Bullous emphysema: Description, Causes and Risk Factors:
As we all know, when we breathe, the air passes through the nose and then enters the windpipe and eventually travels down to the bronchial tubes. These bronchial tubes perform an important task of regulating flow of the air in the lungs. The air inhaled moves in and out of the lungs through these bronchial tubes. A close examination of the respiratory system reveals that the bronchial tubes form a tree like structure inside the lungs. The two bronchi that enter the left and right lungs respectively, branch out, thus making way for smaller bronchial tubes. These subdivisions of the bronchial tubes terminate at a point known as air sacs (alveoli) that appear like a bunch of grapes. Believe it or not but our lungs contain over 600 million alveoli.
Bullous lung disease is an entity characterized by the presence of bullae (an elevation of the skin filled with serous fluid) in one or both the lung fields, with normal intervening lung. On the other hand, bullous emphysema is the presence of bullae in a patient with chronic obstructive pulmonary disease (COPD) and is characterized by the presence of centrilobular emphysema in the nonbullous lung.
In most cases, people diagnosed with bullous emphysema have the habit of smoking. Viral or bacterial infections of the lungs such as bronchitis can also lead to bullous emphysema. In chronic bronchitis, the tubes through which air freely moves to and from the lungs do not work properly. This is because in this condition the walls of the tubes are swollen, thus narrowing the air passages in the lungs. Thus, inhaling air through partially blocked airways can also make the air sacs inflamed. Air pollution is yet another issue, we face in our day-to-day life, that can damage the lungs and eventually cause bullous emphysema.
Most people with bullous emphysema experience shortness of breath, wheezing, coughing up phlegm, and centralized pain in their chests, especially when engaging in physical activity. Some patients suffer from nausea, loss of appetite, and fatigue as a result of constant breathing problems. Lowered oxygen levels in the blood can result in heart problems, weakness, and discoloration of the fingernails and toenails.
Diagnosis of bullous emphysema begins with a medical history and physical examination.
Chest Examination: The physician will next perform a simple examination of the chest area with a stethoscope to listen for:
Crepitations, a noise resembling a paper bag being rumpled.
Spirometry: Spirometry measures the volume and force of air as it is exhaled from the lungs. It measures airway obstruction, can identify COPD early, and the results are standardized so they are always consistent.
The patient is asked to breathe in and to exhale forcefully into an instrument. This is repeated several times. The force of the air is then measured. From the results, the physician determines two important values:
The forced vital capacity (FVC): FVC is the maximum volume of air that can be exhaled (breathed out) with force, and is an indicator of lung size, elasticity, and how well the air passages open and close.
The forced expiratory volume in one second (FEV1): FEV1 is the maximum volume of air exhaled in 1 second. Airflow is considered to be limited if the outflow of forced exhalation stays low over the course of 1 second. People with COPD have a decline in FEV1 over time. FEV1 is measured as "percent of predicted:"
Tests for Measuring the Ability of the Lung to Exchange Oxygen and Carbon Dioxide:
Arterial Blood Gas: The physician may request an arterial blood gas test to determine the amount of oxygen and carbon dioxide in the blood (its saturation). Low oxygen (hypoxia) and high carbon dioxide (hypercapnia) levels often indicate chronic bronchitis, but not always bullous emphysema. A blood gas analysis that shows very low oxygen levels is useful for determining which patients would benefit from oxygen therapy. This procedure typically involves drawing blood from an artery in the wrist.
Pulse Oximetry Test: A safe and painless test for measuring oxygen in the blood is called pulse oximetry, which involves placing a probe on the finger or ear lobe. The probe emits two different lights, and the amount of each light the blood absorbs is related to how much oxygen the red blood cells carry. This test measures only oxygen in the blood, however, and not carbon dioxide. Results should be taken together with other tests to determine the need for medication or oxygen therapy.
Carbon Monoxide Diffusing Capacity: The DLCO (diffusing capacity of lung for carbon monoxide) test determines how effectively gases are exchanged between the blood and airways in the lungs. Patients should not eat or exercise before the test, and they should not have smoked for 24 hours. The patient inhales a mixture of carbon monoxide, helium, and oxygen and holds his or her breath for about 10 seconds. The gas levels are then analyzed from the exhaled breath. Results can help physicians differentiate emphysema from chronic bronchitis and asthma. Patients with emphysema have lower DLCO results, indicated by a reduced ability to take up oxygen. Such results are also important in helping to determine appropriate candidates for lung reduction surgery. Carbon monoxide levels that are 20% or less than predicted values pose a very high risk for poor survival.
Exhaled Breath: The measurement of nitric oxide (NO) in exhaled breath can be a simple method of diagnosing COPD and monitoring the effects of therapy. In most patients with COPD, no levels are below normal. Levels above normal in a patient with COPD indicate that the person also has asthma.
In order to determine the size or extent of damage to air sacs, CT scans may be used. Once diagnosed, a patient with bullous emphysema will be given an individualized treatment plan.
Although, bullous emphysema treatment depends upon the underlying condition, the main aim is to decrease the inflammation of the air sacs and correct the disturbed airflow of the lungs. If a patient smokes, they are directed to quit immediately. Oral or steroid inhalers may be prescribed. Supplemental oxygen is sometimes used. Bacterial infections of the lungs caused by bullous emphysema are usually treated with antibiotics. In order to reduce the size of the inflamed air sacs, steroids in the form of inhalers, might be prescribed. If bullous emphysema has reached the advanced stage, the person may suffer from collapsed lungs, a condition in which there is abnormal accumulation of air in the space between the chest wall and the lungs. This restricts the ability of lungs to enlarge while breathing. Doctors consider this condition as a serious problem and in such cases a surgery is performed to remove the abnormal air build up.
Bullectomy either via video-thoracoscopy or conventional thoracotomy is the treatment of choice for giant bullous lung disease, even is asymptomatic. Bullectomy is indicated for symptomatic patients who have incapacitating dyspnea or chest pain, and who have complications related to the bullous disease.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.