What are the symptoms and treatment for pneumothorax in an infant with suspected pertussis?

Pneumothorax in Infants with Suspected Pertussis

Clinical Presentation of Pneumothorax

Pneumothorax is a recognized complication of severe pertussis in infants, resulting from the intense pressure generated during paroxysmal coughing episodes. 1

Key Symptoms to Recognize:

• Sudden deterioration in respiratory status during or after severe coughing paroxysms 1
• Unilateral decreased chest expansion on the affected side 2
• Dullness to percussion (though this may be less reliable in small infants) 2
• Reduced or absent breath sounds on the affected side 2
• Cyanosis due to ventilation-perfusion mismatch, which may worsen acutely 2
• Increased work of breathing with tachypnea and retractions 1
• Oxygen saturation below 92% indicating severe disease 2

Context of Pertussis Presentation:

Infants with pertussis typically present with atypical disease features before pneumothorax develops 1:

• Apneic spells as the initial presentation, often with minimal cough 1
• Paroxysmal coughing that increases in frequency and severity over 2-6 weeks 1
• Post-tussive vomiting following coughing episodes 1
• Worsening symptoms at night when paroxysms are most frequent 1

Diagnostic Approach

Immediate Evaluation:

• Chest radiograph (anteroposterior view) to identify air in the pleural space 2
• Transillumination at the bedside for rapid assessment in unstable infants 3
• Lung ultrasound as an alternative rapid diagnostic tool 3
• Oxygen saturation monitoring with levels below 92% indicating severe disease requiring urgent intervention 2

Ultrasound must be used to confirm the presence of pleural air and guide any intervention. 2

Pertussis Confirmation:

• Nasopharyngeal culture and PCR testing to confirm pertussis diagnosis 1
• Blood culture to rule out secondary bacterial pneumonia 2

Treatment Algorithm

Immediate Management of Pneumothorax:

1. Observation alone for small, asymptomatic pneumothoraces in stable infants 3
2. Needle thoracocentesis for symptomatic pneumothorax causing respiratory compromise 3
3. Chest tube placement (pigtail or straight) for large or tension pneumothorax 3

Pertussis-Specific Treatment:

Azithromycin is the preferred first-line antibiotic for infants with pertussis, regardless of disease stage. 1, 4

• Macrolide antibiotics reduce duration and severity of symptoms when given early 1
• Supportive care is the mainstay of management, including monitoring for apneic episodes 1
• Hospital admission is mandatory for infants under 6 weeks with pertussis, typically requiring 2-6 weeks of hospitalization depending on complications 1

Monitoring for Additional Complications:

Infants with pertussis and pneumothorax are at high risk for multiple complications 5, 6:

• Pulmonary hypertension requiring aggressive management 5, 6
• Seizures from hypoxia or encephalopathy 1, 5
• Secondary bacterial pneumonia occurring in approximately 13% of cases 1
• Feeding difficulties and weight loss requiring nutritional support 1

Critical Risk Factors

Age less than 6 months, particularly under 2 months, carries the highest risk for severe disease and death with a case-fatality ratio of 1.8%. 1

Additional high-risk features include 1:

• Unvaccinated or incompletely vaccinated status
• Prematurity (gestational age <37 weeks)
• Hispanic ethnicity (observed in mortality studies)

Infection Control and Prophylaxis

Isolation Requirements:

• Respiratory droplet precautions until 5 days of appropriate antibiotic treatment are completed 2, 4
• Surgical mask should be worn by healthcare workers within 3 feet of the patient 2

Household Contact Management:

All household and close contacts must receive macrolide antibiotic prophylaxis for 14 days, regardless of age and vaccination status. 7

• Erythromycin for 14 days (40-50 mg/kg/day for children) 7
• Azithromycin for 5 days (10 mg/kg day 1, then 5 mg/kg/day for 4 days) 7
• Clarithromycin for 10-14 days (15-20 mg/kg/day in two divided doses) 7

Common Pitfalls to Avoid

• Failing to consider pertussis in young infants presenting with apnea and minimal cough, delaying diagnosis until pneumothorax develops 1, 8
• Underestimating severity based on initial presentation, as infants can deteriorate rapidly 5
• Delaying chest imaging when respiratory status changes during paroxysmal coughing 2
• Not providing prophylaxis to all household contacts, allowing continued transmission 7
• Assuming vaccination provides complete protection, as maternal antibodies wane and infants are vulnerable before completing their primary series 1