Adult Asthma

It used to be that having asthma meant choosing between breathing problems and side effects of asthma medicine (Asthma symptoms vary in severity from occasional mild bouts of breathlessness to daily wheezing that persists despite taking large doses of medication. ). But today’s asthma treatments have freed people from that choice. You can now breathe easier thanks to highly effective medications with few or no side effects. For people with more than occasional, mild symptoms, today’s standard of care calls for consistent, daily use of asthma medications even when you feel well. And with the help of updated asthma guidelines, described in this report, you and your doctor can choose the most effective drugs and dosages to control your asthma while keeping your medication levels as low as possible.

This report provides facts about adult asthma and advice about how best to manage it. For starters, asthma is not just a childhood condition. Many adults have lived with asthma for years; others have been diagnosed only recently. This report is geared specifically to the often neglected adult asthma community. If you have had asthma since childhood, the advances in medical understanding and treatment of this disorder may surprise you and inspire you to make adjustments in your care. And if you have been only recently diagnosed or are trying to manage asthma in addition to other medical conditions, such as heart disease, this report provides practical advice and suggestions.

There is a lot of good news to share. Many treatments have become available since the 1990s, including selective and long-acting bronchodilators, leukotriene modifiers, and biological therapies such as monoclonal antibodies. Because of the tremendous progress in understanding and treating asthma, most people with asthma can now expect to achieve good control of this disorder and live fully functional lives. While millions of Americans live with asthma, the death rate from asthma is declining in the United States, an indication that more Americans are managing their disease well.

In this report, you will learn what asthma is, read about developments in treatment, and discover simple steps you can take to reduce exposure to asthma triggers. You will learn how to plan in advance for an asthma attack so that you remain safe and healthy. You’ll also have an opportunity to consider how to control your asthma in different real-life scenarios, so that you feel prepared for almost any situation. Armed with the knowledge and skills outlined in this report, you will become asthma smart — and as healthy as possible.

Adult “Asthma” Symptoms

Asthma symptoms vary in severity from occasional mild bouts of breathlessness to daily wheezing that persists despite taking large doses of medication. After exposure to asthma triggers, symptoms rarely develop abruptly but progress over a period of hours or days. Occasionally, the airways have become seriously obstructed by the time the patient calls the doctor.

The classic symptoms of an asthma attack include:

•Wheezing when breathing out is nearly always present during an attack. Usually the attack begins with wheezing and rapid breathing, and, as it becomes more severe, all breathing muscles become visibly active.
•Shortness of breath (dyspnea). Shortness of breath is a major source of distress in patients with asthma. However, the severity of this symptom does not always reflect the degree to which lung function is impaired. Some patients are not even aware that they are experiencing shortness of breath. Such patients are at particular risk for very serious and even life-threatening asthma attacks, since they are less conscious of symptoms. Those at highest risk for this effect tend to be older, female, and to have had the disease for a longer period of time.
•Coughing. In some people, the first symptom of asthma is a nonproductive cough. Some patients find this cough even more distressing than wheezing or sleep disturbances.
•Chest tightness or pain. Initial chest tightness without any other symptoms may be an early indicator of a serious attack.
•Neck muscles may tighten, and talking may become difficult or impossible.
•Rapid heart rate.
•Sweating.
•Chest pain occurs in about three-quarters of patients. It can be very severe, although the pain’s intensity is not necessarily related to the severity of the asthma attack itself.

Causes of Adult Asthma

Asthma has dramatically risen worldwide over the past decades, particularly in developed countries, and experts are puzzled over the cause of this increase. The mechanisms that cause asthma are complex and vary among population groups and even from individual to individual. Many asthma sufferers have allergies, and some researchers are targeting common factors in both these conditions. Not all people with allergies have asthma, however, and not all cases of asthma can be explained by allergic response.

Asthma is most likely to be caused by a convergence of factors that can include genes (probably several) and various environmental and biologic triggers (e.g., infections, dietary patterns, hormonal changes in women, and allergens).

