Epidemiological Factors – Lung Disease

00:01 So in this lecture, I'm going to discuss the clinical assessment of patients with lung disease. We can divide this into three main factors. One is assessing the epidemiological factors which are present for the patient: age, sex, ethnicity, country of origin. The second is taking a good history. And the third is examination. The third component (the examination) I will discuss in a subsequent lecture. Demography and respiratory disease is important.

00:26 It's very important, in fact, because which disease a patient is likely to have will be dictated by their age and, to a lesser extent, by their sex, their ethnic origin, their country of birth. So for example, somebody who's 20 years old with breathlessness will not have COPD. They've not had a long enough history of smoking to develop COPD in almost every circumstance. Somebody who's born in the UK and has lived there their whole life and lives at, say, in a country village rather than in one of the larger towns like London, is very unlikely to develop tuberculosis, because their exposure to tuberculosis is minimal.

01:07 So we can divide the lung diseases into three categories: the ones that really affect younger people, the ones that affect middle age, and the ones which are commoner in the elderly.

01:17 Now, the ones that affect the middle age and the elderly overlap largely. But the younger patient really is not going to get the nasty diseases such as lung cancer and COPD. So young adults might have asthma, a pneumothorax, pulmonary emboli, pneumonia, sarcoidosis.

01:35 And some causes of bronchiectasis are common in young people... are… affect young people, such as cystic fibrosis, for example. In the middle age, you start to worry about lung cancer, obstructive sleep apnea, but pneumonia is still present. Asthma is still quite possible. But COPD is coming in as a potential cause of obstructive lung function in these patients. And there are other diseases—bronchiectasis, pulmonary emboli, interstitial lung disease—which are increasingly common as you get older. In the elderly, the major lung diseases that patients get are lung cancer, pneumonia, and COPD, and pleural problems. But they also do get bronchiectasis, pulmonary emboli, interstitial lung disease. And it's not impossible to have asthma, because they could have had asthma for most of their life.

02:18 There are some respiratory diseases that are commoner in men and some which are commoner in women. Examples for men are COPD, lung cancer, pneumoconiosis (because that's due to occupational exposure), mesothelioma (again, because that's due to occupational exposure) are all commoner in men, as is the primary pneumothorax, which affects young men. And sleep apnea seems to be largely a male problem rather than a female problem, because of the structure of the back of the pharynx in men compared to women.

02:45 Diseases which are commoner in women are asthma, obesity hyperventilation, pulmonary emboli (because of the hormonal relationship), bronchiectasis (for reasons which are unknown), and primary pulmonary hypertension, which is a very rare disease, but a very serious one that affects largely young women. Country of origin and disease examples… Well, things like tuberculosis and HIV infection, bronchiectasis are much more likely in patients who are born in the developing countries such as South Asia or sub-Saharan Africa. There are some also specific genetic ethnicity issues, so Afro-Caribbean patients are particularly likely to get sarcoidosis, and cystic fibrosis is a genetic problem that affects Caucasians largely but not explicitly… not exclusively. So knowing age, sex, ethnic origin, place of birth gives you a feel for the sort of diseases the patient is likely to suffer from.