This document discusses the approach to bullous lung disease. It defines a bulla as a large air-containing space within the lung larger than 1 cm in diameter. Bullae can occur with emphysema, pulmonary fibrosis, or in otherwise normal lungs. HRCT is useful for evaluating the size, number and relationships of bullae. Pulmonary function testing may show obstructive lung disease, hyperinflation and reduced diffusion capacity. For surgical candidates, bullectomy or lung volume reduction surgery may be considered to treat symptoms or complications like spontaneous pneumothorax.

1. Approach to bullous lung disease
Dr. Abhishek Tandon
MD (Respiratory Medicine) Resident
Pt. B.D. Sharma PGIMS Rohtak

2. Introduction
• Bullous lung disease is characterized by the development of bullae within
the lung parenchyma.
• A bulla is an air-containing space within the lung parenchyma that arises
from destruction, dilatation, and confluence of airspaces distal to terminal
bronchioles and is larger than 1 cm in diameter and its walls are composed
of attenuated and compressed parenchyma.
• Bullae occur in various clinical contexts: (1) with emphysema (“bullous
emphysema”); (2) with pulmonary fibrosis, as in the late stages of
sarcoidosis or complicated pneumoconiosis; (3) in so-called “vanishing
lung,” in which the parenchyma is rapidly replaced by multiple bullae; and
(4) in lungs that are otherwise normal (“bullous lung disease”)

4. • Distinctions are drawn between bullae, blebs, and cysts
• A bleb is an accumulation of air between the two layers
of the visceral pleura that arises when the thin covering
of the bleb ruptures and permits entry of air
• Cysts are epithelial-lined cavities that may resemble
bullae on radiographs.

7. Etiology
• Bullae may originate in a variety of clinical and
pathogenetic set tings: (1) with emphysema of distal
acini; (2) in the setting of cigarette smoking; (3) in
conjunction with scar tissue formation, which “traps”
areas of normal lung, enlarges airspaces by traction on
surrounding intact alveoli, or produces retraction or
shrinkage of intact walls of adherent alveoli; (4) in the
setting of intravenous drug abuse; (5) as a result of
chronic inflammation and destructive changes in terminal
and first-order respiratory bronchioles, resulting in
airspace distention from delayed emptying; and (6) with
a1-antitrypsin deficiency.

8. Pathogenesis
• Several hypotheses have been proposed over the years for how
bullae develop, although none have been proved.
• These include (1) weakness of the alveolar walls predisposes to the
formation of bullae, particularly at the apices of the lungs, where
pleural pressures are most negative. This theory underscores the
proclivity of bullae for the upper lobes and stresses the influence of
mechanical forces acting upon flawed tissue. (2) Inflammatory
disease of a bronchiole leads to progressive air trapping and
“tension airspaces.” (3) Disordered collateral ventilation produces
the findings. (4) The same mechanisms responsible for generalized
emphysema are operative in the formation of bullae. (5) Underlying
paraseptal emphysema produces bullous disease.
• Of all the hypotheses, that of underlying paraseptal emphysema is
the most popular.

9. Classification

10. Evaluation and diagnosis

11. symptoms
Bullae cause symptoms via two distinct mechanisms:
•Bullae may interfere with ventilation of adjacent areas of
preserved lung, preventing them from expanding fully with
inspiration or, in severe cases, causing frank atelectasis.
•Bullae are space-occupying lesions that take up relatively
large volumes of the chest cavity without contributing to
functional gas exchange. Because they may enlarge with
exercise as a result of air-trapping, bullae may contribute to
dynamic hyperinflation, altering chest wall mechanics (e.g.,
diaphragm flattening and barrel chest) and increasing the
work of breathing.

12. • Sometimes asymptomatic and found only incidentally on
imaging.
• Typically, the symptoms are those of COPD:
 Shortness of breath or chest tightness, particularly with
exertion
 Cough
 Sputum production
 Occasionally, a sense of abdominal fullness or bloating,
usually associated with severe obstruction and
prominent air-trapping on pulmonary function testing
 Rarely chest pain due to air-trapping within a bulla,
causing distention of visceral pleura

13. • Symptoms are typically insidious,
• But if sudden and severe dyspnea or chest pain in a
patient with bullous lung disease suspect -
pneumothorax due to a ruptured bulla or bleb.
• Rarely, fever and malaise +/- increased sputum
production, may signal an infected bulla.

14. C-Xray

15. HRCT
CT provides valuable anatomic information
about the size, number, and relationships
of bullae, as well as crowding of adjacent
lung and disposition of the pulmonary
vasculature
• High resolution computed
tomography (HRCT) shows that
large bullae are frequently
associated not only with distal
acinar (paraseptal) emphysema,
but also with centriacinar
emphysema—the type of
emphysema usually associated
with cigarette smoking.

16. • Pulmonary function testing may be normal, particularly
in patients whose bullae are surrounded by normal lung
parenchyma.
• However, they usually demonstrate obstructive lung
disease. Common abnormalities include airflow
obstruction, hyperinflation (i.e., elevated total lung
capacity), air trapping (i.e., elevated residual volume),
and reduced diffusion capacity.
• Other signs of bullous lung disease may include
hypoxemia, particularly with exertion; hypercapnea; and
reduced exercise capacity.

17. On chest CT, giant bullae are predominantly located in the upper lobes
and are generally subpleural. However, in patients with a1-antitrypsin
deficiency, bullae are most commonly located at the lung base.
Approximately half of the patients have bilateral bullae and,
occasionally, deviation of the mediastinal structures to the contralateral
side may be noted.
CT has been used to create three-dimensional reconstructions of
bullae, which can then be used to calculate bullae volumes

20. Nuclear imaging

21. PFT
• Pulmonary function testing is not
diagnostic of bullous lung disease, but it is
critical in evaluating its functional
significance, guiding medical therapy, and
evaluating the likelihood of benefit from
surgical intervention

22. • Spirometry establishes the presence or absence of
airflow obstruction and reflects its severity. The forced
expiratory volume in 1 second (FEV1) is used to grade
severity, as well as selects appropriate candidates for
surgical bullectomy.
• Measurement of total lung capacity (TLC) and residual
volume (RV), is used to evaluate for hyperinflation and
air-trapping respectively. Because of the frequency of
severe air trapping in patients with bullous lung disease,
gas dilution methods may underestimate true lung
volumes. Consequently, plethysmography when it is
available is the preferred method for lung volume
measurement.

23. • A decreased diffusing capacity for carbon
monoxide (DLCO) can support the diagnosis of
emphysema or bullous disease, but is
nonspecific. The DLCO is also used to select
candidates for surgical treatment.

24. • Diagnostic procedures like bronchoscopy and lung
biopsies have essentially no role in the evaluation of
bullous lung disease.
• In surgical candidates, cardiac testing like
echocardiography, stress testing, and cardiac
catheterization may be considered as appropriate, in
evaluating for pulmonary arterial hypertension. In
addition, testing for coexistent IHD may be warranted.
These conditions may be contraindications for
bullectomy and lung volume reduction surgery.

25. Complication
• The major complications of bullous lung
disease are fluid accumulation(including
infection) in the bulla, spontaneous
pneumothorax, bronchogenic cancer,
chest pain, and hemoptysis.

31. Surgical management

34. Thankyou