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Pertussis: Differential Diagnoses & Workup

Author: Hazel Guinto-Ocampo, MD, Consulting Staff, Assistant Professor of Pediatrics, Department of Pediatrics, Division of Emergency Medicine, Nemours Children's Clinic, AI duPont Hospital for Children
Coauthor(s): Bryon K McNeil, MD, Medical Director, Bioterrorism and Emergency Preparedness, Clinical Assistant Professor, Departments of Internal Medicine and Emergency Medicine, Via Christ Regional Medical Center; Stephen C Aronoff, MD, Waldo E Nelson Chair and Professor, Department of Pediatrics, Temple University School of Medicine
Contributor Information and Disclosures

Updated: May 27, 2009

Differential Diagnoses

Afebrile Pneumonia Syndrome
Bronchiolitis
Chlamydial Infections
Mycoplasma Infections
Respiratory Syncytial Virus Infection

Other Problems to Be Considered

Other illnesses that mimic clinical pertussis include the following:

  • Adenoviral respiratory infection: Children present with fever, sore throat, and conjunctivitis.)
  • Mycoplasmal pneumonia: Patients with mycoplasmal infections have more pronounced systemic symptoms, fever and headache may occur, and rales may be appreciated on chest auscultation.
  • Chlamydial pneumonia: Young infants with chlamydial infections present with staccato cough, purulent conjunctival discharge, tachypnea, rales, and wheezing.
  • Respiratory syncytial virus infection: Patients present with predominantly lower respiratory tract signs (eg, wheezing, rales).

Workup

Laboratory Studies

Laboratory confirmation of pertussis is difficult and delayed. Therefore, clinicians need to make the diagnosis of pertussis presumptively in patients with a history of intense paroxysmal coughing with or without whooping, color changes, posttussive vomiting, incomplete or absent pertussis vaccination, and finding of lymphocytosis on laboratory examination.

  • A clinical case of pertussis is defined as one of the following:
    • An acute coughing illness that lasts at least 14 days in a person with at least one characteristic pertussis symptom (ie, paroxysmal cough, posttussive vomiting, or inspiratory whoop)
    • A cough that lasts at least 14 days in an outbreak setting
  • A confirmed case is defined as one of the following:
    • Any cough illness in which B pertussis is isolated and cultured
    • A case consistent with the clinical case definition confirmed by polymerase chain reaction (PCR) findings or epidemiologic linkage to a laboratory-confirmed case
  • The criterion standard for diagnosis of pertussis is isolation of B pertussis in culture.

    A photomicrograph of <em>Bordetella (Haemophilus)...

    A photomicrograph of Bordetella (Haemophilus) pertussis bacteria using Gram stain technique.

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    A photomicrograph of <em>Bordetella (Haemophilus)...

    A photomicrograph of Bordetella (Haemophilus) pertussis bacteria using Gram stain technique.

    • Obtain the culture specimen by performing deep nasopharyngeal aspiration or holding a flexible swab (Dacron or calcium alginate) in the patient's posterior nasopharynx for 15-30 seconds or until a cough is produced.
    • Promptly inoculate the sample special media (preferred media include Regan-Lowe or Bordet-Gengou agar and modified Stainer-Scholte media). B pertussis usually grows after 3-4 days; however, culture findings cannot be considered negative for pertussis until after 10 days.
    • Recovery rates are highest during the catarrhal or early paroxysmal phase and are low after the fourth week of illness.
    • Culture findings can be negative in patients who were previously immunized, have received antimicrobial therapy, or have been coughing for more than 3 weeks. A negative culture finding does not exclude the diagnosis of pertussis.
  • PCR assay and antigen detection are increasingly used to assist in diagnosing pertussis. Advantages include greater sensitivity, more rapidly available results, and use later in the disease course or after antimicrobial therapy because the tests do not rely on the isolation of viable organisms.10  Their use is limited by lack of standardization and incomplete understanding of the correlation between test results and the course of the illness.
  • Although serologic tests have potential in helping diagnose pertussis, they are currently available for investigational use only.
  • The use of direct fluorescent assay (DFA) of nasopharyngeal secretions is not recommended by the Centers for Disease Control and Prevention (CDC) due to its poor sensitivity and specificity.
  • Leukocytosis (15,000-50,000 103/µL) with absolute lymphocytosis occurs during the late catarrhal and paroxysmal phases. It is a nonspecific finding but correlates with severity of the disease. One study showed that among infants suspected of having pertussis, an absolute leukocyte count of less than 9400/μ L excluded almost all infants who had a negative pertussis test finding.11

Imaging Studies

  • Imaging studies typically add little to the diagnosis of pertussis but should be obtained when clinically indicated, based on examination or if the patient requires supplemental oxygen.
  • Chest radiography may reveal perihilar infiltrates or edema with variable degrees of atelectasis. Consolidation is indicative of secondary bacterial infection or, rarely, pertussis pneumonia. Occasionally, pneumothorax, pneumomediastinum, or air in the soft tissues may be seen.

More on Pertussis

Overview: Pertussis
Differential Diagnoses & Workup: Pertussis
Treatment & Medication: Pertussis
Follow-up: Pertussis
Multimedia: Pertussis
References
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References

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  2. Pertussis--United States, 2001-2003. MMWR Morb Mortal Wkly Rep. Dec 23 2005;54(50):1283-6. [Medline].

  3. Centers for Disease Control and Prevention. Recommended immunization schedules for persons aged 0-18 years - United States, 2008. MMWR. 2008;57(1):Q1-Q4. [Full Text].

