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ASTHMA REVIEW | Learn more about Asthma
What is asthma?
Physicians in ancient Greece used the word "asthma" to describe breathlessness or gasping. They believed that asthma was derived from internal imbalances, which could be restored by healthy diet, plant and animal remedies, or lifestyle changes. Asthma is a chronic inflammation of the bronchial tubes [bronchi/airways] that causes swelling and narrowing of the airways. The result is difficulty breathing. The bronchial narrowing is usually either totally or at least partially reversible with treatments. Signs and symptoms include shortness of breath, chest tightness, cough and wheezing. Asthma involves only the bronchial tubes and does not affect the air sacs [alveoli] or the lung tissue [the parenchyma of the lung] itself. Bronchial tubes that are chronically inflamed may become overly sensitive to allergens (specific triggers) or irritants (nonspecific triggers). The airways may become "twitchy" and remain in a state of heightened sensitivity. This is called "Bronchial Hyperreactivity" (BHR). It is likely that there is a spectrum of bronchial hyperreactivity in all individuals. However, it is clear that asthmatics and allergic individuals (without apparent asthma) have a greater degree of bronchial hyperreactivity than non-asthmatic and nonallergic people. In sensitive individuals, the bronchial tubes are more likely to swell and constrict when exposed to triggers such as allergens, tobacco smoke, or exercise. Amongst asthmatics, some may have mild BHR and no symptoms while others may have severe BHR and chronic symptoms.
Most Prescribed Medications [Sorted by Popularity]
Prednisone®, Deltasone®, Serevent®, Advair Diskus®, Albuterol®, Ventolin®, Proventil®, Fluticasone & Salmeterol oral inhaler, Advair Diskus, Singulair®, Pulmicort inhaler, Aristocort®, Quibron-T®, CROMOLYN-INHALATION CAPSULES
Normal Bronchial Tubes
Before we can appreciate how asthma affects the bronchial airways, we should first take a quick look at the structure and function of normal bronchial tubes.
The air we breathe in through our nose and mouth passes through the vocal cords (larynx) and into the windpipe (trachea). The air then enters the lungs by way of two large air passages (bronchi), one for each lung. The bronchi divide within each lung into smaller and smaller air tubes (bronchioles), just like branches of an inverted tree. Inhaled air is brought through these airways to the millions of tiny air sacs (alveoli) that are contained in the lungs. Oxygen (O2) passes from the air sacs into the bloodstream through numerous tiny blood vessels called capillaries. Similarly, the body's waste product, carbon dioxide (CO2), is returned to the air sacs and then eliminated upon each exhalation.
Normal bronchial tubes allow rapid passage of air in and out of the lungs to ensure that the levels of O2 and CO2 remain constant in the blood stream. The outer walls of the bronchial tubes are surrounded by smooth muscles that contract and relax automatically with each breath. This allows the required amount of air to enter and exit the lungs to achieve this normal exchange of O2 and CO2. The contraction and relaxation of the bronchial smooth muscles are controlled by two different nervous systems that work in harmony to keep the airways open.
The inner lining of the bronchial tubes, called the bronchial mucosa, contains: (1) mucus glands that produce just enough mucus to properly lubricate the airways; and (2) a variety of so-called inflammatory cells, such as eosinophils, lymphocytes, and mast cells. These cells are designed to protect the bronchial mucosa from the microorganisms, allergens, and irritants we inhale, and which can cause the bronchial tissue to swell. Remember, however, that these inflammatory cells are also important players in the allergic reaction. Therefore, the presence of these cells in the bronchial tubes causes them to be a prime target for allergic inflammation.
People with asthma also frequently "cough" in an attempt to expel the thick mucus plugs. Reducing the flow of air may result in less oxygen passing into the bloodstream and if very severe, carbon dioxide may dangerously accumulate in the blood.
Why inflammation is so important?
