walking. A very rare condition, ADEM typically comes on rapidly, often after a viral or bacterial infection. Children are more likely to have ADEM, while MS is more likely to occur in adults.