What is the recommended diagnostic test and treatment for a patient suspected of having pertussis?

From the Guidelines

For patients suspected of having pertussis, the recommended diagnostic test is a nasopharyngeal swab for PCR testing, which offers rapid results with high sensitivity, especially during the first 2-3 weeks of illness, as stated in the 2019 study 1. The diagnosis of pertussis can be made based on clinical presentation, which includes paroxysms of coughing, inspiratory whooping, and posttussive vomiting, as well as laboratory confirmation through PCR or culture from nasopharyngeal specimens 1. Some key points to consider in the diagnosis and treatment of pertussis include:

• The use of nasopharyngeal swab for PCR testing as the preferred diagnostic method due to its high sensitivity and rapid results 1.
• The importance of starting antibiotic treatment early, within the first 1-2 weeks of symptoms, to reduce transmission and prevent complications, with macrolides being the first-line therapy 1.
• The recommendation for azithromycin as the preferred macrolide, with a dosage of 10 mg/kg on day 1, then 5 mg/kg days 2-5 for children, and 500 mg on day 1, then 250 mg days 2-5 for adults 1.
• The consideration of trimethoprim-sulfamethoxazole as an alternative option for patients who cannot tolerate macrolides 1.
• The need for supportive care, including respiratory support, adequate hydration, and careful monitoring for complications, especially in infants 1.
• The importance of updating vaccination status for both patients and contacts, and providing antibiotic prophylaxis to close contacts, regardless of vaccination status 1.

From the FDA Drug Label

Pertussis (whooping cough) caused by Bordetella pertussis. Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them noninfectious Some clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals.

The recommended diagnostic test for pertussis is not explicitly stated in the provided drug labels. Key points about treatment are:

• Erythromycin is indicated for the treatment of pertussis caused by Bordetella pertussis.
• Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals.
• Some clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals 2.

From the Research

Diagnostic Tests for Pertussis

The following diagnostic tests are indicated for pertussis:

• Polymerase chain reaction (PCR) [ 3, 4,5,6,7 ]
• Culture [ 3, 4,6,7 ]
• Serology (anti-pertussis toxin IgG) 4
• Nasopharyngeal IgA 5

Specimen Collection

The optimal timing of specimen collection for the various tests is:

• PCR and culture: within the first two weeks of cough 4
• Serology: after the second week of cough 4
• Nasopharyngeal IgA: peaks in the fifth week postinfection 5

Test Sensitivity and Specificity

The sensitivity and specificity of each diagnostic test are:

• PCR: 90.6% sensitive, 100% specific 4
• Culture: 64.0% sensitive, 100% specific 4
• Serology: sensitivity increased using composite reference standard analysis (CRS) and latent class analysis (LCA) 4
• Nasopharyngeal IgA: valuable in diagnosis of pertussis, especially in cases with delayed presentation 5

Comparison of Specimen Types

The following specimen types have been compared for the detection of B. pertussis:

• Nasopharyngeal swabs, nasopharyngeal aspirates, and induced sputum: performed similarly for the detection of B. pertussis infection in young infants by PCR 7