Difficult or laboured breathing (dyspnoea) is a common symptom and signifies obstruction to the flow of air into and out of the lungs as in asthma, or a disease of the lungs, e.g. emphysema, or a disease of the heart. Dyspnoea at rest has a greater significance than the one which appears only on exertion. The severest degree of dyspnoea is one in which the patient has to sit up to ease his breathing. Dyspnoea may be of acute onset or it may be chronic.
Dyspnoea of acute onset is commonly caused by asthma or pneumonia, heart disease or by a foreign body such as solid food stuck in the respiratory tract. There are other less common causes also. The causes are detailed below.
Asthma is the commonest cause of acute attacks of breathlessness. The attacks are caused by allergy or hypersensitivity to some matter suspended in the air, e.g., house dust, smoke, fumes, moulds, pollens, scent, etc. Irritants like cigarette smoke, colds, vigorous exercise, and sudden exposure to cold air are likely to start a flare-up.
There is a widespread spasm of bronchial muscles and allergic inflammation of the bronchial lining, which reduces the lumen of the bronchi, causing obstruction to the flow of air, resulting in dyspnoea and cough. Wheezing sounds may be audible. Fever is absent, unless secondary infection supervenes. Dyspnoea usually lasts for a few hours and then subsides. But it may last longer, even days; this condition is “status asthmaticus”. It is dangerous and needs urgent treatment. The asthma may become chronic with low grade symptoms and the wheeze present most of the time. This usually happens when infection supervenes.
With each attack of asthma the lungs are inflated as there is expiratory difficulty. After the attack is over, the lungs tend to come back to their normal position. But after repeated attacks and chronicity, the lungs may remain in the inflated position. This is emphysema; see below under “chronic dyspnoea”
The attacks are treated with bronchodilator drugs and corticosteroids given by inhaler, or as tablets or injections. The patient should avoid the precipitating and allergic factors mentioned above.
This is an entirely different condition and has nothing to do with bronchial asthma. The cause lies in the dysfunction of the left side of the heart due to heart disease, such as rheumatic valvular disease, heart attacks, etc., or severe hypertension. The left ventricle of the heart fails to pump out all the blood it receives from the lungs; back pressure in the lungs develops leading to pulmonary (lung) congestion and oedema. It is this congestion and oedema of the lungs which is responsible for the breathlessness and makes the patient sit up to ease his breathing. Dyspnoea is produced by exertion also. Coughing is also present. In acute cases, watery, sometimes blood-stained, sputum may be produced and the patient may be cyanosed (blue) due to lack of oxygen in the blood.
If the right side of the heart also fails, the liver becomes enlarged; ascites (collection of fluid in the abdomen) and oedema (swelling) of the feet appear.
Cardiac asthma is a serious complication of heart disease and needs urgent cardiological care. The patient should be admitted to a hospital. It is worth remembering that an asthma occurring for the first time after about 40 years of age is unlikely to be bronchial asthma but cardiac in origin.
Dyspnoea is accompanied by high fever and cough.
Acute Respiratory Obstruction
Acute obstruction to respiration may be caused by a foreign body such as a coin accidently swallowed by a child, or a solid, inadequately chewed piece of food going the wrong way into the respiratory tract. It may lodge anywhere — throat, larynx, trachea or a bronchus. Such accidents are common in children. Example: Choking on food
Pneumothorax is the presence of air outside the lung in the pleural cavity, a potential space between the two layers of the pleura which cover the lungs and line the rib cage. A tear in the pleura causes leakage of air into the pleural cavity.
The cause may be trauma, e.g., the sharp margin of a fractured rib; tuberculosis of the lung or rupture of emphysematous bulla.
The presence of air outside the lung causes collapse of the lung and its respiratory function ceases, resulting in respiratory embarrassment and dyspnoea.
The tear may be valvular, so that there is a progressive increase in the pressure of air and increasing embarrassment of respiration and heart action (tension pneumothorax). It is a medical emergency, and urgent steps are required to relieve the pressure of air.
An x-ray of the chest and clinical signs in the chest, which your doctor will elicit, make the diagnosis. He will also rule out the possibility of underlying tuberculosis, because in such cases infection also gets into the space and pleura effusion (fluid) or empyema (pus) may form. Such patients need intensive antitubercular treatment.
