Initially the disease may present with
fasciculations of the intrinsic hand muscles, which later change to weakness
and atrophy and then spread proximally to the shoulder girdle. However,
involvement of the various muscle groups is inhomogeneous. As the disease
progresses, atrophy and weakness involve most of the skeletal muscles,
including those of the tongue, pharynx, larynx, and chest. Swallowing
problems, with frequent choking and bronchopulmonary aspirations, are common.
The sensibility is not affected. Serum creatine phosphokinase levels are
normal, no cardiac involvement is seen, and intellectual function remains
unchanged. Loss of autonomic control with orthostatic hypotension and
tachycardia has been described. Extraocular muscles, bladder, and anal
sphincter muscles typically are spared. Some patients with cancer exhibit a
symptom complex similar to ALS as part of a paraneoplastic syndrome. Some
researchers have reported decreased levels of insulin-like growth factor-1
(IGF-1) in patients with ALS. Patients with ALS may benefit from treatment
with recombinant human IGF-1, although survival remains the same. Riluzole
is a benzothiazole glutamate antagonist medication that may prolong
tracheostomy-free survival but not overall survival. Because no effective
therapy exists to date, the prognosis remains grim. Death usually results
from pulmonary complications within 5 to 10 years after the first symptoms.