Review Question - QID 220785

This unvaccinated boy who presents with prodromal coryza and mild cough followed by a paroxysmal cough with an inspiratory whoop, subconjunctival hemorrhage, and marked lymphocytosis most likely has pertussis. The most appropriate treatment for infection with Bordetella pertussis is azithromycin.

Bordetella pertussis is a gram-negative coccobacillus transmitted by respiratory droplets that is responsible for pertussis. Risk factors for pertussis include a lack of vaccination and immunocompromised states. This organism colonizes mucosal surfaces and produces toxins that activate adenylate cyclase to impair phagocytosis, as well as impair cilia to prevent normal clearance of respiratory secretions. Pertussis initially presents with the catarrhal stage with coryza and mild cough. This is followed by the paroxysmal stage with a dry cough and associated cyanosis, post-cough inspiratory “whoop,” post-tussive emesis, and marked lymphocytosis. The infection resolves in the convalescent stage. Prophylaxis against pertussis consists of the DTaP vaccine (which contains an acellular pertussis vaccine) in childhood, as well as boosters with the Tdap vaccine. Treatment is with macrolide antibiotics such as azithromycin, clarithromycin, and erythromycin.

Tiwari et al. review the CDC recommendations for antimicrobial treatment and post-exposure prophylaxis for pertussis. They discuss how macrolides are effective against B. pertussis. They recommend the use of macrolides for both treatment and prophylaxis for pertussis.

Figure/Illustration A is a clinical photograph demonstrating subconjunctival hemorrhages (blue circle). This finding is classically seen in patients with pertussis.

Incorrect Answers:
Answer 1: Amoxicillin can be used to treat pneumonia due to Streptococcus pneumoniae. This most commonly would present as lobar pneumonia with a cough that is productive of sputum.

Answer 3: Oseltamivir is a neuraminidase inhibitor that can be used to treat acute uncomplicated influenza within 48 hours of illness onset in healthy adults. Influenza presents with a sudden onset of cough, myalgias, and fevers without post-tussive emesis or inspiratory whoop.

Answer 4: Palivizumab is a monoclonal antibody that can be used for prophylaxis against respiratory syncytial virus (RSV) infection in immunocompromised children. Studies have not shown it to be effective for the treatment of RSV bronchiolitis in immunocompetent or immunocompromised children. Patients with RSV are typically under 2 years of age and are also less likely to have post-tussive vomiting, paroxysmal cough, and marked lymphocytosis.

Answer 5: Rifampin, isoniazid, pyrazinamide, and ethambutol are appropriate antimicrobial therapies for infection with Mycobacterium tuberculosis. Pulmonary tuberculosis may present with failure to thrive, chronic unremitting cough, and prolonged fever. Lymphocytosis and paroxysmal coughing are less likely.

Bullet Summary:
Bordetella pertussis classically presents with paroxysmal cough followed by an inspiratory whoop, post-tussive emesis, and lymphocytosis and may be treated with azithromycin.