What causes symptoms in MS?
MS attacks the protective covering — myelin — of the brain and spinal cord, causing inflammation and often damaging the myelin in patches. When this happens, the usual flow of nerve impulses along nerve fibres (axons) is interrupted or distorted. The result may be the wide variety of MS symptoms, depending upon what part or parts of the central nervous system are affected. Not all people with MS will experience all symptoms and often the symptoms will improve during periods of remission.
There are a variety of ways to manage symptoms, ranging from pharmacological treatments to non-medicinal strategies such as physiotherapy, occupational therapy, exercise programs and alternative and complementary treatments. The following is a list of some of the more common MS symptoms.
Most Common MS Symptoms
Balance, and vertigo, or dizziness problems are common in MS and their management can be difficult. Balance and dizziness may present as symptoms of a relapse, or may be permanent, and can pose increased safety risk for falls.
MS lesions in the brain or spinal cord can disrupt the normal bladder process by interfering with the transmission of signals between the brain and urinary system.
Bowel dysfunction in MS most commonly presents as constipation but can include diarrhea and incontinence.
Cognitive changes can be one of the earliest manifestations of demyelination associated with MS and will affect between 40-70% of people. Memory problems, especially short term memory, are the most common.
Depression is more prevalent in people with MS than in the general population and may be of a reactive nature, not only at the time of diagnosis but throughout the course of the disease.
MS fatigue can be one of the most disabling symptoms of MS; up to 90% of people with MS experience fatigue.
Gait (difficulty walking)
Several factors may contribute to gait disturbance such as muscle weakness, spasticity, balance and co-ordination problems, fatigue and pain.
Heat Intolerance (Uhthoff's Phenomena)
Many people with MS experience sensitivity to increased body temperature. Demyelinated fibers in the central nervous system can be very sensitive to even small elevations of core body temperature resulting in conduction delays or even conduction block.
Optic neuritis, inflammation of the optic nerve, presents as sudden onset of visual blurring or loss of vision in one eye, particularly in the central visual field.
About 50% of people with MS will experience some MS related pain during the course of the disease and it can take several forms.
Paroxysmal symptoms refer to a sudden onset of a neurological symptom, or cluster of symptoms that may last over seconds to minutes, repeating a few to very many intervals per day.
Sensory Impairment, Numbness / Tingling
Numbness is the most common sensory symptom, and usually occurs with an onset in one or more limbs.
MS can affect sexual feelings and functions both directly (primary sexual effects) and indirectly (secondary and tertiary sexual effects).
Spasticity (see also Pain)
Spasticity in MS is related to alterations in the normal excitory / inhibitory balance on the nerves responsible for movement, caused by lesions in central pathways and can be both intermittent (spasms) and tonic (stiffness).
Tremor is a movement disorder with an involuntary, relatively rhythmic pattern, related to demyelination in the cerebellum and its pathways.
Weakness is a common symptom of MS. Motor weakness is related to impaired nerve conduction due to inflamed and / or damaged central nerve pathways.
Less Common MS Symptoms
Bipolar Affective Disorder (Mood Lability)
Mood swings alternating between mania and depression, known as bipolar disorder, are more common in MS than in the general population.
Difficulty Speaking (Dysarthia)
Dysarthria result from a variety of neurological disturbances and can range from mild difficulty enunciating words to sounding like speaking with marbles in one’s mouth. Speech can sound garbled, and unclear.
Difficulty Swallowing (Dysphagia)
Dysphagia can commonly be mild choking, most often with liquids but can also be quite severe. The variation of MS involvement offers the potential for a wide variety of swallowing difficulties.
Dry mouth in MS is usually related to side-effects of medications.
A worsening or aggravation of existing symptoms, or even the emergence of new ones just before the menstrual cycle, followed by an improvement during menstruation or immediately following, can happen.
Inappropriate affect (pseudo bulbar affect, emotional incontinence, involuntary emotional expression disorder-IEED) is uncontrolled or involuntary laughter and/or crying, and can be a distressing symptom in MS.
Poor Coordination (Incoordination)
Poor coordination in MS results from cerebellar involvement and can be one of the most disabling symptoms of MS.