Multiple Sclerosis (M.S.) involves damage to the nerves that control all different parts of our bodies. The technical term is “demyelinating,” breakdown of the myelin sheath that covers nerves. It’s most likely an auto-immune condition, in which the immune system mistakenly attacks that part of the body. Symptoms of M.S. are varied; at first they come and go, but eventually become permanent. The disease usually begins between 15- and 50-years old.
Genetics plays a role, although the risk of a brother or sister also getting M.S. is 5% at most. There’s evidence of increased risk for a patient’s children, but the risk is small. The disease may possibly be triggered by some common virus, but this hasn’t been proved. M.S. is more common in northern than southern climates (reverse in the southern hemisphere), but even this theory has been reconsidered recently. Bottom Line: the disease isn’t rare, and its cause is unknown.
Since many different parts of the nervous system may be involved, symptoms are different in every patient. An attack is defined as symptoms lasting at least 24 hours, without fever or infection. The common ones include the following:
- Numbness & tingling in just one part of the body, often with loss of sensation
- New visual loss getting worse over hours, often with eye pain (Optic Neuritis)
- Double vision
- Problems with balance & with walking
- Vertigo (usually later in the disease; the vast majority of Vertigo isn’t M.S.)
- Bladder problems: can’t urinate for a day, or incontinence (losing urine) (large amounts, not just drops)
- Electric shock runs down body when bending the neck forward (Lhermitte’s Sign)
- Weakness or near-paralysis of both legs
- Heat sensitivity — any of the above symptoms gets worse in heat (including hot showers) (called Uhthoff phenomenon)
- Excessive Fatigue along with any of the above symptoms
The diagnosis of M.S. is made by finding 2 different abnormalities of the brain or spinal cord “separated in time & space.” “Separate in time” means that they don’t occur together; that’s because attacks come and go (relapses and remissions; get worse get better). “Separate in space” means different parts of the nervous system (“multiple”).
We like, or actually need, to see the abnormalities ourselves. We can’t just hear that last year the patient had such-and-such a symptom for a month; we want to do an actual examination. This obviously may delay diagnosis. But nowadays, we have various tests.
The MRI can see nerve demyelination even without symptoms. There are ways to measure how fast nerve impulses travel, especially through the eyes to the brain, to find damage on one side compared to the other (visual evoked responses). There are also tests of nerve damage that can be identified by spinal tap (finding “oligoclonal bands” in spinal fluid). So a Neurologist can diagnosis M.S. without actually finding the abnormalities on physical examination.
M.S. is a tricky disease, since it consists of relapses & remissions. Patients usually feel well for a number of years, but then the relapses (attacks) become more & more frequent, leading to permanent disability. Treatment can delay this; it’s possible that the earlier the treatment, the better long-term success. Unfortunately, treatment has possibly-dangerous side-effects, and it’s impossible to tell which patients benefit most from starting which drugs at what point.
Overall, an average M.S. patient winds up needing a cane to walk by around age 60, and may have about a 10-year shorter life-span than those without the disease. However, the problem here is defining “average patient,” since the course of disease can play out so differently from person to person.