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Bullous Emphysema

Bullous Emphysema

1. Definition

A. WHO and ATS Definition of Emphysema
B. Emphysema is characterized by an increase beyond normal in the sizes of air spaces distal to the terminal non-respiratory bronchiole that arises from the destruction of their walls

2. Characteristics

A. Definition confused by overlap in etiology and symptomatology among
1) emphysema
2) asthma
3) chronic bronchitis
B. 2/3 of adults show some emphysema at autopsy
1) 10% have severe clinical disease
2) 10% of cigarette smokers have significant chronic airflow obstruction associated with chronic bronchitis

3. Pathogenesis

A. Earlier studies: Infective, degenerative, obstructive mechanical factors
B. Present studies: Enzymatic mechanisms of tissue destruction
1) Protease pathogenesis hypothesis
a) Destruction of the interstitium is due to an excess of proteolytic enzymes (elastase) in relation to the availability of proteolytic inhibitors
b) Heritable alpha -1 anti-trypsin deficiency
c) Animal studies with elastolytic proteolases

4. Alpha -1 protease inhibitor (alpha-1 anti-trypsin)

A. Major protease in human lower respiratory tract
B. Cigarette smoke - oxidative inactivation of alpha-1 anti-protease by oxidants in smoke or econdarily by active oxygen species liberated by pulmonary phagocytes
1) Alveolar macrophage cells of smokers - increased amounts of oxygen radicals and peroxide
2) Decrease elastin resynthesis after elastolytic destruction of lung tissue in animals

5. Alpha-1 Antiprotease (anti-trypsin)

A. Plasma protease inhibitor - synthesized in liver
B. Primary site of action is alveolar structure of lung
C. Inhibits PMN leukocyte elastase
D. Protects elastic fibers from hydrolysis
E. Enzyme deficiency - risk of pulmonary disease 20-30 times that of the general population
1) 40,000 people in the US
2) 1-2% of those with emphysema
3) Synthesis controlled by autosomal and allelic gene system
a) Most are homozygous for PiM - nl phenotype
b) PiZ phenotype - severe deficiency of the enzyme
c) Homozygous with PiZ phenotype have 10-15% of nl

6. Anatomic Classification of Emphysema

A. Four types - by the way it involves the acinus
1) Proximal acinar emphysema (centrilobular)
a) Associated with cigarette smoking and inflammation of distal airways
2) Symptomatic chronic airflow obstruction
B. Panacinar (panlobular)
1) Involves entire acinus uniformly
a) Alpha-1 anti-trypsin deficiency and other Pi-associated emphysema
2) Worse in lower zones of the lung

7. Distal acinar (paraseptal)

A. Distal acinus, ducts, and alveolar sacs
B. Fibrosis
C. Subpleural location - PTX and BULLOUS disease
D. Irregular
1) Affects acinus in an irregular manner
2) Always associated with scarring and fibrosis
3) Occurs to some degree in all lungs

8. Clinical Classification

A. Compensatory emphysema
1) Not really emphysema - no acinar destruction
2) Infantile lobar emphysema; localized emphysema with infection; bronchial tumor or aspirated FB; compensatory changes after pulmonary resection
B. Diffuse obstructive emphysema
1) Major component of COPD
2) Type A or dry emphysema: Cough, dyspnea, barrel chest, CXR with overinflation, flat diaphragms, no fibrosis and decreased pulmonary vasculature; pan-acinar type destruction; prognosis good
3) Type B or wet emphysema: No obvious CXR or clinical signs; severe cough; copious sputum production; rales; wheezing; cyanosis; dyspnea later; CXR - moderate hyperinflation; fibrosis in lower lobes; increase in central pulmonary vascularity with tapering
4) Centrilobular changes; prognosis poor

9. Surgical Treatment

A. Unsuccessful in providing improvement
B. Associated with high mortality
C. Limited resections have some validity
1) Bullous emphysema: Congenital cysts to blebs
2) Bleb: Intrapleural airspace - separated from alveoli by a thin pleural covering that can rupture spontaneously
3) Bulla: Subpleural airspace usually larger than a bleb that results from the destruction of pulmonary tissue
D. Bullous emphysema: Refers to thin walled air sacs under tension that cause compression atelectasis of normal pulmonary tissue
1) Single/multiple/coalesce
2) Air/fluid/infection

10. Bullae

A. Can form all pathologic forms of emphysema
B. Periacinar bullae are probably most common in patients who are referred for surgery
C. Can develop fluid
D. Infection

11. Selection of patients for bullous surgery is based upon clinical, radiologic and physiologic data

A. Must compare symptoms of bulla to symptoms of underlying pulmonary disease
B. Dyspnea is most common symptom of bullous disease
C. Presence alone implies good surgical result
D. Cor-pulmonale and right heart failure does not necessarily contraindicate surgery
E. PFT's: +/-
F. Review old CXR's
G. Bronchography - clumping of airways
H. Perfusion scans - split pulmonary functions
I. Pulmonary arteriography
J. Exercise PFT's
K. CT scanning

