Emphysema is a form of chronic obstructive pulmonary disease (COPD), which involves enlarged air spaces and destroyed alveoli in the lungs. Panacinar emphysema refers to the uniform destruction of the whole air sac or alveolus. It can occur among smokers, but it is mostly observed among patients who have the genetic disorder called alpha 1-antitrypsin (AAT) deficiency. In general, panacinar emphysema and the other types of emphysema are irreversible diseases that lead to permanent airflow limitation. Treatment involves long-term therapy with bronchodilators and/or steroids.
Pathologists who examine lung biopsy samples usually do the differentiation of panacinar emphysema from other types of emphysema. Panacinar emphysema involves the entire alveolus and is found in the bases of the lungs. Centriacinar or centrilobular emphysema involves the respiratory bronchioles first, then spreads to the alveoli. Paraseptal emphysema involves the alveolar sacs, ducts, and terminal bronchioles, but the involvement is adjacent to lung septae or lung pleura.
Cigarette smoking is usually the cause of emphysema. Among COPD patients, the causal relationship between smoking and emphysema is evident, with 80 to 90% admitting to being long-term smokers. The AAT deficiency syndrome, which is due to the deficient production of alpha 1-antitrypsin, is a genetic disorder that causes emphysema. Alpha 1-antitrypsin is an enzyme that inhibits the action of elastase, the enzyme that degrades elastin. This leads to net alveolar wall breakdown and panacinar emphysema.
Less common causes of emphysema include aging, intravenous drug use, and immunodeficient states such as human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), and autoimmune diseases. In particular, intravenous injections of methadone and methylphenidate have been shown to result in panacinar emphysema. Connective tissue diseases, such as Marfan syndrome, also increase the risk of emphysema.
Panacinar emphysema follows the general pathophysiology of emphysema. Exposure to noxious stimuli, such as cigarette smoke and pollution, precedes emphysema development. These noxious substances stimulate an inflammatory response, leading to release of various inflammatory mediators such as white blood cells, and substances such as cytokines, that destroy the lung parenchyma. Proteases, which are enzymes that break down proteins, are also released, and these proteases break down elastin, an important protein in the alveolar walls. With elastin breakdown, the alveoli lose their elasticity and recoil, the air spaces become permanently enlarged, and the airways become narrowed.
When emphysema is diagnosed, staging is done to determine the appropriate emphysema treatment and emphysema prognosis. The most important measure in emphysema treatment is to totally avoid any form of lung irritation, particularly cigarette smoke. Symptomatic relief of difficulty of breathing, chronic cough, and abundant phlegm production is achieved through medications like bronchodilators, anticholinergics, and corticosteroids. Bronchodilators include salbutamol and formoterol, anticholinergics include ipratropium, and steroids include fluticasone and budesonide. Emphysemic patients may need supplemental oxygen.
Emphysema and pneumonia can occur at the same time. Symptoms of pneumonia in an emphysemic patient include acute difficulty of breathing, increased severity of cough, and increased thickness and amount or a change in color of phlegm. When pneumonia occurs in conjunction with emphysema, antibiotics are given and steroids are stopped in order to eradicate the pneumonia-causing organism.