When the chronic congestion of the kidneys is secondary to emphysema of the lungs, the course of affairs is much the same. The patient goes on for a number of years with the ordinary symptoms of emphysema, and then gradually or suddenly becomes worse. Dyspnoea, dropsy, anæmia, cerebral symptoms make their appearance, and the case terminates in the same way as the cardiac cases.
DURATION.—How long congestion of the kidneys may exist without producing symptoms it is hard to say. Certainly it may exist for a number of days without any apparent disturbance of the functions of the kidney. Whether it may exist for a time, give symptoms, and then disappear, is uncertain; the rule seems to be that the lesion, when once well established, persists up to the death of the patient.
TREATMENT.—It must be acknowledged that we can hardly hope for a cure of the lesion of the kidneys, and that even alleviation of the symptoms is not always possible. The mechanical cause of the obstruction to the venous circulation cannot be removed, and it is not only the functions of the kidneys that are disturbed, but those of the lungs, liver, spleen, stomach, and small intestine. Still, we can do something. The iodide of potassium, convallaria, caffeine, and digitalis may be of service in equalizing and strengthening the heart's action, and at the same time act as diuretics. Inhalations of the nitrite of amyl dilate the arteries and capillaries, and so unload the veins. Opium is the great remedy for the dyspnoea, although it must be given with caution. Inhalations of ether may render the patient's last days more comfortable.
BRIGHT'S DISEASE OF THE KIDNEYS.
After considering separately the condition of chronic congestion of the kidney, we find that there are a group of kidney diseases characterized by certain rational symptoms, changes in the urine, and alterations in the structure of the kidneys which are popularly known by the name of Bright's disease.
Various attempts have been made to classify these cases.
1. All the kidney lesions have been supposed to correspond to the stages of an inflammatory process—a stage of congestion, a second stage of exudation, and a third stage of contraction.
2. The disease has been divided, according to its clinical symptoms, simply into acute and chronic Bright's disease.
3. The gross appearances have been taken as a standard, and the cases are classed as examples of large white kidney, atrophied kidney, waxy kidney, etc.