Multiple sclerosis (MS) is an autoimmune disorder in which the body's immune system fails to properly recognize its own tissues and tries to destroy them. MS is believed to target its attacks on myelin (the sheath that wraps around filaments extending from nerve cell bodies), causing inflammation and damage to nerve cells. Damage caused by the mistaken immune system produces a variety of debilitating symptoms that typically progress over time.
Fatigue
Many individuals with multiple sclerosis experience severe fatigue that lasts for months or years. Like many other MS symptoms, there may be periods in which symptoms remit only to come back again some time later. This fatigue may be caused by substances secreted by immune cells. A study published in the November 2005 issue of the Journal of Immunology identifies a substance called macrophage migration inhibitory factor (MIF) that, when present, spurs the progression of MS and symptoms like fatigue. The research (conducted with mice) determined that high levels of MIF blocked the production of the corticosteroid known as cortisol in humans. Those with low levels of this hormone showed immune system changes that predicted a worsening of MS symptoms. Alternatively, those with low levels of MIF and high levels of cortisol showed reduced inflammation and lack of disease progression.
Neuromuscular and Sensory Symptoms
As the immune system attacks the myelin in the nerve cells of brain and spinal cord tissues, it causes a disruption in nerve signals that causes progressive neurological symptoms related to motor and sensory function. Weakness, tingling or numbness of the limbs, problems with walking, balance and coordination and even paralysis may occur.
Spasticity, or sustained muscle contractions or movements, is one of the more common side effects of MS, resulting in uncontrollable spasms or feelings of pain and tightness in the extremities (particularly the legs).
Some individuals may experience persistent mild sensory symptoms such as tingling, itching, burning or warmth in various areas of the body, as well as chronic pain. Impairments in bladder and bowel control and sexual function are also common.
Cognitive and Emotional Symptoms
Multiple sclerosis can affect cognitive (brain) functioning, impairing abilities to problem solve, plan, maintain and shift attention, perform calculations, learn and remember. It can also cause language problems, interfering with a person's ability to understand and produce speech. Roughly 50 percent of people with MS will develop cognitive symptoms.
Emotional symptoms like irritability, mood swings, severe depression and uncontrollable fits of laughing and crying (pseudobulbar affect) are also side effects of neurological impairment from the malfunctioning immune system.
Vision Symptoms
Vision can be one of the first areas affected by MS. The acute onset of double vision, eye pain or blurred vision is common. Reduced visual contrast or other reductions in visual clarity may also occur.
Less Common Symptoms
The immune system's attack on nerve cell function can cause a number of less common symptoms. These include slurred speech, problems swallowing, hearing disorders, tremor, headache, breathing problems, itching and seizures.
References
- Harvard: The Immune System's Terrible Mistake
- Journal of Immunology; "Cutting Edge: Macrophage Migration Inhibitory Factor Is Necessary for Progression of Experimental Autoimmune Encephalomyelitis"; ND Powell et al; 2005
- National MS Society: Multiple Sclerosis Symptoms