The Allergic Response
Nearly half of adults with asthma have an allergy-related condition, which, in most cases developed first in childhood. (In patients who first develop asthma during adulthood, the allergic response usually does not play a strong causal role.) Important irritants or allergens include:

•Dust mites, specifically mite feces, which are coated with enzymes that contain a powerful allergen. These are the primary allergens in the home.
•Animal dander.
•Pollen. An asthma attack from an allergic response to pollen is more likely to occur during extreme air changes, such as thunderstorms. Major weather changes, such as El Nino, can affect the timing of allergy seasons. For example, in 1998, when the effects of El Nino were very strong, allergy and asthma attacks were markedly increased, and maximum tree pollen counts occurred 2 to 4 weeks earlier and mold counts 2 to 3 months earlier than in the previous year.
•Molds. A 2002 study suggested that molds might produce a worse asthma attack in adults than other allergens.
•Fungi.
•Cockroaches. Cockroaches are major asthma triggers and may reduce lung function even in people without a history of asthma.
•Fossil Fuels. Certain chemicals may trigger allergic rhinitis. Some experts believe that refined fossil fuels, such as diesel fuel and particularly kerosene, may be important triggers for allergic rhinitis. And, in people who already have allergies or asthma, exposure to such fossil fuels may worsen symptoms.

The Allergic Process. The allergic process, called atopy, and its connection to asthma is not completely understood. It involves various airborne allergens or other triggers that set off a cascade of events in the immune system leading to inflammation and hyperreactivity in the airways. One description is as follows:

•The conductor in an orchestra of immune factors that contribute to allergies and asthma appears to be a category of white blood cells known as helper T cells, in particular a subgroup called Th2 cells.
•Th2 cells overproduce interleukins (ILs), immune factors that are molecular members of a family called cytokines, which are involved in the inflammatory process.
•Interleukins 4, 9, and 13 may be responsible for a first-phase asthma attack. These interleukins stimulate the production and release of antibody groups known as immunoglobulin E (IgE). (People with both asthma and allergies appear to have a genetic predisposition for overproducing IgE.)
•During an allergic attack, these IgE antibodies can bind to special cells in the immune system called mast cells, which are generally concentrated in the lungs, skin, and mucous membranes. This bond triggers the release of several active chemicals, importantly potent molecules known as leukotrienes. These chemicals cause airway spasms, overproduce mucus, and activate nerve endings in the airway lining.
•Another cytokine, interleukin 5, appears to contribute to a late-phase inflammatory response. This interleukin attracts white blood cells known as eosinophils. These cells accumulate and remain in the airways after the first attack. They persist for weeks and mediate the release of other damaging particles that remain in the airways.
The Immune Response. Researchers are investigating the role that T cells play in asthma. T cells are white blood cells that are involved in the immune response. Researchers had focused on the T cell called type 2 helper (Th2) cells. However, a 2006 breakthrough study in the New England Journal of Medicine suggested that a different type of T cell may play a stronger role in asthma than previously thought.

Researchers discovered that these cells, called natural killer T cells, are far more common in the lungs of people with asthma than in the lungs of healthy people. Natural killer T cells are very rare, but researchers found them in 60% of people with moderate-to-severe persistent asthma. While this research is preliminary, it may explain why corticosteroid drugs do not work well for some patients with asthma: Steroid drugs target Th2 and other inflammatory cells, not natural killer T cells. Researchers think that further investigation of natural killer T cells may lead the way to new types of asthma drugs. If these cells prove to be involved in asthma, then drugs that eliminate them might become an important new treatment.

Remodeling and Causes of Persistent Asthma
Over the course of years the repetition of the inflammatory events involved in asthma can cause irreversible structural and functional changes in the airways, a process called remodeling. The remodeled airways are persistently narrow and can cause chronic asthma. Researchers are trying to determine how this process occurs:

Interleukins. Some researchers are looking at potent immune factors, including interleukins 11 and 13. They have been linked to a number of processes possibly involved in remodeling, including scarring in the airways and overgrowth of cells in the smooth muscles that line the airways.

Growth Factors. Compounds known as vascular endothelial growth factor (VEGF) have been observed in the airways of patients with asthma. VEGF is a powerful promoter of cell growth in blood vessel linings, and some researchers believe it may be major factor in remodeling.

Genetic Factors
About one-third of all persons with asthma share this condition with another member of their immediate family. Asthma may be more likely to pass to children from their mother than from their father. Both allergies and asthma are strongly associated with hereditary factors, sharing certain genetic markers, but they are not always inherited together.

