Getting the correct diagnosis of multiple sclerosis is a challenge in itself. For starters, no single test can make the determination conclusively. But there's more: Not everyone has all of the common symptoms of MS -- numbness, tingling, pain, fatigue, and heat sensitivity -- and the ones you do have can be symptoms of a variety of MS mimics, conditions mistaken for MS.
To piece together the puzzle, doctors look at the person's medical history, the results of a neurological exam, an MRI, and sometimes a spinal tap, explained Jack Burks, MD, a neurologist at Burks and Associates Health Care and Research Consulting Group in Reno, Nev., and chief medical officer of the Multiple Sclerosis Association of America. “The diagnosis also can require eliminating the possible MS mimicker diseases,” he said. That leads to an MS diagnosis by exclusion.
Here are conditions that can be mistaken for MS, starting with the most common:
Lupus. Like MS, lupus is an autoimmune disorder that can cause muscle pain, swelling of joints, fatigue, and migraines and that affects more women than men. “Lupus can begin just like MS,” Dr. Burks said. People with lupus don’t always have its typical rash and arthritis right away, making symptoms seem even more like MS.
Lyme disease. Lyme disease is an infection of the central nervous system transmitted through a tick bite. Symptoms include fatigue, headache, and muscle and joint aches -- just like MS. If you live in an area known for Lyme disease or recently traveled to one, your doctor will want to rule out the possibility, Burks said.

Stroke. Stroke and MS are both diseases of the brain. Symptoms of an MS flare can be similar to a stroke: loss of vision, difficulty walking, loss of feeling in limbs usually on one side of the body, and difficulty speaking. “While MS can occur in 70 year olds, if the person is older, you tend to think of stroke, not MS,” Burks said. A stroke needs immediate attention -- if you think you’re experiencing a stroke, call 911.
Fibromyalgia. Fibromyalgia and MS have some similar symptoms, including headache, joint and muscle pain, numbness and tingling of extremities, and fatigue. Like MS, fibromyalgia also affects women more often than men. But unlike MS, fibromyalgia will not show up on an MRI.
Sjogren's syndrome. Sjogren's is another autoimmune disorder, and the symptoms of many autoimmune disorders can overlap, Burks said. Sjogren’s causes fatigue and musculoskeletal pain and is more prevalent in women. The telltale signs are dry eyes and dry mouth, which makes it different from MS, he noted.

Vasculitis. This inflammatory disorder can mimic MS, said Kathleen Costello, MS, ANP-BC, MSCN, associate vice president of the Clinical Care Advocacy, Services and Research Department of the National Multiple Sclerosis Society. Vasculitis can affect your joints and cause joint pain. When it affects your eyes, you can have blurred vision. When it affects nerves, you can have numbness, tingling, and weakness in limbs.
Myasthenia gravis. Myasthenia gravis causes muscle weakness that, like in MS, often appears gradually over months to a year or two. It also causes double vision and difficulty walking and swallowing. The difference is that MS is an autoimmune disorder of the central nervous system, whereas myasthenia gravis is a disorder of the skeletal muscles.
Sarcoidosis. Sarcoidosis is another disorder that may share some neurological symptoms with MS: decreased vision, numbness, muscle weakness, and bowel and bladder changes. Though sarcoidosis can affect the brain, it usually starts in the lungs.

Vitamin B12 deficiency. Vitamin B12 plays a role in the metabolism of fatty acids needed to maintain the myelin sheath, the protective covering of the nerve fibers in the brain and spinal cord. When you’re deficient in B12, you can have MS-like symptoms such as fatigue, memory loss, and even depression. It can be identified with a simple blood test.
Acute disseminated encephalomyelitis (ADEM). This is a severe inflammatory attack affecting the brain and spinal cord. The symptoms are similar to MS, with 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 in adults.
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More rare MS mimics include:
  • Human T-cell lymphotropic virus-1, which can cause progressive spinal cord dysfunction
  • Migraines
  • Behcet’s disease, an inflammation of blood vessels throughout the body
  • Neurosyphilis, the advanced form of syphilis
  • Dural arteriovenous fistulas, abnormal structures of blood vessels along the spinal cord 
  • Binswanger’s disease, a type of vascular dementia
If you experience symptoms of any of these disorders, see a neurologist. Only with a correct MS diagnosis can you plan appropriate treatment for the condition.