In nerve leprosy we often get atrophy of the small muscles of the hand and of the muscles of the forearm. The contracture which takes place under these circumstances gives the “claw hand.” In tubercular and mixed forms of leprosy we may get in addition trophic disturbances of the fingers and toes and also extraneous infections which may ultimately result in amputation of fingers or toes. This process, going on over a considerable time or being repeated, results often in stumping of fingers or hands or toes and feet.
In addition to these openly destructive processes there is often seen in leprosy a condition of subcutaneous absorption of all the tissues. In this way the distorted finger nail may come to occupy a seat over the knuckle or even (though rarely) further up the back of the hand or arm. Briefly in leprosy we have, as representing the pathology, muscular atrophy from nerve involvement, periostitis and arthritis, interstitial absorption of bone and contractures resulting in mutilation of fingers, toes, hands and feet from trophic disturbance and intercurrent bacterial infection.
Beriberi.—In this disease we have muscular atrophies, especially of the muscles innervated by the peroneal and ulnar nerves, similar to those following other forms of peripheral neuritis.
Amoebiasis.—There have been reported very rarely disintegrating lesions of muscles and cutaneous tissues in which amoebae have been found.
Heat Cramps.—In those working in firerooms or steel-mills, the excessive heat to which they are subjected may cause various manifestations of heat prostration, among which the painful muscle cramps are prominent. These cramps are similar to those which are such a feature of Asiatic cholera and in each instance are supposed to be the result of dehydration of muscle tissue.
Trichinosis.—Acute muscle pain is a feature of the stage of muscle penetration by the larval Trichinella spiralis. In the disease we have a fever suggestive of typhoid fever and oedema about the face. A marked eosinophilia is characteristic. Another helminthic parasite which may invade the muscles of man is the larval Taenia solium. This must be of extreme rarity because infection with the adult T. solium is most rare and it is only accidental that the embryonic stage would occur in man. It is a fact that the common tapeworm of man, Taenia saginata, is found in the human host only as a sexually mature parasite in the intestines; there is never a cysticercus stage in the muscles.
Myositis purulenta tropica.—We may have a suppurative myositis with a single abscess formation or with disseminated foci or a diffuse purulent infiltration. The attending fever and toxaemia are similar to those attending any deep abscess formation. Abscess formation in the muscles has been reported from various parts of the tropics, especially the Gold Coast. It is possible that F. bancrofti infections are concerned in some of these conditions.
Filariasis.—Filarial abscesses were found in the ilio-psoas muscles in four cases. Wise and Minett found evidences of adult filarial worms (F. bancrofti) in 22 out of 28 deep-seated abscesses, which were examined by them.