COPD essentially refers to lung function which has been damaged,​ usually by heavy smoking, in someone who is genetically susceptible to the disease. There are two forms of COPD:

Chronic bronchitis is a condition in which the lining of the two bronchial tubes (lung airways) becomes inflamed and thickens. Mucus forms, making it difficult for the airways to carry air into the lungs.

Emphysema is the failure of the tiny air sacs or alveoli to oxygenate the lungs, resulting in shortness of breath. This happens when the air sacs, found in each lobe of the lung, are damaged and lose their elasticity to expand and contract.

Many patients have overlapping features of both chronic bronchitis and emphysema. In both cases, the lung damage results in narrowing of the airways, thus restricting the flow of air in and out of the lungs.

What causes weight loss in COPD patients?

The following factors can cause people with COPD to lose weight:

• Burning up more energy than normal even for the simplest physical activity.

  Even normal activities like dressing and washing will require high-energy output, resulting in weight loss.

• Feeling too depressed to eat

  The debilitating effects of COPD on everyday life can affect the patient’s emotional and psychological well-being – and interest in food.

COPD is an irreversible disease which becomes progressively worse if left untreated. People with very severe COPD feel breathless even at rest and may suffer lung failure eventually. Common symptoms of COPD include:

1. Shortness of breath (dyspnea)
2. Persistent cough with mucus
3. Wheezing
4. Chest tightness
5. Respiratory infections

Ref: Q15​​