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Wheezing and Breathing Difficulty
Chronic Lung Disease
The basic function of the lungs is to exchange oxygen in the air we breathe in and carbon dioxide dissolved in the blood. The inspired air and the blood in the lungs are separated by a very thin membrane ideally suited to exchange these gases. As we age the total airflow into and out of the lungs (vital capacity) decreases and the lungs become less elastic. These and other changes increase the likelihood that we will experience age-related lung conditions.
The cough is part of the body's normal respiratory defenses. Coughing is usually caused by respiratory infections that resolve in a short time. If the cough lasts more than three to four weeks, however, it is considered a persistent cough.
Smokers are most likely to have a persistent cough, but, unfortunately, older smokers are less likely to seek medical attention for it. Persistent cough in people with no previously known lung disease and whose lungs look normal on chest X rays is usually discovered by careful examination.
A persistent cough is usually due to one of four things: airways that are very reactive (asthma), postnasal drip, chronic bronchitis, and the regurgitation of liquids and other materials from the stomach into the lungs (aspiration). Less common causes include heart failure, lung disease, and drugs.
Cough has been associated with some drugs, specifically those widely used for treating high blood pressure and heart failure, called angiotensin-converting enzyme inhibitors. Individuals who develop a cough while taking these medications should notify their physician for a substitute medication. Another class of drugs, called beta-adrenergic blockers, also used for treating high blood pressure may provoke coughing as a result of mild airway obstruction, but this is relatively uncommon.
Causes for a persistent cough can best be identified through a physical examination and interview with the primary physician. Additional testing, such as looking into the lungs with an instrument called a fiber-optic bronchoscope, is not usually necessary but can sometimes provide useful information. The treatment of cough depends upon its cause. Stopping smoking is also very important. Medication adjustment can be helpful.
The air we breathe normally passes through flexible little tubes with thin muscular walls in our lungs. These little airways can contract when they are irritated, which makes it more difficult to exhale (see Figure 33). When we try to force air through these constricted passages, we produce a sound called a wheeze. Wheezing implies a spasm of the muscles in the airways, which causes a temporary obstruction of airflow.
Breathing difficulty refers to a shortness of breath with very minimal activity or an inability to sleep flat in bed without becoming breathless.
Whereas wheezing can be due to lung problems, such as allergic asthma and chronic obstructive pulmonary disease, not all causes of wheezing or breathing difficulty are due to disease in the lungs. Congestive heart failure is an important exception. In heart failure, the fluid pressure in the lungs increases, causing water and salt solutions to leak into the lungs. This can overwhelm the lungs' ability to drain themselves and narrow the airways by pushing on them. People with this condition may have symptoms resembling that of a person with asthma--wheezing, chest tightness, sweating, and a gray complexion, but it is important to remember that these symptoms are more apt to be caused by heart failure in older people. Recurrent aspiration of stomach contents can cause intermittent wheezing that also mimics asthma. In addition, blood clots in the lungs can produce shortness of breath and sometimes wheezing (see Figure 34). Because these other conditions are also potentially life-threatening, any older person with wheezing should ask a physician to undertake a careful evaluation.
The physician's evaluation includes an examination of the lungs and heart. An X ray of the chest is sometimes obtained, and blood tests and an electrocardiogram are frequently ordered.
The basic treatment of wheezing caused by asthma is to open the airways with medications chemically related to adrenaline and to reduce the reactive nature of the airways. Wheezing and breathing difficulty due to other causes, such as congestive heart failure, respond to appropriate treatment of the underlying condition.
Difficulty in expelling air from the lungs is a common element of a number of disorders known as chronic obstructive pulmonary disease (COPD). These disorders include emphysema, chronic bronchitis, and asthma. In elderly people, it may be very difficult to distinguish the symptoms and physical signs of asthma from those of the less treatable disorders, emphysema and chronic bronchitis.
Emphysema is a condition where the small air spaces in the lungs are destroyed, leaving the lungs with large holes like Swiss cheese (see Figure 33). Chronic bronchitis is the clinical description of a condition wherein a person coughs up sputum (mucus or phlegm) every day for at least three months during two consecutive years. If strictly applied, this description applies to 50 percent of smokers. In a small proportion of people with chronic bronchitis there is difficulty in removing air from the lungs. This is caused by the thickening of the lining of the airways and the presence of secretions, which are often colonized with bacteria. While all these conditions seem clear-cut, most people have combinations of emphysema and chronic bronchitis; relatively few people have pure cases of one or the other.
Smoking is the primary cause in the overwhelming majority of people with COPD. Hereditary factors and certain occupations may also play a role or can also predispose a person to COPD.
