Community-acquired pneumonia differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Pneumonia should be differentiated from other conditions that cause cough, fever, shortness of breath and tachypnea, such as asthma, COPD, CHF, cancer, GERD, and pulmonary emboli.

**Differential Diagnosis of Pneumonia** ^[1]^[2]^[3]
Disease	Findings

Acute bronchitis	No infiltrates seen on the CXR.
Asthma	Past medical history, no infiltrates seen on chest X Ray.
Bronchiolitis obliterans	Should be suspected in patients with pneumonia who do not respond to antibiotics treatment.
Congestive heart failure	Bilateral pulmonary edema, shortness of breath.
COPD	Past medical history, no infiltrates on chest X Ray, fever is uncommon
Empyema	CXR showing features of pleural effusion, inflammatory markers on thoracocentesis.
Endocarditis	Finding of septic pulmonary emboli
Gastroesophageal reflux disease (GERD)	Normal chest X ray, symptoms worsening during night and associated with meals.
Lung abscess	CXR showing signs of lung abscess, such as unilateral and single mass involving posterior segments of the upper lobes, air-fluid levels may be seen.
Lung cancer	Weight loss, clear sputum. CT scan and biopsy are helpful in ruling out malignancy.
Pertussis	Productive cough for weeks, nasopharyngeal aspirate aids in diagnosis.
Pulmonary embolus	A high degree of suspicion should be kept for pulmonary embolus in patients with a sudden onset of chest pain. Chest X ray may be normal. Fever could be present.
Sinusitis	Sinus tenderness, post nasal drip.
Vasculitis	Systemic manifestations of collagen vascular disease may be seen.


Normal chest X-ray	Abormal chest X-ray

Acute exacerbation of chronic obstructive pulmonary disease Influenza Acute bronchitis Pertussis Asthma with viral infection	Congestive heart failure accompanied by viral infection Aspiration pneumonia Pulmonary infarction Acute exacerbation of pulmonary fibrosis Acute exacerbation of bronchiectasis Acute eosinophilic pneumonia Hypersensitivity pneumonitis Pulmonary vasculitis Cocaine-induced lung injury
Adapted from N Engl J Med 2014; 370:543-551^[4]

↑ Schiele F, Muller J, Colinet E, Siest G, Arzoglou P, Brettschneider H; et al. (1992). “Interlaboratory study of the IFCC method for alanine aminotransferase performed with use of a partly purified reference material”. Clin Chem. 38 (12): 2365–71. PMID 1458569.
↑ Castro-Guardiola A, Armengou-Arxé A, Viejo-Rodríguez A, Peñarroja-Matutano G, Garcia-Bragado F (2000). “Differential diagnosis between community-acquired pneumonia and non-pneumonia diseases of the chest in the emergency ward”. Eur J Intern Med. 11 (6): 334–339. PMID 11113658.
↑ Ahnsjö, Sven (1935). “Contribution to the Differential Diagnosis of Pneumonia in Childhood”. Acta Paediatrica. 17 (3): 439–446. doi:10.1111/j.1651-2227.1935.tb07697.x. ISSN 0803-5253.
↑ Solomon, Caren G.; Wunderink, Richard G.; Waterer, Grant W. (2014). “Community-Acquired Pneumonia”. New England Journal of Medicine. 370 (6): 543–551. doi:10.1056/NEJMcp1214869. ISSN 0028-4793.