Symptoms
Among the most common symptoms of lung disorders are cough, shortness of breath (dyspnea), wheezing, and a crowing sound when breathing (stridor). Problems in the lungs can also lead to coughing up of blood (hemoptysis), a bluish discoloration of the skin due to a lack of oxygen in the blood (cyanosis), and chest pain. Prolonged lung disease can even produce changes in other parts of the body, including finger clubbing. Some of these symptoms do not always indicate a respiratory problem. Chest pain, for example, may also result from a heart or gastrointestinal disorder, and shortness of breath can be caused by a heart problem.
Cough
A cough is a sudden, explosive movement of air; the function of a cough is to clear material from the airways.
Coughing, a familiar but complicated reflex, is one way in which the lungs and airways are protected. Along with other mechanisms, coughing helps to protect the lungs from particles that have been inhaled (aspirated). Coughing sometimes brings up sputum (also called phlegm)--a mixture of mucus, debris, and cells expelled by the lungs.
Coughing occurs when the airways are irritated. Respiratory infections--either bacterial or viral--irritate the airways and are a common cause of coughing. Allergies can irritate the airways as well. People who smoke cough because of the irritating effects of the smoke and because of the damage smoking causes to the cells that line the airways, including the hairlike projections that normally cleanse the airways of debris (cilia).
Coughs vary considerably. A cough may be distressing, especially if coughing episodes are accompanied by chest pain, shortness of breath, or unusually large amounts of or very sticky sputum. However, if coughing develops over decades, as it may in a smoker, the person may hardly be aware of it.
Information about a cough helps a doctor determine its cause. Therefore, a doctor may ask:
- How long the cough has been present
- What time of day the cough occurs
- Which factors--such as cold air, posture, talking, eating, or drinking--influence the cough
- Whether the cough is accompanied by chest pain, shortness of breath, hoarseness, dizziness, or wheezing
- Whether the cough brings up sputum or blood
- The color of the sputum
The appearance of the sputum may help the doctor identify the cause. A yellowish, greenish, or brownish appearance usually indicates a bacterial infection. Clear but very sticky (mucoid) sputum is characteristic of asthma. A doctor may examine the sputum microscopically; bacteria and white blood cells seen under the microscope are additional indications of infection. The presence of a specific type of white blood cell (eosinophil) suggests asthma. A cough may also produce blood, which commonly suggests bronchitis, but may also suggest more serious disorders.
Treatment
Because coughing plays an important role in bringing up sputum and clearing the airways, a cough that produces a lot of sputum generally should not be suppressed. Treating the underlying cause--such as an infection, fluid in the lungs, or asthma--is more important. For example, antibiotics can be given for an infection, or inhalers can be used for asthma. Depending on the severity of the cough and its cause, a variety of drugs may be needed for treatment. Many people need to have their coughs suppressed somewhat at night to allow them to sleep.
Antitussive Therapy: Antitussive drugs suppress a cough. All opioids are antitussives because they suppress the cough center in the brain. Codeine is the opioid used most often for cough. Codeine may cause nausea, vomiting, and constipation; it may also be addictive. If codeine is taken for a prolonged period, the dose needed to suppress a cough may need to be increased. Opioid cough suppressants can make people drowsy and are not always safe, and doctors reserve them for special situations.
Several non-opioid cough suppressants, such as dextromethorphan and benzonatate, are effective antitussives that also work by suppressing the cough center in the brain. These drugs, and others, are the active ingredients in many over-the-counter and prescription cough medications (see Section 2, Chapter 18). They are not addictive and produce little drowsiness. In certain people, especially those who are coughing up an abundant amount of sputum, frequent use of these cough suppressants is not recommended.
Steam inhalation, for example from a vaporizer, can help stop a cough by reducing irritation in the throat (pharynx) and airways. The moisture from the steam also loosens secretions, making them easier to cough up. A cool-mist humidifier can achieve the same result. Many doctors believe that drinking sufficient water can produce good hydration and is as effective as steam inhalation for loosening secretions.
Expectorants and Mucolytics: Expectorants help loosen mucus by making bronchial secretions thinner and easier to cough up, although these drugs do not suppress a cough. Over-the-counter preparations containing guaifenesin or terpin hydrate are the most common (see Section 2, Chapter 18). A small dose of syrup of ipecac may help in children, especially in those who have croup.
