What Is Paroxysmal Nocturnal Dyspnea?

Paroxysmal nocturnal dyspnea is usually not difficult to fall asleep, but after falling asleep at night, it is necessary to sit up because of chest tightness and shortness of breath. More common in patients with left ventricular insufficiency, patients with congestion worsened when lying, suddenly woke up in sleep, forced to sit up. In mild cases, the symptoms disappear after several minutes to tens of minutes, and some patients are accompanied by cough and foamy sputum. Some patients with bronchospasm and dry lung sounds are similar to bronchial asthma, also known as cardiogenic asthma. Severe cases can cough pink foamy sputum and develop into acute pulmonary edema. Essentially due to congestion of the pulmonary circulation, common in left heart failure. Treatment should clearly identify the primary disease that causes paroxysmal nocturnal dyspnea and treat the cause.

Basic Information

English name

paroxysmal nocturnal dyspnea

Visiting department

Respiratory Medicine

Common causes

It is often caused by rheumatic heart disease, hypertension heart disease, coronary heart disease, etc., and is more common in left heart failure.

Common symptoms

After falling asleep at night, sudden chest tightness and shortness of breath may be accompanied by cough, foamy sputum, bronchospasm, and dry lungs

Etiology and common diseases of paroxysmal nocturnal dyspnea

Occurrence mechanism

(1) Exacerbation of pulmonary congestion: After the patient lays asleep, the blood flow in the lower body veins increases, and the edema fluid that accumulates in the interstitial space of the sagging part due to gravity during the day also returns to the blood due to changes in body position, so the congestion and edema in the lungs Significantly intensified.

(2) Ventilation resistance is large: the tension of the vagus nerve center rises when falling asleep, the diameter of the bronchus becomes smaller, and the ventilation resistance increases.

(3) Low sensitivity of nerve reflex: The sensitivity of nerve reflex decreases during deep sleep, so only when the pulmonary congestion develops to be more serious, can it stimulate the respiratory center, causing sudden onset of breathing difficulties, forcing to sit up and breathe open.

2. Common diseases

Such as rheumatic heart disease, hypertension heart disease, coronary heart disease and so on.

Differential diagnosis of paroxysmal nocturnal dyspnea

1. Paroxysmal nocturnal dyspnea can be relieved a few minutes after sitting up, but some with cough, foamy sputum, and 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 and breathing, frequent coughing, often producing foamy sputum, with irritability, and blue lips ,Sweating.

Paroxysmal nocturnal dyspnea

Physical examination

(1) The patient's posture, posture and mental state. Sit breaths are seen in left heart failure and severe bronchial asthma; the ipsilateral side is common in pleural effusion; panic and restlessness are seen in pulmonary edema; chest pain and painful expressions are seen in acute myocardial infarction. Severe carbon monoxide or cyanide poisoning, severe acidosis, or pulmonary encephalopathy often have varying degrees of consciousness disturbance.

(2) Changes in breathing frequency, rhythm, and depth, with or without three concave signs. Deep breathing, seen in diabetes or uremia, acidosis; shallow breathing, seen in emphysema, respiratory muscle palsy, or sedative overdose; tidal breathing seen in cerebral arteriosclerosis or increased intracranial pressure.

(3) Whether the jugular vein is swollen, the shape and expansion of the thorax, pay attention to whether there is thoracic deformity, asymmetry or chest wall tenderness.

(4) With or without signs of lung and pleural lesions. Contradictory movements of the chest and abdomen or asymmetric breathing movements on both sides, dull dullness or drum sounds, dry and wet snoring sounds, abnormal breathing sounds

(5) Whether there are signs of heart disease and heart failure. Pay attention to whether there is an enlarged heart, abnormal heart sounds, and pathological murmurs.

(6) Whether there is a large amount of ascites and signs of dehydration.

(7) Whether there are cyanosis, clubbing fingers and lower limb edema.

2. Auxiliary inspection

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

(2) X-ray examination: enlargement of left ventricle, enhancement of hilar shadows, and pulmonary edema, cloud-like shadows in the lungs.

(3) Echocardiography: Evaluate the systolic and diastolic function of the heart; find underlying heart disease and factors that affect heart failure.

(4) Others: radionuclide examination, cardio-pulmonary oxygen exercise test, cardiac catheterization and coronary angiography.

Principles of Paroxysmal Nocturnal Dyspnea

Treatment should clearly identify the primary disease that causes paroxysmal nocturnal dyspnea and treat the cause.