9. Dyspncea is one of the most frequent and interesting of the symptoms of nephritis. There is a dyspncea clue to fluid in the pleural cavities, or to oedema of the lungs; a dyspncea due to pressure on the diaphragm by fluid in the abdomen; and a dyspncea due to bronchitis or to contraction of the bronchi ; but the most important form of dyspncea is one which is independent of all these causes and is di rectly caused by disturbances of the circulation. It belongs to both forms of chronic nephritis, but is more common with nephritis with out exudation. The patients, as a rule, in addition to the nephritis have pulmonary emphysema, chronic endarteritis, hypertrophy of the left ventricle, or chronic endocarditis. Not infrequently one or more of these lesions are much more advanced and apparently more important than the kidney disease. Especially is this the case with chronic endarteritis, which gives many of the most marked examples of this form of dyspnoea with but very little nephritis.
The dyspncea may come on at any time in the course of a ne phritis; very often it is the first symptom which causes the patient to seek medical advice. It begins with attacks, which at first are brought on by bodily and mental exertion, or come on of themselves at an early hour in the morning. In none of the attacks do we hear the characteristic breathing of bronchial asthma. The attacks at first only last for an hour or so, and during the rest of the day the breathing is comfortable. But even in these mild attacks the patients cannot lie down. As time goes on the attacks become more frequent and of longer duration. Finally comes the terrible period when the breathing is always bad, the patients cannot lie down at all, and yet go on living for weeks and months.
The treatment of this dyspncea is often for a time extremely satisfactory. The patients are enabled to live and work in comfort for many years. But each succeeding attack is harder to control than the first, and finally there comes a time when everything fails and the dyspncea continues although the patient is stupefied with drugs.
The object of treatment is to relieve the disturbances of the cir culation; if this can be done the clyspncea is also relieved. To effect
this the most exact study of the circulation is required. For each patient the character of the heart's action and of the pulse, both relatively and separately, must be determined. Based on this knowl edge is the intelligent use of cardiac stimulants and sedatives, of arterial dilators, of regulation of the functions of the stomach, liver, and intestines, of rest or exercise. There is no one plan of treatment for all, nor even one plan for the same patient in all attacks.
Increased Arterial is not always classed with the urmmic symptoms. It is, however, one of the most frequent and important of the symptoms of chronic nephritis, and it is by it that many of the so-called urfemic symptoms are produced.
It has been believed that this increased tension of the blood in the arteries is due to chronic changes in the walls of the arteries and capillaries which interfere with the passage of the blood through them. The explanation is very probably true up to a certain point, but it does not account for the attacks of increased arterial tension which come and go within a few hours. I do not see how these can be produced except by the temporary contraction of arteries which have a well-developed muscular coat, such as the radial artery. I think that it is possible to demonstrate after death in such arteries an hypertrophy of the muscular coat, in patients who have had many attacks of increased arterial tension.
If this is admitted, then we have to find a reason for the attacks of contraction of the arteries which last for hours or for weeks, and which can often be controlled by the drugs which dilate the arteries.
Such attacks of contraction of the arteries occur with: Angina pectoris; Chronic endocarditis ; Chronic arteritis ; Pulmonary emphysema; Chronic nephritis.
It seems as if such a contraction of the arteries must be due to some irritating substance in the blood. But whether there is only one poison which acts in this way or several poisons, and how such poison or poisons are produced, we do not know.