**4.4.1 Congenital lobar emphysema**

124 Chronic Obstructive Pulmonary Disease – Current Concepts and Practice

supplying an emphysematous area(Reid.1967;Thurlbeck,1976,1991 as cited in Shapiro

These are intrapleural collections of air, a form of interstitial emphysema. They may arise from interstitial emphysema of the newborn period or pulmonary barotrauma complicating

Cysts are air spaces lined by epithelium, which usually have the characteristics of bronchial epithelium., They are classically known as intrapulmonary bronchogenic cysts and usually occur near the tracheal bifurcation, but they may be seen more peripherally in the lung parenchyma(Reed & Sobonya,1974;Rogers & Osmer,1964 as cited in Shapiro SD,2010).

Air space distention with or without alveolar rupture and is often reversible. "Simple air space enlargement" in which there is no destruction or loss of orderly appearance of the lung acinus, occurs in the contralateral lung following pneumonectomy(Compensatory overinflation or emphysema). Air spaces, particularly alveolar ducts, enlarge with advancing age, resulting in what has been termed "senile emphysema". Obstructive overinflation results from partial obstruction of a bronchus or bronchiole, when it becomes more difficult for air to leave the alveoli than to enter; there is a gradual accumulation of air distal to the obstruction, the so-called bypass, ball valve, or check valve type of obstruction.

mechanical ventilation. Ruptured blebs can cause spontaneous pneumothorax.

SD,2010).

**4.3.3 Blebs** 

**4.3.4 Cysts** 

**4.3.5 Overinflation** 

These conditions are listed in Table 1.

Intrinsic Obstruction of Major Bronchus:

Compensatory Hyperinflation:

 Tumor—benign or malignant Postinflammatory stricture

Extrapulmonary sequestration

 "Congenital Lobar Emphysema" Intrinsic Obstruction of Bronchioles: Unilateral acquired Bronchitis Bronchiolitis Obliterans

Congenital Malformation of Bronchus:(Defective Cartilage or Mucosal Fold)

Table 1. Conditions with overinflation mimicking Emphysema

 Atelectasis Post-lobectomy

 Foreign body Amyloid

 Tumor Nodes

Extrinsic Obstruction: Congenital Aberrant vessel

It is characterized by hyperinflation of one or more of the pulmonary lobes resulting from congenital deficiency of the bronchial cartilage, external compression by aberrant vessels, bronchial stenosis, redundant bronchial mucosal flaps or kinking of the bronchus caused by herniation into the mediastinum. The disease usually becomes apparent in the neonatal period but are delayed for as long as 5-6 mo in 5% of patients. The disease primarily involves lower lobes and occurs in familial preponderance. Treatment by immediate surgery and excision of the lobe may lifesaving, but some patients respond to medical treatment or selective intubation of the unaffected lung.
