What are the signs, symptoms, and treatment options for walking pneumonia?

Walking Pneumonia: Signs and Symptoms

Walking pneumonia, typically caused by Mycoplasma pneumoniae, presents with gradual onset of nonproductive cough, sore throat, low-grade fever, and the ability to remain ambulatory despite having pneumonia—distinguishing it from more severe bacterial pneumonias that cause acute illness. 1

Clinical Presentation

Primary Symptoms

• Gradual onset of respiratory symptoms over several days, contrasting with the sudden onset typical of pneumococcal pneumonia 1, 2
• Nonproductive cough that is often persistent and may be the dominant symptom 1
• Sore throat frequently accompanies the respiratory symptoms 1
• Low-grade fever (often <38.5°C), which is less pronounced than in typical bacterial pneumonia 3, 1
• Headache and myalgia are common systemic symptoms, particularly in school-aged children and young adults 3

Additional Clinical Features

• Arthralgia may be present, especially in older children and adolescents 3
• Wheezing occurs in approximately 30% of mycoplasma pneumonias and is more common in older children, which can lead to confusion with asthma 3
• Crackles on auscultation may be detected on physical examination 3
• Patients remain ambulatory and appear less toxic compared to those with typical bacterial pneumonia, hence the term "walking pneumonia" 1

Distinguishing Features from Typical Bacterial Pneumonia

Key Differences

• Absence of high fever: Unlike pneumococcal pneumonia which typically presents with fever >38.5°C, walking pneumonia usually has lower-grade fever 3, 1
• Lack of severe respiratory distress: Patients do not exhibit significant tachypnea, chest recession, or signs of increased work of breathing (grunting, nasal flaring, lower chest wall indrawing) that characterize severe bacterial pneumonia 3
• Gradual vs. sudden onset: Mycoplasma pneumonia develops over days, while pneumococcal pneumonia starts suddenly with fever and tachypnea 3, 2
• Nonproductive vs. productive cough: Walking pneumonia typically has a dry cough, whereas bacterial pneumonia develops productive cough once alveolar debris enters the airways 3

Radiographic Findings

• Interstitial infiltrates are the most common pattern 1
• Patchy infiltrates distributed throughout the lung fields 1
• Plate-like atelectasis may be visible 1
• Nodular infiltration can occur 1
• Hilar adenopathy may be present 1

Age-Specific Considerations

• Most common in young adults: Mycoplasma pneumoniae is responsible for approximately 43% of community-acquired pneumonia cases in patients aged 17-44 years 1
• School-aged children: Fever, arthralgia, headache, cough, and crackles in a school-child strongly suggest mycoplasma infection 3
• Can resemble other conditions: In children, mycoplasma pneumonia can mimic pneumococcal, staphylococcal pneumonias, or adenoviral illness when wheezing is prominent 3

Important Clinical Pitfalls

Common Diagnostic Challenges

• Clinical features alone cannot reliably establish etiology: The clinical presentation of pneumonia (symptoms, signs, and radiographic findings) cannot be used with adequate sensitivity and specificity to definitively diagnose the causative organism 3
• Wheezing may mislead diagnosis: The presence of wheeze in mycoplasma pneumonia can lead to misdiagnosis as asthma, particularly without radiography 3
• No single clinical criterion is definitive: Fever and tachycardia are non-specific and variably present, and no one clinical sign has high enough sensitivity and specificity for reliable diagnosis 3

Treatment Approach

• First-line therapy: Macrolide antibiotics, preferably azithromycin 500 mg initially, then 250 mg daily for 4 days 1
• Alternative agents for treatment failure: Tetracyclines (doxycycline or minocycline) or fluoroquinolones (levofloxacin) may be needed if macrolide resistance is suspected or treatment fails 4
• Macrolide resistance: Particularly prevalent in East Asia (especially China), though substantially lower in Europe and North America 4
• Immunomodulators for refractory cases: Corticosteroids and intravenous immunoglobulin may be beneficial in refractory mycoplasma pneumonia with excessive immune response 4