Progressive muscular atrophy is a rare condition characterized by the deterioration of the lower motor nerve cells. It is most often associated with amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, and motor neuron disease (MND). Progressive muscular atrophy is an active, advancing disease, though its progression is typically slow and is distinguished by the gradual wasting away of muscles in the extremities, which slowly extends to other areas of the body.
From a pathological perspective, progressive muscular atrophy takes hold when ganglionic cells — nerve cells within a mass of tissue — begin to deteriorate. Muscles gradually shrink and turn pale as use becomes more and more limited until it is impossible to utilize the muscles at all. Because of its slow wearing-away of the muscular system, the disease is sometimes known as wasting palsy.
Research suggests that there may be two subtypes of progressive muscular atrophy. In the first type, distribution of the disease is random throughout the body, making it difficult to detect. The second type progresses differently. The disease will affect one extremity before entering into a long latent period and then spreading to another extremity.
ALS and other forms of MND are the primary conditions that cause progressive muscular atrophy. It has been shown to have strong hereditary roots and has also developed as the result of physical injury, prolonged exposure to cold temperatures, and extreme muscular exertion. The condition may also be caused by various types of infection, including influenza, diphtheria, measles, and typhoid fever.
Progressive muscular atrophy, or PMA, is predominantly an adult disease. The average age range of PMA patients is between 30 and 50 years old. Studies have shown that the condition strikes males at a much higher rate than females.
The primary symptom of PMA is the notable weakening of a muscle or muscles. This often occurs first in the hand. The thumb muscles may atrophy, followed by the other fingers until the hand takes on a claw-like appearance and is rendered virtually unusable. From the hand, PMA works its way up the arm and into the shoulder. These muscles also begin to waste away before the disease works its path through the rest of the body; it usually affects the right hand before the left.
The lower extremities may become affected first, though by and large, they are the last areas to be impacted by PMA. In its late stages, the condition will take hold of the muscles in the lower part of the body. When it hits the diaphragm, breathing becomes difficult, if not impossible, for the patient.