A large majority of patients present ing retinal lesions die within a year after they are first discovered. Out of 419 of Bell's cases he found that 72 per cent. were fatal at the end of the first year and 90 per cent. within two years. Possauer reports that all men applicants at his clinics were dead within two years. Of the women 32 per cent. survived that period. It seems that among private patients only 59 per cent. of the men died within two years and 53 per cent. of the women. Edward Jackson (Medical News, Feb. 15. 1902).
Etiology. — Sometimes the cause of the slow, primary, diffuse degeneration. atrophy, and fibroid contraction of the kidneys is quite obscure, and in certain cases it would seem to be "only an an ticipation of the gradual changes which take place in the organ in extreme old age" (Osler), — the "senile kidney." Heredity undoubtedly plays a part in the causation of certain cases, and its influence has extended down through the third and fourth generations.
Age and sex also exert an influence, the disease being more common in males than in females, and usually beginning near middle life. It is rarely manifested symptomatically until the fiftieth or six tieth year. A special tendency to scle rotic degeneration of the arteries, from whatever injurious influence, whether chemicotoxic or parasitic, renders the patient more prone to interstitial ne phritis, though prolonged irritation by such agents may also cause the disease in persons whose cellular nutrition is usually not defective. Alcoholism, uric acid, and lead, giving rise to chronic poisoning, have all been assigned as causes of the disease.
Chronic malaria and syphilis also probably exert a causative influence.
Habitual overeating and overdrinking no doubt frequently cause granular atro phy and sclerosis of the organ, owing to the imperfect assimilation of the sub stances ingested and the constant excre tion of irritating products by the kidney caused thereby. A wide-spread cause of the disease is the continuous and even moderate use of alcohol for many years: especially is this true in the case of spirituous liquors. It is just as probable that the excessive use of red meats in the diet leads to the production of the uric acid that induces the renal condi tion (uricTmia-lithmmia) by deranging the hepatic function (Murchison).
Gout may also cause chronic Bright's disease, and is allied to the above; this occurs perhaps more frequently in Eng land than in this country, where lithae mia and nervous dyspepsia are more often seen.
Striimpell states that severe articular rheumatism is sometimes followed by contracted kidney.
Chronic nephritis when met with in ehlorotics depends upon an arterial lesion; patients affected with the two diseases are clearly descendants of gouty arteriosclerotic ancestors. Lanccreaux
OWL de l'Acad. de Mad. de Paris, p. 727, '93).
Appearance of great quantities of uric acid in the blood of nephritis not as constant as observations of Jacobi might lead one to think. Fodor (Centralb. ffir klin. Med., Sept. 7, '95).
The absorption of toxic substances from the intestinal tract plays the most important role in the etiology of chronic nephritis. The importance of this is very practically acknowledged by the range of dietetic treatment for the affec tion. The morning purge, colonic tion. and excitation of the intestinal functions generally, lead to prompt amelioration of the nephritic symptoms. On the other hand. serious nephritic con ditions are ushered in by intestinal acci dents. The first symptoms of urcemia or of kidney insufficiency are usually noted in the gastrointestinal tract. The coated tongue, the nausea, the pain in the back, the oxaluria, etc., are all common symp toms of nephritis and intestinal dis turbance. After the kidney function is lowered the liver-cells degenerate be cause of the presence of toxic sub stance; the liver then fails to metab olize substances that come to it, and adds its own quota of toxic material to the blood, which still further irri tates the kidney. The vicious circle of influence thus formed continually de teriorates the general condition.
The inactive life of many city peophe is undoubtedly a cause for the develop ment of toxic systemic products that irritate the kidneys. Almost invariably such people overeat. and this adds to the manufacture of toxins. In these patients the urine is often quite toxic when injected into animals. The basis of these metabolic disturbances is often an atonic intestinal catarrh. This con dition, however, is perhaps itself a manifestation of urtemic conditions. Constipation is a very uncertain effect. Though long continued in some people, it fails to produce any serious systemic effect, while in others its existence for a comparatively short time produces many and even serious symptoms. Orprostasis provides in the material de tained in the intestinal tract a very favorable culture-medium for mierones. These not only produce poisons them selves, which are absorbed with serious effects, but they also consume normal food-material in the intestines and leave only degradation products to be taken up for the body-nutrition. These factors are especially active in the production of chronic nephritis, and the realization if this furnishes the best indications for treatment. A. B. Elliott (Proceedings Amer. Med. Assoc.; Medical News, June 21, 1902).