Bronchial asthma and cardiac asthma
Bronchial asthma is another name for the common form of asthma. The term ‘bronchial’ is occasionally used to differentiate it from what doctors sometimes call ‘cardiac’ asthma, which is not true asthma but breathing difficulties caused by heart failure. Although the two conditions have similar symptoms, including shortness of breath and wheezing (a whistling sound in the chest), they have quite different causes.
In cardiac asthma, the reduced pumping efficiency of the left side of the heart leads to a build up of fluid in the lungs (pulmonary oedema). This fluid build-up can cause breathlessness and wheezing. Cardiac asthma has very similar symptoms to bronchial asthma. The main symptoms and signs of cardiac asthma are:
- shortness of breath with or without wheezing;
- rapid and shallow breathing;
- an increase in blood pressure and heart rate; and
- a feeling of apprehension.
The pattern of shortness of breath helps doctors determine which type of asthma you have — people with bronchial asthma tend to experience shortness of breath early in the morning, whereas people with heart failure and cardiac asthma often find they wake up breathless a few hours after going to bed, and have to sit upright to catch their breath. This is because in people with heart failure, lying down for prolonged periods will cause fluid to accumulate in the lungs leading to shortness of breath.
Both bronchial and cardiac asthma can make people short of breath when they exert themselves. In bronchial asthma, symptoms are usually brought on by vigorous exercise and tend to be worse after the exercise than during it. On the other hand, cardiac asthma tends to happen during less vigorous exertion — someone with heart failure can find themselves short of breath while climbing stairs, or in severe cases, while getting dressed.
People with heart failure also often have problems with swollen ankles that worsen during the course of the day. They may also feel very tired, put on weight and have to urinate frequently.
Cardiac asthma can be a life-threatening condition, and you should consult your doctor if you think you have symptoms of cardiac asthma.
For most people with bronchial asthma, the pattern is periodic attacks of wheezing alternating with periods of quite normal breathing. However, some people with bronchial asthma alternate between chronic (long-term) shortness of breath and episodes in which they feel even more breathless than usual.
Risks for developing bronchial asthma include being a person who is genetically susceptible to asthma and being exposed early in life to indoor allergens, such as dust mites and cockroaches, and having a family history of asthma or allergy. Exposure to the effects of tobacco smoke before birth or during early childhood also increases the risk of developing bronchial asthma.
Bronchial asthma attacks can be triggered (precipitated or aggravated) by various factors, including:
- respiratory tract infections;
- cold weather;
- allergens (substances that trigger an allergic reaction) such as pollen and house dust mites;
- cigarette smoke and other air pollutants; and
Some people can develop asthma due to an intolerance that their body develops to aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) (in which case exposure to aspirin or NSAIDs can trigger an asthma attack). Other medicines, such as beta-blockers, can worsen or unmask bronchial asthma. Other people develop asthma due to an allergy that they develop to certain chemicals in the workplace (this is called ‘occupational asthma’, in which case exposure to the chemical triggers an asthma attack).
The symptoms of bronchial asthma include:
- a feeling of tightness in the chest;
- difficulty in breathing or shortness of breath;
- wheezing; and
- coughing (particularly at night).