Under the vague term indigestion there is comprised a number of disorders which have one feature in common, e.g., the inability to digest ordinary food in the painless, unconscious manner characteristic of health. This indigestion may show itself in a number of different ways. Pain or discomfort after meals is one of the most prominent symptoms; this may be severe or slight in character; it may occur immediately after the ingestion of food, or some hours later. Heartburn and waterbrash are other manifestations which are often very distressing. Flatulence is another prominent symptom; this may take the form of belching up of wind, or of passage of flatus by the bowel, or of a tightness and oppression in the abdomen. Loss of appetite, nausea, general physical and mental depression, and derangement of the bowels, especially constipation, are other subjective symptoms commonly met with. It must be recognised that indigestion is merely a symptom. It may be a symptom of -

1. Chronic constitutional disease in which the digestion is involved secondarily, e.g. tuberculosis; or it may result from:

2. Local disease in the stomach, intestines, or other viscus, of an organic nature; or:

3. Local disease in the stomach or intestines of a functional character. By that we mean that no structural change is present, so far as can be determined by our present methods of investigation. It is probable that this group depends on alterations in the gastric and intestinal secretions of a nature not yet fully understood.

A few words may be said on the diagnosis of the cause of indigestion.

Diagnosis Of The Cause Of Indigestion

An accurate diagnosis of the cause of indigestion must precede any attempts at its remedial treatment by means of diet. Keeping in view the points already laid down, we must first determine whether the indigestion is an expression of a chronic constitutional derangement. The most important constitutional conditions which give rise to indigestion are tuberculosis, chronic renal disease, and heart disease. In every case, therefore, we must exclude them as the cause; if found to be secondary to one of these conditions, the treatment has to be directed to the primary condition (q.v.). Tuberculosis is frequently the cause of indigestion in young people; and with regard to this it should be borne in mind that the indigestion may be an early symptom of the tuberculosis, and may precede by many months the development of active tuberculous disease in the lungs or elsewhere. Chronic renal disease is often responsible for symptoms of indigestion in adult and elderly subjects; it is not infrequent in practice to find that the existence of chronic renal disease is ascertained for the first time by the routine examination of the urine in cases in which the symptoms have been entirely those of "indigestion." In the case of organic heart disease, severe anemia, rheumatoid arthritis, and some other disorders, we are less likely to overlook the true nature of the indigestion than in cases of tuberculosis and renal disease already referred to.

The second point is to determine whether the indigestion is the result of an organic lesion of the stomach or bowel, or other organ. If we exclude acute gastritis, which is not a cause of indigestion in the ordinary sense, the conditions to which attention must be directed are the following: -

1. Lesions in the stomach or duodenum, especially gastric or duodenal ulcer, hyperchlorhydria, dilatation of the stomach, and chronic gastric catarrh; the last mentioned, it should be noted, may be associated with malignant disease.

2. Appendicitis. Pain in the epigastrium and other symptoms of indigestion may be present, and may be the chief indications of appendicular mischief.

3. Catarrh of the gall-bladder or bile-ducts, often associated with some pancreatic disease.

4. Floating kidney, and various uterine and ovarian disorders may be the cause of the " indigestion".

It is very important to keep these points in mind. If we do so, we will avoid a mistake by no means infrequently made, of treating certain cases - as examples of " functional indigestion " - for weeks or months, with little or no success, which are later cured by other clinicians who have detected the underlying cause in the appendix, kidney, or uterus, etc.