Dr. Travell: The list of chronic diseases of the skeletal muscles which we have considered today
includes myasthenia gravis, myotonia congenita, myotonia atrophica, familial periodic
paralysis, amyotrophic lateral sclerosis, progressive muscular atrophy, progressive
muscular dystrophy, the myopathies of Graves' disease, dermatomyositis and fibromyositis
These conditions are distinguished from each other by a variety of clinical features
and their differential diagnosis is not ordinarily difficult. However myasthenic symptoms
may sometimes complicate the picture of Graves' disease and raise the question of
the coexistence of a primary muscular dystrophy and hyperthyroidism. The fact that
iodine administration in Graves' disease reduces the spontaneous creatinuria and increases
the retention of creatine often serves to differentiate the two. Neostigmine relieves
the myasthenic symptoms in both conditions and does not influence creatine excretion
in either. In view of the diagnostic, and at times prognostic value of the creatine
tolerance test, the normal values and standard conditions for this test are discussed.
The causes of the chronic muscular diseases listed above are unknown and their treatment
is, for the most part, unsatisfactory. The drugs and measures which received special
consideration are neostigmine, thymectomy, quinine, ephedrine, epinephrine, calcium,
potassium chloride, cytochrome C, vitamin E with accessory factors and glycine.
In myasthenia gravis, removal of the thymus appears to cure a small proportion of
cases. Neostigmine is highly effective in relieving the muscular weakness and fatigue.
It is a double-edged sword and proper dosage is a matter of the greatest importance.
There was a belief that the therapeutic effect resulted from its inhibition of cholinesterase,
but now there is new evidence indicating that the beneficial effect is due to direct
stimulation of the muscle, and that excessive doses may increase the weakness through
the anticholinesterase action which gives rise to a curare-like effect of the increased
acetylcholine at the muscle.
In familial periodic paralysis, an oral dose of 5 Gm. of potassium chloride often
relieves the attack promptly, and doses of 2 to 4 Gm. daily may prevent recurrences.
In myotonia congenita, quinine, in oral doses of from 0.3 to 0.6 Gm. several times
daily, often accelerates the muscular relaxation after a movement. Epinephrine and
calcium are also sometimes of value.
There are preliminary observations indicating that daily intravenous doses of 50 mg.
of cytochrome C may control the muscular disability of amyotrophic lateral sclerosis
and related diseases.
New observations suggest that in progressive muscular dystrophy and dermatomyositis
certain “accessory substances” are needed for the utilization of vitamin E, as indicated
by diminished urinary excretion of creatine, following their administration. Preparations
which when fed together with vitamin E to patients with these disorders have been
shown to have an effect on creatine excretion, include normal gastric juice, certain
sugars present in pectin and wheat germ, and also gastric mucin which contains some
of the polysaccharides shown to act as “accessory substances.” The clinical importance
of these dietary factors has not as yet been satisfactorily demonstrated. The results
open up the vista, however, that the etiology of these, and possibly of other members
of this group of diseases, may be specific nutritional defects, and point the way
to new lines of investigation for the solution of the vexing problems of therapy in
these progressive muscular diseases.