The most common type of emphysema associated with alpha-1 antitrypsin deficiency?
Ans. C. Panacinar.(Ref. H-17th/pg. 1638)EMPHYSEMA# Emphysema is characterized by destruction of gas-exchanging airspaces, i.e., the respiratory bronchioles, alveolar ducts, and alveoli. Their walls become perforated and later obliterated with coalescence of small distinct airspaces into abnormal and much larger airspaces.# Macrophages accumulate in respiratory bronchioles of essentially all young smokers. Bronchoalveolar lavage fluid from such individuals contains roughly five times as many macrophages as lavage from non- smokers.# In smokers' lavage fluid, macrophages comprise >95% of the total cell count, and neutrophils, nearly absent in nonsmokers' lavage, account for 1-2% of the cells. T lymphocytes, particularly CD8+ cells, are also increased in the alveolar space of smokers.Emphysema is classified into distinct pathologic types, the most important being centriacinar and panacinar:A. Centriacinar emphysema:a. The type most frequently associated with cigarette smoking.Qb. Characterized by enlarged airspaces found (initially) in association with respiratory bronchioles.c. Most prominent in the upper lobes and superior segments of lower lobes and is often quite focal.QB. Panacinar emphysema:a. refers to abnormally large airspaces evenly distributed within and across acinar units.b. Panacinar emphysema is usually observed in patients with alAT deficiency.c. Has a predilection for the lower lobes.d. However, garden-variety smoking-related emphysema is usually mixed, particularly in advanced cases, and these pathologic classifications are not helpful in the care of patients with COPD.The pathogenesis of emphysema can be dissected into four interrelated events:1) Chronic exposure to cigarette smoke may lead to inflammatory cell recruitment within the terminal airspaces of the lung.2) These inflammatory cells release elastolytic proteinases which damage extracellular lung matrix3) Loss of matrix-cell attachment leads to apoptosis of structural cells of the lung.4) Ineffective repair of elastin and perhaps other extracellular matrix components result in airspace enlargement that defines pulmonary emphysema.Lab findings FINDINGS:# Pulmonary function testing shows airflow obstruction with a reduction in FEV1 and FEV1/FVC.# Radiographic studies may assist in the classification of the type of COPD. Obvious bullae, paucity of parenchymal markings, or hyperlu cency suggest the presence of emphysema. Increased lung volumes and flattening of the diaphragm suggest hyperinflation but do not provide information about chronicity of the changes.# CT scan is the current definitive test for establishing the presence or absence of emphysema in living subjects . From a practical perspective, the CT scan does little to influence therapy of COPD except in those individuals considering surgical therapy for their disease.# Recent guidelines have suggested testing for alAT deficiency in all subjects with COPD or asthma with chronic airflow obstruction. Measurement of the serum alAT level is a reasonable initial test. For subjects with low alAT levels, the definitive diagnosis of alAT deficiency requires PI type determination. This is typically performed by isoelectric focusing of serum.Rx:# Only three interventions--smoking cessation, oxygen therapy in chronically hypoxemic patients, and lung volume reduction surgery in selected patients with emphysema--have been demonstrated to influence the natural history of patients with COPD.# There is currently suggestive, but not definitive, evidence that the use of inhaled glucocorticoids may alter mortality.
Centraacinar
Panlobular
Panacinar
Irregular
Respiration