A disease characterized by a slow, but progressive, loss of power
and by muscular atrophy. Anatomically, it is characterized by
degeneration of the ganglion cells of the gray matter in the cord.
This atrophic affection develops just opposite to that of chronic
anterior poliomyelitis. It is commonly a disease of males in middle
life. Syphilis, rheumatism and lead poisoning predispose. It sometimes
follows cold, wet, exposure, traumatism, mental worries, overuse
of certain muscles, or prolonged emotional excitement. Hereditary
influences are present in some cases. In all cases =lesions= are
detected in the =vertebræ= and =ribs=, corresponding to the innervation
of the diseased areas. Very likely these lesions are the starting
point of the disease, by impairing nutrition to the motor cells of the
anterior cornu, and thus resulting in atrophy.
=Pathologically=, the muscles are wasted, the fibers undergo fatty
degeneration and there is an overgrowth of connective tissue. The
peripheral motor fibers are degenerated. The anterior nerve roots
leading to the horns are atrophied. The large ganglion cells of the
anterior horns are atrophied, or even entirely removed. The neurogliar
tissue is increased. There is sclerosis of the anterior and lateral
pyramidal tracts of the cord in the majority of cases. (See Amyotrophic
Lateral Sclerosis). The pyramidal tracts have been found degenerated
through the pons and internal capsule, even up to the motor cortex.
When bulbar symptoms are present, there is degeneration of the motor
nuclei of the medulla. The posterior columns are not involved.
=Symptoms.=—Irregular pains, numbness or exhaustion are usually felt
in the region that is soon to become wasted. The upper extremities
are first affected. The muscles of the ball of the thumb waste first,
then the interossei. From atrophy of the interossei and lumbricales
and contraction of the long extensor and flexor muscles, the deformity
known as “claw hand” results. The wasting creeps up from the forearm,
arm and shoulder. The muscles of the trunk are gradually affected.
The muscles of the lower extremity may escape entirely. The platysma
myoides does not waste and is often hypertrophied. The face muscles
are attacked late or not at all. The affected muscles often twitch.
Deformities and contractures develop, notably lordosis. Sensation
is not impaired although the patient may complain of numbness and
coldness. The bladder and rectum are not affected, but sexual power
may be lost. The paralysis is flaccid and the reflexes absent in the
so-called =atonic cases=. In =atonic= atrophy there is more or less
spasm, the reflexes are greatly increased, there are often contractures
and the wasting is usually trifling.
=Diagnosis.=—Differential diagnosis has to be made from syringomyelia,
chronic anterior poliomyelitis, lead palsy and muscular dystrophies.
=Prognosis.=—The prognosis of progressive muscular atrophy is not
favorable, although a number of cases have been greatly helped by an
extended course of treatment.
=Treatment.=—The treatment consists of a thorough, stimulating
treatment of the innervation of the affected regions, with manipulation
of the muscles and parts diseased. =Correction= of the =lesions= to
the =vertebræ= and =ribs=, which are involving the innervation to
the diseased tissues, is of primary importance. A cure cannot be
expected when degeneration of the nerve centers has occurred; still,
the progress of the disease may be checked in many cases, and the
patient occasionally gain considerable strength. When atrophy starts
in the muscles of the ball of the thumb, the lesion is to the median
nerve, and derangements of the cervical vertebræ, from the fifth to the
seventh, may be found. Attention to the general health is important.
Outdoor life is preferable and gymnastic exercises are of value, but do
not overtax the strength.