Adult 'whooping cough'

I’m waiting for the health department to issue another ‘Pertussis Alert’, like they did last year.

Whooping cough is not something that I learnt a great deal about, or saw a lot of, while studying to be a respiratory specialist. Perhaps it was not deemed serious enough a condition. As a result, I have had to slowly shed a skepticism towards this organism, Bordetella pertussis, and the role it plays in respiratory disease in adults. In clinical practice I have occasionally been embarrassed by failure to detect the diagnosis in patients referred with troublesome cough – being pipped to the post by diligent general practitioners. It seems, however, that I am not alone. A review of the literature on PubMed in search of a decent review of management of infection with Bordetella pertussis, cause of whooping cough in children, was disappointing.

Why does this matter? We just diagnosed another patient with pertussis infection last week – the diagnosis being based on the clinical presentation and the presence of specific IgA on serological testing. My impression of that woman’s illness was that it seemed very much like the illness doing the rounds of my family in recent weeks, which brought it close to home. Full sympathy to her husband who valiantly tried to remain in the marriage bed through distressing bouts of coughing at night time.

General practitioners around the region are making the diagnosis more often than me. The impression is of a significant outbreak. It is certainly not a rare disease.

Amongst the papers I have found and read in my renewed enthusiasm for this bug, the most interesting was a paper in the Brazilian infectious disease journal This paper, freely available online, beautifully describes the sort of clinical presentation I have seen a couple of times with this infection. In the case they present, the symptoms were ‘ cough and a fear of sleep’.

They make the points well that:
- the cough of pertussis is not just paroxysmal. The paroxysms are violent and uncontrolled and
- as a consequence are associated with an inability to breathe during coughing bouts (‘I just get short of breath with the coughing’) and
- in adults, who are able to clear away laryngeal secretions during the day, the paroxysms are predominantly a nocturnal problem (secretions build up and occlude the airway at night time, resulting in fragmentation of sleep). That means that we doctors, who see them in the light of day, seldom witness the worst of it.

The authors of that paper also suggest that rather than serology, PCR of upper airway secretions should be utilized early.

I tend to have referred to me patients with chronic cough only; the wait for an appointment cures many ills. Bordetella pertussis, we doctors have been taught, may be an important cause of chronic cough in adults. Of course, it must, by definition, also be cause of ‘acute’ cough (every chronic cough begins sometime) - mostly an acute and distressing coughing illness. I think it’s worth reflecting on whether we should apply ourselves more often to making the diagnosis early. By the time the patient has had the cough for more than 5 days, it is unlikely that antibiotics (generally macrolides are most useful - the best evidence being for clarithromycin and azithromycin) do anything more than shorten the period of infectivity. Certainly a recent Cochrane review suggested as much; there is no evidence that any treatments have an impact on symptoms.

It may be that if we listen carefully to the symptoms our patients relay to us early in the history of a coughing illness (how would a child with whooping cough describe their symptoms if they could talk?) and target investigations appropriately, early use of antibiotics – which is otherwise discouraged in upper respiratory infections – for adult patients with ‘whooping cough’ could save our patients a lot of inconvenience and demoralizing ill health.

Andrew