My study notes for all pathologists

1. FLASHPATH
H A Z E M A L I

2. DIFFUSE
PANBRONCHIOLITIS
H A Z E M A L I

3. CLINICAL
Diffuse Panbronchiolitis is considered one of the “obstructive lung
diseases” that include:
• Chronic bronchitis
• Emphysema
• Bronchiectasis
• Asthma

4. CLINICAL
Obstructive airway disease Restrictive airway disease
General features Increase in resistance to
airflow due to obstruction at
any level
Reduced expansion of lung
parenchyma
Total lung capacity (TLC) Increased Reduced
Forced Expiratory Volume in
one second (FEV1)
Reduced Normal

5. CLINICAL
• Diffuse panbronchiolits is rare disease of unknown etiology
• Almost exclusively in Japanese
• Associated with HLA BW54
• Presents with productive cough, dyspnea, and often with history of
chronic sinusitis
• Often complicated by Infections (e.g. Pseudomonas, H. influenza)
• Antibiotics are effective in slowing the course of the disease
• Especially macrolides (erythromycin)
• If untreated  bronchiectasis and respiratory failure

6. GROSS
• Early cases:
– Diffuse, numerous, small yellow nodules (4 mm)
• Advanced cases (untreated):
– Bronchiectasis

7. MICROSCOPY
• Dense, bronchiolo-centric
chronic inflammatory infiltrate
– Distribution: interstitial
• small bronchioles and surrounding alveolar walls
– Characteristic: rich in foamy macrophages
• Acute / organizing pneumonia may be seen
• Advanced cases (untreated)
– Bronchiectasis
– Bronchiolar fibrosis (constrictive bronchiolitis)

8. SPECIAL STUDIES
• Culture and sensitivity:
– Haemophilus influenza and Pseudomonas aeruginosa
• Positive Cold hemagglutinins (some cases)
– but Mycoplasma antibodies are generally lacking
• Positive Rheumatoid factor (some cases)
– but few patients with diffuse panbronchiolitis have overt RA

9. DIFFERENTIAL DIAGNOSIS
Chronic
bronchitis
Bronchiectasis Asthma
Small-airway
disease
“bronchiolitis”
Emphysema
Site L a r g e a i r w a y s ( B r o n c h i ) Bronchioles Alveoli
Major
pathology
• Mucous gland
hyperplasia
• Excess mucus
• Inflammation
• Airway
dilation &
scarring
• Thickened
basement
membrane
• Smooth
muscle
hyperplasia
• Excess mucus
• Inflammation
(eosinophils)
• Inflammatory
scarring &
obliteration
• Airspace
enlargement
• Wall
destruction
• No fibrosis
Other obstructive lung diseases:

10. DIFFERENTIAL DIAGNOSIS
Also:
• Connective tissue diseases (especially rheumatoid arthritis)
• Mycoplasma infection
Clinical correlation is recommended

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H a z e m A l i