Bullous Disease
Of the Lungs

Bullae For You

What a Bulla Is
Definition
Thin-walled–less than 1 mm
Air-filled space
In the lung
> 1 cm in size when distended
Walls may be formed by pleura, septa,
or compressed lung tissue

What a Bulla Isn’t
Other Terminology
Pneumatocoele: thin-walled (< 1mm), gas-filled space in the lung developing in association with acute pneumonia, usually staph, and usually transient
Cavity: gas-containing space in the lung having a wall > 1 mm thick
Cyst: thin-walled, air- or fluid-filled, with a wall that contains respiratory epithelium, cartilage, smooth muscle and glands
Bleb: intrapleural  cystic space, uncommon

Bulla
Terminology
One is a bulla
Two or more are bullae (bully)
Diseases which contain bullae are bullous diseases

Other Latin
What is a singular tic called?
What is the pleural of femur?
What is the pleural of tibia?
What is the pleural of esophagus?

Bullae
General
Enlarge progressively over a period of months to years
Most are associated with emphysema
May become infected or lead to pneumothorax

Primary Bullous Disease
Familial occurrence
Increased incidence in Marfan's and Ehlers-Danlos
No airway obstruction and normal parenchyma between bullae
Unlike emphysema

Types of Bullae
Type 1
Originate in a subpleural location usually in upper part of lung
Narrow neck
Produce passive atelectasis of adjacent lung tissue
Paraseptal emphysema

Types of Bullae
Type 2
Superficial in location
Very broad neck
Anterior edge of upper and middle lobes and along diaphragm
Contain blood vessels and strands of partially destroyed lung
Spontaneous pneumothorax

Types of Bullae
Type 3
Lie deep within lung substance
Like type 2, contain residual strands of lung tissue
Affect upper and lower lobes with same frequency

Bullae
Radiologic Signs
Seen more in upper lobes
Thin-walled, sharply demarcated areas containing no visible blood vessels
Only portion of wall is usually seen
Trap air
Larger on expiration

Infected Bullae
Signs
Air-fluid level
Differentiation from lung abscess
Bulla contains less fluid
Much thinner wall
No surrounding pneumonitis
Patients less sick with infected bulla
Clearing may take weeks to months

Bullous Disease
Spontaneous Pneumothorax
Commonly occurs with small bulla affecting lung apices
May be difficult to differentiate large bulla from PTX
CT may help

Bullous Disease
Clinical
1° bullous disease usually has no symptoms
When large, surgical removal may be performed
Patients with COPD show little difference clinically or functionally with or without bullae