Western Differentiation

Dyspnoea (breathlessness) can have many different causes in Western medicine. However, apart
from general causes such as anemia, they all relate either to the lungs or heart.

In fact, breathlessness can arise either from a disease of the lungs themselves (such as asthma,
bronchitis or emphysema), or from a heart disease affecting the lungs (such as left ventricular
heart failure).

The most common causes of chronic breathlessness can be summarized with a diagram (Figure
3.2Figure 3.2).

Causes in Lungs

Asthma

This consists in the constriction of the bronchi on exhalation. It may arise during childhood in
atopic individuals, i.e. those who easily form antibodies to commonly-encountered allergens
such as house dust, pollen or house-dust mites. Such patients often suffer from other allergic
diseases such as allergic rhinitis or atopic eczema. This is called early-onset or extrinsic asthma
and will be discussed in a separate chapter (Chapter 5). In other cases, it starts in later life in
non-atopic individuals and is called late-onset or intrisic asthma. This type of asthma is not due
to an allergic reaction.

In both types the main manifestations are breathlessness on exertion and wheezing and coughing
which may be worse at night.

Chronic Bronchitis

This is due to narrowing of the bronchioles by mucus and oedema of mucous membranes within
the lungs. It is this narrowing that causes the breathlessness.

This condition occurs in middle-aged or elderly people and the main distinguishing sign to
differentiate it from asthma is a chronic productive cough with abundant expectoration. It also
differs from asthma in so far as the breathlessness is often worse in the morning (rather than at
night as in asthma). Another feature of this condition is the propensity to frequent chest
infections.