What are the physical signs of pneumonia (pna)?

Physical Signs of Pneumonia

The most reliable physical signs of pneumonia are tachypnea (respiratory rate >20 breaths/min in adults, age-adjusted in children), fever ≥38°C, and focal chest examination findings including crackles, bronchial breath sounds, and dullness to percussion—though no single finding or combination can definitively rule in pneumonia without imaging. 1, 2

Key Physical Examination Findings

Vital Sign Abnormalities

• Tachypnea is the single most sensitive physical finding, with respiratory rate >20 breaths/min in adults indicating possible pneumonia 1, 3
• Fever ≥38°C is common but non-specific, occurring variably across different pneumonia etiologies 1
• Tachycardia frequently accompanies pneumonia but has low specificity 1
• Hypoxemia (SpO₂ <93-95%) indicates more severe disease and warrants immediate attention 1, 4

Chest Examination Signs

• Crackles (rales) on auscultation are the most common focal finding, though they persist beyond 7 days in 20-40% of patients even with appropriate treatment 1, 3
• Bronchial breath sounds suggest consolidation but are present in only a minority of cases 3, 2
• Dullness to percussion indicates underlying consolidation or pleural effusion 3, 5
• Decreased or diminished breath sounds over affected areas suggest pneumonia 1, 2

Signs of Severe Respiratory Distress

• Chest indrawing/intercostal retractions indicate increased work of breathing, particularly important in children (OR 8.9 for severe illness) 1, 4
• Grunting on expiration signals severe respiratory compromise (OR 2.9 for severe illness) 1, 4
• Nasal flaring demonstrates accessory muscle recruitment 1, 4
• Use of accessory muscles including sternocleidomastoid contraction 3

Clinical Presentation Patterns

Respiratory Symptoms

• Cough with or without sputum production is nearly universal but non-specific 1, 6, 3
• Dyspnea or difficulty breathing strengthens the diagnosis when combined with other findings 1, 3
• Pleuritic chest pain suggests pleural involvement and increases likelihood of bacterial pneumonia 1, 3

Systemic Signs

• Sweating, fevers, rigors are common constitutional symptoms 1, 3
• Myalgias and malaise occur frequently but lack specificity 1, 3

Critical Diagnostic Limitations

The absence of all vital sign abnormalities AND all chest auscultation abnormalities substantially reduces the likelihood of pneumonia, potentially eliminating the need for chest radiography. 2 However, several important caveats exist:

• Clinical symptoms and signs lack sufficient sensitivity and specificity to diagnose pneumonia definitively without imaging 1, 2
• Up to 40% of patients cannot produce sputum for examination 5
• Physical findings may be minimal early in disease (<3 days duration) 7
• Elderly patients and those with underlying conditions may present atypically with fewer classic findings 1

Adjunctive Testing to Strengthen Clinical Diagnosis

C-Reactive Protein (CRP)

• CRP >30 mg/L combined with suggestive symptoms and signs significantly increases pneumonia likelihood 1
• CRP <10 mg/L in the absence of dyspnea and daily fever makes pneumonia less likely 1
• The CHEST guidelines suggest measuring CRP when diagnosis remains uncertain after clinical assessment 1

Age-Specific Considerations

In children, the British Thoracic Society recommends considering bacterial pneumonia when fever >38.5°C occurs together with chest recession AND respiratory rate >50/min in children under 3 years 7. WHO-defined tachypnea has 74% sensitivity and 67% specificity for radiologically-confirmed pneumonia in children under 5 years 7.

In adults, the combination of fever, pleuritic pain, dyspnea, tachypnea, and new localizing chest signs provides the strongest clinical evidence for pneumonia 1, 6.

Common Pitfalls to Avoid

• Do not rely on fever and tachycardia alone—these are too non-specific and present variably across different etiologies 1
• Absence of runny nose combined with breathlessness, crackles, tachycardia, and fever ≥38°C is more suggestive of pneumonia than upper respiratory infection 1
• Radiographic findings often lag behind or progress despite clinical improvement, so do not use imaging timing alone to assess treatment response 1
• Physical examination findings resolve at different rates: fever typically resolves in 2-4 days, leukocytosis by day 4, but crackles persist beyond 7 days in 20-40% of cases 1