Multiple sclerosis (MS) is known to cause many and various potential difficulties, from common issues like fatigue and vision problems to less common ones like breathing problems and hearing loss.

Problems directly associated with multiple sclerosis are usually referred to as “symptoms.” This category includes issues with movement or walking, balance difficulties, and sensations related to nerve damage like numbness or tingling.

But another term, “complications,” is used to describe problems indirectly related to MS, or to direct effects of the disease that are less common or cause substantial disability or distress.

Here is what defines a complication of MS, as well as an overview of some of the more common MS complications.

What Is an MS Complication?

There’s no universal standard to define a complication of MS, as opposed to a symptom, according to Jaime Imitola, MD, director of the division of multiple sclerosis and translational neuroimmunology at UConn Health in Farmington, Connecticut.

In most health conditions, says Dr. Imitola, the word “complications” refers to issues that develop outside the normal scope of the disease or as a result of sustained damage.

But there’s more than one way to define the scope of a disease. One way to view MS, says Imitola, is as “damage that occurs in the cerebrum, the top of the brain, or the spinal cord. And that defines what the complications might be.”

In other words, any noticeable symptom that occurs as a result of this internal damage could be considered a complication.

In practice, though, the most common symptoms of MS are usually considered to be within the normal scope of the disease, so “complications” is reserved for issues that arise from ongoing or long-standing disease, or those that aren’t directly due to nerve damage.

The range of complications you may develop because of ongoing damage is largely based on where your lesions are, says Imitola.

If you have extensive damage in your cortex, he notes, you can develop cognitive issues: memory, calculation, or attention problems.

If you have extensive brain stem damage, you can develop facial paralysis or complications in your motor and sensory pathways, including issues with walking, speech, and swallowing.

And if you have damage in your spinal cord, you can develop gait instability or other issues with walking.

When it comes to problems that indirectly result from nerve damage, the most common complication is injury caused by falls, says Imitola.

Other common indirect problems include urinary tract infections — which bladder dysfunction makes more likely — and pressure sores in people who use wheelchairs or are otherwise immobile for long periods of time.

While it’s important for doctors to emphasize that a major goal of multiple sclerosis treatment is to prevent or delay complications, says Imitola, people recently diagnosed with the disease should also be prepared for what their future might hold.

“Your life is going to change, and we have to address that issue,” he notes. “You try to diagnose early, treat aggressively, and tell the patient what to expect.”

Common MS Complications

Here are some of the more common issues that can occur because of ongoing damage from MS.

Vision Problems

Eye problems in MS often happen early in the course of the disease but can develop later as well.

Some types of MS-related vision problems include optic neuritis (inflammation of the optic nerve), diplopia (double vision), nystagmus (uncontrolled movement of the eyes), and internuclear ophthalmoplegia (impaired horizontal eye movement).

Vision problems often improve over time, but your vision may not return fully to its previous state.

Foot Drop

This common issue involves muscle weakness that makes it difficult to lift your foot at your ankle. As a result, it can be more difficult to walk.

Foot drop is caused by damage to the nerve that sends signals to the muscles that flex your ankle.

If an MS relapse causes sudden foot drop, the issue will likely improve over time, but foot drop in progressive MS is likely to stay the same or get worse.

A number of treatments for foot drop exist, including physical therapy, braces, and electrical stimulation devices.

Bladder Dysfunction

Bladder problems are very common in MS and can include overactive or underactive bladder — or both at different times in the same person.

People with MS may also lack the ability to hold in their urine (incontinence), have difficulty starting to urinate (hesitance), or not fully empty their bladder (retention).

People with untreated bladder dysfunction are more likely to experience bladder or urinary tract infections (UTIs). It’s important to treat UTIs and take steps to help prevent them.

Swallowing Problems

Known as dysphagia, problems with swallowing can be scary and sometimes dangerous.

A number of steps may help people with MS avoid swallowing difficulties, including posture changes and physical maneuvers, changing the consistency of food and beverages, and exercises to strengthen muscles. A speech language pathologist can assess swallowing and help make recommendations to reduce the risk of aspiration.

Breathing Problems

MS may reduce your ability to exhale fully or cough effectively, which can increase your risk for lung infections like pneumonia.

