Asthma

 

Introduction 

 

Asthma is a chronic breathing problem that affects the airways in the lungs. These airways also known as bronchial tubes, are responsible to allow air to move in and out of the lungs. When your airways are inflamed, it causes repeated episodes of wheezing (a whistling sound when exhaling), breathlessness, chest tightness, and nighttime or early morning coughing.

 

Airways of an asthma patient always remain inflamed. There are a number of factors which can act as triggers for asthma. These triggers may swell up your airways and tighten the muscles around the airways. Eventually, it makes  difficult for air to pass in and out of the lungs.

 

Scientific synonyms: Status Asthmaticus, Bronchospasm, Bronchoconstriction, Bronchial asthma 

 

 

Onset age: Unspecified time in life

 

Asthma affects people of all ages, but it is more commonly seen in childhood. It has been observed that in some children, who were diagnosed with asthma, the condition improves or disappears as they get older.  Some children diagnosed with asthma found that the condition improved or disappeared completely as they got older. Asthma that occur at the age of 40, 50, 60 or even later also which is known as adult-onset asthma.[1]

 

Organ System: Lungs, Respiratory System

 

Sex: No gender Predilection

 

Asthma is a chronic inflammatory airway disease which has a higher prevalence in boys than in girls before puberty but in adulthood the scenario changes and its prevalence becomes high in women than in men. However, the complexity of the disease makes it difficult to explain a single straightforward mechanism which can explain gender difference found in asthma.[2] 

 

According to a few studies, it has been found that sex hormones regulate asthma pathophysiology via multiple pathways, but some mechanisms remain unclear.[3]

 

 

The fundamental causes of asthma are not yet completely known. However, the combination of genetic with environmental factors has been found as the strongest risk factor for developing asthma. Exposure to such factors may provoke allergic reactions or irritate the airways. These factors are : 

 

• Indoor allergens (for example house dust mites in bedding, carpets and stuffed furniture, pollution and pet dander)
• Outdoor allergens (such as pollens and molds)
• Tobacco smoke
• Chemical irritants in the workplace 
• Air pollution

 

The other variants that may trigger asthma can be cold air, extreme emotional arousal such as anger or fear, and physical exercise. Aspirin and some other non-steroids anti-inflammatory drugs, and beta-blockers are few other triggers of asthma.

According to a few studies, urbanization has been associated with an increase in symptoms of asthma, but the exact nature of this relationship is not clear.[4]

 

 

Risk Factors[5]

 

There are various risk factors which can act as a trigger in asthma. Severe respiratory infection as a child, an allergic condition, exposure to certain chemical irritants or having parent with asthma are the most common risk factors for developing asthma. Some other common risk factors are: 

 

• Family History: If you have a parent with asthma, you are 3 to 6 times more prone to develop than someone who does not have a parent with asthma.

• Viral respiratory infections: Respiratory problems during infancy and childhood can cause wheezing. Children who usually experience viral respiratory infections are on high risk of developing asthma.

• Allergies: Few allergic conditions, such as atopic dermatitis (eczema) or allergic rhinitis (hay fever), are  risk factors for developing asthma.

• Occupational exposures: If you have asthma, exposure to certain elements in the workplace can increase the chances of developing chronic asthma. In few people, certain dusts (industrial or wood dusts), chemical fumes and vapors, and molds exposure may be responsible for first time asthma.

• Smoking: Cigarette smoke irritates the airways. Smokers have a high risk of asthma. Asthma is more likely to happen those individuals whose mothers smoked during pregnancy or who were exposed to secondhand smoke (passive smoke).

• Air Pollution: Exposure to the main component of smog (ozone) raises the risk of asthma. Those who grew up or live in urban areas have a higher risk for asthma. 

• Obesity: Children and adults who are overweight or obese are at a greater risk of asthma. Although the reasons are unclear, low grade inflammation in the body that is caused by extra weight has been associated with cases of asthma by some experts. Obese patients often use more medications, suffer worse symptoms, and are less able to control their asthma than patients in a healthy weight range.

