A 52-year-old man with chronic alcoholism presents with acute onset fever, cough, and dyspnea. Chest X-ray shows consolidation limited to the right lower lobe with air bronchograms. Which single feature best distinguishes lobar pneumonia from bronchopneumonia in this patient?

Question

Accepted Answer

D. Consolidation respecting anatomical lobar boundaries. ## Distinguishing Lobar from Bronchopneumonia

### Pathological Definition

**Key Point:** Lobar pneumonia consolidates an entire lobe in a sequential manner (red hepatization → gray hepatization → resolution), respecting anatomical boundaries. Bronchopneumonia spreads along airways without regard to lobar anatomy.

### Radiological Hallmarks

| Feature | Lobar Pneumonia | Bronchopneumonia |
|---------|-----------------|------------------|
| **Distribution** | Entire lobe or segment; homogeneous | Patchy, multifocal; bronchocentric |
| **Boundaries** | Respects lobar/segmental anatomy | Crosses lobar boundaries |
| **Air bronchograms** | Present (hallmark) | May be present but less prominent |
| **Lobar involvement** | Single lobe common | Multiple lobes, bilateral |
| **Causative organism** | *Streptococcus pneumoniae* (classic) | Various organisms; aspiration, immunocompromised |

### Why This Feature Discriminates

**High-Yield:** The **consolidation respecting lobar boundaries** is the single best radiological discriminator. Lobar pneumonia produces a sharply demarcated opacity confined to one lobe; bronchopneumonia produces ill-defined, patchy infiltrates that do not follow anatomical lobar lines.

**Clinical Pearl:** Air bronchograms (branching lucencies within consolidation) are present in both but are more conspicuous and uniform in lobar pneumonia. However, they are not discriminatory because they can occur in bronchopneumonia as well.

### Mnemonic
**LOBAR:** **L**obe-respecting, **O**rganized consolidation, **B**oundary-defined, **A**ir bronchograms prominent, **R**estrictive anatomy.

**BRONCHO:** **B**ronchus-centered, **R**amifying along airways, **O**verlapping lobes, **N**o anatomical respect, **C**hronic/aspiration risk, **H**eterogeneous, **O**ften multifocal.

[cite:Robbins 10e Ch 15]

Answer

A. Presence of air bronchograms within the consolidated area

Answer

B. Patchy, multifocal distribution involving multiple lobes and bronchi

Answer

C. Involvement of the lower lobes predominantly

A 52-year-old man with chronic alcoholism presents with acute onset fever, cough, and dyspnea. Chest X-ray shows consolidation limited to the right lower lobe with air bronchograms. Which single feature best distinguishes lobar pneumonia from bronchopneumonia in this patient?

Explanation

Distinguishing Lobar from Bronchopneumonia

Pathological Definition

Radiological Hallmarks

Why This Feature Discriminates

Mnemonic

Practice similar questions

Join our NEET PG community

Feature	Lobar Pneumonia	Bronchopneumonia
Distribution	Entire lobe or segment; homogeneous	Patchy, multifocal; bronchocentric
Boundaries	Respects lobar/segmental anatomy	Crosses lobar boundaries
Air bronchograms	Present (hallmark)	May be present but less prominent
Lobar involvement	Single lobe common	Multiple lobes, bilateral
Causative organism	Streptococcus pneumoniae (classic)	Various organisms; aspiration, immunocompromised