The chest x-ray shows air space opacification with air bronchograms in the right upper lobe with medial sparing.

The patient was commenced on intravenous antibiotic therapy and improved. The causative agent was streptococcus pneumoniae.

Organisms causing lobar consolidation with air bronchogram are:

• Streptococcus pneumoniae.
• Legionella pneumophilia.
• Klebsiella pneumoniae (bulging fissure sign – downward bulging of the horizontal fissure due to heavy exudate).
• Haemophilus influenzae.

All patients with air space consolidation, after treatment with antibiotics, should have a repeat chest x-ray 6 week later to ensure resolution. Pulmonary malignancy especially alveolar cell carcinoma can mimic pneumonia.

Reference: Brant and Helms’ Fundamentals of Diagnostic Radiology, 5th Edition.