The person with COPD usually has a history of cigarette smoking, complains of being short of breath on exertion, and has higher levels of coughing and sputum production. The onset of these symptoms is hard to pinpoint, and the progression of symptoms is usually slow. The degree of airflow limitation may go undetected until another illness adds an additional burden on the respiratory system. Sometimes people with COPD develop a very large barrellike chest and it takes them a long time to empty their lungs of air with each breath.
There are a number of tests available to detect COPD. The most useful and one of the simplest testing devices is called a spirogram. As a person breathes in and out of the spirogram, it measures the amount of air in the lungs as well as the emptying rate of the lungs. Additional tests include taking blood samples from an artery (usually in the wrist) to determine the amount of oxygen, carbon dioxide, and acid in the blood.
A person can be diagnosed as having asthma if the physician can demonstrate that the breathing difficulty can be corrected (reversed). This normally involves using the spirogram before and after the patient has inhaled medication that opens up the airways. An improvement of about 15 percent on the spirogram test indicates that the airways are responding to the medication, and therefore the breathing condition is asthma. There is also a test to attempt to provoke asthma, where the patient inhales a substance known to constrict the airways. If the lung function falls by 20 percent, the airways are reacting--in this case by constricting--and can therefore be treated. These different tests of airway responsiveness do not completely overlap, and a person may show that breathing capacity can be affected by one test but not on the other. Asthma occurs much more commonly in older people than originally thought. Recent studies have documented that between 15 and 50 percent of older people may have airway obstruction that can be successfully treated.
The treatment of COPD aims to maintain independent function of the person by avoiding infections and additional lung injury. Stopping cigarette smoking is very important. Drug treatment can reduce wheezing, cough, and sputum production, and can improve shortness of breath.
With an increasing number of new medications available for the treatment of COPD, one would expect that the disability and death rate of the disorder would decline. In fact, the death rate due to COPD has increased not only in the United States but throughout the world. The reasons for this increase are unknown, but some people feel that the marked increase in cigarette smoking following World War II may play an important role. Other environmental pollutants such as ozone, other gases containing nitrogen, sulfur dioxide, carbon monoxide, and small particles of dust also have an effect on lung function.
Aspiration of liquid and other materials into the airways can be a serious problem. When substances such as bacteria from the mouth, stomach contents, or foreign bodies are aspirated, they may produce local irritation of the air passages or progress to pneumonia (see page 346). Actually, everyone aspirates small amounts of saliva and oral bacteria, but the body's immune system usually prevents infection. When the amount aspirated is too great for the immune system to deal with, or when the body is already weakened, the resulting lung infection can be serious.
Important predisposing factors for serious aspiration include recent stroke, seizure disorder, alcohol abuse, general anesthesia, any chronic illness that produces debilitation, and tubes placed in the airways or stomach for breathing or feeding.
The symptoms of aspiration can be subtle, but may include rapid breathing, fever, wheezing, or breathing that is more difficult at night (as aspiration is more common while lying down).
While aspiration is not entirely preventable, one can decrease the chances of significant aspiration by keeping the head and shoulders slightly elevated at all times, especially at night, and minimizing drugs that decrease the level of consciousness such as alcohol, antihistamines, or other sedatives.
At the turn of the 20th century a leading scientist could find only 374 reported cases of lung cancer in the entire world. Today, lung cancer is the leading cause of cancer death in the United States; half of all lung cancers occur in elderly people. Lung cancer can arise from the cells that line the lung's airways (the bronchi and bronchioles) or the cells that form the lung tissue.
Cigarette smoking causes 80 to 90 percent of all lung cancers. Other risk factors include exposure to ionizing radiation and numerous occupational hazards, including exposure to asbestos and uranium. People who stop smoking immediately lower their risks and can eventually reduce their cancer risks to that of nonsmokers.
Lung cancer usually produces symptoms that are not immediately noticed, but lead to its eventual detection. Most of the symptoms are not very specific and are sometimes ignored or inappropriately considered to be part of another illness. For example, a persistent cough may be initially attributed to bronchitis. Any new symptom in an elderly smoker raises the possibility of lung cancer (see Table 30).
For practical purposes, lung cancers are divided into two major groups based on the way they appear under the microscope. Smallcell lung cancers constitute about one-fourth of cases while the remaining three-fourths are called non-small-cell cancers.
Surgery is the only form of life-prolonging treatment for non-small-cell lung cancers; therefore, any evaluation of the severity and extent of the disease is aimed at establishing whether or not the tumor can be removed surgically. To determine this, the physician considers the combined results of a physical examination, blood analysis, a bone scan, and special X rays of the chest to determine the spread of the tumor. Sometimes special X rays of the brain are also taken, because this type of cancer frequently spreads to the nervous system and brain.
