Mycoplasma pneumoniae and Bordetella pertussis in patients with persistent cough in primary care

Thesis

Background Persistent cough following an acute respiratory tract infection is a challenging and frequently encountered problem in primary care. Mycoplasma pneumoniae (M. pneumoniae) and Bordetella pertussis (pertussis) particularly predispose patients to persistent cough. Whilst the incidence of M. pneumoniae is highest in children, pertussis may also occur in adults.

Method Four studies were conducted for this thesis. First, a systematic review to assess the diagnostic accuracy of symptoms and signs in the clinical recognition of M. pneumoniae. Second, a retrospective analysis of a cohort of children with persistent cough to assess the prognostic value of diagnosing M. pneumoniae. Third, a prospective cohort study to estimate the prevalence of M. pneumoniae and pertussis in children with persistent cough following recent changes in vaccination policy. Fourth, a double-blind randomised placebo-controlled trial to determine the effectiveness of montelukast in the treatment of persistent cough and pertussis-induced cough in adults.

Results M. pneumoniae and pertussis can each be found in one-sixth of children who present in primary care with persistent cough. Although coverage with the preschool pertussis booster vaccine is high, its efficacy wanes rapidly, with the likelihood of pertussis increasing by 30% per year after vaccination. Montelukast is not an effective treatment for persistent cough, but may be an effective treatment for pertussis-induced cough.

Median duration of cough in children with M. pneumoniae is only one-third of that in children with pertussis (39 days versus 118 days). However, the diagnostic accuracy of symptoms and signs in the clinical recognition of M. pneumoniae is limited. Since M. pneumoniae occurs in cyclical epidemics, clinicians should consider current prevalence of M. pneumoniae when making a clinical diagnosis.

Conclusions Diagnosing M. pneumoniae and pertussis can help clinicians give patients an explanation for their cough and inform them about its likely prognosis. At the moment, clinicians should adopt a conservative approach to managing postinfectious persistent cough. A further trial is needed to assess the efficacy of montelukast for the treatment of pertussis-induced cough.

Authors: Wang, KY

• Publication date: 2012
• DOI: 10.5287/ora-zrk8mvz8q
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: Cough; Respiratory Tract Infection; Whooping cough; Mycoplasma pneumoniae
• Subjects: Infectious diseases; Respiratory medicine; Paediatrics