What is paroxysmal cough?

Paroxysmal Cough: Definition and Clinical Significance

Paroxysmal cough is characterized by recurrent prolonged coughing episodes with multiple bursts of expiratory airflow and an inability to breathe during these spells, often leading to gasping for air between episodes. 1

Clinical Characteristics of Paroxysmal Cough

Paroxysmal cough is a hallmark symptom of several respiratory conditions, most notably pertussis (whooping cough). The key features include:

• Recurrent, sudden episodes of multiple, forceful coughs
• Difficulty breathing during coughing spells
• Often followed by a deep inspiration that may produce a "whooping" sound
• Frequently accompanied by posttussive vomiting
• May cause facial discoloration during episodes
• Often worse at night and after exposure to cold air 1

Paroxysmal Cough in Pertussis

Pertussis infection typically progresses through distinct stages:

1. Catarrhal stage (1-2 weeks):

   • Initial virus-like illness with conjunctivitis, rhinorrhea, fever, malaise
   • Mild cough that gradually worsens 1

2. Paroxysmal stage (2-6 weeks):

   • Characterized by severe paroxysmal coughing
   • May include the classic inspiratory "whoop" (series of expiratory bursts followed by sudden loud inspiratory sound)
   • Posttussive vomiting is common
   • Apnea may occur, especially in infants 1

3. Convalescent stage (weeks to months):

   • Gradual resolution of symptoms
   • Cough may persist for extended periods 1

Diagnostic Value of Paroxysmal Cough

The 2019 CHEST guidelines indicate that paroxysmal cough has significant diagnostic value:

• In adults with acute (<3 weeks) or subacute (3-8 weeks) cough, the absence of paroxysmal cough makes pertussis unlikely (high specificity) 1
• In children with acute cough (<4 weeks), paroxysmal cough suggests possible pertussis 1

Associated Symptoms and Complications

Paroxysmal coughing episodes can lead to several complications:

• Posttussive vomiting (vomiting induced by coughing)
• Inspiratory whooping sound
• Facial discoloration during episodes
• Apnea (especially in infants)
• Pneumothorax (up to 5% of cases)
• Rib fractures (up to 4%)
• Epistaxis and subconjunctival hemorrhage
• Syncope or loss of consciousness (3-6%)
• Weight loss and sleep disturbance 2, 1

Clinical Significance in Different Age Groups

The presentation and significance of paroxysmal cough varies by age:

• Infants: May not exhibit classic whooping sound; more likely to present with apnea or vomiting; at highest risk for severe complications including death 1
• Children: More likely to present with classic symptoms including whooping and posttussive vomiting 1, 3
• Adolescents and adults: Often present with prolonged cough without classic whooping sound; complications typically related to chronic cough 4

Diagnostic Approach

When paroxysmal cough is present, especially with other characteristic symptoms, clinicians should:

1. Consider pertussis in any afebrile patient with paroxysmal cough lasting ≥7 days, especially if accompanied by whoop and/or apnea 3
2. Look for supporting laboratory findings such as leukocytosis (≥16,000/ml) and lymphocytosis (≥11,000/ml) 3
3. Confirm diagnosis with polymerase chain reaction (PCR) testing or culture of nasopharyngeal specimens 1

Management Implications

Recognition of paroxysmal cough should prompt:

• Appropriate respiratory isolation precautions
• Consideration of antibiotic therapy (macrolides preferred) to reduce transmission
• Notification of public health authorities for suspected pertussis cases
• Evaluation of close contacts for prophylaxis 2, 5

Paroxysmal cough is a distinctive clinical feature that should alert clinicians to consider pertussis and other serious respiratory conditions, prompting appropriate diagnostic testing, treatment, and public health measures.