MS can cause a wide range of symptoms which result from damage to the CNS. In MS this damage is caused by demyelination, a process during which inflammatory cells attack myelin, the fatty covering that insulates axons (nerve fibers).
What causes MS symptoms?
Once the myelin insulation has been lost, the exposed nerve fibers can be further damaged or may break. Damage to myelin and axons slows down or disrupts the transmission of nerve impulses along one or more nerve pathways of the CNS. This disruption of the nerve signals causes the symptoms associated with MS.
Symptoms that appear during an MS relapse (exacerbation, attack, or flare-up) may appear gradually or all of a sudden and progress over a few days, after which time they may stabilize or plateau in severity over a period of days or weeks. In relapsing forms of MS, an exacerbation is typically followed by partial or complete remission, the process of which may take several weeks or months. MS attacks happen, on average, every 2 to 3 years. However, they may occur as frequently as every few months in more aggressive cases. A relapse which seems to occur less than 30 days following a previous relapse is considered to be part of the original relapse. Relapses may involve new symptoms or a worsening of previous symptoms.
Common and less common MS symptoms are shown below:
Most Common MS Symptoms
- Optic neuritis: an inflammation of optic nerve causing reduced vision or blindness, often sudden
- Double vision or diplopia
- Reduced contrast sensitivity
- Internuclear ophthalmoplegia or INO, resulting in blurred vision
- In males: impaired genital sensation, decreased sexual drive, erectile dysfunction, delayed ejaculation, or decreased force of ejaculation
- In females: impaired genital sensation, including pain, numbness, or itching, decreased sexual drive and/or lubrication, diminished orgasmic response, or weakness in vaginal muscles
- Paresthesia: tingling or “pins and needles”
- Somatic pain
- Headache (may be comorbid with MS)
- Trigeminal neuralgia: pain in the nerves of the face
- Paraplegia: weakness in both legs
- Possible weakness in legs, arms, hands, hip flexors, shins, or other muscle groups
- Extreme stiffness, loss of elasticity of arm and leg muscles
- Muscle spasms causing pain and limiting function
- Difficulty with memory, attention, or problem-solving
- Impaired judgment or ability to make decisions
- Sensory overload
- Mood swings, depression, stress, or anxiety
- Pseudobulbar affect: uncontrolled laughing or crying
- Inappropriate behavior
Less common symptoms
- Brief episodes of unconsciousness and abnormal movements
- Not the same as Paroxysmal symptoms: brief episodes of spasms, pain, or blurred vision (Uhthoff’s syndrome)
- Oscillating movement of arms, head, neck, or trunk
- Tremors can also affect the vocal cords
- Progressive weakening of chest muscles which control breathing
- Pneumonia infections