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COPD

This is a good example of what happens. Notice the thickened bronchioles and the enlarged alveoli.

Definition

A chronic, slowly progressing an worsening with fixed airway obstruction, as opposed to the reversible airway obstruction of asthma. It is actually two conditions: chronic bronchitis and chronic emphysema:

  • Bronchitis is a clinical term defined as chronic cough and sputum for at least 3 months each year for 2 consecutive years.
  • Emphysema is an anatomical term defined as permanent enlargement of airspaces distal to the terminal bronchioles together with destruction of their walls

Epidemiology

Common.jpg
Mostly seen in older people, but about 1 in 20 of the population has it to some degree. So pretty bloomin' common.

Pathophysiology

Risk Factors

  • Smoking - this is the major cause. About 90% of cases are caused by cancer sticks.
  • Occupational - working an area with loads of dust or down a mine.
  • Air pollution - living in Mexico city
  • Genetic - people with Alpha 1-antitrypsin deficiency lose the ability to reign in a gunk clearing enzyme, so it attacks healthy lung tissue.

Clinical Features

Medical Emergencies -
Emergency.gif
Acute exacerbation of COPD can be a medical emergency, just like asthma attack, so you need to treat it fast!

History

The amount of cough and sputum is generally related to the degree of bronchitis. Basically, look for breathlessness, cough and wheeze, with no return to normal between attacks. It will be getting progressively worse too.

  • Patients with severe bronchitis get accompanied with hypercapnia, hypoxaemia and cyanosis. This leads to them being called blue bloaters.
  • With severe emphysema there is just overventilation in order to produce normal levels of pO2 and pCO2 – thus the term pink puffers.

Examination

On respiratory examination there will also be:

  • Tachypnea - fast breathing.
  • Wheeze or crackles on auscultation.
  • Hyperinflation - a large, expanded, or "barrel" chest.
  • Use of accessory muscles - the patient using shoulder muscles to help them breathe.

Investigations

Pulmonary function tests:

  • Reduced vital capacity
  • Reduced FEV1:FVC ratio
  • Reduced Peak Expiratory Flow Rate

Management

If they are acutely presenting, and struggling to breath, it could well be acute exacerbation of COPD, or pneumonia. Either way, you need to treat that.

However, long term, basically, you get it and you slowly get worse. There's no cure.

You can go on oxygen with emphysema, but you have to be careful as the respiration mechanism in the brain will probably be based on pO2 not pCO2, so a sudden increase in oxygen level will stop them breathing.

Prognosis