Swelling, or inflammation, is a typical response of the body to injury or infection. The blood flow increases to the affected site and cells rush in and ward off the offending problem. The healing process has begun. Usually, when the healing is complete, the inflammation subsides. Sometimes, the healing process causes scarring. The central issue in asthma, however, is that the inflammation does not resolve completely on its own. In the short term, this results in recurrent "attacks" of asthma. In the long term, it may lead to permanent thickening of the bronchial walls, called airway "remodeling." If this occurs, the narrowing of the bronchial tubes may become irreversible and poorly responsive to medications. Therefore, the goals of asthma treatment are: (1) in the short term, to control airway inflammation in order to reduce the reactivity of the airways; and (2) in the long term, to prevent airway remodeling.
What boosts an asthma attack?
There is a number of agents that may activate or aggravate asthma symptoms. Not all asthmatics react to the same triggers. Additionally, the effect that each trigger has on the lungs varies from one individual to another. In general, the severity of your asthma depends on how many agents activate your symptoms and how sensitive your lungs are to them. Most of these triggers can also worsen nasal or eye symptoms. Triggers fall into two categories: Allergens ("specific"), Nonallergens - mostly irritants (nonspecific). Once your bronchial tubes (nose and eyes) become inflamed from an allergic exposure, a re-exposure to the offending allergens will often activate symptoms. These "reactive" bronchial tubes might also respond to other triggers, such as exercise, infections, and other irritants.
Common Asthma Triggers
- Allergens -"Seasonal" pollens;
- Year-round dust mites, molds, pets, and insect parts; Foods, such as fish, egg, peanuts, nuts, cow's milk, and soy;
- Work-related agents -Latex;
- Irritants -Respiratory infections, such as those caused by viral "colds," bronchitis, and sinusitis;
- Drugs -Aspirin, other NSAIDs (nonsteroidal antiinflammatory drugs), and beta blockers (used to treat blood pressure and other heart conditions);
- Tobacco smoke -Outdoor factors, such as smog, weather changes, and diesel fumes; Indoor factors, such as paint, detergents, deodorants, chemicals, and perfumes;
- Nighttime -GERD (gastroesophageal reflux disorder);
- Exercise -Especially under cold dry conditions;
- Work-related factors -Chemicals, dusts, gases, and metals;
- Emotional factors -Laughing, crying, yelling, and distress;
- Hormonal factors -Premenstrual syndrome.
Asthma Forms: Allergic (extrinsic) & Nonallergic (intrinsic)
Often physicians may refer to asthma as being "extrinsic" or "intrinsic." A better understanding of the nature of asthma can help explain the differences between them. Extrinsic, or allergic asthma, is more common (90% of all cases) and typically develops in childhood. Approximately 80% of children with asthma also have documented allergies. Typically, there is a family history of allergies. Additionally, other allergic conditions, such as nasal allergies or eczema, are often also present. Allergic asthma often goes into remission in early adulthood. However, in 75% of cases, the asthma reappears later.
Intrinsic asthma represents about 10% of all cases. It usually develops after the age of 30 and is not typically associated with allergies. Women are more frequently involved and many cases seem to follow a respiratory tract infection. The condition can be difficult to treat and symptoms are often chronic and year-round.
Asthma common symptoms and signs
The symptoms of asthma vary from person to person and in any individual from time to time. It is important to remember that many of these symptoms can be subtle and similar to those seen in other conditions. All of the symptoms mentioned below can be present in other respiratory, and sometimes, in heart conditions. This potential confusion makes identifying the settings in which the symptoms occur and diagnostic testing very important in recognizing this disorder. Asthma may have the following major symptoms: Shortness of breath - especially with exertion or at night; Wheezing - a whistling or hissing sound when breathing out (Usually begins suddenly, Comes in episodes, May be worse at night or in early morning, Gets worse with cold air, exercise, and heartburn (reflux), May go away on its own, Is relieved by bronchodilators (drugs that open the airways)); Coughing - may be chronic; usually worse at night and early morning (with or without sputum (phlegm) production); and may occur after exercise or when exposed to cold, dry air; Chest tightness - may occur with or without the above symptoms; Intercostal retractions (pulling of the skin between the ribs when breathing).
