EMPHYSEMA

Emphysema

Emphysema

Introduction

Mphysema is a chronic and irreversible lung condition which affects 4.7/100,000 persons in the United States. The primary cause of emphysema is tobacco smoking; other causes include chronic exposure to toxins and fumes. Some patients are more susceptible to the effects of tobacco smoking than others, suggesting a genetic predisposition to develop chronic obstructive pulmonary disease (COPD) (Ryman, 1999).

Physiology/Pathophysiology

Emphysema is one of a group of conditions called COPD; these diseases obstruct airflow. During inspiration, air enters the lungs through the trachea (windpipe) to reach air passages known as bronchi. Bronchi repetitively branch into progressively smaller and smaller branches (envision an upsidedown tree, without the leaves) until finally reaching thin-walled structures called alveoli (tiny air sacks). The walls of the alveoli interface with the bloodstream (capillaries) where oxygen crosses over the alveolar-capillary membrane to enter the circulation. Oxygen is needed by all organs for normal function; when oxygen transfer ceases to occur, organs die (Treacher, 2000).

In emphysema, destruction of the alveoli occurs through repetitive exposure to toxins such as tobacco smoking; stimulation of inflammation and the action of enzymes (e.g., elastase), cause destruction of the alveolar supporting structures. Without the supporting structures, the alveoli balloon out and oxygen is unable to cross over to enter the bloodstream. The net effect of this is low oxygen in the blood stream, called hypoxemia. Administration of supplemental oxygen can be successful early on in helping to overcome low oxygen levels in the bloodstream, but eventually, as emphysema progresses, this may not be adequate to allow for maintenance of life.

Alpha-1 antitrypsin deficiency is an inherited condition estimated to be responsible for only 1 to 2 percent of all cases of emphysema. These patients lack adequate amounts of the protein responsible for keeping an enzyme called elastase in check; left unchecked, elastase destroys healthy lung tissue. Al-pha-1 antitrypsin is a protein produced by the liver; deficiency of this protein leads to development of emphysema and cirrhosis of the liver. Screening for al-pha-1 antitrypsin should be undertaken in all patients with emphysema as recognition of genetic deficiency of this protein should cause the practitioner to carefully evaluate whether or not the patient should receive artificial supplementation. In addition, development of pulmonary hypertension (elevated blood pressure in the pulmonary blood vessels) commonly develops in patients with emphysema. This is often irreversible and can be quite debilitating, leading to failure of the right side of the heart (also called cor pulmonale). This is a common cause of death in patients with emphysema (Rom 1990).

Signs And Symptoms Of Emphysema

Signs and symptoms of emphysema include shortness of breath (also called dyspnea). Dyspnea is often initially noted only on exertion (i.e., walking, running) however, with progression, eventually will be present at rest. Coughing, with or without phlegm production are frequently noted, as is wheezing (a musical noise sounding similar to a deflating accordion, noted on exhalation). Because patients with emphysema are predisposed to recurrent infections in the lungs, the first time a patient is diagnosed with emphysema may be ...