Some people have mild symptoms, such as blurred vision and numbness and tingling in the limbs. In severe cases, a person may experience paralysis, vision loss, and mobility problems. However, this is rare.
Scientists do not know exactly what causes MS, but they believe it is an autoimmune disorder that affects the central nervous system (CNS). When a person has an autoimmune disease, the immune system attacks healthy tissue, just as it might attack a virus or bacteria.
In the case of MS, the immune system attacks the myelin sheath that surrounds and protects the nerve fibers, causing inflammation. Myelin also helps the nerves conduct electrical signals quickly and efficiently.
Multiple sclerosis means “scar tissue in multiple areas.”
When the myelin sheath disappears or sustains damage in multiple areas, it leaves a scar, or sclerosis. Doctors also call these areas plaques or lesions. They mainly affect:
There are four types of MS:
Clinically isolated syndrome (CIS): This is a single, first episode, with symptoms lasting at least 24 hours. If another episode occurs at a later date, a doctor will diagnose relapse-remitting MS.
Relapse-remitting MS (RRMS): This is the most common form, affecting around 85% of people with MS. RRMS involves episodes of new or increasing symptoms, followed by periods of remission, during which symptoms go away partially or totally.
Primary progressive MS (PPMS): Symptoms worsen progressively, without early relapses or remissions. Some people may experience times of stability and periods when symptoms worsen and then get better. Around 15% of people with MS have PPMS.
Secondary progressive MS (SPMS): At first, people will experience episodes of relapse and remission, but then the disease will start to progress steadily.
The most common symptoms of MS are:
Muscle weakness: People may develop weak muscles due to lack of use or stimulation due to nerve damage.
Numbness and tingling: A pins and needles-type sensation is one of the earliest symptoms of MS that can affect the face, body, or arms and legs.
Lhermitte’s sign: A person may experience a sensation like an electric shock when they move their neck, known as Lhermitte’s sign.
Bladder problems: A person may have difficulty emptying their bladder or need to urinate frequently or suddenly (urge incontinence). Loss of bladder control is an early sign of MS.
Bowel problems: Constipation can cause fecal impaction, which can lead to bowel incontinence.
Fatigue: This can undermine a person’s ability to function at work or at home. Fatigue is one of the most common symptoms of MS.
Dizziness and vertigo: These are common problems, along with balance and coordination issues.
Sexual dysfunction: Both males and females may lose interest in sex.
Spasticity and muscle spasms: This is an early sign of MS. Damaged nerve fibers in the spinal cord and brain can cause painful muscle spasms, particularly in the legs.
Tremor: Some people with MS may experience involuntary quivering movements.
Vision problems: Some people may experience double or blurred vision, a partial or total loss of vision, or red-green color distortion. This usually affects one eye at a time. Inflammation of the optic nerve can result in pain when the eye moves. Vision problems are an early sign of MS.
Gait and mobility changes: MS can change the way people walk, because of muscle weakness and problems with balance, dizziness, and fatigue.
Emotional changes and depression: Demyelination and nerve-fiber damage in the brain can trigger emotional changes.
Learning and memory problems: These can make it difficult to concentrate, plan, learn, prioritize, and multitask.
Pain: Pain is a common symptom in MS. Neuropathic pain is directly due to MS. Other types of pain occur because of weakness or stiffness of muscles.
In the later stages, people may experience changes in perception and thinking and sensitivity to heat.
MS affects individuals differently. For some, it starts with a subtle sensation, and their symptoms do not progress for months or years. Sometimes, symptoms worsen rapidly, within weeks or months.
The doctor will carry out a physical and neurological examination, ask about symptoms, and consider the person’s medical history.
No single test can confirm a diagnosis, so a doctor will use several strategies when deciding whether a person meets the criteria for a diagnosis.
Other conditions have symptoms that are similar to those of MS, so a doctor may suggest other tests to assess for other possible causes.
MS is a potentially severe health condition that affects the nervous system. Progression of MS is different for each person, so it is hard to predict what will happen, but most people will not experience severe disability.
As researchers learn more about genetic features and changes that occur with MS, there is also hope that they will be able to predict more easily which kind of MS a person will have and establish the most effective treatment from the earliest stage.