Drugs that reduce the thickness of mucus (called mucolytics), such as acetylcysteine, are sometimes used when thick, sticky bronchial secretions are a major problem. In cystic fibrosis, dornase alfa (inhaled recombinant human deoxyribonuclease I) is used to help thin the pus-filled mucus that results from chronic respiratory tract infections.
Antihistamines, Decongestants, and Bronchodilators: Antihistamines, which dry the respiratory tract, have little or no value in treating a cough, except when it is caused by an upper airway allergy. With coughs from other causes, such as bronchitis, the drying action of antihistamines can be harmful, thickening respiratory secretions and making them difficult to cough up.
Decongestants such as phenylephrine that relieve a stuffy nose are not useful in relieving a cough, unless the cough is caused by postnasal drip.
Bronchodilators such as inhaled sympathomimetic agents or oral theophylline may be prescribed if a cough occurs with airway narrowing (bronchoconstriction), as happens in asthma and emphysema. They are rarely useful for people who do not have an underlying lung disease. However, some people who develop wheezing and prolonged cough after viral lung infections appear to benefit from short-term use of bronchodilators.
Dyspnea
Dyspnea (also referred to as shortness of breath) is the unpleasant sensation of difficulty in breathing.
An increase in breathing occurs normally during exercise and at high altitudes, but the increase seldom causes discomfort. Breathing is also increased at rest in people with many illnesses, whether of the lungs or of other parts of the body. For example, people with a fever generally breathe faster.
With dyspnea, faster breathing is accompanied by the sensation of running out of air. The person feels a sensation of not being able to breathe fast enough or deeply enough. Other sensations include an awareness of increased muscular effort to expand the chest when breathing in or to expel air when breathing out, the uncomfortable sensation that inhaling (inspiration) is urgently needed before exhaling (expiration) is completed, and various sensations most often described as tightness in the chest.
Types of Dyspnea
People who have lung disease often experience dyspnea when they physically exert themselves. During exercise, the body makes more carbon dioxide and uses more oxygen. The respiratory center in the brain accelerates breathing when blood levels of oxygen are low or blood levels of carbon dioxide are high. If the heart or lungs are not functioning properly, even a little exertion can lead to dramatic increases in breathing rates and dyspnea. As lung disease becomes more severe, dyspnea may even occur at rest.
Dyspnea may result from restrictive or obstructive lung disorders. Restrictive lung disorders (such as idiopathic pulmonary fibrosis (see Section 4, Chapter 50)) cause stiff lungs (lungs that do not expand well during inhalation). Severe curvature of the spine (scoliosis) causes restriction by reducing the movement of the rib cage. In restrictive disorders, dyspnea occurs because of increased effort and a high rate of breathing due to this stiffness. In obstructive disorders (such as chronic bronchitis, emphysema, asthma), resistance to airflow is increased because the airways are narrowed. Because the airways widen when the person inhales, air can usually be pulled in, but that air cannot be exhaled from the lungs as fast as normal, because the airways narrow on exhalation and breathing becomes more labored.
Pulmonary function testing (see Section 4, Chapter 39) can measure the degree of restriction and obstruction. A respiratory problem may include both restrictive and obstructive defects.
Because the heart pumps blood through the lungs, the heart must function properly for the lungs to function normally. If the heart is pumping inadequately, fluid may accumulate in the lungs, a condition called pulmonary edema. This condition causes dyspnea that is often accompanied by a feeling of smothering or heaviness in the chest. The fluid accumulation in the lungs may also lead to airway narrowing and wheezing--a condition called cardiac asthma (see Section 3, Chapter 25).
Orthopnea is shortness of breath when a person lies down that is relieved by sitting up. Some people whose heart pumps inadequately experience this condition. Paroxysmal nocturnal dyspnea is a sudden, often terrifying, attack of shortness of breath during sleep. The person awakens gasping and must sit or stand to take a breath. This condition is an extreme form of orthopnea and a sign of severe heart failure (see Section 3, Chapter 25).
Dyspnea can also occur in people who have anemia or blood loss because of a decreased number of red blood cells, which carry oxygen to the tissues. The person breathes rapidly and deeply, in a reflex effort to try to increase the amount of oxygen in the blood.
Someone with severe kidney failure feels out of breath and may begin to pant quickly because of a combination of metabolic acidosis, heart failure, and anemia.
