Diagnosis and Management of Pertussis

Introduction to Pertussis Management

The American Thoracic Society recommends initiating empirical treatment with a macrolide antibiotic immediately without waiting for laboratory confirmation in patients with suspected pertussis 1, 2
A cough lasting ≥2 weeks with paroxysmal episodes is a diagnostic criterion for pertussis until proven otherwise 1, 2
The diagnosis of pertussis should be made clinically when there is paroxysmal cough, even without post-tussive vomiting or inspiratory stridor, although these symptoms support the diagnosis 1, 2

Azithromycin is the preferred first-line treatment due to its better side effect profile and compliance 2
Erythromycin 1-2 g/day in adults for 2 weeks is an alternative 2
Clarithromycin is an effective alternative with better tolerability 2
Treatment should be started immediately without waiting for culture results, as early therapy (within the first 2 weeks) decreases paroxysms and prevents transmission 1, 2
After 2 weeks of symptoms, the benefit of antibiotics is limited but may still be offered 1, 2
Patient isolation for 5 days from the start of antibiotic treatment is recommended 1, 2, 3

Nasopharyngeal aspirate or Dacron swab for B. pertussis culture is the test of choice 1, 2
Bacterial isolation is the only definitive way to confirm the diagnosis 1, 2
PCR is not routinely recommended due to the lack of a universally validated technique 1, 2
Paired serology (IgG/IgA against pertussis toxin) can be used for presumptive diagnosis if there is a 4-fold increase between acute and convalescent phases 1, 2

Ipratropium inhalation is the first-line treatment for post-infectious cough 4, 5
Dextromethorphan 60 mg (optimal dose for suppression of the cough reflex) can be used when other measures fail 4, 6
Prednisone 30-40 mg/day for a short period can be used for severe paroxysms 4, 5

If the presentation is not pertussis, consider post-infectious cough (3-8 weeks), prolonged bacterial bronchitis, and chronic causes (if persisting >8 weeks) 4, 5, 7
For post-infectious cough, use ipratropium inhalation as the first line, and consider corticosteroids if it persists despite ipratropium 4, 5
Do not use antibiotics if there is no confirmed bacterial infection 4, 5

Do not wait for laboratory confirmation to start treatment if there is a clinical suspicion of pertussis - delay decreases effectiveness 1, 2, 3
Do not use antibiotics indiscriminately in post-infectious viral cough where they have no role 4, 5
Do not forget isolation - the patient is contagious until 5 days after starting antibiotics 1, 2, 3
Do not use subtherapeutic doses of dextromethorphan - doses available over the counter are insufficient; 60 mg is needed for optimal effect 6
Do not prescribe codeine - it has no greater efficacy than dextromethorphan but a worse side effect profile 6
Do not classify as chronic cough before 8 weeks - at 2 weeks, it is still in the acute/subacute phase 4, 5