9. Chronic diseases of the lungs and heart, by enfeebling the muscular movements which take part in defecation, as well as by the general feebleness and the chronic intestinal catarrh and indigestion which they create, are causes of constipation. Chronic diseases of the liver, especially cirrhosis, are also causes. Constipation accompanies obesity, for in very fat persons the abdominal walls have but little power of contraction; the muscle-layer is thin and flaccid. There is also in such persons in advanced life an accumulation of fat in the mesentery and around the colon. The muscle of the bowel is in a state of fatty degeneration, and atony and dilatation of the gut follow.
10. Painful affections about the rectum and anus deter persons from yielding to the desire for defecation. Fissure of the anus is the principal one of these, but fistula, hemorrhoids, and local eczema have a similar influence. A simple rigidity or spasmodic stricture of the anal sphincter creates constipation.4
4 Kunemann, De la Constipation compliqués de Contraction du Sphincter anal, et de son Traitement par la Dilatation de l'Anus, Paris, 1851.
11. Constipation is a symptom in chronic cachexiæ and wasting diseases, in the convalescence of acute exhausting illness, as typhoid fever and pneumonia, or in persons bedridden from any cause. Defective nutrition and degeneration of the muscle-fibre of the intestine explain these cases. In some of them, with improved nutrition, regeneration takes place with a return of contractility.
12. Disorders of the digestive system have constipation as a consequence and a symptom. The reflex sympathy between the movements of the stomach and of the intestines brings this about in gastric diseases.5 It occurs in gastric cancer and ulcer, in acute and chronic gastritis, in dilatation of the stomach, and in pyloric stricture. The small amount of ingesta entering the duodenum in these diseases diminishes the bulk of fecal matter. In acute intestinal catarrh diarrhoea is the rule, but the bowels may be constipated in intense inflammation and ulceration of the mucous membrane, as is often the case in typhoid fever. In chronic intestinal catarrh constipation is more common in the mild forms than diarrhoea. The thickening and irritation of the mucous membrane lead to a diminution of reflex excitability and loss of elasticity and contractility in the muscular coat. Hence, except in cases where the inflammation is low down or where ulcers have formed, constipation is a more frequent symptom than diarrhoea. The alteration in the quantity and character of the intestinal secretions in chronic catarrh is stated to be an important element. This is to some extent true. Mucus, which is the chief product of this condition, leads to indigestion and fermentation of the intestinal contents and to increased irritation of the mucous membrane. The evolved gas distends the bowel and weakens its contractile power. The fecal mass when it reaches the rectum has an excess of mucus within it or around it which makes its expulsion more difficult. But the diminution or absence of bile does not constipate. In simple jaundice diarrhoea is not uncommon, and an excess of bile does not of necessity cause diarrhoea.6
5 Leube, in Ziemssen's Cyclopædia, vol. vii. p. 211.
6 Legg, op. cit., p. 271.
The effects of the modifications of the pancreatic secretion are not well known. Pancreatitis is attended by constipation. Fatty diarrhoea is believed to follow occlusion of the pancreatic duct by pancreatic calculi and chronic catarrh of the duct. Peristalsis is lost in peritonitis from the muscular coat being infiltrated with serum and paralyzed, but tuberculous peritonitis is frequently accompanied by diarrhoea.
13. Loss of fluids by abundant perspiration, by diuresis, diabetes and lactation, increases the dryness of the bowel contents and hinders free evacuations. This is observed as a result of the arrival in a tropical climate and in very hot weather in any climate. The profuse sweats accompanying phthisis, acute rheumatism, intermittent fever, and unusual exercise cause constipation. Another explanation which applies to this has been offered by Good and Eberle, who ascribe constipation to the excessive action of the absorbents in the small intestine, by which the fluid portion is too rapidly and too thoroughly removed.7 Exercise by promoting activity of the functions in general may induce constipation in this way. In spermatorrhoea the stools are infrequent. An insufficient amount of water taken with food is another cause.
7 Dick, Braithwaite's Retrospect, xvii. p. 152.