Hyperventilation syndrome causes people to feel that they cannot get enough air, and they breathe heavily and rapidly. This condition is commonly caused by anxiety rather than a physical problem. Many people who experience this syndrome are frightened and may believe they are having a heart attack. The symptoms result from changes in the blood gas levels (mostly from a lowering of the carbon dioxide level) caused by the overbreathing. People may experience a change in consciousness usually described as a feeling that events occurring around them are far away, and they may experience a tingling feeling in the hands and feet and around the mouth.
Chest Pain
Chest pain may arise from the pleura (the two-layered membrane covering the lungs), the lungs, or chest wall. Alternatively, chest pain may arise from internal structures that are not part of the respiratory system, especially the heart. In these cases, the chest pain does not indicate a lung disorder.
Pleuritic pain, a sharp pain arising from an inflammation of the pleura (pleurisy), is made worse by deep breathing and coughing. The pain can be reduced by keeping the chest wall still--for example, by holding the side that hurts and avoiding deep breathing or coughing. Usually, the site of the pain can be pinpointed, although it may move over time. Pleurisy at the base of a lung may be felt as pain in the shoulder of the affected side. Pleural effusion, a fluid buildup in the space between the two layers of pleura (see Section 4, Chapter 52), may produce pleuritic pain at first, but the pain often subsides as the two layers are separated by accumulating fluid. There are many causes of pleuritic pain, including viral and bacterial infections, cancer, and blood clots that travel through the bloodstream to the lungs (pulmonary embolism (see Section 4, Chapter 46)) lodging in the pulmonary arteries.
Pain arising from other lung disorders (such as a lung abscess or tumor) is usually more difficult to describe than pleuritic pain. The pain is often described as a vague, deep-seated ache in the chest. Almost any injury to the lungs or airways can cause such pain.
Pain can also originate in the chest wall itself. This pain may worsen with deep breathing or coughing and often is confined to one area in the chest wall, which also feels sore when pressed. The most common causes are chest wall injuries, such as broken ribs and torn or injured muscles located between the ribs (intercostal muscles). Even hard coughing can injure these muscles, causing days or weeks of pain. A tumor growing into the chest wall may cause pain in a small spot or, if it grows into an intercostal nerve, may cause pain along the whole area supplied by that nerve (referred pain (see Section 6, Chapter 78)). Shingles, caused by the varicella-zoster virus, sometimes causes chest pain during each breath before the telltale rash appears (see Section 18, Chapter 198).
Wheezing
Wheezing is a whistling, musical sound during breathing resulting from partially obstructed airways.
Wheezing results from an obstruction somewhere in the airways. It may be caused by a general narrowing of the airways (as in asthma or chronic obstructive pulmonary disease), by a local narrowing (as with a tumor), or by a foreign particle lodged in an airway. The most common cause of recurrent wheezing is asthma, although many people who have never had asthma wheeze at some time in their lives.
A doctor usually is able to detect wheezing by listening with a stethoscope as the person breathes. Loud wheezing can be heard easily without a stethoscope. When wheezing is caused by a local narrowing, the doctor may detect a vibration that accompanies the wheezing by palpating the chest wall over the area of obstruction (such as a tumor or a foreign object) when the person breathes forcefully. A persistent wheeze that occurs in one location in a smoker may be due to lung cancer, and even if a chest x-ray is unrevealing, doctors may perform bronchoscopy (see Section 4, Chapter 39). Pulmonary function testing (see Section 4, Chapter 39) may be needed to help measure the extent of airway narrowing and to assess the benefits of treatment.
Stridor
Stridor is a crowing sound during breathing resulting from a partial blockage of the throat (pharynx), voice box (larynx), or windpipe (trachea); stridor is often more evident when the person inhales.
Stridor is usually loud enough to be heard at some distance, but it may be audible only during a deep breath. The sound is caused by turbulent airflow through a narrowed upper airway. In children, the cause may be an infection of the epiglottis (see Section 23, Chapter 272) or an inhaled foreign object. In adults, the cause may be a tumor, an abscess, swelling (edema) in the upper airway, or a malfunction of the vocal cords.
Stridor causing dyspnea when the person is at rest is a medical emergency. In such cases, a tube may be inserted through the person's mouth or nose (tracheal intubation) or by a small surgical incision directly into the trachea (tracheostomy) to allow air to get past the blockage and avoid suffocation.
