Infections and mobility issues are common complications of MS.

Multiple sclerosis, or MS, is associated with a wide range of symptoms that affect numerous body parts and systems.

For instance, the disease often affects the muscles, causing loss of balance, spasms, and weakness.

It can also lead to difficulty chewing and swallowing, and it even affects bladder and bowel control.

But these symptoms are only the beginning: When left untreated, MS can cause life-threatening complications.

Infection-Related MS Complications

It may come as a surprise, but people with MS are at high risk of contracting a number of infections.

Bladder problems are very common in people with MS, affecting at least 80 percent of them, according to the National MS Society.

Some people have trouble holding their urine (incontinence), while others can’t fully empty their bladder (retention).

If the bladder isn’t completely emptied, the retained urine may allow bacteria and fungi to grow out of control, creating a serious urinary tract infection.

This bladder dysfunction may also lead to kidney infections.

In the worst cases, the microbes find their way into the bloodstream, which can cause what’s known as sepsis, a chemical response in the blood that creates a whole-body inflammation that, in turn, may cause organ failure and death.

In fact, sepsis may be the biggest cause of MS-related deaths, according to a 2014 report in the journal PLoS One.

Sometimes, people with MS have trouble chewing and swallowing. This can allow foods and liquids, including your own mucus, to go the wrong way down and deposit in the lungs.

That may lead to a potentially fatal complication: aspiration pneumonia, which develops from inflammation and fluid accumulation in the lungs.

Multiple sclerosis may also cause the respiratory muscles to become weakened, reducing airway clearance, which raises the risk of lung and other respiratory tract infections.

Lung infections were the second-biggest cause of MS-related deaths in study PLoS One reported in 2014. Other research gives it the top spot for cause of death in people with MS.

Other MS Complications

The good news is that most people with MS are not severely physically disabled, and are still able to walk, according to the National MS Society.

However, many do require canes or crutches, and complications do happen among people with MS who aren’t disabled.

For instance, weakened muscles and balance issues from MS increase the risk of physical trauma from falls and accidents.

For those who are disabled by MS, long hours in bed or in a wheelchair can cause pressure sores, also known as bedsores and pressure ulcers.

As the name implies, these sores are injuries to skin tissue resulting from prolonged pressure in particular spots.

These sores must be taken seriously because they can cause difficult-to-treat infections and may develop into life-threatening sepsis.

Lack of walking and movement also weakens muscles.

What’s more, decreased mobility and the lack of weight-bearing activity can increase a person’s risk of osteoporosis, which can lead to broken bones, especially when combined with the high risk of falling among people with MS.

Corticosteroid drugs also increase the risk of developing osteoporosis.

This is particularly unfortunate, since these drugs are an important option for reducing inflammation and treating an MS relapse, or attack, which is the development of new symptoms or worsening of old ones.

Multiple Sclerosis and Depression

Scientists don’t fully understand the relation between depression and MS.

On the one hand, depression may be a direct physical effect of MS.

MS develops when the immune system attacks the protective myelin sheaths that envelop nerve fibers in the central nervous system, which includes the spinal cord and the brain.

So it’s plausible that when there is damage to myelin sheaths, and then the underling nerve fibers of brain areas involved with emotion (such as the hippocampus), people may develop behavioral changes including depression.

Multiple sclerosis can also change what is known as the body’s neuroendocrine system, which oversees hormone release, including hormones implicated in depression, such as serotonin.

On the other hand, depression may develop as a result of the stresses and challenges associated with having MS.

The medications used to treat MS, such as interferon beta, can also cause depression.