Emergency symptoms: • Extreme difficulty breathing • Bluish color to the lips and face • Severe anxiety due to shortness of breath • Rapid pulse • Sweating • Decreased level of alertness, such as severe drowsiness or confusion, during an asthma attack.
Additional symptoms that may be associated with this disease: • Nasal flaring • Chest pain • Tightness in the chest • Abnormal breathing pattern-breathing out takes more than twice as long as breathing in • Breathing temporarily stops.
Asthma is caused by inflammation in the airways. When an asthma attack occurs, the muscles surrounding the airways become tight and the lining of the air passages swell. This reduces the amount of air that can pass by, and can lead to wheezing sounds. Most people with asthma have wheezing attacks separated by symptom-free periods. Some patients have long-term shortness of breath with episodes of increased shortness of breath. Still, in others, a cough may be the main symptom. Asthma attacks can last minutes to days and can become dangerous if the airflow becomes severely restricted. In sensitive individuals, asthma symptoms can be triggered by breathing in allergy-causing substances (called allergens or triggers). Triggers include pet dander, dust mites, cockroach allergens, molds, or pollens. Asthma symptoms can also be triggered by respiratory infections, exercise, cold air, tobacco smoke and other pollutants, stress, food, or drug allergies. Aspirin and other non-steroidal anti-inflammatory medications (NSAIDS) provoke asthma in some patients. Approximately 20.5 million Americans currently have asthma. Many people with asthma have an individual or family history of allergies, such as hay fever (allergic rhinitis) or eczema.
Signs and tests
Allergy testing may be helpful in identifying allergens in patients with persistent asthma. Common allergens include pet dander, dust mites, cockroach allergens, molds, and pollens. Common respiratory irritants include tobacco smoke, pollution, and fumes from burning wood or gas.
The doctor will use a stethoscope to listen to the lungs. Asthma-related sounds may be heard. However, lung sounds are usually normal between asthma episodes. Tests may include: • Lung function tests • Peak flow measurements • Chest x-ray • Blood tests, including eosinophil count (a type of white blood cell) • Arterial blood gas.
What medications are better in the treatment of asthma?
Historically, one of the first medications used for asthma was adrenaline (epinephrine). Adrenaline has a rapid onset of action in opening the airways (bronchodilation). It is still often used in emergency situations for asthma. Unfortunately, adrenaline has many side effects, including rapid heart rate, headache, nausea, vomiting, restlessness, and a sense of panic.
Most asthma medications work by relaxing bronchospasm (bronchodilators) or reducing inflammation (corticosteroids). In the treatment of asthma, inhaled medications are generally preferred over tablet or liquid medicines which are swallowed (oral medications). Inhaled medications act directly on the airway surface and airway muscles where the asthma problems initiate. Absorption of inhaled medications into the rest of the body is minimal. Therefore, adverse side effects are fewer as compared to oral medications. Inhaled medications include beta-2 agonists, anticholinergics, corticosteroids, and cromolyn sodium. Oral medications include aminophylline, leukotriene antagonists, and corticosteroid tablets.
In some asthma patients, avoidance of aspirin, or other NSAIDs (commonly used in treating arthritis inflammation) is important. In other patients, adequate treatment of backflow of stomach acid (esophageal reflux) prevents irritation of the airways. Measures to prevent esophageal reflux include medications, weight loss, dietary changes, and stopping cigarettes, coffee, and alcohol. Examples of medications used to reduce reflux include omeprazole (Prilosec) and ranitidine (Zantac). Patients with severe reflux problems causing lung problems may need surgery to strengthen the esophageal sphincter in order to prevent acid reflux (fundoplication surgery).
Medications chemically similar to adrenaline have been developed. These medications, called beta-2 agonists, have the bronchodilating benefits of adrenaline without many of its unwanted side-effects. Beta-2 agonists are inhaled bronchodilators which are called "agonists" because they promote the action of the beta-2 receptor of bronchial wall muscle. This receptor acts to relax the muscular wall of the airways (bronchi), resulting in bronchodilation. The bronchodilator action of beta- 2 agonists starts within minutes after inhalation and lasts for about four hours. Examples of these medications include albuterol (Ventolin, Proventil), metaproterenol (Alupent), pirbuterol acetate (Maxair), and terbutaline sulfate (Brethaire).
