All of the following are characteristic features of lobar pneumonia EXCEPT:

Question

Accepted Answer

C. Bronchi remain patent with minimal involvement, leading to patchy infiltrates. ## Distinguishing Lobar vs Bronchopneumonia

**Key Point:** Lobar pneumonia and bronchopneumonia differ fundamentally in anatomical distribution, causative organisms, and pathological progression. Understanding these distinctions is essential for NEET PG pathology.

### Lobar Pneumonia: Defining Features

| Feature | Lobar Pneumonia |
|---------|------------------|
| **Distribution** | Entire lobes; segmental consolidation |
| **Bronchial involvement** | Bronchi are PATENT; minimal airway involvement |
| **Common organism** | *Streptococcus pneumoniae* (most frequent) |
| **Pathological stages** | Red → Gray → Resolution (classic 4 stages) |
| **Exudate type** | Fibrinous; rich in fibrin and inflammatory cells |
| **Pleural involvement** | Fibrinous pleuritis common |
| **Onset** | Sudden; preceded by chill and fever |

### Bronchopneumonia: Contrasting Features

| Feature | Bronchopneumonia |
|---------|-------------------|
| **Distribution** | Patchy; around bronchi and bronchioles |
| **Bronchial involvement** | Bronchi are OCCLUDED by purulent exudate |
| **Common organisms** | *Staphylococcus aureus*, *Haemophilus influenzae*, gram-negatives |
| **Pathological stages** | No classic stages; suppuration and abscess formation |
| **Exudate type** | Purulent; neutrophil-rich |
| **Pleural involvement** | Less common |
| **Onset** | Insidious; often secondary to aspiration or viral infection |

**High-Yield:** The key distinction is **bronchial patency**. In lobar pneumonia, bronchi remain open (patent), allowing air to enter consolidated tissue. In bronchopneumonia, bronchi are plugged with purulent material, causing patchy infiltrates around airways.

### Why Option 4 is Incorrect

Option 4 states: "Bronchi remain patent with minimal involvement, leading to patchy infiltrates." This is a **contradictory and incorrect statement** for lobar pneumonia:
- **Patent bronchi** ✓ (correct for lobar pneumonia)
- **Patchy infiltrates** ✗ (this is the hallmark of *bronchopneumonia*, not lobar pneumonia)

Lobar pneumonia produces **consolidation of entire lobes**, not patchy infiltrates. Patchy infiltrates around bronchi are the defining feature of bronchopneumonia.

**Clinical Pearl:** On chest X-ray, lobar pneumonia shows a dense, homogeneous consolidation that respects lobar boundaries ("air bronchogram" may be visible). Bronchopneumonia shows scattered, ill-defined opacities around the hilum and bases.

**Mnemonic:** **LOBAR = LOBULAR + AIRWAY PATENT**
- **L**obar = **L**arge consolidated **L**obe
- **B**roncho = **B**ronchi **B**locked (occluded)

[cite:Robbins 10e Ch 15]

Answer

A. Pathologically progresses through stages of red hepatization, gray hepatization, and resolution

Answer

B. Consolidation typically involves entire lobes in a segmental distribution

Answer

D. Streptococcus pneumoniae is the most common causative organism

All of the following are characteristic features of lobar pneumonia EXCEPT:

Explanation

Distinguishing Lobar vs Bronchopneumonia

Lobar Pneumonia: Defining Features

Bronchopneumonia: Contrasting Features

Why Option 4 is Incorrect

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Feature	Lobar Pneumonia
Distribution	Entire lobes; segmental consolidation
Bronchial involvement	Bronchi are PATENT; minimal airway involvement
Common organism	Streptococcus pneumoniae (most frequent)
Pathological stages	Red → Gray → Resolution (classic 4 stages)
Exudate type	Fibrinous; rich in fibrin and inflammatory cells
Pleural involvement	Fibrinous pleuritis common
Onset	Sudden; preceded by chill and fever

Feature	Bronchopneumonia
Distribution	Patchy; around bronchi and bronchioles
Bronchial involvement	Bronchi are OCCLUDED by purulent exudate
Common organisms	Staphylococcus aureus, Haemophilus influenzae, gram-negatives
Pathological stages	No classic stages; suppuration and abscess formation
Exudate type	Purulent; neutrophil-rich
Pleural involvement	Less common
Onset	Insidious; often secondary to aspiration or viral infection