 

Symptoms of Asthma include: 

• Dry cough, especially at night or in response to specific “ triggers” 
• Tightness or pressure in the chest 
• Wheezing (a whistling sound - when exhaling) 
• Shortness of breath after exercise or physical exertion
• Difficulty in breathing 
• Colds that go to the chest or “hang on” for 10 days or more

 

 

To diagnose asthma, your doctor will discuss your medical history with you and perform a physical exam. You may need a lung function test and may be other tests. 

 

• Lung Function Tests: 

Lung function tests measure your breathing pattern to help your doctor to diagnose and monitor asthma. There are different types of lung function tests. Your doctor may use a combination of tests to help confirm an asthma diagnosis. These tests can also help to understand your asthma medicines are working or not.[7]

 

• Types of lung functions tests : 

 

Most lung function tests require you to exhale or inhale using a device or a mouthpiece connected to a device. Your doctor may ask you to stop taking certain medicines before appointment.

Major tests used for diagnosis of asthma are : 

• Spirometry: This is the recommended test to confirm asthma. During this test, you breathe into a mouthpiece that is connected to a device called a spirometer, or to a laptop. It measures the amount of air you are able to breathe in and out and its rate of flow. In this you need to  take a deep breath and then exhale forcefully.

• Peak flow meter: This test uses a peak flow meter. It is a small device that you breathe into to measure the rate at which you can force air out of your lungs. During the test, you breathe in as deeply as you can and then blow into the device as hard and fast as possible. If you are diagnosed with asthma, you can use a peak flow meter at home to help track your condition. However, a peak flow meter cannot be used to diagnose asthma.

• FeNO Test:A FeNO test is also called exhaled nitric oxide testing which measures the amount of inflammation in your lungs. When you have asthma, your airways become inflamed and produce nitric oxide. With the help of this test the level of  inflammation in your airways can be detected by measuring the amount of nitric oxide present.

• Provocation test: If you are experiencing signs and symptoms of asthma even when all other test reports were normal, your doctor may suggest a test that produces a mild reaction under controlled laboratory conditions. If you do not have asthma, the low doses won’t affect you, unlike those with asthma.

 

These lung function tests are some of the most common types used. There are also other types of lung function tests your doctor may use to diagnose and manage your asthma, depending on age, symptoms, medical history, and more.[8]

 

Most children who have asthma develop their first symptoms before 5 years of age. However, asthma in young children (aged 0 to 5 years) can be hard to diagnose.

 

Sometimes it is hard to tell whether a child has asthma or any other childhood condition. This is because similar symptoms of asthma also occur with other conditions.

Also, many young children who wheeze because of cold or respiratory infections do not necessarily continue to have asthma after they’re 6 years old. A child may wheeze because he or she has small airways that become even narrower during colds or respiratory infections. The airways grow as the child grows older, so wheezing no longer occurs when the child gets colds in future.

A young child who has frequent wheezing with colds or respiratory infections is more likely to have asthma if: 

• One or both parents have asthma 
• The child has signs of allergies, including the allergic skin condition eczema
• The child has allergic reaction to pollens or other airborne allergens 
• The child wheezes even when he or she does not have a cold or other infection

 

The most certain way to diagnose asthma is with a pulmonary function test (spirometry), a medical history, and a physical exam. However, it is hard to do pulmonary function tests in children younger than 5 years. Thus, doctors must rely on children’s medical histories, signs and symptoms, and physical exams to make a diagnosis. 