A new group of long-acting beta-2 agonists has been developed with a sustained duration of effect of 12 hours. These inhalers can be taken twice a day. Salmeterol xinafoate (Serevent) is an example of this group of medications. The long-acting beta-2 agonists are generally not used for acute attacks. Beta-2 agonists can have side effects, such as anxiety, tremor, palpitations or fast heart rate, and lowering of blood potassium.
Just as beta-2 agonists can dilate the airways, beta blocker medications impair the relaxation of bronchial muscle by beta-2 receptors and can cause constriction of airways, aggravating asthma. Therefore, beta blockers, such as the blood pressure medications propanolol (Inderal), and atenolol (Tenormin), should be avoided by asthma patients if possible.
The anticholinergic agents act on a different type of nerves than the beta-2 agonists to achieve a similar relaxation and opening of the airway passages. These two groups of bronchodilator inhalers when used together can produce an enhanced bronchodilation effect. An example of a commonly used anticholinergic agent is ipratropium bromide (Atrovent). Ipratropium takes longer to work as compared with the beta-2 agonists, with peak effectiveness occurring two hours after intake and lasting six hours. Anticholinergic agents can also be very helpful medications for patients with emphysema.
When symptoms of asthma are difficult to control with beta-2 agonists, inhaled corticosteroids (cortisone) are often added. Corticosteroids can improve lung function and reduce airway obstruction over time. Examples of inhaled corticosteroids include beclomethasone dipropionate (Beclovent, Beconase, Vancenase, and Vanceril), triamcinolone acetonide (Azmacort), and flunisolide (Aerobid). The ideal dose of corticosteroids is still unknown. The side effects of inhaled corticosteroids include hoarseness, loss of voice, and oral yeast infections. Early use of inhaled corticosteroids may prevent irreversible damage to the airways.
Cromolyn sodium (Intal) prevents the release of certain chemicals in the lungs, such as histamine, which can cause asthma. Exactly how cromolyn works to prevent asthma needs further research. Cromolyn is not a corticosteroid and is usually not associated with significant side effects. Cromolyn is useful in preventing asthma but has limited effectiveness once acute asthma starts. Cromolyn can help prevent asthma triggered by exercise, cold air, and allergic substances, such as cat dander. Cromolyn may be used in children as well as adults.
Theophylline (Theodur, Theoair, Slo-bid, Uniphyl, Theo-24) and aminophylline are examples of methylxanthines. Methylxanthines are administered orally or intravenously. Before the inhalers became popular, methylxanthines were the mainstay of treatment of asthma. Caffeine that is in common coffee and soft drinks is also a methylxanthine drug! Theophylline relaxes the muscles surrounding the air passages and prevents certain cells lining the bronchi (mast cells) from releasing chemicals, such as histamine, which can cause asthma. Theophylline can also act as a mild diuretic, causing an increase in urination. For asthma that is difficult to control, methylxanthines can still play an important role. Dosage levels of theophylline or aminophylline are closely monitored. Excessive levels can lead to nausea, vomiting, heart rhythm problems, and even seizures. In certain medical conditions, such as heart failure or cirrhosis, dosages of methylxanthines are lowered to avoid excessive blood levels. Drug interactions with other medications, such as cimetidine (Tagamet), calcium channel blockers (Procardia), quinolones (Cipro), and allopurinol (Xyloprim) can further affect drug blood levels.
Corticosteroids are given orally for severe asthma unresponsive to other medications. Unfortunately, high doses of corticosteroids over long periods can have serious side effects, including osteoporosis, bone fractures, diabetes mellitus, high blood pressure, thinning of the skin and easy bruising, insomnia, emotional changes, and weight gain.
