Pertussis Management for OSCE Exam
Clinical Presentation and Diagnosis
Suspect pertussis in any patient with cough lasting ≥2 weeks accompanied by paroxysms, post-tussive vomiting, or inspiratory whooping, regardless of vaccination status. 1, 2
Key Clinical Features to Assess:
- Paroxysmal cough (most sensitive finding) 2, 3
- Post-tussive vomiting (highly specific) 1, 2
- Inspiratory whoop (classic but often absent in vaccinated children and adults) 1, 3
- Absence of fever (helps distinguish from other respiratory infections) 2
- Duration of symptoms (catarrhal stage: 1-2 weeks; paroxysmal stage: 2-6 weeks; convalescent stage: weeks to months) 3
Diagnostic Testing:
- Obtain nasopharyngeal swab immediately for culture or PCR testing 2
- PCR is now preferred over culture in clinical practice due to higher sensitivity 2
- Culture remains the gold standard for definitive diagnosis but has lower sensitivity 2, 4
- Do not wait for test results to initiate treatment if clinical suspicion is high 2
Antibiotic Treatment
Start azithromycin immediately for confirmed or probable pertussis—it is the first-line treatment due to superior tolerability, shorter duration, and better compliance compared to erythromycin. 1, 2, 5
Azithromycin Dosing:
- Day 1: 10 mg/kg (maximum 500 mg) as single dose 1, 5
- Days 2-5: 5 mg/kg (maximum 250 mg) once daily 1, 5
Alternative Macrolides:
- Clarithromycin: 7.5 mg/kg (maximum 500 mg) twice daily for 7 days 1, 5, 6
- Erythromycin: 40 mg/kg/day divided in 3-4 doses for 14 days (higher side effect profile) 7
- Trimethoprim-sulfamethoxazole: Use only if macrolide allergy/intolerance (children: TMP 8 mg/kg/day, SMX 40 mg/kg/day for 14 days) 7
Treatment Timing and Efficacy:
- Antibiotics are most effective when started during the catarrhal stage (first 1-2 weeks), reducing symptom duration by approximately 50% 1, 5
- Even during paroxysmal stage, antibiotics remain critical for eradicating bacteria and reducing transmission, though they won't significantly shorten symptoms 2, 5
- Primary goal is transmission prevention, not symptom relief in established disease 1
Therapies to AVOID:
- Do not use β-agonists, antihistamines, corticosteroids, or pertussis immunoglobulin—these have no proven benefit 1
Isolation and Infection Control
Implement respiratory droplet precautions immediately and maintain for 5 days after starting appropriate antibiotics, or for 21 days after cough onset if antibiotics cannot be given. 7, 1
Patient Placement:
- Private room preferred 7
- Can cohort with other confirmed pertussis patients after 5 days of treatment 7, 1
Contact Management
All household and close contacts require macrolide prophylaxis for 14 days, regardless of age and vaccination status—this is non-negotiable. 7, 1, 2
Definition of Close Contact:
- Face-to-face contact with symptomatic patient 7
- Sharing confined space >1 hour with symptomatic patient 7
- Direct contact with respiratory secretions (cough/sneeze on face, sharing utensils, kissing) 7
Prophylaxis Regimen (Same as Treatment):
- Azithromycin: 10 mg/kg (max 500 mg) day 1, then 5 mg/kg (max 250 mg) days 2-5 1, 5
- Alternative: Clarithromycin or erythromycin with same dosing as treatment 7
- Must be initiated within 21 days of exposure 5
Vaccination Update for Contacts:
- Children <7 years who haven't completed 4-dose primary series: Complete series with minimal intervals 7
- Children with completed primary series but no dose within 3 years: Give booster dose 7
- During outbreaks: Accelerate vaccination schedule for incompletely vaccinated children 7
Age-Specific Considerations
Infants <6 Months (Especially <2 Months):
- Require immediate hospitalization due to highest risk for severe complications 2
- Monitor for apnea, pneumonia, seizures, hypoxic encephalopathy, and death 2, 3
Vaccinated Children (Including 19-Month-Olds):
- Vaccination reduces but does not eliminate infection risk—breakthrough infections occur due to waning immunity beginning 5-10 years post-vaccination 1
- Median cough duration: 29-39 days; spasmodic cough: 14-29 days 1
- Often present with atypical symptoms, potentially lacking characteristic "whoop" 1
- Risk of hospitalization significantly lower (1-2%) compared to unvaccinated 1
- Can still transmit disease to others despite vaccination 1
Adolescents and Adults:
- 72-100% report paroxysmal cough, difficulty breathing, and sleep disturbance 7
- 50-70% have post-tussive vomiting 7
- Cough typically lasts >3 weeks, with 47% coughing >9 weeks 7
- Tdap booster recommended at 11-12 years of age 7
Complications to Monitor
Common Complications:
- Weight loss and sleep disturbance (monitor closely) 1, 5
- Post-tussive vomiting (can lead to dehydration) 1
Pressure-Related Effects:
Infectious Complications:
Neurological Complications (Rare but Serious):
Critical Pitfalls to Avoid
Do not dismiss pertussis based solely on vaccination status—breakthrough infections are common and should be actively considered 1
Do not assume typical "whooping" presentation—vaccinated children and adults often have atypical symptoms with persistent cough only 1, 4
Do not delay testing or treatment while waiting for classic symptoms—early intervention reduces transmission and may shorten disease course 1
Do not forget contact prophylaxis—secondary attack rates exceed 80% among susceptible household contacts 1, 2
Do not use adjunctive therapies (β-agonists, steroids, antihistamines)—they provide no benefit 1
Vaccination Status and Future Doses
- Children with well-documented pertussis should receive DT vaccine (not DTaP) for remaining doses to ensure diphtheria and tetanus protection 1
- No recommendation exists for additional pertussis vaccine doses after documented pertussis disease 7, 1
- Neither vaccination nor natural disease provides lifelong immunity—reinfection is possible 1, 5