Difficulty in breathing or dyspnoea is described as the increased awareness of one’s laborious breathing. Difficulty in breathing is one of the commonest complaints a patient will present with, next to fever and upper respiratory tract infection. It may be a symptom in a varied range of pathological entities and in a similar range of varied body systems. This is sometimes confused with asthma, where there is a component of difficulty breathing, but is associated with an expiratory wheeze. So with regards to the pathophysiology, symptoms, and management we will discuss on the similarities and the dissimilarities of bronchial asthma and cardiac asthma.
Bronchial Asthma
Bronchial asthma (BA) is a respiratory tract condition, where there is an element of chronic inflammatory process, with reversible narrowing of the airways and an associated airway hyper responsiveness. This is usually caused by immune mediated mechanisms and/or direct contact with minute particles. There are oedematous cells with, mucus plugs, secretion of mucus and thickened basement membranes. Here on examination of the lungs the patient will have bilateral wheezing sounds/ rhonchi. The management of this condition is done through using oxygen and bronchodilators like beta agonists, with long term usage of corticosteroids to retard the chronic inflammatory process. If not properly managed there can be sudden death following life threatening asthma attacks or respiratory failure.
Cardiac Asthma
Cardiac asthma (CA) is a condition where there is either an acute left ventricular failure (left heart failure) or congestive (left and right) cardiac failure. In this condition, the hearts left side has become damaged leading to reduced capacity to pump the blood out of the heart. Thus, blood backtracks into the pulmonary veins, and the capillary baskets around the alveoli of the lungs. The hydrostatic pressure finally gives way to the transudation of fluids into the alveoli reducing the effective surface are for the diffusion of gases. This will lead to a feeling of drowning, where the patient complains of dyspnoea. Here on examination of the lungs, there will be bilateral basal fine crepitations. The management will be based on oxygenation and reducing the fluids in the lungs with morphine, and reducing the overall load to the heart with the use of a loop diuretic like Furosemide, and controlling the blood pressure. Unless this is properly managed with the underlying condition, there is a risk of death due to repeated episodes or chronic heart failure.
What is the difference between Bronchial Asthma and Cardiac Asthma?
Both these conditions present with dyspnoea and feelings of dread in the patient. Most of the symptoms are similar but with dissimilar past histories. On examination, BA will have rhonchi and CA will have crepitations. The pathophysiology of the two is different with BA having an immune mediated airway narrowing, and CA having a transudative pulmonary oedema. The management of BA is based on bronchodilatation and with CA, the management being the removal of fluids from the alveoli. Both these conditions carry the risk of death with either of them.
In summary these two conditions, which are different in pathophysiology, signs and management will present with indistinguishable symptoms, unless properly prodded. And if mistaken, CA can lead to death if treated as for BA, because salbutamol (a beta agonist) causes increased heart rate and rising pulmonary oedema as a result.