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Myasthenia Gravis (MG) is not uniform
in the way it affects people. Different people have difficulties
with different muscle groups - severity may fluctuate, and reaction
to treatment can vary as well. The course of the condition is variable,
but in most cases progressive.
For this reason, the disease is very
confusing to the undiagnosed myasthenic (and puzzling to the unsuspecting
physician). At one time the myasthenic may function normally, and
at another time experience severe loss of strength. Others may think
that the myastenic is lazy, or that they are suffering from a psychological
problem. This can lead to frustration and emotional stress, which
only exasperates the condition.
There are many factors that can
trigger episodes of weakness in myasthenics, including other illnesses
(e.g. viral respiratory infections), drugs that affect the neuromuscular
junction, hot weather, pregnancy, and emotional upset. The undiagnosed
myasthenic might not connect the various symptoms to one condition.
It should be noted that pregnancy can worsten, improve or have
no effect on the condition - that is, a woman will not know how
pregnancy will affect her condition until she is actually pregnant.
The symptoms of MG often consist of muscle fatigability with the
myasthenic complaining of worsening of symptoms later in the day
after their muscles have been fatigued or after being repetitively
exercised.
Usually, weakness of the eye muscle
is the first noticeable symptom. The disease may stay there, or
it may progress to the rest of the body. The symptoms range from
difficulty in eye motion resulting in double vision or droopy eyelids,
to weakness and fatigability in the arms and legs. Other symptoms
may include fatigue of throat muscles, resulting in swallowing difficulties
and choking, fatigue of the muscles of speech, resulting in slurred
and unintelligible speech, or difficulty in breathing.
Ocular Symptoms
Ocular myasthenia is when MG confines
itself to the eye muscles. The impact of the condition on eye muscles
include:
· a drooping of one or both
eyelids,
· double or blurred vision
· weakness of the muscles that move the eyeballs.
During a fatigue ocular episode, a
myasthenic's window of vision becomes restricted to the narrow slits
between the droopy upper lids and the lower lid. For this reason,
a number of myasthenics walk around with their noses in the air
(when their neck muscles are strong enough to support their head)!
Bright lights can aggravate the symptom.
In a minority of myasthenics (around
15%), MG is limited to ocular problems. But for most whose first
symptoms are ocular, MG eventually moves onto other parts of the
body within a couple of years.
Three different
serial pictures to demonstrate fatigue of eyelid muscles as the
patient keeps looking up.
After a few minutes of rest, the eyelids have returned to near-normal
position.
Posey
& Spiller
Fatigue (Ptosis) in a patient with MG
Oral Symptoms
Oral symptoms include difficulties
with:
· swallowing (dysphagia)
· chewing,
. speaking and
· breathing.
Muscle weakness in the pharynx (the
section of the alimentary canal that extends from the mouth and
nasal cavities to the larynx, where it becomes continuous with
the esophagus) is another early sign of MG.
Swallowing difficulties are of particular
concern as they can be dangerous. Myasthenics typically do well
at the beginning of a meal but tire at the end, making swallowing
too difficult. Some deteriorate to a point where there is total
loss of ability to chew and swallow. At this point, food may stick
in the throat, or food and drink may start to go the wrong way,
for example into the windpipe, causing coughing and choking.
Foods which may trigger MG symptoms
may be:
. very hot
. spicy
. dry and britty
Foods which require a lot of chewing
effort, such as tough meats or chewy sweets, could also tire out
the myasthenic and cause difficulty in swallowing.
In situations where swallowing is
too difficult, then the myasthenic may be advised not to eat or
drink at all until symptoms improve. They will be alternatively
fed in accordance with a dietician's recommendation or be fed
intravenously.
MG can affect one's speech in a number of ways. Fatigue sets into
muscles of:
· the throat (not allowing
one to swallow their saliva)
· the tongue (not allowing one to adequately move the tongue
around the mouth, and not move it quickly enough)
· the jaw (not being able to move it quickly enough)
· the mouth (not being able to manipulate the mouth to
form the sounds)
One's speech may sound nasal or slurred.
And the weakness of the facial muscles results in the inability
to even smile.
In a minority of myasthenics, the
voice box may be affected resulting in an inability to talk at all.
MG also affects the ability to breath.
Deterioration can be abrupt and may lead to the patient being put
on a respirator. If breathing or coughing becomes insufficient,
the patient is said to be in "crisis," and mechanical
breathing assistance in a hospital may be necessary.
In a myasthenic crisis, a respirator
may be necessary for breathing.
A study found that of 175 myasthenics surveyed:
· 30% had oral, pharyngeal
(throat) or laryngeal (voice) complaints.
· half of that 30% had swallowing disorders.
· 13% had dysarthria (slurring, fatiguing speech)
· 2% had dysphonia (voice disorders).
Generalised MG (Head, Neck, Arms and Legs)
This is where many muscle groups are
affected. The typical myasthenic may feel strong on awakening from
a night's rest or a nap, but experiences increasing muscle fatigue
as the day progresses.
Within the first year after onset
about half of the ocular myasthenics will go on to experience involvement
of other muscles, and another 30% do so during the next two years.
Numbness, heaviness, muscular spasm,
or loss of control of the limb can be experienced by the myasthenic.
Limb weakness is often not symmetrical, with one side being weaker
than the other. Shoulder weakness is demonstrated by trouble holding
up an arm to comb or shampoo one's hair, or to shave or put on makeup.
The grip may become weak opening jars (and child-proof medicine
bottles), hips may be weak getting out of deep chairs or the bathtub,
and legs may tire climbing stairs or when walking distances.
MG is in itself painless, but the
strain of supporting weak limbs or the neck can be painful.
Another symptom, which is not often
mentioned in literature, but complained of by some mysthenics is
a sense of loss of balance.
The problem with MG, particularly
in the undiagnosed myasthenic, is that an episode can occur without
warning and can make what is normally a non-threatening activity
into a dangerous one. For example, a myasthenic can really injure
themselves if there is sudden muscular weakness as they take a
step and suddenly find themselves flat on the footpath! Even worse
is the sudden muscular weakness whilst driving a car - sudden
double vision, heavy eyelids, loss of control of the right leg,
weakening arm muscles - all make a terrifying trip for the unsuspecting
undiagnosed myasthenic.
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