CASE 4: SHORTNESS OF BREATH

History
A 26-year-old teacher has consulted her general practitioner (GP) for her persistent cough.
She wants to have a second course of antibiotics because an initial course of amoxicillin
made no difference. The cough has troubled her for 3 months since she moved to a new
school. The cough is now disturbing her sleep and making her tired during the day. She
teaches games, and the cough is troublesome when going out to the playground and on
jogging. In her medical history she had her appendix removed 3 years ago. She had her
tonsils removed as a child and was said to have recurrent episodes of bronchitis between
the ages of 3 and 6 years. She has never smoked and takes no medication other than an
oral contraceptive. Her parents are alive and well and she has two brothers, one of whom
has hayfever.

Examination
The respiratory rate is 18/min. Her chest is clear and there are no abnormalities in the nose,
pharynx, cardiovascular, respiratory or nervous systems.

INVESTIGATIONS
• Chest X-ray is reported as normal.
• Spirometry is carried out at the surgery and she is asked to record her peak flow rate at
home, the best of three readings every morning and every evening for 2 weeks.
Spirometry results are as follows:
Actual Predicted
FEV1 (L) 3.9 3.6–4.2
FVC (L) 5.0 4.5–5.4
FER (FEV1/FVC) (%) 78 75–80
PEF (L/min) 470 440–540
FEV1: forced expiratory volume in 1 s; FVC, forced vital capacity; FER, forced expira-
tory ratio; PEF, peak expiratory flow.

Questions
• What is your interpretation of these findings?
• What do you think is the likely diagnosis and what would be appropriate treatment?

ANSWER 4
The peak flow pattern shows a degree of diurnal variation. This does not reach the diag-
nostic criteria for asthma but it is suspicious. The mean daily variation in peak flow from
the recordings is 36 L/min and the mean evening peak flow is 453 L/min, giving a mean
diurnal variation of 8 per cent. There is a small diurnal variation in normals and a vari-
ation of 15 per cent is diagnostic of asthma. In this patient the label of ‘bronchitis’ as a
child was probably asthma. The family history of an atopic condition (hayfever in a
brother), and the triggering of the cough by exercise and going out in to the cold also sug-
gest bronchial hyper-responsiveness typical of asthma.

Patients with a chronic persistent cough of unexplained cause should have a chest X-ray.
When the X-ray is clear the cough is likely to be produced by one of three main causes in
non-smokers. Around half of such cases have asthma or will go on to develop asthma over
the next few years. Half of the rest have rhinitis or sinusitis with a post-nasal drip. In around
20 per cent the cough is related to gastro-oesophageal reflux. A small number of cases will
be caused by otherwise unsuspected problems such as foreign bodies, bronchial ‘adenoma’,
sarcoidosis or fibrosing alveolitis. Cough is a common side-effect in patients treated with
angiotensin-converting-enzyme (ACE) inhibitors.

In this patient the diagnosis of asthma was confirmed with an exercise test which was
associated with a 25 per cent drop in peak flow after completion of 6 min vigorous exer-
cise. Alternatives would have been another non-specific challenge such as methacholine
or histamine, or a therapeutic trial of inhaled steroids.

After the exercise test, an inhaled steroid was given and the cough settled after 1 week.
The inhaled steroid was discontinued after 4 weeks and replaced by a 2-agonist to use
before exercise. However, the cough recurred with more evident wheeze and shortness of
breath, and treatment was changed back to an inhaled steroid with a  2-agonist as
needed. If control was not established, the next step would be to check inhaler technique
and treatment adherence and to consider adding a long-acting 2-agonist. In some cases,
the persistent dry cough associated with asthma may require more vigorous treatment
than this. Inhaled steroids for a month or more, or even a 2-week course of oral steroids
may be needed to relieve the cough. The successful management of dry cough relies on
establishing the correct diagnosis and treating it vigorously.