Certain exercises and lifestyle measures may help your breathing. It’s important to see your doctor whenever you experience a change in your breathing or symptoms of an infection.

Emotional Difficulties

MS can lead to depression and anxiety, both directly through the disease process and because of the stress of living with the condition.

People with MS can also experience sudden changes in their emotions, such as laughing or crying for no apparent reason (pseudobulbar affect).

And sometimes, people with MS may find it difficult to recognize facial expressions in other people.

Sexual Difficulties

MS can cause sexual dysfunction in a number of ways, including reduced libido, erectile dysfunction, reduced vaginal lubrication, fatigue, and emotional difficulties.

It’s usually possible to take steps to improve your sex life when you have MS, which will vary depending on what’s causing your difficulties.

Useful options for many people include lubricants, medications for erectile dysfunction, and psychotherapy or sex therapy.

Chronic Pain

People with MS may develop chronic pain for a number of reasons, including directly from nerve damage, because of muscle spasticity, or because of immobility and fatigue.

Certain drugs may help you manage your pain, and which you take will depend on the cause of your symptoms. It’s important to see your doctor to get your pain accurately diagnosed and treated effectively.

Exercise and physical therapy may be effective treatments for pain, as can lifestyle measures and alternative remedies like good nutrition, meditation, and acupuncture.

Skin or “Phantom” Symptoms

Most people with MS experience paresthesias, which are abnormal, temporary sensations including numbness, prickling, or pins and needles.

Other symptoms include losing feeling on the skin completely (hypoesthesia) and dysesthesias (painful sensations that can affect the legs, feet, arms, and hands), which feel like burning, prickling, stabbing, ice cold, or electrical sensations.

Itching (pruritis) is another form of dysesthesia.

Other abnormal sensations that may be experienced by people with MS include insects crawling, water dripping, wetness, pressure, and vibration in particular areas of the body. Some people, like this blogger, have described these feelings as “phantom” sensations, because nothing is actually happening to the skin (the sensations are caused by damage to the central nervous system).

Various treatments may help relieve MS-related skin symptoms, including anti-seizure medications, antidepressants, lidocaine patches, and topical creams.

Pressure Sores

If your MS has significantly reduced your mobility, you may develop pressure sores from sitting or lying in the same position for too long.

Loss of sensation related to MS may make it more difficult to realize that areas of your body are under pressure and at risk for sores.

It’s important to relieve pressure as often and effectively as you or your caregivers can, as well as to keep your skin clean and dry to prevent sores and let existing sores heal.

Blood Clots

Like pressure sores, blood clots may develop because of reduced movement and extended sedentary periods.

If a blood clot in your leg travels to your lungs, it may become a life-threatening condition called pulmonary embolism, blocking blood flow to your lungs.

Injury from a fall, and the time spent recovering from it, can also increase your risk of blood clots.

It’s important to move as much as your mobility level allows and to follow lifestyle measures like staying hydrated and eating well to reduce your risk of blood clots.

Bowel Dysfunction

About 68 percent of people who have MS experience bowel dysfunction. This complication is more common if you have disease involvement of the spinal cord.

Constipation is the most common bowel problem among people who have MS. Others experience involuntary bowel or fecal incontinence, due to MS interrupting or slowing the transmission of signals to and from the brain.

For relief, try eating more fiber, drinking more fluids, working with your doctor to adjust any medication that may be exacerbating your bowel dysfunction, establishing a regular bowel routine, and getting regular exercise. If bowel dysfunction persists, discuss the complication with your neurologist.

Resources We Love

National Multiple Sclerosis Society

The National Multiple Sclerosis Society is a nonprofit organization that aims to find a cure for MS. It also provides information about symptoms, diagnosis, treatment, resources, and support for MS.

National Institute of Neurological Disorders and Stroke (NINDS)

Part of the National Institutes of Health, NINDS aims to seek knowledge about the brain and nervous system and to reduce the burden of neurological disease. Its website offers information about the symptoms, prognosis, and treatment of MS.

Cleveland Clinic

The Cleveland Clinic, a nonprofit academic medical center, is one of the largest and most respected hospitals in the United States and a leader in research, education, and health information. Its website offers information about bladder and bowel dysfunction in MS.

Complications of Multiple Sclerosis