Hemoptysis
Hemoptysis is the coughing up of blood from the respiratory tract.
Although hemoptysis can often be frightening, most causes turn out not to be serious. Infection is the most common cause. Unexplained or large amounts of blood in the sputum require evaluation by a doctor.
Tumors, especially those due to lung cancer, account for up to 20% of cases of hemoptysis. Doctors check for lung cancer in smokers older than 40 (and even in younger smokers if the person started smoking in adolescence) who develop hemoptysis, even if the sputum is only blood streaked. Death of lung tissue (see Section 4, Chapter 46)) from blockage of an artery by a blood clot (pulmonary embolism) may also cause hemoptysis.
Sometimes, especially in people who are critically ill, a catheter is placed into the pulmonary artery to measure the blood pressure in the heart and in the blood vessels of the lungs. If the balloon on the catheter ruptures the vessel, bleeding can become very severe. High blood pressure in the pulmonary veins, as may occur in heart failure and mitral valve stenosis, may also cause hemoptysis. Other lung circulation problems, including arteriovenous malformations, may cause hemoptysis.
Diagnosis
If hemoptysis is severe or unexplained, a diagnostic evaluation is necessary. Bronchoscopy may be needed to identify the bleeding site. A scan using a radioactive marker (lung perfusion scan (see Section 4, Chapter 46)) may reveal a pulmonary embolism. Despite testing, the cause of hemoptysis is not found in 30 to 40% of cases; however, when hemoptysis is severe, the cause is usually found.
Treatment
Mild hemoptysis may require no treatment or only antibiotics to treat an infection. Bleeding may produce clots that block the airways and lead to further breathing problems; therefore, coughing is important to keep the airways clear and should not be suppressed with antitussive drugs. If a large clot blocks a major airway, doctors may have to remove the clot using bronchoscopy.
Bleeding from smaller vessels usually stops by itself. However, bleeding from a major vessel usually requires treatment. A doctor may try to close off the bleeding vessel using a procedure called bronchial artery embolization. Using x-rays for guidance, the doctor passes a catheter into the vessel and then injects a chemical, fragments of a gelatin sponge, or a wire coil to block the blood vessel and thereby stop the bleeding. Bleeding caused by an infection or heart failure usually subsides if the underlying disorder is treated successfully. Sometimes bronchoscopy or surgery may be needed to stop the bleeding, or surgery may be needed to remove a diseased portion of the lung. These high-risk procedures are used only as last resorts. If clotting abnormalities are contributing to the bleeding, a transfusion of plasma, clotting factors, or platelets may be needed.
Cyanosis
Cyanosis is a bluish discoloration of the skin resulting from an inadequate amount of oxygen in the blood.
Cyanosis occurs when oxygen-depleted blood, which is bluish rather than red, circulates through the skin. Cyanosis can be caused by many types of severe lung or heart disease that produce low levels of oxygen in the blood. It can also result from certain blood vessel and heart malformations that allow blood to flow directly into veins returning blood from the lungs to the heart or into the left side of the heart. A bypass (shunt) exists if a malformation returns blood directly to the heart without ever flowing past the air sacs of the lung (alveoli) where oxygen is extracted from the air.
The amount of oxygen in the blood can be determined by arterial blood gas analysis (see Section 4, Chapter 39). Chest x-rays, blood flow studies, and lung and heart function tests may be needed to determine the cause of decreased oxygen in the blood and the resulting cyanosis. Pulse oximetry, which utilizes an electrode clipped on a finger or an earlobe, allows the doctor to continuously monitor the oxygen concentration in a person who is critically ill. Oxygen therapy is often the first treatment given.
Finger Clubbing
Finger clubbing is an enlargement of the tips of the fingers or toes and a loss of the angle where the nails emerge.
Finger clubbing occurs when the amount of soft tissue beneath the nailbeds increases. The reason this increase occurs is not clear, but clubbing seems to occur with some pulmonary disorders (lung cancer, lung abscess, bronchiectasis), but not with others (pneumonia, asthma, emphysema). Finger clubbing also occurs with some congenital heart diseases or, in some cases, may be inherited and not indicate any disease.
 See the figure Recognizing Finger Clubbing.
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