Paroxysmal nocturnal dyspnea

Introduction Paroxysmal nocturnal dyspnea, usually no difficulty in falling asleep, but after a night of sleep, sudden chest tightness, shortness of breath and need to be forced to sit up. When the patient was lying down, the blood was aggravated, suddenly awakened during sleep, and forced to sit up. Symptoms disappear after a few minutes to tens of minutes, and some patients have cough and cough foam. Some patients with bronchospasm, double lung dry rales, similar to bronchial asthma, also known as cardiogenic asthma. Severe cases can cough pink foam sputum, develop into acute pulmonary edema. The essence is caused by systemic congestion, which is common in left heart failure.

Cause

The mechanism of paroxysmal dyspnea at night is:

(1) After the patient falls asleep, the blood flow in the lower body vein increases, and the edema fluid accumulated in the interstitial space of the sagging area due to gravity during the day is also returned to the blood due to the change of body position, so the congestion and edema of the lung is obviously intensified.

(2) At the time of falling asleep, the vagus nerve center is increased in tension, the bronchial diameter is reduced, and the ventilation resistance is increased.

(3) The sensitivity of nerve reflexes during sleep is reduced, so that only when the pulmonary congestion develops to a serious degree, can the respiratory center be stimulated, causing sudden onset of breathing difficulties, forcing to sit up and breathe.

an examination

Related inspection

Respiratory muscle function measurement dynamic electrocardiogram (Holter monitoring)

Physical examination

1. Patient position, demeanor and mental state. Sitting breathing is seen in left heart failure, severe bronchial asthma; lateral position, common in pleural effusion; convulsions, seen in pulmonary edema; chest pain, painful expression seen in acute myocardial infarction. Severe carbon monoxide or cyanide poisoning, severe acidosis, or pulmonary encephalopathy often present varying degrees of disturbance of consciousness.

2, the jugular vein with or without anger, chest shape and expansion, pay attention to the presence or absence of thoracic deformity, asymmetry or chest wall tenderness. Whether there is abscess, edema or tumor in the throat.

3, skin and mucous membranes with or without subcutaneous emphysema and anemia.

4. Exhaled gas has a special smell. If the exhaled breath is rotten apple flavor, consider diabetic ketoacidosis.

5, respiratory frequency, rhythm and depth changes, with or without three concave signs. Deep breathing, found in diabetes or uremia acidosis; superficial respiratory, seen in emphysema, respiratory muscle paralysis or sedative excess; tidal breathing seen in cerebral arteriosclerosis or increased intracranial pressure.

6, with or without signs of lung and pleural lesions. Whether there is contradiction between chest and abdomen movement or asymmetry of respiratory movement on both sides, whether there is percussion dullness or drum sound, whether there is dry or wet rales, and whether there is abnormal breathing sound.

7, with or without signs of heart disease and heart failure. Pay attention to whether there is expansion of the heart, abnormal heart sounds and pathological murmurs.

8, whether there is a large amount of ascites, with or without dehydration.

9, with or without blemishes, clubbing and lower extremity edema.

Auxiliary inspection

1. General examination: including blood biochemistry, electrolytes, urine routine, electrocardiogram, etc.

2. X-ray examination: the left ventricle is enlarged, the hilar shadow is enhanced, and when the pulmonary edema is present, there is a cloud-like shadow in the lungs.

3. Echocardiogram: evaluation of cardiac function: systolic function and diastolic function; 2 found basic heart disease and other conditions that have an impact on heart failure.

4. Others: radionuclide examination, heart-lung oxygen exercise test, cardiac catheterization and coronary angiography.

Differential diagnosis

1, paroxysmal nocturnal dyspnea can be relieved after a few minutes of sitting, but some with cough, foamy sputum, if accompanied by asthma, can be called cardiogenic asthma.

2, paroxysmal nocturnal dyspnea can develop into pulmonary edema, manifested as severe dyspnea, breathing 40 to 50 times per minute, sitting breathing, frequent coughing, often bursting with foam, accompanied by irritability, lips and blue ,Sweating.

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