12. No single test shows which patients with bullous emphysema will benefit from surgery

A. Each requires careful study
1) Surgical techniques
2) Surgical objective: Remove as little functioning pulmonary tissue as possible
3) Complications:
B. Air leaks (prolonged)
C. Residual PTX
1) Mortality rate: 10-22%
D. Related to severity of underlying disease
E. Better selection, mortality rate decreases
1) Median sternotomy - less morbidity
2) Intracavitary suction
3) Epidural anesthesia with lateral thoracotomy

13. Alpha-1 Anti-trypsin Deficiency

A. Onset before 40 years
B. Higher incidence in females
C. Family history important
D. CXR: Emphysematous changes in lower of chest
E. Angiograms and scintigrams show greater perfusion in upper lobes than the bases
F. Ventilation scans show basal air trapping
G. Tx:
1) Replacement Tx with alpha-1 protease inhibitor - some early success
2) Lung transplantation

PNEUMOTHORAX

14. Classification

A. Spontaneous
1) Primary
a) No underlying pathology
2) Secondary
a) Underlying pulmonary disorders
3) Catamenial
4) Neonatal
B. Traumatic
1) Iatrogenic
a) Thoracentesis, mechanical ventilation, central vein cath., post- operative
2) Blunt, penetrating
C. Diagnostic
1) Air-contrast study of pleuropulmonary pathology

15. Causes of Secondary Spontaneous Pneumothorax

A. Airway disease
1) Bullous disease
2) COPD
3) Asthma
4) Cyst (congenital)
5) Cystic fibrosis
B.' Interstitial disease
1) Idiopathic pulmonary fibrosis
2) Eosinophilic granuloma
3) Sarcoidosis
4) Tuberous sclerosis
5) Collagen vascular disease

16. Causes of Secondary Spontaneous Pneumothorax

A. Infections
1) Anaerobic pneumonia
2) Staphylococcal pneumonia
3) Gram-negative pneumonia
4) Lung abscess
5) Actinomycosis
6) Nocardiosis
7) Tuberculosis
8) Atypical mycobacteria
B. Neoplasms
1) Primary
2) Metastatic

17. Other diseases

A. Endometriosis
B. Ehlers-Danlos syndrome
C. Pulmonary embolism
D. Marfan's syndrome

18. Indications for Thoracotomy

A. Massive air leak that prevents re-expansion of the lung
B. Persistent air leak > 7-10 days
C. Second episode of spontaneous PTX
D. Complications of PTX
1) Hemothorax
2) Empyema
3) Chronic PTX
E. Specific surgical indications for conditions that cause secondary spontaneous PTX
1) Occupational indications after first episode
2) Airline pilots
3) Scuba divers
4) Individuals in remote areas
F. Previous contralateral PTX
1) Bilateral simultaneous PTX
2) Presence of large cysts visible on CXR

19. Clinical Presentation and CXR

A. In 80% symptoms occur at rest or during normal activity
B. Pain - most frequent - pleuritic/sharp
C. Dyspnea - second most common symptom
1) Large PTX
2) Underlying pulmonary disease
3) Pronounced with tension PTX
D. Orthopnea
E. Hemoptysis
F. Non-productive cough
G. > 25% - diminished motion of chest wall on the affected side
H. Cyanosis
I. Hyper-resonant; tympanitic
J. Decreased breath sounds
K. Subcutaneous emphysema/mediastinal emphysema
L. Tracheal deviation
M. CXR

20. Primary Spontaneous Pneumothorax

A. Young adults, 85% < 40 years
B. 9 per 100,000
C. Tall, thin male, 25 to 30, smoker, family history
D. Previous history, 90% chance it is on the same side
E. Simultaneous bilateral - 10%
F. Ruptured bleb - 15% seen on CXR at apex, along fissures
1) 85% found at thoracotomy
G. Recurs with increasing frequency
1) 50% after first episode
2) 62% after second episode
3) 80% after third episode
H. Secondary spontaneous pneumothorax
1) 20% event is related to underlying pulmonary disease

21. Spontaneous Pneumothorax

A. Neonatal Spontaneous Pneumothorax
1) Hyaline membrane disease
2) Renal malformation
3) Potter's syndrome
4) Meconium aspiration
5) Cystic fibrosis in children
B. Catamenial Spontaneous Pneumothorax
1) Occurs during menstruation
2) Third and fourth decades
3) 90% on the right side
4) Does not occur during periods of non-ovulation
5) Four possible causes
a) Rupture of bleb
b) Alveolar rupture due to PF2
c) Air into pleural cavity from GYN tract
d) Pleural/pulmonary endometriosis

22. Management of Spontaneous Pneumothorax

A. Observation if PTX < 20%
B. Thoracenteses 30-70% effective
C. Thoracostomy
D. Chemical pleurodesis
E. Mechanical pleurodesis
F. Treatment of underlying disease

23. Caveats

A. One can never be faulted for placing a chest tube (unless the chest tube was placed in the abdomen).
B. The first thing into the chest is your finger.
C. Usually, do not place a chest tube below the nipple line.