Atrophy

Under various circumstances and as the result of many different causes the condition known as atrophy may take place^[1]. It is the shrinkage or wasting away of tissues, and may take place in any part of the body. The brain, heart, liver, nerves, spinal cord and various organs, and the bones and skin and muscles are all subject to atrophy. The condition and the means taken to prevent it or overcome it are fully considered in the articles treating of the diseases of the various organs and tissues which may be thus affected.

^[1] Atrophy is not necessarily a pathological condition - it occurs naturally with aging in, for example, the thymus, tonsils and skeletal muscle.

Athetosis

Involuntary Muscular Contractions. — In this condition, which occasionally accompanies certain forms of paralysis, the extremities, especially fingers and toes, undergo uncontrollable spasms. These spasms may consist in the members being firmly separated or flexed. They may occur during sleep and may be increased by fright or other emotions. Treatment is in accordance with that for paralysis.^[1]

^[1] There is no standard treatment for the symptom.

Atelectasis

Pulmonary Collapse. — From compression or from obstructions in the lungs, air may be prohibited from entering the air cells, and the result will be collapse of the vesicles. It very frequently occurs in children during the course of whooping cough, bronchitis, measles and croup^[1]. It is exceedingly fatal in very young persons and in the aged. It is fully treated of as capillary bronchitis in the article on Bronchitis.

^[1] Wikipedia suggests that it most commonly occurs as post-surgical atelectasis.

Ataxy

Locomotor Ataxy. Tabes Dorsalis.

A very peculiar condition of the nervous system is known under this name^[1], characterized by loss of sensitiveness of the skin and inability to control movements of the limbs. It was formerly classed as a form of paralysis. It comes on insiduously. Pains of a neuralgic or rheumatic character, headache, impaired vision, frequent desire to urinate and "pricking" sensations of the limbs or extremities, are early symptoms. Soon inability to control the movements of the limbs becomes manifest, and trying to walk with the eyes shut will cause staggering. Applications of heat, pricking with pins, etc., on portions of the back fail to cause any sensations. Many other symptoms may be manifested. It is a disease of middle life, and its causes are various. Long exposure to cold and moisture, sexual excesses, syphilis, poisoning by lead, arsenic or ergot^[2], and injuries to the spine have been known causes.

Treatment. — If possible the patient should visit the southern mountains or seek an equable and dry climate. Electricity to the spine is of great advantage. The cause must be ascertained and remedial treatment based accordingly. Narcotics must be prohibited. Vapor baths and massage are of great value. The disease lasts from a few months to twenty-five years or even longer.

^[1] Ataxy isn't a term commonly used now - myelopathy is used to refer to pathology of the spinal cord.
^[2] Ergot poisoning, which is caused by the ingestion of ergot fungi most prominently found on rye, is uncommon now.