The Symptomatic Treatment of The Cough in Whooping Cough

Article type
Authors
Pillay V, Swingler G
Abstract
Background: There are between 20 - 40 million cases of whooping cough annually world-wide, 90% of which occur in developing countries, resulting in an estimated 200 - 300 000 fatalities each year. Much of the morbidity is due to the paroxysmal cough. Corticosteroids, salbutamol (a beta2 -adrenergic stimulant), and pertussis-specific immunoglobulin have been proposed as standard treatment for the cough. Antihistamines have also been administered. No systematic review of the effectiveness of any of these interventions or others have been performed.

Objective: In this systematic review we aim to assess the effects of interventions to suppress coughing paroxysms in whooping cough.

Methods: Randomised and quasi randomised controlled trials of any intervention suppressing the cough in whooping cough; excluding antibiotics and vaccines. All interventions aimed at suppressing the cough in children or adults with whooping cough with any of the following outcome measures; i) frequency of paroxysms of coughing (our primary outcome), ii) frequency of vomiting, iii) frequency of whoop, iv) frequency of cyanosis, v) development of serious complications, vi) mortality from any cause, vii) side effects due to medication, viii) admission to hospital, ix) duration of hospital stay. We searched the Cochrane Controlled Trials register, Acute Respiratory Infectious Disease Group Specialised trials register, MEDLINE, LILACS, scanned reference lists of identified trials, contacted authors of identified trials and the relevant pharmaceutical companies. Studies were selected, quality assessed and data extracted by two reviewers independently. Effects were expressed as mean differences or in meta analysis as weighted mean difference s with 95% confidence intervals.

Results: Nine studies satisfied the inclusion criteria but four had insufficient data for further meta - analysis of our pre-specified outcomes. Studies were old and poorly reported. The largest study had a total sample size of 49 and the smallest study nine. All studies were performed in industrialised settings.
Eligible studies assessed diphenhyramine, pertussis immunoglobulin, dexamethasone and salbutamol. No statistically significant benefit was found for any interventions. Diphenhydramine was associated with a mean increase of 1.90 coughing spells per 24 hours [95%CI -4.66; 8.46] and pertussis immunoglobulin a mean decrease in hospital stay of 0.70 days [95% CI -3.79; 2.39], and a mean reduction of 3.10 whoops per 24 hours [95% CI -6.22; 0.02]. Dexamethasone resulted in a mean decrease in hospital stay of 3.45 days [95% CI -15.34; 8.44] and salbutamol in a weighted mean decrease in coughing paroxysms of 0.95 per 24 hours [95% CI -6.21; 4.31].

Conclusion: Fairly reliable assessments have been performed on diphenhyramine, pertussis immunoglobulin, dexamethasone and salbutamol, yet insufficient evidence exists to draw conclusions about the effects of any of them.