Research on the genetics of these conditions is confusing. Of some significant promise, researchers have identified a gene (ADAM33), which has been linked to asthma. The gene regulates one of the enzymes called metalloproteases, which are involved with the smooth muscle in the airway. A mutation of this gene could play a role in airway changes that occur after inflammation.

Female Hormones
Hormones or changes in hormone levels appear to play a role in the severity of asthma in women.

Menstrual-Related Asthma. Between 30 – 40% of women with asthma experience fluctuations in severity that are associated with their menstrual cycle. One study indicated that women with menstrually associated asthma tend to have the following characteristics:

•Older age
•Had asthma for a long time
•Had severe asthma attacks that were likely to occur 3 days before and 4 days into the menstrual period
Oral contraceptives (OCs) theoretically should help asthma sufferers by leveling out hormonal changes, but they do not appear to have much effect. (There have been a few reports of asthma exacerbation with OCs, but these are uncommon events.)

Asthma during Pregnancy. During pregnancy, one-third of women with asthma suffer more from the condition, one-third suffer less, and one-third experience no difference in severity. Some studies suggest that expectant mothers carrying a female baby tend to have more severe asthma symptoms than do those who are bearing a male.

Menopause and Asthma. Around the time of menopause (called perimenopause) when estrogen declines, the risk for hospitalization in women with asthma increases fourfold compared to previous years. Studies have not demonstrated that that hormone replacement therapy (HRT), which contains estrogen, has much benefit.

NSAIDs and Acetaminophen
About 10% of adults and some fewer children have aspirin-induced asthma (AIA). With this condition, asthma gets worse when patients take aspirin. Aspirin is one of the drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs). Although aspirin is used to reduce inflammation in other disorders, it appears to have the opposite effect in many asthma cases. It is not wholly known why this occurs. AIA often develops after a viral infection. It is a particularly severe asthmatic condition, associated with up to 25% of asthma-related hospitalizations. In about 5% of cases, aspirin is responsible for a syndrome that involves multiple attacks of asthma, sinusitis, and nasal congestion. Such patients also often have polyps (small benign growths) in the nasal passages.

Patients with aspirin-induced asthma (AIA) should avoid aspirin and most likely other NSAIDs, including ibuprofen (Advil) and naproxen (Aleve).

Exercise-induced asthma (EIA) is a limited form of asthma in which exercise triggers coughing, wheezing, or shortness of breath.

Nocturnal Asthma
Asthma occurs primarily at night (nocturnal asthma) in as many as 75% of patients with asthma. Attacks often occur between 2 and 4 A.M. Factors that might play role in nocturnal asthma may include one or more of the following:

•Chemical and temperature changes in the body during the night that increase inflammation and narrowing of the airways
•Delayed allergic responses from exposure to allergens during the day
•The wearing off of inhaled medications toward the early morning
•An increase in acid reflux (back up of stomach acid) that causes airways to narrow
•Postnasal drip that occurs during sleep
•Conditions relating to sleep, such as sleep apnea or sleeping on one’s back, which may worsen any asthma attack that occurs at night
Some experts believe that nocturnal asthma may actually be a unique form, with its own specific biologic mechanisms that occur only at night and which reduce natural steroid hormones (which block inflammation).

Contributing Medical Conditions
Infections. The role of infections in asthma is complicated. Respiratory infections may play a role in some cases of adult-onset asthma, but may be protective against asthma in small children. (In both children and adults with existing allergic asthma, however, an upper respiratory tract infection often worsens an attack.)

Researchers are particularly interested in the organisms Chlamydiapneumoniae and Mycoplasmapneumoniae adenovirus. They are major causes of both mild and serious respiratory infections and are becoming important suspects in many cases of severe adult asthma. (If such respiratory infections occur in young children, they are unlikely to affect adult-onset asthma.)

In one study, patients whose asthma occurred after infections had more severe conditions than those whose asthma was due to other causes. The infection-initiated asthma, however, lasted only 5.6 years compared to 13.3 years in the non-infection group.

In any age group, respiratory infections worsen existing asthma in people who have it already. Rhinovirus (the common cold virus) has been reported to be the most common infection associated with asthma attacks. In one study, it was associated with 61% of asthma exacerbations in children and 44% in adults. Some research suggests that colds promote allergic inflammation and increase the intensity of airway responsiveness for weeks.

