EDEMA 157 



Hydrothorax and Ascites. Associated with the formation of edema 

 in the skin occurs the development of similar processes in the body cavities. 

 Especially common are hydrothorax and ascites. In fact, either may occur 

 early and become a prominent factor in the condition of the patient when 

 there is little or no subcutaneous edema. 



In heart failure hydrothorax occurs most frequently on the right side, 

 although it is often bilateral. This preponderance is variously attributed 

 either to the habit of most persons, especially those with heart disease, of 

 lying on the right side, or to pressure of a distended right heart on the 

 azygos veins of that side. In other cases there is a disposition to ascites, 

 due probably to pressure on the veins of the abdominal cavity. 



The Liver. Edematous swelling of the liver and other internal organs 

 is especially common in heart disease. The enlargement of the liver com- 

 monly seen in heart failure is in part a result of edema of that organ, and 

 in part a result of distention due to passive congestion. 



The Kidneys. Some of the changes in the character and amount of 

 the urine excreted in the course of passive congestion may be due to in- 

 volvement of the kidneys by edema. Such changes in the urine, however, 

 are due in part directly to the diminished rate and volume of blood flow 

 through the kidneys, and in part to the effect of changes in the physico- 

 chemical constitution of the blood. 



The Lungs. Slight edema of the lungs is often one of the earliest 

 manifestations of heart failure. This occurs usually at the base of the 

 lungs, and may be detected on auscultation by the presence of fine moist 

 rales on deep inspiration. 



In the later and graver forms of heart failure the disturbance may 

 become severe, until finally pronounced pulmonary edema occurs. When 

 this takes place there is a sudden outpouring of fluid into the alveoli, with 

 consequent expectoration of "large amounts of frothy, blood-stained fluid. 

 Relief from this condition may occur either promptly or after the lapse of 

 varying lengths of time. In some instances there is only one attack, but 

 in others, recurring pulmonary edema is a prominent feature of the 

 disease. Such an attack may be the terminal event. 



Edema of the lungs, as well as of other internal organs, is less common 

 in association with edema due to other causes than to circulatory failure. 

 It may occur from local irritation of the lungs from poisonous gases, and 

 is not uncommon as a complication of lobar pneumonia. 



Special Forms of Edema. The general manifestations of the various 

 forms of edema are similar. There are, however, certain points relating to 

 the occurrence of these forms and to their clinical features, to which atten- 

 tion must be called. For this purpose it is convenient to adopt an etiolog- 

 ical classification of the forms which are to be discussed. 



Edema from mechanical causes is typified in the edema of heart 

 failure, in which the disturbance in rate and volume of blood flow seems 