All other cases usually get well in due course of time as air gets gradually absorbed.
Pleurisy with Effusion
Although it usually causes chronic dyspnoea, sometimes the symptoms may be acute if there is a large and rapid collection of fluid. It is described under chronic dyspnoea below.
Prolonged confinement to bed for any reason, e.g. an operation, heart attack, etc causes stasis of blood and clotting in the leg veins (venous thrombosis). If the blood clot breaks loose (embolus), it travels up to the right side of the heart and thence into an artery of the lung, causing obstruction to the flow of blood. The corresponding portion of the lungs gets infracted (damaged). This causes bleeding and difficulty of respiration. The condition needs anticoagulant drugs/injections to prevent further extension of thrombosis and embolism.
Prevention is best. Too prolonged recumbency, especially in old people, is inadvisable, and, during the period of enforced rest, leg movements should be encouraged in the bed to prevent stasis and clotting of blood in the leg veins. However, once venous thrombosis has occurred, all movements will have to stop for a few days to prevent the clot from breaking loose and embolising into the lung.
Some neurotic individuals, especially young women, may complain of dyspnoea without an underlying cause. There is frequent sighing respiration, bizarre and irregular breathing pattern during waking hours, but normal during sleep. The symptoms are worse when sympathetic relatives and friends are around. Other features, e.g., hysterical fits, may be present. It is a harmless condition; reassurance is all that is necessary.
Dyspnoea of long duration and of gradual onset is commonly due to obesity and chronic asthma, emphysema, chronic left heart failure and anaemia. Sometimes other causes, like pleurisy with effusion or tumour of the lung, are found. These conditions are described as follows.
It is a common cause of chronic dyspnoea. The person has to carry an extra load of inert fat which causes breathlessness on exertion. Obesity in older age group is not uncommonly associated with serious diseases like diabetes, high blood pressure and ischemic heart disease; these conditions add their own weight. See chapter 47 for details and management.
Addition of infection makes a case of bronchial asthma chronic, so that mild difficulty of breathing, especially on exertion, is present most of the time. There is, in addition, chronic wheeze, cough and sputum. Emphysema (see below) gradually develops and makes the breathing difficulty progressively worse. Treatment is given by suitable antibiotics in addition to bronchodilator and corticosteroid drugs given by mouth and / or inhaler.
Our lungs are masses of spongy tissues with numerous septa separating the air spaces. Chronic cough and airway obstruction may occur as a result of excessive smoking, asthma or chronic bronchitis. Over the years, these septa break. This destroys the elasticity of the lungs, increases the blood pressure in the pulmonary circuit of blood vessels and thus puts a strain on the right side of the heart and leaves the lungs in a perpetually expanded state, unable to take in enough air, reducing their vital capacity and resulting in progressive dyspnoea.
Treatment is essentially preventive by giving up smoking and proper treatment of chronic bronchitis or asthma.
Chronic Left Heart Failure
Rheumatic valvular heart disease in the young and ischemic heart disease in the elderly are common causes of chronic left heart failure. Difficulty of breathing is induced by slight exertion or on lying down in bed at night. Detailed cardiological investigations and proper treatment are necessary. Rheumatic valvular disease may be amenable to surgical correction.
Anaemia reduces the oxygen-carrying capacity of the blood. To compensate for it the lungs and heart have to function at a higher rate, resulting in breathlessness. Treatment is directed towards correction of anaemia.
Pleurisy with Effusion
The usual cause of the presence of fluid in the pleural cavity is tuberculosis of the lung. Pneumonia and cancer deposits can also cause the effusion.
The effusion causes collapse of the lung, disturbing its function and causing dyspnoea, which is proportional to the amount of fluid and the rapidity with which it has formed.
In young people complaining of prolonged low grade fever, lassitude and breathing difficulty on exertion, tubercular pleurisy may be found to be the cause. Similar symptoms in the elderly may signify malignancy. Detailed physical examination and investigations, including an x-ray of the chest, and laboratory examination of the pleural fluid obtained by tapping, maybe required for diagnosis.
Treatment depends upon the cause. In the usual type of pleurisy, which is tubercular, antitubercular treatment is given.