Bullous Emphysema

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BULLOUS EMPHYSEMA

1.  Definition 

WHO and ATS Definition of Emphysema 
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 

 Definition confused by overlap in etiology and symptomatology among 

emphysema 
asthma 
chronic bronchitis

 2/3 of adults show some emphysema at autopsy 

10% have severe clinical disease 
10% of cigarette smokers have significant chronic airflow obstruction associated with chronic bronchitis

3.  Pathogenesis 

 Earlier studies: Infective, degenerative, obstructive mechanical factors 
 Present studies: Enzymatic mechanisms of tissue destruction 

Protease pathogenesis hypothesis 

Destruction of the interstitium is due to an excess of proteolytic enzymes (elastase) in relation to the availability of proteolytic inhibitors 
Heritable alpha -1 anti-trypsin deficiency 
Animal studies with elastolytic proteolases

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

Major protease in human lower respiratory tract 
Cigarette smoke - oxidative inactivation of alpha-1 anti-protease by oxidants in smoke or econdarily by active oxygen species liberated by pulmonary phagocytes 

Alveolar macrophage cells of smokers - increased amounts of oxygen radicals and peroxide 
Decrease elastin resynthesis after elastolytic destruction of lung tissue in animals

5.    Alpha-1 Antiprotease (anti-trypsin) 

Plasma protease inhibitor - synthesized in liver 
Primary site of action is alveolar structure of lung 
Inhibits PMN leukocyte elastase 
Protects elastic fibers from hydrolysis 

Enzyme deficiency - risk of pulmonary disease 20-30 times that of the general population 

40,000 people in the US 
1-2% of those with emphysema 
Synthesis controlled by autosomal and allelic gene system 

Most are homozygous for PiM - nl phenotype 
PiZ phenotype - severe deficiency of the enzyme 
Homozygous with PiZ phenotype have 10-15% of nl

6.  Anatomic Classification of Emphysema 

 Four types - by the way it involves the acinus 

  Proximal acinar emphysema (centrilobular) 

   Associated with cigarette smoking and inflammation of distal airways 

  Symptomatic chronic airflow obstruction 

 Panacinar (panlobular) 

  Involves entire acinus uniformly 

  Alpha-1 anti-trypsin deficiency and other Pi-associated emphysema 

 Worse in lower zones of the lung 

7.   Distal acinar (paraseptal) 

  Distal acinus, ducts, and alveolar sacs 
  Fibrosis 
  Subpleural location - PTX and BULLOUS disease 

Irregular 

  Affects acinus in an irregular manner 
  Always associated with scarring and fibrosis 
  Occurs to some degree in all lungs 

8.  Clinical Classification 

 Compensatory emphysema 

Not really emphysema - no acinar destruction 
Infantile lobar emphysema; localized emphysema with infection; bronchial tumor or aspirated FB; compensatory changes after pulmonary resection 

 Diffuse obstructive emphysema 

Major component of COPD 
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 
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 
Centrilobular changes; prognosis poor 

 9.  Surgical Treatment 

 Unsuccessful in providing improvement 
 Associated with high mortality 
 Limited resections have some validity 

  Bullous emphysema: Congenital cysts to blebs 
  Bleb: Intrapleural airspace - separated from alveoli by a thin pleural covering that can rupture spontaneously 
  Bulla: Subpleural airspace usually larger than a bleb that results from the destruction of pulmonary tissue 

 Bullous emphysema: Refers to thin walled air sacs under tension that cause compression atelectasis of normal pulmonary tissue 

  Single/multiple/coalesce 
  Air/fluid/infection 

10.   Bullae 

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

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

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

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

  Each requires careful study 

 Surgical techniques 
 Surgical objective: Remove as little functioning pulmonary tissue as possible 
 Complications: 

  Air leaks (prolonged) 
  Residual PTX 

 Mortality rate: 10-22% 

  Related to severity of underlying disease 
  Better selection, mortality rate decreases 

 Median sternotomy - less morbidity 
 Intracavitary suction 
 Epidural anesthesia with lateral thoracotomy 

13.  Alpha-1 Anti-trypsin Deficiency 

 Onset before 40 years 
 Higher incidence in females 
 Family history important 
 CXR: Emphysematous changes in lower ½ of chest 
 Angiograms and scintigrams show greater perfusion in upper lobes than the bases 
 Ventilation scans show basal air trapping 
 Tx: 

