Section III Common Symptoms (dyspnea) Dr. Zhuoren Lu First Hospital Xian Jiaotong University

C. Dyspnea 1. Definition: shortness of breath. It is purely subjective. 2. Causes of dyspnea (1) pulmonary dyspnea a) Obstructive disease of airways  Large airway obstruction produces “ inspiring dyspnea ”  Obstruction of intrathoracic airways produces “ expiring dyspnea ” -- asthmatic wheezing

b) Ephysema and Diffuse parenchymal lung disease c) Disease of chest wall and respiratory muscles (2) Cardiac dyspnea: In left ventricular failure, the hydrostatic pressure in the pulmonary capillaries exceeds oncotic pressure of plasma, transudation of fluid from capillaries to alveoli takes place. (3)Miscellaneous causes of dyspnea

3. Some types of dyspnes (1) Exertional dyspnes: Dyspnea during exertion is the earliest symptom of left ventricular failure. (2) Acute pulmonary edema: Usually it occurs in individuals with already compromised heart, with sudden increase of blood pressure in hypertensive person, sudden increases of pulse rate, unusual exertion, rapid intravenous infusions of fluid, and so on.

(3) Orthopnea: a form of dyspnea in which the patient must assume a sitting position to avoid respiratory distress. (4)Paroxysmal nocturnal dyspnea: The cause is that the patient is already on the borderline of pulmonary edema. The result is an increase of pulmonary capillary pressure and pulmonary edema. (5)Cardiac asthma: It is asthmatic breathing in the patient with heart disease. It frequently occurs during attacks of paroxysmal nocturnal dyspnea.