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Pertussis
Mary Cataletto, MD, FAAP, FCCP
Margaret J. McCormick, MS, RN
image BASICS
Highly contagious disease; aka whooping cough
DESCRIPTION
  • Human host: adults most common reservoir
  • Can affect all ages
  • Worldwide distribution
  • May be endemic or epidemic with outbreaks every 3 to 5 years
  • Seasonality: can occur year-round; peaks late summer-autumn
  • Transmission: person to person via aerosolized respiratory droplets
  • Effective vaccine available but neither vaccine nor infection confer lifelong or 100% immunity.
  • System(s) affected: respiratory
  • Synonym(s): whooping cough
EPIDEMIOLOGY
Incidence
2012 was the most recent peak year with 48,277 reported cases in the United States (1)
ETIOLOGY AND PATHOPHYSIOLOGY
  • Toxin mediated
  • Infectious process with predilection for ciliated respiratory epithelium
  • Bordetella pertussis (responsible for ˜95% of cases)
  • Bordetella parapertussis
RISK FACTORS
  • Exposure to a confirmed case
  • Non- or underimmunized infants and children
  • Pregnancy
  • Premature birth
  • Chronic lung disease
  • Immunodeficiency (e.g., AIDS)
  • Infants <6 months of age account for ˜90% pediatric pertussis hospitalizations (2).
GENERAL PREVENTION
  • Public health measures
    • Surveillance activities
    • Prevention programs
    • Outbreak management
  • Care of exposed persons
    • Household and close contacts
    • Child care workers
    • Health care workers
  • Immunization
    • Vaccine products
    • Boosters
    • CDC and the Advisory Committee on Immunization Practices recommends one Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccination to all adolescents 11 to 12 years of age and one dose of Tdap for all adults age 18 years and older to provide increased herd immunity.
Pediatric Considerations
  • Primary immunization series against pertussis followed by boosters
  • Maternal immunization and cocooning are important strategies to help reduce neonatal pertussis (3).
Geriatric Considerations
The incidence of pertussis in individuals age 50 years and older has increased between 2006 and 2010 (5).
COMMONLY ASSOCIATED CONDITIONS
  • Apnea
  • Secondary bacterial pneumonia
  • Sinusitis
  • Seizures
  • Encephalopathy
  • Urinary incontinence
image DIAGNOSIS
PHYSICAL EXAM
  • Classic pertussis has three phases, which occur over 6 to 10 weeks:
    • Catarrhal phase: rhinorrhea, mild cough, low-grade fever
    • Paroxysmal phase: Cough occurs in bursts, with increased intensity and frequency, often followed by an inspiratory whoop and/or posttussive vomiting.
    • Convalescent phase: Coughing paroxysms decrease in frequency and intensity.
  • In the absence of paroxysms or complications, the physical exam may be normal.
DIFFERENTIAL DIAGNOSIS
  • B. parapertussis
  • Mycoplasma pneumoniae
  • Chlamydia trachomatis
  • Chlamydophila pneumoniae
  • Bordetella bronchiseptica
  • Respiratory syncytial virus
  • Adenovirus
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • Nasopharyngeal culture (gold standard): 100% specific and permits strain identification and antimicrobial resistance testing. Collect secretions from the back of the throat through the nose, using a Dacron or calcium alginate swab or syringe filled with saline. For best results, collect specimen during the first 2 weeks of cough—sensitivity decreases after 2 weeks (6)[C].
  • Polymerase chain reaction (PCR) assays: Most commonly used because of improved sensitivity and turnaround time (6)[C].
  • Specificity may vary between assays and must be interpreted within clinical context and local pertussis epidemiology. CDC “Best Practice” guidelines exist for PCR assays, although they have not yet received FDA approval. Six accurate results can be obtained during the first 3 weeks from onset of cough. Dacron swabs should be used as calcium alginate swabs are inhibitory to PCR (2,3).
  • Serology: available commercially; however, there is no FDA-approved test or standardization
    • The CDC uses single point serology obtained between 2 and 8 weeks following cough onset when titers are expected to be at their peak (3).
Follow-Up Tests & Special Considerations
  • Evaluation and follow-up for associated conditions and complications
  • Chest radiograph (2 views) to evaluate for the presence of pneumonia
  • EEG/neuroimaging may be considered in infant with seizures or acute life-threatening events (ALTEs).
  • Infants <1 month of age who are treated with macrolides should be monitored for the possible development of hypertrophic pyloric stenosis.
image TREATMENT
GENERAL MEASURES
Waiting rooms, during transport and procedures: Patients with suspected pertussis should wear masks.
MEDICATION
Pertussis illness may be less severe only if antibiotics are started early, that is, before the onset of paroxysms or during the catarrhal phase (2). Antibiotics can also help to prevent the spread of pertussis to close contacts and is necessary for stopping the spread of pertussis.
First Line
  • Empiric antibiotic therapy should be initiated at the time diagnostic testing is performed if sufficient clinical suspicion for pertussis is present.
