Differential Diagnosis for Decreased Breath Sound, Egophony, and Dullness to Percussion in the Right Lung

• Single Most Likely Diagnosis
  • Pneumonia: This condition is characterized by inflammation of the lung tissue, often due to infection. The symptoms of decreased breath sounds, egophony (a harsh, nasal sound heard when speaking), and dullness to percussion are classic for lung consolidation, which is commonly seen in pneumonia. The presence of these signs, especially when localized to one lung, strongly suggests pneumonia as the primary diagnosis.
• Other Likely Diagnoses
  • Pulmonary Edema: Fluid accumulation in the lungs can lead to decreased breath sounds and dullness to percussion. While pulmonary edema typically presents bilaterally, it can be unilateral, especially if caused by conditions like pulmonary embolism or aspiration.
  • Pleural Effusion: The accumulation of fluid in the pleural space can cause decreased breath sounds and dullness to percussion over the affected area. Egophony might not be as prominent but can be present if there is significant lung compression or atelectasis.
  • Atelectasis: Collapse of lung tissue can result in decreased breath sounds and can sometimes cause dullness to percussion if significant. Egophony might be present, especially if the atelectasis is due to an obstructive cause.
• Do Not Miss Diagnoses
  • Pulmonary Embolism: Although it might not always present with the classic triad of decreased breath sounds, egophony, and dullness to percussion, pulmonary embolism is a life-threatening condition that requires immediate diagnosis and treatment. It can cause infarction of lung tissue, leading to these physical examination findings.
  • Empyema: An infection of the pleural space can present similarly to pneumonia or pleural effusion but requires specific treatment, including drainage of the infected fluid.
• Rare Diagnoses
  • Lung Abscess: A localized collection of pus within the lung can cause decreased breath sounds, dullness to percussion, and sometimes egophony if it communicates with a bronchus. It's less common than pneumonia but can present similarly.
  • Diaphragmatic Hernia: Although rare, a diaphragmatic hernia can cause lung compression and atelectasis, leading to decreased breath sounds and dullness to percussion. It's more likely to be considered in the context of trauma or congenital conditions.