ETIOLOGY.—Chronic intestinal catarrh has many of the same causes as the acute form; it is the expression of a large number of different pathological states and complicates many general and local diseases.
It is very common in children under two years of age, and is associated with change in diet in weaning and with the irritability of all the tissues during dentition. It is also a frequent disease in old persons, being due to imperfect mastication, the weakness of digestion, portal congestion, the gouty diathesis, and other causes.1 Men have the disease more frequently than women. Hereditary influence and idiosyncrasy predispose to chronic catarrh of the bowel as to catarrh of the bronchi. Bad hygiene, want of cleanliness with an unhealthy condition of the skin, constant breathing of foul air due to want of proper ventilation, animal decomposition, or overcrowding predisposes to chronic diarrhoea. The chronic diarrhoeas among soldiers in camps,2 among the inmates of prisons, workhouses, and asylums, are examples of these influences. Overwork, especially mental overwork with anxiety, and privation of sleep act in the same direction. In the chronic constitutional diseases and in many chronic diseases of organs diarrhoea sooner or later appears, and very generally is the immediate cause of death. In phthisis pulmonum, whether tubercular or not, simple catarrh of the bowel is nearly always present.
1 La Diarrhée chez les Viellards, Paris, Thèsis, 1865, No. 112. See also works of Durand-Fardel and Charcot and Loomis.
2 According to the statistics prepared in 1871 by T. B. Hood of the U.S. Pension Office, chronic diarrhoea was the disease for which a pension was granted in 20 per cent. of all cases of disability from disease and in 75 per cent. of all the diseases of the digestive system (Report of Commissioner of Pensions, 1871).
During the course of chronic Bright's disease, more frequently in the cirrhotic form, lesions are developed in the intestine which cause obstinate diarrhoea. The discharge of urea into the intestine, and its conversion into carbonate of ammonium, which acts as an irritant to the mucous membrane, is the reason of the diarrhoea in this disease, according to Luton and Treitz;3 and in so far as the discharge represents the escape of urea by the bowel, it may be regarded as salutary. In gout, especially in old persons, periodical diarrhoea gives relief. Chronic gouty subjects assert that they are not benefited by colchicum until it has purged them. The lithic-acid diathesis, pyæmia, septicæmia, scurvy,4 diabetes, leucocythæmia, Addison's disease, and syphilis5 have diarrhoea during some part of their progress. The malarial cachexia is often attended with a diarrhoea which quinia alone will relieve; this symptom may occur periodically or be constant.
3 A. Luton, Des Séries morbides, Affections urémiques de l'Intestin, Paris, Thèsis, 1859, No. 38, p. 45; also, Treitz, "Ueber urämische Darmaffectionen," Prager Vierteljahrschrift, Bd. 64, 1859, S. 143.
4 See testimony as to the influence of scurvy in promoting diarrhoea (Woodward, Med. and Surg. History of the War, Part 2, Medical Volume, p. 638).
5 A. Trousseau, "Comments on a Case of Syphilitic Diarrhoea cured by Mercury," Clinique méd., Paris, 1868, t. iii. p. 123.
Disease of the liver, heart, or lungs, by retarding the circulation in the portal system, causes venous stasis and catarrh in the gastro-intestinal mucous membrane. The chief conditions which bring this about are tumors compressing the mesenteric veins, cirrhosis of the liver, tumors pressing on the ascending vena cava, valvular disease of the right and left heart, fatty degeneration or dilatation of the heart, cardiac debility from chronic exhausting diseases, fibroid phthisis, chronic pneumonic phthisis, chronic pleurisy, and pulmonary emphysema.
An unsuitable diet may not set up an acute catarrh, but may slowly induce changes of a chronic nature in the mucous membrane. This is the case in infants fed upon artificial food instead of breast-milk, or when the digestion is overtaxed after weaning. In adults food difficult of digestion and over-eating bring about the same result. Alcohol, spices, and condiments, if taken in excess, and the habitual use of purgatives, lead to chronic inflammation of the intestine.