For small-cell lung cancer, the physician's first goal is to take X rays of the brain in order to establish whether the disease is limited to one area or is widespread. This distinction is important because it determines both treatment options as well as the person's likely survival. In limited disease spread, all of the detected cancer is confined to a single part of the chest that can receive radiation therapy. In extensive disease spread, the tumor cannot be effectively irradiated. Radiation therapy appears to work by producing chemical substances in the radiated tissues called free radicals. These chemicals interact with the cell DNA, leading to cell death. A problem with radiation therapy is that normal cells as well as tumor cells are affected. Another form of cancer treatment is to use anticancer drugs (chemotherapy) that kill cancer cells, but they also can cause problems for normal cells. Although chemotherapy alone or in combination with radiation therapy to the chest is the standard treatment for small-cell lung cancer, these two regimens can be difficult for an older person to tolerate. It is controversial whether radiation of the brain can help reduce the spread of the tumor. In individuals with lung cancer who are over the age of 65, brain irradiation has been associated with progressive dementia.
Table 30. Symptoms of Lung Cancer
Pneumonia, an infection of the lungs, is the fifth leading cause of death by disease in the United States. It is the most common cause of death in very elderly people and is found in about half of elderly individuals at autopsy. Pneumonia is 50 times more likely to develop in a person who is hospitalized or in a nursing home compared with a person living at home.
The symptoms and causes of pneumonia, the course of the illness, and the mortality rate of pneumonia are significantly different for old people compared with young people. Table 31 summarizes some of the contrasting features between young and old pneumonia patients. Older people are more likely to have unusual symptoms, a more rapid decline, and a higher death rate. It is important for you to know that vaccinations for influenza and pneumonia caused by pneumococcus are available. (Prevention of pneumonia is discussed on page 44.)
Table 31. Contrasting Features of Pneumonia Between Young and Older People
The organisms that produce pneumonia in older people are not always the same as those responsible for pneumonia in younger people. No single organism can be identified as the cause of pneumonia in half of the cases of pneumonia.
Infectious organisms reach the lungs either by inhalation or by aspiration of liquid from the mouth or stomach. Examples of pneumonia caused by breathing in the infectious organisms are tuberculosis, influenza virus, and legionella (the organism producing Legionnaires' disease). Most organisms producing pneumonia get to the lungs by aspiration (see page 344 for a discussion of aspiration).
The typical symptoms of pneumonia are fever, cough, and sputum production; these occur in older people but may be subtle or even absent. A sudden change in mental function can be an early clue.
Initially, most older people with pneumonia require hospitalization. Antibiotic therapy is usually given without knowing specifically which organisms are causing the pneumonia. Appropriate changes are made when laboratory data suggest a particular organism. Individuals can be managed in the nursing home if (1) they are stable, (2) there is 24-hour-a-day monitoring by experienced nursing personnel, (3) a laboratory is readily accessible, and (4) a physician is available on a regular basis to see them.
Tuberculosis is an infection caused by mycobacterium tuberculosis. This has lived with man throughout history as evidenced by findings in Egyptian mummies and prehistoric remains. Tuberculosis (from the Latin, meaning "swelling") was named because it forms hard nodules (tubercles). The infection most often involves the lungs but other body organs can be affected.
People who are over the age of 65 account for approximately 30 percent of the newly diagnosed cases of tuberculosis each year in the United States. In this age group, 85 to 90 percent of the tuberculosis cases are to be found among community-living individuals and about 10 to 15 percent are among nursing home patients. However, institutionalized older people have an increased likelihood of developing tuberculosis.
The majority of cases of active tuberculosis occurs in people over age 65 that were infected 50 to 70 years ago when 80 percent of people were infected before age 30. Most of these people carry the tuberculosis organism in their bodies where it remains dormant until changes in the immune system reactivate it. Conditions leading to this reactivation include malnutrition, diabetes mellitus, smoking, alcohol abuse, malignancy, or other serious illness.
The older person with tuberculosis often has very vague symptoms, such as weakness, fatigue, cough, and weight loss.
The infection is often discovered only when the physician or health care personnel suspect that it is present and attempt to confirm this suspicion with a series of tests. A skin test is extremely helpful in determining if the infection is present, but its application and interpretation may not be conclusive for the older person. A chest X ray is usually obtained to check for any abnormalities that are consistent with tuberculosis. Sputum is sent to the laboratory for testing. If the results of these procedures are inconclusive, other tests may be necessary.
The treatment of active tuberculosis in the older person is the same as that for the general population. Isoniazid and rifampin is the combination of medication usually given for six to nine months. There are, however, other medications used to treat tuberculosis.