Clinical Case Study in Occupational and Environmental Medicine
A nurse with persistent cough and wheeze
(Note: The absence of finger clubbing makes bronchiectasis even more unlikely.)
The pattern of her dynamic spirometry with both FEV1 and FVC reduced but especially the FEV1 (and hence a reduced FEV1 / FVC ratio) is typical of obstructive lung disease.
The reversibility after inhalation of a Beta agonist shows that this is asthma and not Chronic Obstructive Pulmonary Disease (COPD). (Moreover her history makes COPD quite unlikely.)
Serial measurements of Peak Expiratory Flow (PEF) would have been very helpful - especially earlier on in her illness. Even at this stage they are likely to show a diurnal pattern especially with an early morning dip and a large enough variation to indicate a diagnosis of asthma and not of COPD.
Earlier on in her illness two hourly measurements of PEF would have been even more helpful provided they were done properly. They would need to have been kept up regularly during working hours (or if woken up by night) for a period of three to four weeks whether at work or not. Diligent records would have had to have been kept of her work days, exposures, times of exposure and treatment. Preferably the first reading in the days off work should be at the same time as on work days.
A tall order for some patients!
But such a serial PEF recording could clinch the diagnosis of occupational asthma. Besides a typical diurnal pattern of PEF in asthma it would have been likely to show daily means, maxima and minima of PEF improving whilst off work, and then deteriorating over days exposed at work.
There are many parallels between the approach used by a clinician in making a diagnosis of occupational disease in an individual and the approach used by an epidemiologist to determine that a particular agent causes occupational (or other environmental) disease in a population. You can learn more about this here.
But in the meantime you are faced with an ill patient, and she wants you to make her better...
How would you treat her?
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Acknowledgement:The case description on which this educational resource is based is (c) copyright of the University of Manchester. It is temporarily housed on this website for technical and other reasons.