GERD. At least half of patients with asthma have gastroesophageal reflux disease (GERD), the cause of heartburn. It is not entirely clear which condition causes the other or whether they are both due to common factors.

Heartburn is a condition where the acidic stomach contents back up into the esophagus causing pain in the chest area. This reflux usually occurs because the sphincter muscle between the esophagus and stomach is weakened. Standing or sitting after a meal can help reduce the reflux that causes heartburn. Continuous irritation of the esophagus lining as in gastroesophageal reflux disease is a risk factor for the development of adenocarcinoma.
Some theories for the causal connection between GERD and asthma are:

•Acid leaking from the lower esophagus in GERD stimulates the vagus nerve, which runs through the gastrointestinal tract. This stimulated nerve triggers the nearby airways in the lung to constrict, causing asthma symptoms.
•Acid backup that reaches the mouth may be inhaled into the airways (aspirated). Here, the acid triggers a reaction in the airways that cause asthma symptoms.
GERD is sometimes hard to detect and might be a contributor in the following patients:

•Those who do not respond to asthma treatments
•Those whose asthma attacks follow episodes of heartburn
•Those whose attacks worsen after eating or exercise
•Those whose coughs follow episodes of acid reflux. (One study found that GERD was associated with about half of the episodes of coughs and wheezes in patients with asthma.)
Treating GERD symptoms with anti-acid drugs may resolve asthma in some (but not all) patients who share both conditions. A small 2005 observational study found that while GERD was common in patients with asthma, treatment of GERD had no effect on asthma symptoms. [See In-Depth Report #85: Heartburn and gastroesophageal reflux disease.]

Sinusitis. Almost half of children and adults with allergic asthma have sinus abnormalities, and in various studies, between 17 – 30% of patients with asthma develop true sinusitis. The presence of sinusitis, however, does not appear to increase the severity of asthma.

What is adult-onset asthma?
When a doctor makes a diagnosis of asthma in people older than 20, it is known as adult-onset asthma.

Among those who may be more likely to get adult-onset asthma are:

Women who are having hormonal changes, such as those who are pregnant or who are experiencing menopause
Women who take estrogen following menopause for 10 years or longer
People who have just had certain viruses or illnesses, such as a cold or flu
People with allergies, especially to cats
People who are exposed to environmental irritants, such as tobacco smoke, mold, dust, feather beds, or perfume. Irritants that bring on asthma symptoms are called “asthma triggers.” Asthma brought on by workplace triggers is called “occupational asthma.”

What is the difference between childhood asthma and adult-onset asthma?
Adults tend to have lower lung capacity (the volume of air you are able to take in and forcibly exhale in one second) after middle age because of changes in muscles and stiffening of chest walls. This decreased capacity may cause doctors to miss the diagnosis of adult-onset asthma.

How is adult-onset asthma diagnosed?
Your asthma doctor may diagnose adult-onset asthma by:

Taking a medical history, asking about symptoms, and listening to you breathe
Performing a lung function test, using a device called a spirometer to measure how much air you can exhale after first taking a deep breath. The device also measures how fast you can empty your lungs. You may be asked at some time before or after the test to inhale a short-acting bronchodilator (medicine that opens the airways by relaxing tight muscles and that also help clear mucus from the lungs).
Performing a methacholine challenge test. This asthma test may be performed if your symptoms and spirometry test do not clearly show asthma. When inhaled, methacholine causes the airways to spasm and narrow if asthma is present. During this test, you inhale increasing amounts of methacholine aerosol mist before and after spirometry. The methacholine test is considered positive, meaning asthma is present, if the lung function drops by at least 20%. A bronchodilator is always given at the end of the test to reverse the effects of the methacholine.
Performing a chest X-ray. An X-ray is an image of the body that is created by using low doses of radiation reflected on special film or a fluorescent screen. X-rays can be used to diagnose a wide range of conditions, from bronchitis to a broken bone. Your doctor might perform an X-ray exam on you in order to see the structures inside your chest, including the heart, lungs, and bones. By viewing your lungs, your doctor can see if you have a condition other than asthma that may account for your symptoms. Although there may be signs on an X-ray that suggest asthma, a person with asthma will often have a normal chest X-ray.

