How Inflammation in MS Affects Your Body

Multiple sclerosis (MS) is a chronic inflammatory condition that affects more than 2 million people worldwide. MS is associated with demyelination of the central nervous system (CNS, the brain and spinal cord), resulting in flares and remissions that affect your vision, balance, and muscle coordination.

MS occurs when your immune system attacks the myelin sheath, the coating around your nerve fibers responsible for the speedy and efficient transmission of nerve signals throughout the body.

Although inflammation is a major driver of demyelination (damage to the myelin sheath), the underlying process by which this occurs is relatively not well understood. This article will discuss the link between inflammation and MS and how inflammation affects the body. 

The Link Between Inflammation and MS

The exact link between inflammation and MS remains a mystery. It is believed that overactive immune cells (T cells) in genetically susceptible individuals attack the myelin sheath of nerve cells, causing neurological dysfunction.

These overactive T cells secrete cytokines (chemical messengers that regulate the inflammatory response). This process contributes to an inflammatory cascade that damages nerves in the brain and spinal cord. 

Mouse studies have found that immune cells in the gut—group 3 innate lymphoid cells (ILC3s) that normally protect against inflammation—may have the opposite effect in multiple sclerosis. Specifically, when these cells are found in the brain, they have been shown to have proinflammatory (causing inflammation) rather than anti-inflammatory effects.

Effects of MS on Your Body

Multiple sclerosis can have effects throughout your body.

Primary vs. Secondary Symptoms

MS symptoms vary based on the location and extent of demyelination. Some symptoms, like optic neuritis (impairment of the optic nerve), are fairly specific and unique to MS. Others, like fatigue and erectile dysfunction, are more general and nonspecific, meaning they can be caused by other conditions.

An MS flare may present with one or more of the following common symptoms:

• Fatigue
• Muscle dysfunction: Characterized by tremors, spasticity (muscle stiffening), and weakness
• Bowel and bladder dysfunction: Characterized by frequent urination, urinary urgency or hesitancy, incontinence, constipation, and/or frequent urinary tract infections
• Vision problems: Such as optic neuritis
• Sexual dysfunction: Especially erectile dysfunction
• Cognitive dysfunction: Can lead to short-term memory loss and difficulty concentrating
• Vertigo: A sensation of spinning and unsteadiness
• Generalized pain: Sensations such as electrical nerve zings, numbness, tingling, prickling, stabbing, tearing, or feelings of pressure

Less common symptoms include:

• Trigeminal neuralgia or tic douloureux: Shock-like or burning sensations in the face that occur due to damage to the fifth cranial nerve (the trigeminal nerve) 
• Glossopharyngeal neuralgia: Pain in the tongue, throat, ear, or tonsils due to damage to the ninth cranial nerve (the glossopharyngeal nerve)
• Itchiness (pruritus)
• Difficulty swallowing 
• Difficulty breathing: Due to weakness in the respiratory muscles 
• Temporary hearing loss
• Seizure
• Pseudobulbar affect: A phenomenon characterized by uncontrollable laughing or crying (especially in situations that do not call for such reactions) due to nerve damage in the cerebellum

Secondary symptoms are complications that can arise from primary symptoms or medical conditions that are left untreated. Some common secondary symptoms include:

• Depression
• Bladder dysfunction, which can cause repeated urinary tract infections
• Decreased bone density (increased fracture risk), loss of muscle tone, and poor posture due to inactivity
• Shallow breathing due to generalized muscle weakness and inactivity
• Pressure sores from immobility
  

Your Skeletal System 

MS does not directly impact the skeletal system but may indirectly impact it. Fatigue and muscle weakness increase the risk of osteopenia (low bone density) and osteoporosis (progressive bone thinning). Low bone density is associated with higher fall risk(can cause you to fall) and can lead to bone fractures.

Older females are particularly impacted by conditions of secondary systems that affect the skeletal system. They have a higher risk of osteoporosis than males due to reduced estrogen levels at menopause.

Your Nervous System

Multiple sclerosis affects your nervous system in many ways.

Hearing and Vision Loss

The brain stem largely controls vision and hearing. Any damage to this part of the brain can lead to vision or hearing loss.

Vision loss due to optic neuritis (inflammation of the optic nerve) is often the first sign of MS. Optic neuritis can present as a frightening dimming or blurring of vision. Other vision symptoms may include:

• Pain with eye movement
• Color blindness
• Appearance of blind spots
• Appearance of flashing or flickering lights
  

Fatigue, stress, and extreme heat are possible triggers of optic neuritis. Vision loss is usually temporary. Rest, cooling, and high-dose steroids are the standard treatment for optic neuritis.

Some studies have shown that Black Americans with MS have a higher prevalence of optic neuritis than White Americans with MS.