  • P.797

  • Azithromycin is the first line of treatment for treatment and for postexposure prophylaxis (5-day course) (6)[C].
  • If administered during catarrhal stage, these antibiotics may ameliorate disease.
  • If administered after cough is established, antibiotics will have no individual benefit but may help to limit spread (6)[C].
Second Line
Trimethoprim-Sulfamethoxazole (TMP-SMX) (for persons >2 months of age) if:
  • They cannot tolerate macrolides.
  • They are infected with a macrolide-resistant strain.
ISSUES FOR REFERRAL
Evaluation and treatment of infants <6 months of age, especially those born prematurely, who are unimmunized and those who require hospitalization.
ADDITIONAL THERAPIES
Symptomatic treatment of the cough in pertussis (e.g., corticosteroids, &bgr;2-adrenergic agonists, pertussis-specific immunoglobulin, antihistamine, and leukotriene receptor antagonist) have not shown consistent benefit (4)[B].
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
  • Small, frequent meals may be necessary to ensure adequate nutrition.
  • Correct fluid and electrolyte abnormalities.
  • Infants may require IV fluids.
IV Fluids
Indicated for dehydration and when oral fluids are either contraindicated or poorly tolerated.
Nursing
  • In addition to standard precautions, hospitalized patients should be isolated with respiratory precautions for 5 days after the initiation of effective antibiotic treatment and for 3 weeks after onset of paroxysms in older patients if antibiotics are not used.
  • Gentle suctioning of nasal secretions
  • Avoid stimuli that trigger paroxysms.
  • Respiratory monitoring including pulse oximetry
  • Educate each family about the importance of immunizations.
  • Discuss chemoprophylaxis with each family.
Discharge Criteria
  • Clinically stable
  • Able to tolerate oral feedings
image ONGOING CARE
Supportive
FOLLOW-UP RECOMMENDATIONS
  • Monitor infants who received EES or azithromycin for pyloric stenosis.
  • Neurologic and/or pulmonary follow-up as necessary
Patient Monitoring
ICU care may be necessary for severely ill or compromised patients.
DIET
IV fluids/nutrition may be required to treat dehydration or supplement poor oral intake.
PATIENT EDUCATION
  • American Academy of Pediatrics: http://www.aap.org
  • Centers for Disease Control and Prevention: http://www.cdc.gov
PROGNOSIS
  • Complete recovery in most cases
  • Most severe morbidity and highest mortality in infants <6 months of age
REFERENCES
1. Centers for Disease Control. 2013 Final pertussis surveillance report. Final 2013 reports of notifiable diseases. Updated August 15, 2014. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6332a6.htm. Accessed November 14, 2015.
2. Lopez MA, Cruz AT, Kowalkowski MA, et al. Trends in hospitalizations and resource utilization for pediatric pertussis. Hosp Pediatr. 2014;4(5):269-275.
3. Swamy GK, Wheeler SM. Neonatal pertussis, cocooning and maternal immunization. Expert Rev Vaccines. 2014;13(9):1107-1114.
4. Committee on Obstetric Practice. ACOG committee opinion no. 521: update on immunization and pregnancy: tetanus, diphtheria, and pertussis vaccination. Obstet Gynecol. 2012;119(3):690-691.
5. McGuiness CB, Hill J, Fonseca E, et al. The disease burden of pertussis in adults 50 years old and older in the United States: a retrospective study. BMC Infect Dis. 2013;13:32.
6. American Academy of Pediatrics. Pertussis (whooping cough). In: Kimberlin DW, Brady MT, Jackson MA, et al, eds. Red Book: 2015 Report of the Committee on Infectious Diseases. 30th ed. Elk Grove Village, Il: American Academy of Pediatrics; 2015:608-621
7. US Food and Drug Administration. Azithromycin: drug safety communication—risk of potentially fatal heart rhythms. http://www.fda.gov/Safety/Medwatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm343350.htm. Accessed November 14, 2015.
Additional Reading
&NA;
  • Centers for Disease Control and Prevention. Best Practices for Healthcare Professionals on the use of Polymerase Chain Reaction (PCR) for Diagnosing Pertussis. Atlanta, GA: Centers for Disease Control and Prevention; 2011.
  • Wang K, Bettiol S, Thompson MJ, et al. Symptomatic treatment of the cough in whooping cough. Cochrane Database Syst Rev. 2014;(9):CD003257.
Codes
&NA;
ICD10
  • A37.90 Whooping cough, unspecified species without pneumonia
  • A37.80 Whooping cough due to other Bordetella species w/o pneumonia
  • A37.10 Whooping cough due to Bordetella parapertussis w/o pneumonia
Clinical Pearls
&NA;
  • Pertussis is a highly contagious infection.
  • A high index of suspicion is needed. During the primary or catarrhal phase, the presentation may be nonspecific.
  • Immunization (primary series and boosters), isolation, and early treatment of affected cases as well as chemoprophylaxis are key components to controlling the spread of pertussis.