  Replacement Tx with alpha-1 protease inhibitor - some early success 
  Lung transplantation 

PNEUMOTHORAX 

14.  Classification 

 Spontaneous 

  Primary 

   No underlying pathology 

  Secondary 

   Underlying pulmonary disorders 

  Catamenial 
  Neonatal 

 Traumatic 

  Iatrogenic 

   Thoracentesis, mechanical ventilation, central vein cath., post-   operative 

  Blunt, penetrating 

 Diagnostic 

  Air-contrast study of pleuropulmonary pathology 

15.  Causes of Secondary Spontaneous Pneumothorax 

 Airway disease 

  Bullous disease 
  COPD 
  Asthma 
  Cyst (congenital) 
  Cystic fibrosis 

 Interstitial disease 

  Idiopathic pulmonary fibrosis 
  Eosinophilic granuloma 
  Sarcoidosis 
  Tuberous sclerosis 
  Collagen vascular disease 

16.  Causes of Secondary Spontaneous Pneumothorax 

 Infections 

  Anaerobic pneumonia 
  Staphylococcal pneumonia 
  Gram-negative pneumonia 
  Lung abscess 
  Actinomycosis 
  Nocardiosis 
  Tuberculosis 
  Atypical mycobacteria 

 Neoplasms 

  Primary 
  Metastatic 

17.   Other diseases 

  Endometriosis 
  Ehlers-Danlos syndrome 
  Pulmonary embolism 
  Marfan's syndrome 

18.  Indications for Thoracotomy 

 Massive air leak that prevents re-expansion of the lung 
 Persistent air leak > 7-10 days 
 Second episode of spontaneous PTX 
 Complications of PTX 

  Hemothorax 
  Empyema 
  Chronic PTX 

 Specific surgical indications for conditions that cause secondary spontaneous PTX 

  Occupational indications after first episode 
  Airline pilots 
  Scuba divers 
  Individuals in remote areas 

 Previous contralateral PTX 
 Bilateral simultaneous PTX 
 Presence of large cysts visible on CXR 

19.  Clinical Presentation and CXR 

 In 80% symptoms occur at rest or during normal activity 
 Pain - most frequent - pleuritic/sharp 
 Dyspnea - second most common symptom 

  Large PTX 
  Underlying pulmonary disease 
  Pronounced with tension PTX 

 Orthopnea 
 Hemoptysis 
 Non-productive cough 
 > 25% - diminished motion of chest wall on the affected side 
 Cyanosis 
 Hyper-resonant; tympanitic 
 Decreased breath sounds 
 Subcutaneous emphysema/mediastinal emphysema 
 Tracheal deviation 
 CXR 

20.  Primary Spontaneous Pneumothorax 

 Young adults, 85% < 40 years 
 9 per 100,000 
 Tall, thin male, 25 to 30, smoker, family history 
 Previous history, 90% chance it is on the same side 
 Simultaneous bilateral - 10% 
 Ruptured bleb - 15% seen on CXR at apex, along fissures 

  85% found at thoracotomy 

 Recurs with increasing frequency 

  50% after first episode 
  62% after second episode 
  80% after third episode 

 Secondary spontaneous pneumothorax 

  20% event is related to underlying pulmonary disease 

21.  Spontaneous Pneumothorax 

 Neonatal Spontaneous Pneumothorax 

  Hyaline membrane disease 
  Renal malformation 
  Potter's syndrome 
  Meconium aspiration 
  Cystic fibrosis in children 

 Catamenial Spontaneous Pneumothorax 

  Occurs during menstruation 
  Third and fourth decades 
  90% on the right side 
  Does not occur during periods of non-ovulation 
  Four possible causes 

   Rupture of bleb 
   Alveolar rupture due to PF2 
   Air into pleural cavity from GYN tract 
   Pleural/pulmonary endometriosis 

22.  Management of Spontaneous Pneumothorax 

 Observation if PTX < 20% 
 Thoracenteses 30-70% effective 
 Thoracostomy 
 Chemical pleurodesis 
 Mechanical pleurodesis 
 Treatment of underlying disease 

23.  Caveats 

One can never be faulted for placing a chest tube (unless the chest tube was placed in the abdomen). 

The first thing into the chest is your finger. 

Usually, do not place a chest tube below the nipple line. 

Pneumothorax