Inflammation of the eighth (vestibulocochlear or auditory) cranial nerve can cause plaques that lead to tinnitus (ringing of the ears), hearing loss, and hyperacusis (an intolerance or sensitivity to normal sounds or noises). Studies show that up to 6% of people with MS experience hearing loss.

Speech Issues

Dysarthria, or problems with speech production, is commonly associated with lesions in the brain stem that cause weakness or a lack of coordination of the muscles of the tongue, lips, cheeks, and mouth. As a result, slurred, nasal, or low-volume speech may occur.

The fifth, seventh (facial), eighth, ninth, tenth (vagus), and twelfth (hypoglossal) cranial nerves are all involved in the innervation (causing excitement in nerves) of muscles involved with speech production.

If any of these nerves are affected by MS, it can lead to difficulty pronouncing words or slurred speech. Notably, many of these cranial nerves also control the muscles involved in swallowing. Therefore dysphagia (difficulty in swallowing) may also be observed.

Muscle Weakness

Pain, muscle dysfunction, fatigue, and changes that occur due to lack of movement (deconditioning) may all contribute to muscle weakness. When nerve signals to your muscles are disrupted, it can lead to muscle wasting, fiber loss, muscle contracture (shortening and hardening of muscles), and joint contractures, which may cause weakness, spasticity, and muscle stiffness.  

Balance Problems 

MS can impact your balance in several ways. Disruptions in nerve messaging signals can affect the many parts of your body that need to work together to achieve balance.

Nerve damage in certain parts of the brain, like the cerebellum, may also affect proprioception (the ability to sense the orientation of your body in the environment). If you are feeling weak, fatigued, or have muscle dysfunction, your balance and coordination may be impacted.

Your Digestive System 

MS can greatly impact your digestive system because the proper functioning of your gut depends on continuous feedback between your central nervous system and digestive organs. Digestive system effects of MS include constipation, bladder or bowel dysfunction, difficulty swallowing (dysphagia), and fecal incontinence.

Your Immune System 

MS is an immune-mediated condition. In genetically susceptible individuals, the immune system attacks its own healthy myelin sheath cells that coat your nerve cells. When the myelin becomes damaged, the nerve loses its ability to communicate properly with muscles, tissues, and other organs. Eventually, the nerve may die. 

In MS, immune-system cells, namely macrophages and lymphocytes, destroy myelin and the cells that produce it (oligodendrocytes), leaving behind plaques or lesions. Symptoms of pain, vision loss, and organ dysfunction result from these interrupted nerve signals.

Therefore, the focus of MS research is to better understand the mechanisms of action that underlie MS and to find therapeutic modalities and tools to stop the immune system from attacking myelin in the body.

Your Circulatory System 

Cardiovascular dysfunction in MS is not well understood and therefore likely underrecognized. It can affect this system in a variety of ways leading to changes in blood pressure, heart rate, heart rhythm, and left ventricular systolic function (pumping blood from the heart to the body).

If left untreated, these changes can result in pulmonary edema (the lung's air sacs fill with fluid) or cardiomyopathy (progressive damage to the heart muscle).

Your Reproductive System 

In general, MS does not impact fertility. But some methods of birth control, specifically oral contraceptives, may impact the effectiveness of MS drugs and vice versa. Also, some disease-modifying therapies (DMTs) for MS are not recommended for people who are pregnant or who may become pregnant due to the effects on the embryo or fetus.

MS has been associated with higher rates of erectile dysfunction, which may impact the ability to maintain an erection and ejaculate during sex.

Managing Symptoms From Head to Toe 

No two presentations of MS are the same. MS can have no symptoms in one person and cause vision loss, pain, and fatigue in another, underscoring the need for more research on the link between inflammation and MS.

Work with a healthcare provider on a treatment plan that addresses your symptoms and type of multiple sclerosis. Disease-modifying therapies aimed at slowing the progression of MS, therapies that target specific symptoms, and lifestyle changes are key components of treatment.

If you are interested in participating in a clinical trial, speak with your healthcare provider about which clinical trials may be best for you.

Promising advances in B-cell depletion therapy, aimed at preventing inflammation and immune-mediated damage to the brain and spine, have been shown to prevent or delay the onset of MS. Still, more research is needed to reinforce these findings.

Summary

Multiple sclerosis (MS) is a chronic inflammatory condition that occurs when your immune system attacks the myelin sheath, the coating around your nerve fibers, which are responsible for the speedy and efficient transmission of nerve signals throughout the body.

The inflammation that results can give rise to a number of multi-organ symptoms that affect your vision, balance, and muscle coordination.

A Word From Verywell 

In MS, inflammation is at the root of many symptoms, but you may not experience all or even most MS symptoms. Remember that symptoms vary widely from person to person. No two MS experiences are the same, but proper treatment and a healthy lifestyle can benefit anyone with a progressive condition like MS.