某医学院诊断学呼吸障碍课件

1、同济医学院诊断学呼吸障碍同济医学院诊断学呼吸障碍同济医学院诊断学呼吸障碍同济医学院诊断学呼吸障碍同济医学院诊断学呼吸障碍同济医学院诊Definition: Dyspnea is defined as an awareness of difficulty in breathing It is therefore a symptom, usually described by the patient as “short of breath,” whether the sensation is due to actual difficulty in breathing or is essential

2、ly an awareness of hyperventilation. If the symptom becomes striking, it always companies with dilatation of nares, cyanosis, use of accessory muscles of respiration and abnormalities of respiratory rate, depth or rhythm.Definition:Respiratory diseases Circulatory diseases Poisoning Hematology Neuro

3、psychogenic factorsEtiologyRespiratory diseasesEtiologyRespiratory dyspneaCaused by abnormal ventilation and gas exchange, reduction in ventilatory capacity, hypercapnia and hypoxemia resulting from respiratory disease. Three clininal types: Inspiratory dyspnea Expiratory dyspnea Mixed dyspneaRespir

4、atory dyspneaCaused by aInspiratory dyspneaTends to occur primarily when there is obstruction ( such as inflammation, edema, tumor and foreign body) in larynx, trachea and major bronchi. Characterized by the depression sigh, in which visible indrawing over the sternal notch, the supraclavioular spac

5、es, the intercostal spaces and the epigastrium in the inspiration can be seen. Often accompanied by a coarse, low pitched inspiratory wheezing and dry cough. Inspiratory dyspneaTends to ocExpiratory dyspneaExpiratory dyspnea is due to the decrease of lung elasticity and spasm narrowing of the bronch

6、ioles and smaller bronchi as in emphysema, bronchial asthma and asthmatic bronchitis.Expiration is prolonged and laboured with wheezing. Expiratory dyspneaExpiratory dMixed dyspneaOccurs with the extensive lung disease, such as severe pneumonia, pulmonary fibrosis, massive atelectasis, pleural effus

7、ion and pneumothorax.Results in the decrease of ventilators and gas exchange capacity. Breathing is difficult during both inspiration and expiration.Mixed dyspneaOccurs with the eCardiac dyspnea Cardiac dyspnea is usually attributable to pulmonary vascular congestion resulting from the left and/or r

8、ight heart failure.Cardiac dyspnea Cardiac dyspCardiac dyspneaIn Left-sided heart failure, compliance is reduced, and therefore, ventilation is decreased to the edematous lung regions and vital capacity reduced. Alveoli are stiff and more work is needed to overcome elastic recoil, the high alveolar

9、pressure will stimulate stretch receptor and initiate the inflation reflex resulting in early turning off of inspiration and an increase in respiratory rate. Cardiac dyspneaIn Left-sided hCardiac dyspneaThe dyspnea caused by right-sided heart failure is less severe than that one caused by left-sided

10、. Mechanism: (1) The pressure of right atrial and superior vena cava is the natural stimulus of respiratory center. (2) The decrease of oxygen content and the accumulation of the acid metabolites, such as lactic, stimulate respiratory center. (3) The restriction of the respiratory movement caused by

11、 enlargement of liver resulting from congestion, ascites and pleural effusion. Cardiac dyspneaThe dyspnea cauCardiac dyspnea Symptoms of congestive heart failure can cause orthopnea and paroxysmal nocturnal dyspnea when elevated-filling pressure is present. Cardiac dyspnea Symptoms of orthopneaOrtho

12、pnea is difficulty in breathing in the supine position, this may be relived by sitting up, which reduces the degree of pulmonary congestion by pooling blood in the lower extremities and lowering left ventricular filling pressures, improving the diaphragmatic movement, increasing vital capacity.ortho

13、pneaOrthopnea is difficulparoxysmal nocturnal dyspneaSymptoms: The patient awakes short of breath at night, but often obtain relief by sitting up for a period of time. In the most advanced cases, the patients become acutely dyspneic, cyanotic and very frequently produce foamy sputum tinged with bloo

14、d. Signs: Moist rales at the both lung bases, tachycardia, wheezing and bronchospasm, the markedly accentuated second heart sound in the pulmonic area. paroxysmal nocturnal dyspneaSyMechanism: Supine posture for sleep results in resorbtion of extracellular fluid into the intravascular space, causing

15、 arise in filling pressure. The paroxysmal dyspnea is termed as cardiac asthma. It can be seen in the hypertensive heart disease and coronary heart disease. paroxysmal nocturnal dyspneaMechanism: Supine posture for Toxic dyspneaIn the metabolic acidosis (uremia and diabetic ketosis), the acid metabo

16、lites stimulate the respiratory center, causing deep and regular respiration with snoring.The overdose of morphine and pentobarbital can depress respiratory center causing deep respiration or Cheyne-Stokess respiration Toxic dyspneaIn the metabolic Neuro-Psychogenic dyspneaIn patients suffering from

17、 cerebrovascular diseases (intracranial hemorrhage, elevated intracerebral pressure), the respiratory center loses the blood supply or is compressed. The respiration becomes deep, slow and irregular. In some cases the dyspnea may be psychogenic, which is characterized by repetitive deep, sighing res

18、piration with numbness of extremities or lips, cheiropedal spasm. These are also manifestations of acute hypocapnia and respiratory alkalosis. Neuro-Psychogenic dyspneaIn pHematological dyspnea In severe anemia, sulfhemoglobinemia, methaemoglobinemia or carbon monoxide poisoning the decrease of oxyg

19、en-carrying capacity and oxygen content develop abnormal respiration and increased heart rate. The respiration rate also increases in shock which stimulates respiration center because of hypotension. Hematological dyspnea In sever Accompanied SymptomParoxysmal dyspnea with wheezing. Dyspnea with che

20、st pain. Dyspnea with fever. Dyspnea with cough and purulent sputum. Dyspnea with coma. Accompanied SymptomParoxysmal dyspnea with wheezing It is present in bronchial asthma and cardiac asthma. Paroxysmal severe dyspnea is often seen in acute larynx edema, foreign body in bronchi, massive pulmonary embolism, and spontaneous pneumothorax. Paroxysmal dyspnea with wheeziDyspnea with chest pain. It is frequently observed in lobar pneumonia, pulmonary infarction, spontaneous pneumothorax, acute exudative pleurisy, acute myocardial infarction, and bronchial ca