Expectorants help thin airway mucus, making it easier to clear the mucus by coughing. Potassium iodide is not commonly used and has the potential side-effects of acne, increased salivation, hives, and thyroid problems. Guaifenesin (Entex, Humibid) can increase the production of fluid in the lungs and help thin the mucus, but can also be an airway irritant for some people. In addition to bronchodilator medications for those patients with atopic asthma, avoiding allergens or other irritants can be very important. In patients who cannot avoid the allergens, or in those whose symptoms cannot be controlled by medications, allergy shots are considered. The benefits of allergy shots (desensitization) in the prevention of asthma has not been firmly established. Some doctors are still concerned about the risk of anaphylaxis, which occurs in one in 2 million doses given. Allergy shots most commonly benefit children allergic to house dust mites. Other benefits can be seen with pollens and animal dander.
Asthma Treatment
Treatment is aimed at avoiding known allergens and respiratory irritants and controlling symptoms and airway inflammation through medication. There are two basic kinds of medication for the treatment of asthma: Long-term control medications are used on a regular basis to prevent attacks, not for treatment during an attack.
Types include:
• Inhaled steroids (such as Azmacort, Vanceril, AeroBid, Flovent) prevent inflammation • Leukotriene inhibitors (such as Singulair and Accolate) • Anti-IgE therapy (Xolair), a medicine given by injection to patients with more severe asthma • Long-acting bronchodilators (such as Serevent) help open airways • Cromolyn sodium (Intal) or nedocromil sodium • Aminophylline or theophylline (not used as frequently as in the past) • Sometimes a combination of steroids and bronchodilators are used, using either separate inhalers or a single inhaler (such as Advair Diskus). Quick relief, or rescue, medications are used to relieve symptoms during an attack.
These include:
• Short-acting bronchodilators (inhalers), such as Proventil, Ventolin, Xopenex, and others.
• Corticosteroids, such as prednisone or methylprednisolone) given by mouth or into a vein Persons with mild asthma (infrequent attacks) may use quick relief medication as needed. Those with persistent asthma should take control medications on a regular basis to prevent symptoms. A severe asthma attack requires a medical evaluation and may require a hospital stay, oxygen, and intravenous medications. A peak flow meter, a simple device to measure lung volume, can be used at home to help you "see an attack coming" and take the appropriate action, sometimes even before any symptoms appear. If you are not monitoring asthma on a regular basis, an attack can take you by surprise. Peak flow measurements can help show when medication is needed, or other action needs to be taken. Peak flow values of 50-80% of an individual’s personal best results indicate a moderate asthma attack, while values below 50% indicate a severe attack.
Expectations
There is no cure for asthma, though symptoms sometimes decrease over time. With proper self management and medical treatment, most people with asthma can lead normal lives.
Prevention
Asthma symptoms can be substantially reduced by avoiding known allergens and respiratory irritants. If someone with asthma is sensitive to dust mites, exposure can be reduced by encasing mattresses and pillows in allergen-impermeable covers, removing carpets from bedrooms, and by vacuuming regularly. Exposure to dust mites and mold can be reduced by lowering indoor humidity. If a person is allergic to an animal that cannot be removed from the home, the animal should be kept out of the patient's bedroom. Filtering material can be placed over the heating outlets to trap animal dander. Exposure to cigarette smoke, air pollution, industrial dusts, and irritating fumes should also be avoided. Allergy desensitization may be helpful in reducing asthma symptoms and medication use, but the size of the benefit compared with other treatments is not known.
Asthma related topics
Allergy, Asthma, Asthma Complexities, Asthma in Children, Asthma Over-the-Counter Treatment, Bronchitis, Chronic Cough, Churg-Strauss Syndrome, Home Nebulizer for Asthma.
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 Asthma Facts
Maimonides was a renowned 12th-century rabbi and physician who practiced in the court of the sultan of Egypt. He recommended to one of the Royal Princes with asthma that he eat, drink, and sleep less. He also advised that he engage in less sexual activity, avoid the polluted city environment, and eat a specific remedy–chicken soup.
About 80% of children and 50% of adults with asthma also have allergies!
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