Persistent Cough Points to Pertussis

Abstract

Source: Harnden A, Grant C, Harrison T, et al. Whooping cough in school age children with persistent cough: prospective cohort study in primary care. BMJ. 2006;333:174–177; doi:10.1136/bmj.38870.655405.AEInvestigators from the Universities of Oxford and Auckland evaluated 179 (of 289 eligible) children between 5 and 16 years of age with cough of ≥14 days seen in 18 primary care offices in Oxfordshire, England between October 2001 and March 2005. They determined the prevalence of recent pertussis infection in these children by measuring IgG titers to pertussis toxin. Recent pertussis was diagnosed if there was a 4-fold antibody titer rise in paired sera drawn 4 to 6 weeks apart or a single test >100 ELISA units/ml. Of the 172 children who consented to have blood drawn, 64 (37.5%) were diagnosed with a recent pertussis infection. Of those with recent pertussis infection 32% were exposed to environmental tobacco smoke versus 42% of those who did not have pertussis. There was no gender or age difference in children with or without recent pertussis. However, those with the diagnosis of recent pertussis were significantly more likely to have whooping (50% vs 27%), vomiting (70% vs 39%), and productive cough (70% vs 56%), and less likely to wheeze (30% vs 44%). The mean duration of cough at presentation was not different in those with and without the diagnosis of recent pertussis (45 vs 44 days). However, the total duration of cough was significantly higher in those with pertussis compared to those with negative serologies (median 112 [range, 38–191] vs 58 [24–192] days). Two months after the start of symptoms 85% (46 of 54) of subjects with pertussis were still coughing compared to 49% (45 of 92) who did not have pertussis (P=.001). There was no difference between the 2 groups with regard to the number of school days missed by children or work days missed by parents.Dr. Rathore has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of a commercial product/device. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.This study investigated the common complaint of cough in school-age children. It offers convincing evidence that prolonged cough is often attributable to pertussis in this age group. All clinicians who care for patients of any age group, whether or not they have been immunized, should consider the diagnosis of pertussis in patients presenting with prolonged cough. Although antibiotic treatment may not decrease the severity or duration of the illness, early diagnosis of pertussis may prevent further spread of the infection if prophylaxis is started expeditiously. Until pertussis booster immunization is routinely implemented in early adolescence, pertussis will remain an important public health issue. A high index of suspicion, rapid diagnosis (using molecular techniques), and prophylactic antibiotics are critical in preventing and controlling pertussis outbreaks. (See also AAP Grand Rounds, Nov 2004;12:60–61.1)This study joins many others demonstrating that symptomatic infection with Bordetella pertussis is ubiquitous in all age groups. Nonetheless, clinicians who care for patients, be they pediatric, geriatric, or somewhere in between, too often fail to consider whooping cough when considering the cause of cough illness – often diagnosed as “bronchitis” – even among healthcare workers. Such failures contribute to the spread of infection in families, schools, and hospitals and to the delayed diagnosis of secondary cases. In addition, many clinicians are unfamiliar with or do not have ready access to diagnostic tests such as PCR, FA (fluorescent antibody staining), culture, or serology. Next time you see your internist or family practitioner – when you request your own Tdap booster – ask when they last diagnosed pertussis and if they have nasal swabs in their office. Although the advent of an effective vaccine for adolescents and adults holds great promise, increased awareness of the prevalence of this disease seems a prerequisite to better control.