title: Wheezing in children with pertussis associated with delayed pertussis diagnosis.
abstract: BACKGROUND
  The classic clinical features of paroxysmal pertussis are often absent in older children and adults and after vaccination. The California pertussis epidemic of 2010 occurred in a highly vaccinated population.
  
  
  METHODS
  All pediatric patients (0-18 years) with positive pertussis polymerase chain reaction from July to December 2010 were identified retrospectively from the Kaiser SCAL database. Information extracted by chart review included age at diagnosis, vaccine history, race, cough duration, number of clinic visits before diagnosis, presence of paroxysms, post-tussive emesis or wheezing, treatment for asthma during the course of illness and exposure to confirmed or suspected pertussis cases.
  
  
  RESULTS
  Overall 501 pediatric patients (mean age = 8.4 years) with positive pertussis nasopharyngeal polymerase chain reaction were identified. Complete DTaP series and Tdap vaccine had been received by 93% and 38% of eligible patients, respectively. Paroxysms, post-tussive emesis and wheezing on physical examination were present in 34%, 30% and 8% of patients, respectively. Each was associated with a longer duration of symptoms at diagnosis. Wheezing was associated with a delay in diagnosis (60% requiring >1 clinic visit for diagnosis vs. 29% in the overall population, P < 0.0001). Documented exposures were associated with a more timely pertussis diagnosis (after 9.4 days vs. 14.5 days; P < 0.0001).
  
  
  CONCLUSIONS
  Wheezing is present on examination of some patients with pertussis in a highly vaccinated pediatric population and appears to delay the diagnosis of pertussis. The presence of wheezing should not be used to exclude this diagnosis in children with chronic cough or other reasons to suspect pertussis.
authors.affiliation: From the *Kaiser Permanente Medical Center, Fontana; and †Southern California Permanente Medical Group, Pasadena, CA.
authors.forename: Zackary W
authors.initials: ZW
authors.lastname: Taylor
authors.forename: Bradley
authors.initials: B
authors.lastname: Ackerson
authors.forename: David E
authors.initials: DE
authors.lastname: Bronstein
authors.forename: Kaeryn
authors.initials: K
authors.lastname: Lewis
authors.forename: Evan
authors.initials: E
authors.lastname: Steinberg
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Stone
authors.forename: Roopa
authors.initials: R
authors.lastname: Viraraghavan
authors.forename: Victor K
authors.initials: VK
authors.lastname: Wong
authors.forename: Mark B
authors.initials: MB
authors.lastname: Salzman
mesh_terms: D000293:Adolescent; D002140:California; D002648:Child; D002675:Child, Preschool; D057210:Delayed Diagnosis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D008297:Male; D012135:Respiratory Sounds / Q000503:physiopathology*; D014917:Whooping Cough / Q000175:diagnosis / Q000503:physiopathology*