  4. Mattoo S, Cherry JD. Molecular pathogenesis, epidemiology, and clinical manifestations of respiratory infections due to Bordetella pertussis and other Bordetella subspecies. Clin Microbiol Rev. Apr 2005;18(2):326-82. [Medline].

  5. [Guideline] Bisgard K. Background. Guidelines for the Control of Pertussis Outbreaks. 2000;1-1-1-11. [Full Text].

  6. Vitek CR, Pascual FB, Baughman AL, Murphy TV. Increase in deaths from pertussis among young infants in the United States in the 1990s. Pediatr Infect Dis J. Jul 2003;22(7):628-34. [Medline].

  7. Centers for Disease Control. Pertussis. In: Atkinson W, Hamborsky J, McIntyre L, Wolfe S. Epidemiology and Prevention of Vaccine-Preventable Diseases. 10th ed. Washington DC: Public Health Foundation; 2007:80-96. [Full Text].

  8. Centers for Disease Control and Prevention. Pertussis--United States, 1997-2000. MMWR Morb Mortal Wkly Rep. Feb 1 2002;51(4):73-6. [Medline].

  9. Bisgard KM, Pascual FB, Ehresmann KR, et al. Infant pertussis: who was the source?. Pediatr Infect Dis J. Nov 2004;23(11):985-9. [Medline].

  10. Edwards K, Decker MD. Pertussis vaccine. In: Plotkin SA, Orenstein WA. Vaccines. 4th ed. Philadelphia, PA: Saunders; 2004:471-528.

  11. Guinto-Ocampo H, Bennett JE, Attia MW. Predicting pertussis in infants. Pediatr Emerg Care. Jan 2008;24(1):16-20. [Medline].

  12. American Academy of Pediatrics. Pertussis. In: Pickering LK, ed. Red Book: 2006 Report of the Committee of Infectious Disease. 2006:498-520.

  13. American Academy of Pediatric Committee on Infectious Diseases. Prevention of pertussis among adolescents: recommendations for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Pediatrics. Mar 2006;117(3):965-78. [Medline].

  14. [Best Evidence] Glanz JM, McClure DL, Magid DJ, et al. Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children. Pediatrics. Jun 2009;123(6):1446-51. [Medline]. [Full Text].

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  22. Long S. Academy issues policy on adolescent pertussis vaccine. AAP News. 2006;27:1.

  23. Long S. Pertussis (Bordetella pertussis and B parapertussis). In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. Vol 17. 2004:908-12.

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  27. Mikelova LK, Halperin SA, Scheifele D, et al. Predictors of death in infants hospitalized with pertussis: a case-control study of 16 pertussis deaths in Canada. J Pediatr. Nov 2003;143(5):576-81. [Medline].

  28. Pierce C, Klein N, Peters M. Is leukocytosis a predictor of mortality in severe pertussis infection?. Intensive Care Med. 2000;159:898-900. [Medline].

  29. Tanaka M, Vitek CR, Pascual FB, et al. Trends in pertussis among infants in the United States, 1980-1999. JAMA. Dec 10 2003;290(22):2968-75. [Medline].

  30. Tiwari T, Murphy TV, Moran J. Recommended antimicrobial agents for the treatment and postexposure prophylaxis of pertussis: 2005 CDC Guidelines. MMWR Recomm Rep. Dec 9 2005;54:1-16. [Medline].

  31. Tozzi AE, Celentano LP, Ciofi degli Atti ML, Salmaso S. Diagnosis and management of pertussis. CMAJ. Feb 15 2005;172(4):509-15. [Medline].

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Further Reading

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Keywords

pertussis, whooping cough, coughing, infectious diseases, respiratory tract infection, Bordetella pertussis infection, B pertussis infection, Bordetella parapertussis infection, B parapertussis infection, pneumonia, prematurity, seizures, syncope, hypoglycemia, sudden infant death, upper respiratory infection, nasal congestion, rhinorrhea, sneezing, headache, posttussive vomiting

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Contributor Information and Disclosures

Author

Hazel Guinto-Ocampo, MD, Consulting Staff, Assistant Professor of Pediatrics, Department of Pediatrics, Division of Emergency Medicine, Nemours Children's Clinic, AI duPont Hospital for Children
Hazel Guinto-Ocampo, MD is a member of the following medical societies: American Academy of Pediatrics and American College of Emergency Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Bryon K McNeil, MD, Medical Director, Bioterrorism and Emergency Preparedness, Clinical Assistant Professor, Departments of Internal Medicine and Emergency Medicine, Via Christ Regional Medical Center
Bryon K McNeil, MD is a member of the following medical societies: American Academy of Emergency Medicine and Pennsylvania Medical Society
Disclosure: Nothing to disclose.

Stephen C Aronoff, MD, Waldo E Nelson Chair and Professor, Department of Pediatrics, Temple University School of Medicine
Stephen C Aronoff, MD is a member of the following medical societies: Pediatric Infectious Diseases Society and Society for Pediatric Research
Disclosure: Nothing to disclose.

Medical Editor

Gary J Noel, MD, Department of Pediatrics, Clinical Associate Professor, Weill Medical College of Cornell University
Gary J Noel, MD is a member of the following medical societies: Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Mark R Schleiss, MD, American Legion Chair of Pediatrics, Professor of Pediatrics, Division Director, Division of Infectious Diseases and Immunology, Department of Pediatrics, University of Minnesota Medical School
Mark R Schleiss, MD is a member of the following medical societies: American Pediatric Society, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Society for Pediatric Research
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; sanofi pasteur Honoraria Speaking and teaching; Baxter Healthcare Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
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