Who gets asthma?
Anyone can get asthma at any age. Among those at higher risk for asthma are people who:

Have a family history of asthma
Have a history of allergies (allergic asthma)
Have smokers living in the household
Live in urban areas

How is asthma classified?
Asthma is classified into four categories based upon frequency of symptoms and objective measures, such as peak flow measurements and/or spirometry results. These categories are: mild intermittent; mild persistent; moderate persistent; and severe persistent. Your physician will determine the severity and control of your asthma based on how frequently you have symptoms and on lung function tests. It is important to note that a person’s asthma symptoms can change from one category to another.

Mild intermittent asthma
Symptoms occur less than three times a week, and nighttime symptoms occur less than two times per month.
Lung function tests are greater than 80% of predicted values. Predictions are often made on the basis of age, sex, and height. For a person with asthma, the “predicted” figure could be replaced by the person’s own personal best test value as the figure for comparison.
No medications are needed for long-term control.

Mild persistent asthma
Symptoms occur more three to six times per week .
Lung function tests are greater than 80% of predicted.
Nighttime symptoms three to four times a month.
Moderate persistent asthma
Symptoms occur daily.
Nocturnal symptoms greater than five times per month
Asthma symptoms affect activity, occur more than two times per week, and may last for days.
There is a reduction in lung function, with a lung function test range of 60% to 80% of predicted.

Severe persistent asthma
Symptoms occur continuously, with asthma at night frequently.
Activities are limited.
Lung function is decreased to less than 60% of predicted.
How is asthma treated?
Asthma can be controlled, but there’s no asthma cure. There are certain goals in asthma treatment. If you are unable to achieve all of these goals, it means asthma is not in good control. You should contact your asthma care provider for help with asthma.

The treatment goals include the following:

Live an active, normal life.
Prevent chronic and troublesome symptoms.
Attend work or school every day.
Perform daily activities without difficulty.
Stop urgent visits to the doctor, emergency room, or hospital.
Use and adjust medications to control asthma with little or no side effects.
Properly using asthma medication, as prescribed by your doctor, is the basis of good asthma control, in addition to avoiding triggers and monitoring daily asthma symptoms. There are two main types of asthma medications:

Anti-inflammatories: This is the most important type of medication for most people with asthma. Anti-inflammatory medications, such as inhaled steroids, reduce swelling and mucus production in the airways. As a result, airways are less sensitive and less likely to react to triggers. These medications need to be taken daily, and may need to be taken for several weeks before they begin to control asthma. Anti-inflammatories lead to a reduction in symptoms, better airflow, less sensitive airways, less airway damage, and fewer asthma episodes. If taken every day, they are helpful in controlling or preventing asthma. Oral steroids are taken for acute flares and help increase the efficacy of other medications and help reduce inflammation.
Bronchodilators: These medications relax the muscle bands that tighten around the airways. This action rapidly opens the airways, letting more air in and out of the lungs and improving breathing. As the airways open, the mucus moves more freely and can be coughed out more easily. In short-acting forms, bronchodilators known as beta-agonist relieve or stop asthma symptoms and are very helpful during an asthma episode. In long-acting forms, a beta-agonist may be helpful in preventing exercise-induced asthma.
Asthma medications can be taken by inhaling the medications (using a metered dose inhaler, dry powder inhaler, or asthma nebulizer) or by swallowing oral medications (pills or liquids). If you are also taking drugs for other conditions, you should work with your providers to check drug interactions and simplify medications when possible.
Monitoring symptoms
An important part of treatment is keeping track of how well the lungs are functioning. Asthma symptoms are monitored using a peak flow meter. The meter can alert you to changes in the airways that may be a sign of worsening asthma. By taking daily peak flow readings, you can learn when to adjust medications to keep asthma under good control. Your doctor can also use this information to adjust your treatment plan.

“Asthma” action plan
Based on your history and the severity of asthma, your doctor will develop a care plan called an asthma action plan. The asthma action plan describes when and how to use asthma medications, actions to take when asthma worsens, and when to seek care for an asthma emergency. Make sure you understand this plan; if not, ask your asthma care provider any questions you may have.