title: Clinical and laboratory features of pertussis in hospitalized infants with confirmed versus probable pertussis cases.
abstract: BACKGROUND
  The clinical presentations of pertussis infection have considerable variation. Many infections and illnesses can cause prolonged repetitive paroxysmal cough that could be confused with Bordetella pertussis infection.
  
  
  OBJECTIVE
  This retrospective study was designed to compare the clinico-laboratory findings between two groups of hospitalized infants with confirmed, and those who have clinical pertussis disease; to identify the possible additional diagnostic clues "for the diagnosis of confirmed pertussis disease".
  
  
  METHODS
  The study population consisted of infants ≤12 months of age with clinical diagnosis of pertussis that fulfilled the World Health Organization definition for pertussis or those diagnosed by physicians. Clinico-laboratory findings were compared between two groups of patients (confirmed vs. clinical cases).
  
  
  RESULTS
  From a total of 118 infants admitted with a clinical diagnosis of pertussis, 16% (19/118) were confirmed by laboratory to have confirmed pertussis. Twelve of 19 (63%) and 71.99% of confirmed and clinical cases were younger than 6 months of age, respectively. For most patients, the duration of symptoms before hospitalization was <14 days. There were no significant differences between two groups of patients for paroxysmal cough and facial discoloration. However, whoop and apnea were more common among confirmed pertussis cases: P = 0.01, and P = 0.02, respectively. Leukocytosis (≥16,000/ml) (P = 0.01) and lymphocytosis (≥11,000) (P = 0.02) were reported significantly more frequently in confirmed pertussis cases.
  
  
  CONCLUSIONS
  Given the unavailability of a highly sensitive diagnostic test, in every afebrile patient with paroxysmal cough lasting for ≥7 days associated with whoop and/or apnea, particularly if accompanied by leukocytosis/lymphocytosis, pertussis disease should be considered. In this situation, prompt administration of empiric treatment for cases, and providing control measures to prevent infection transmission to contacts are recommended.
authors.affiliation: Department of Health, Provincial Center for Diseases Control and Prevention, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: J
authors.initials: J
authors.lastname: Shojaei
authors.affiliation: Department of Pediatric Infectious Diseases and Antimicrobial Resistant Nosocomial Infections Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Mj
authors.initials: M
authors.lastname: Saffar
authors.affiliation: Department of Medical Records, Journal of Pediatrics Review Office, Bouali Sina Hospital, Sari, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Hashemi
authors.affiliation: Department of Health, Provincial Center for Diseases Control and Prevention, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Gr
authors.initials: G
authors.lastname: Ghorbani
authors.affiliation: Department of Pediatric Infectious Diseases and Antimicrobial Resistant Nosocomial Infections Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Ms
authors.initials: M
authors.lastname: Rezai
authors.affiliation: Antimicrobial Resistant Nosocomial Infections Research Center, Journal of Pediatrics Review Office, Bouali Sina Hospital, Sari, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Shahmohammadi
keywords: Clinical pertussis; Clinical presentation; Confirmed pertussis; Infant