Multiple Sclerosis: What Are the First Symptoms and How Is It Diagnosed?

The first symptoms of multiple sclerosis (MS) often include vision changes such as blurred or painful vision in one eye, numbness or tingling in the face, arms or legs, weakness, balance trouble and unusual fatigue. These symptoms have many other possible causes, so they do not establish MS on their own. Sudden weakness, trouble speaking or loss of vision needs emergency care. This article covers early MS symptoms, how clinicians reach a diagnosis, what else can look similar, and when to seek care.

What are the first symptoms of multiple sclerosis?

MS is a condition in which the immune system attacks the protective coating around nerves in the brain, spinal cord and optic nerves. According to MedlinePlus (NIH), symptoms vary a great deal from person to person, depending on which nerves are affected. Several factors are thought to contribute to MS, and the exact cause is not fully understood.

Early symptoms often come on over days and may fade over weeks. Many people first notice one of these:

• Vision changes: blurry, dim or painful vision in one eye, often worse with eye movement.
• Numbness or tingling: in the face, an arm, a leg or one side of the body.
• Weakness or heavy limbs: a leg that drags or a hand that feels clumsy.
• Balance and coordination trouble: unsteadiness, dizziness or a sense of spinning. When these come on suddenly, they need emergency care because they can be signs of a stroke.
• Fatigue: a tiredness out of proportion to activity that rest does not fully relieve.

Less often, people report electric-shock sensations down the spine when bending the neck, bladder urgency, bowel changes, slurred speech or double vision. Mood changes, including depression and anxiety, can also occur in people with MS.

Why do MS symptoms come and go?

Many people have a relapsing pattern: a flare of new or worsening symptoms (often called a relapse or attack), followed by partial or full recovery. Between attacks, symptoms may be stable. In other people, symptoms gradually worsen over time. A clinician decides which pattern fits, and this can take time to become clear.

Heat, illness and stress can make existing symptoms feel temporarily worse without a new attack. A neurologist can help sort out a true relapse from a temporary flare of old symptoms.

Optic neuritis and other common first presentations

Inflammation of the optic nerve, called optic neuritis, is one of the common ways MS first shows up. It often causes eye pain with eye movement, muted colors and blurred vision in one eye, usually developing over hours to days. MedlinePlus (NIH) describes optic nerve disorders and notes that they have a range of causes. Optic neuritis can occur without MS, so it does not establish the diagnosis on its own. Any sudden loss of vision or sudden double vision needs emergency care, because a stroke or a blocked blood vessel in the eye can look similar. The same applies to a sudden loss of balance or coordination, sudden severe vertigo, or trouble walking that comes on suddenly, which can also be signs of a stroke.

Other first presentations include numbness that spreads over several days, a spinal cord problem causing leg weakness or bladder changes, and brainstem symptoms such as double vision or vertigo. New numbness in both legs, in the groin or inner thighs (the saddle area), or new loss of bladder or bowel control can signal a spinal cord emergency and needs emergency care.

How is multiple sclerosis diagnosed?

No single test diagnoses MS. Clinicians combine your history, a neurological examination and testing. The goal is to find evidence of damage in more than one area of the central nervous system, at more than one point in time, and to exclude other explanations. Neurologists commonly use a set of diagnostic criteria known as the McDonald criteria for this purpose.

Medical history and neurological exam

Your clinician will ask when symptoms began, how long they lasted, whether they resolved and whether you have had earlier episodes you set aside, such as a past episode of blurred vision or numbness. The exam checks vision, eye movements, strength, reflexes, sensation, coordination and walking.

MRI of the brain and spinal cord

Magnetic resonance imaging (MRI) is a central test. It can show areas of inflammation or scarring, called lesions, in the brain and spinal cord. A contrast dye is sometimes used to show active inflammation. Lesions on MRI can also occur with other conditions, including migraine, small-vessel disease and normal aging, so a radiologist and neurologist interpret the pattern, not just the presence of spots.

Spinal fluid and other tests

A lumbar puncture (spinal tap) can check the spinal fluid for immune markers that are often associated with MS. Evoked potential tests measure how quickly nerves carry signals from the eyes or limbs, and an eye specialist may examine the optic nerve. Blood tests are used mostly to look for other conditions that can mimic MS.

What else can look like MS?

Several conditions can cause similar symptoms or MRI findings, which is one reason diagnosis can take time. They include vitamin B12 deficiency, other autoimmune diseases such as lupus (see Lupus: Why Is It So Hard to Diagnose?), sarcoidosis, certain infections, migraine, stroke and other inflammatory conditions of the nervous system. A published framework on excluding alternative diagnoses in sarcoidosis illustrates how clinicians work through lookalike conditions.

Misdiagnosis can happen in both directions. A paper on communicating a misdiagnosis of MS describes the distress that people experience when a diagnosis is later revised, which is part of why careful review by a neurologist matters. If you have tremor, stiffness or slowed movement rather than numbness and vision change, see Early Signs of Parkinson's Disease Beyond a Tremor. If headache is your main symptom, see Migraine or Something More Serious? How to Tell the Difference.

Fatigue, mood and the emotional side of early MS

Fatigue is among the most common and disabling symptoms. MedlinePlus (NIH) lists many causes of fatigue, such as poor sleep, thyroid problems, anemia and depression, so fatigue alone is not a sign of MS.

Depression and anxiety are more common in people with MS than in the general population, according to the American Academy of Neurology guideline on psychiatric disorders in individuals with MS. A review of affective symptoms in MS describes how mood symptoms can be part of the illness, a reaction to it, or a side effect of treatment. Tell your clinician if your mood has changed, because treatment is available. A review of suicide prevention in neurology patients notes that suicidal thinking deserves direct attention in people with neurological disease. If you are having thoughts of harming yourself, call or text the 988 Suicide and Crisis Lifeline at 988. If you are in immediate danger, call 911.

Treatment after diagnosis

MS has no known cure, but treatment can reduce relapses and may slow progression. Disease-modifying therapies are prescription medicines chosen by a neurologist based on the disease pattern, other health conditions and personal factors such as pregnancy plans. Each has its own prescribing label with warnings and monitoring needs, so ask your prescriber or pharmacist about the label for any medicine you are offered, and do not change or stop a prescription on your own.

During a relapse, clinicians sometimes use a short course of corticosteroids to speed recovery. MedlinePlus (NIH) explains how steroids work and their possible side effects. Physical therapy, rehabilitation, bladder and fatigue management, and mental health care are also part of care. Some people ask about cannabis for symptoms such as spasticity or pain; MedlinePlus (NIH) gives general information, and it is worth discussing with your neurologist because evidence and risks vary.

If you are pregnant or planning pregnancy, talk with your neurologist and obstetric clinician early, since medicine choices matter. See MedlinePlus (NIH) on health problems in pregnancy for general background.

How to prepare for a visit about possible MS

• Write down each symptom, when it started, how long it lasted and whether it went away.
• Include past episodes, even brief or mild ones, such as an earlier bout of blurred vision or numbness.
• List all medicines and supplements, and note any family history of MS or other autoimmune disease.
• Note what makes symptoms worse, such as heat or exertion.
• Bring prior eye exam, imaging or lab records if you have them.

Your primary care clinician may refer you to a neurologist. Waiting for evaluation is stressful, and it can help to remember that most people with these symptoms are still being sorted out, and many have a cause other than MS.

When to Seek Medical Care