SAN DIEGO —Wheezing occurs in only a minority of pertussis infections and is associated with delayed diagnosis, according to a retrospective database review presented here at ID Week 2012.
The presentation of pertussis varies by age and symptoms. The clinical features of pertussis infection include paroxysmal coughing, distinctive inspiratory effort and post-tussive emesis or gagging.
Pertussis without classic symptoms is also common, especially in adults and older children after vaccination. A recent pertussis outbreak in California provided an opportunity for researchers to document which characteristics of pertussis are associated with delayed diagnosis.
Zackary Taylor, MD, of the pediatrics department at Southern California Permanente Medical Group, and colleagues retrospectively identified 501 pediatric patients aged 18 years or younger with positive pertussis by polymerase chain reaction from July to December 2010.
Researchers gathered data from the Kaiser SCAL database. The database included age at diagnosis, vaccine history, race, cough duration, number of clinic visits before diagnosis, presence of paroxysms, emesis, wheezing on auscultation and treatment for and/or diagnosis of asthma during course of illness, according to the study.
Researchers enrolled patients with a mean age of 8.4 years.
According to the study, 93% of patients aged 6 to 10 years received DTaP series. A total of 37% of patients aged 11 to 18 years received Tdap series. A minority of patients at mean ages similar to the overall group presented with post-tussive emesis (30%), paroxysms (34%) and wheezing on a physical (10%), according to results from the study.
Post-tussive emesis, paroxysms and wheezing were all associated with delayed diagnosis (16 days vs. 12 days of cough; P=.01; 2 vs. 1.2 clinic visits; P<.0001), the study found.
Clinicians initially diagnosed most of wheezing patients (60%) with asthma exacerbation. Wheezing in adolescents with pertussis was more common after receiving a prior Tdap vaccine (20% vs. 8.7%; OR=2.7; P=.03), according to results from the study. Among prior Tdap recipients, pertussis with documented wheezing occurred at a younger age (12.7 years) compared with pertussis without wheezing (14 years; P=.02).
“Wheezing is associated with multiple clinic visits and a delay in diagnosis of pertussis by an average of 3 to 4 days, thereby delaying treatment and prolonging the period of communicability,” Taylor concluded in his study.
For more information:
Taylor Z. Abstract #492. Presented at: ID Week; Oct. 17-21, 2012; San Diego.
Disclosure: Taylor and colleagues report no relevant financial disclosures.