Leprosy

LEPROSY (Lepra Arabum, Elephantiasis Graecorum), the greatest disease of mediaeval Christendom, identified, on the one hand, with a disease endemic from the earliest historical times (15oo B.c.) in the delta and valley of the Nile, and, on the other hand, with a disease now common in Asia, Africa, South America, the West Indies and certain isolated localities of Europe.

Leprosy is a bacterial disease the cause being B. leprae. There are many resemblances between the lesions of leprosy and of tu berculosis and many leprous patients contract tubercle. The essential character of leprosy is the replacement of normal tissue by nodular foci of inflammatory cells (including giant cells) sim ilar to those found in syphilis and tuberculosis. The bacilli are found in these cells, sometimes in small numbers, sometimes in masses. The structures most affected are the skin, nerves, mu cous membranes and lymphatic glands.

Symptoms and Effects.

The symptoms vary according to the parts attacked. Three types of disease are usually described—( i) nodular, (2) smooth or anaesthetic, (3) mixed. In the first the skin is chiefly affected, in the second the nerves; the third com bines the features of both. This classification is purely a matter of convenience, and is based on the relative prominence of symp toms, which may be combined in all degrees. The incubation pe riod of leprosy may be many years. The invasion is usually slow and intermittent. There are occasional feverish attacks, with the usual constitutional disturbance and other slight premonitory signs, such as changes in the colour of the skin and in its sensibil ity. Sometimes, but rarely, the onset is acute and the character istic symptoms develop rapidly. These begin with an eruption which differs markedly according to the type of disease. In the nodular form dark red or coppery patches appear on the face, backs of the hands and feet or on the body; they are generally symmetrical, and vary from the size of a shilling upwards. They come with one of the feverish attacks and fade away when it has gone, but only to return. After a time infiltration and thickening

of the skin become noticeable, and the nodules appear. They are lumpy excrescences, at first pink but changing to brown. Thicken ing of the skin of the face produces a highly characteristic appear ance. The tissues of the eye undergo degenerative changes ; the mucous membrane of the nose and throat is thickened, impairing the breathing and the voice ; the eyebrows fall off ; the ears and nose become thickened and enlarged. As the disease progresses the nodules tend to break down and ulcerate, leaving open sores. The patient, whose condition is extremely wretched, gradually becomes weaker, and eventually succumbs to exhaustion or is car ried off by some intercurrent disease, usually inflammation of the kidneys or tuberculosis. A severe case may end fatally in two years, but, as a rule, when patients are well cared for, the illness lasts several years. The smooth type is less severe and more chronic. The eruption consists of patches of dry, slightly discol oured skin, not elevated above the surface. These patches are the result of morbid changes affecting the cutaneous nerves, and are accompanied by diminished sensibility over the areas of skin af fected. At the same time certain nerve trunks in the arm and leg, and particularly the ulnar nerve, are found to be thickened. In the further stages the symptoms are those of increasing degeneration of the nerves. Bullae form on the skin, and the discoloured patches become enlarged ; sensation is lost, muscular power dimin ished, with wasting, contraction of tendons, and all the signs of impaired nutrition. The nails become hard and clawed; per forating ulcers of the feet are common ; portions of the extremi ties, including whole fingers and toes, die and drop off. Later, paralysis becomes more marked, affecting the muscles of the face and limbs. This form of the disease runs a very chronic course, and may last 20 or 3o years. Recovery occasionally occurs. In the mixed form, which is probably the most common, the symp toms described are combined in varying degrees.