 

Doctors also may use a 4-6 week trial of asthma medicines to see how well a child responds.[1]

 

 

Prevention and long-term control are the main factors which can help in stopping asthma attacks before they start. Treatment usually involves learning to recognize your triggers, taking steps to avoid them, and tracking your breathing to make sure your daily asthma medications are keeping symptoms under control.  In general, asthma medications are given by inhalers. Inhalers takes the medicines direct to your lungs. Most people with asthma are prescribed with two main types of asthma inhaler: 

• Reliever inhalers help to relieve symptoms when they happen;
• Preventer inhalers help to protect the airways and reduce the chance of getting asthma symptoms.

Sometimes combination inhalers are prescribed which contain both a long-acting reliever and a steroid preventer. Occasionally, your doctor may decide to prescribe a long-acting reliever inhaler, maintenance and reliever therapy, or a non-steroidal inhaler.

Some people find it easier to use their inhaler with a device called a spacer.

Whichever type of inhaler you are using, the most important thing is that you get your inhaler technique checked regularly. If you are using your inhaler correctly, then you will get the full benefits of the medicine and you will be more likely to stay well despite asthma.

 

Asthma medications are generally divided into two categories: 

Quick relief: These medications are also called reliever medicines. Quick relief medicines are taken at the first sign of symptoms for immediate relief: 

 

1.Short-acting inhaled beta-2-agonists: These agents act as bronchodilators and are used to treat bronchospasm in acute asthmatic attacks. They are used to prevent bronchospasm associated with exercise-induced asthma or nocturnal asthma.

• Albuterol sulfate 
• Pirbuterol
• Levalbuterol 

 

Anticholinergics agents: 

 

• Tiotropium
• Ipratropium 

 

Both types of drugs are bronchodilators which means that they expand the passageways into the lungs (the bronchi), allowing more air in and out and improving breathing. They also help to clear mucus from the lungs by enabling the mucus to move more freely and get coughed out more easily.

 

If you have exercise-induced asthma, your doctor may recommend that you use these medicines before exercise or other stressful physical activity.

Quick relief medicines can stop asthma symptoms, but they do not control the airway inflammation that causes the symptoms. If you find that you need your quick-relief medicine to treat asthma symptoms more than twice a week, or two or more nights a month, then your asthma is not well controlled.

Long term control: Long-term control medicines are taken every day to prevent symptoms and attacks.

Antileukotrienes or leukotriene modifiers: 

• Zafirlukast 
• Montelukast 

Cromolyn sodium: These agents block early and late asthmatic responses, interfere with chloride channels, stabilize the mast cell membrane, and inhibit the activation and release of mediators from eosinophils and epithelial cells. They inhibit acute responses to cold air, exercise, and sulfur oxide.

Inhaled corticosteroids: 

• Ciclesonide 
• Beclomethasone
• Fluticasone
• Budesonide inhaled
• Mometasone 
• Triamcinolone inhaled 
• Flunisolide inhaled 

Long-acting inhaled beta-2-agonists

• Salmeterol
• Methylxanthines 
• Theophylline

Oral corticosteroids

Immunomodulators 

• Omalizumab
• Mepolizumab
• Reslizumab
• Benralizumab
• Dupilumab

 

It is hard to diagnose asthma in children below the age of 5 years. Because of that, it becomes hard to know the benefits of long-term control medicines (quick relief medicines tend to relieve wheezing in young children whether they have asthma or not.) in young children who wheeze or have other asthma symptoms. Doctors will treat infants and young children who have asthma symptoms with long-term control medicines if, after assessing a child, they feel that the symptoms are persistent and likely to continue after 6 years age.

Inhaled corticosteroids can possibly slow the growth of children of all ages. Slowed growth usually is apparent in the first several months of treatment, is generally small, and doesn’t get worse over time. Poorly controlled asthma also may reduce a child’s growth rate. 

However, many experts think the benefits of inhaled corticosteroids for children who need them to control their asthma far outweigh the risk of slowed growth.

 

Doctors may need to adjust asthma treatment for older adults who take certain other medicines such as beta blockers, aspirin and other pain relievers, and anti-inflammatory medicines. These medicines can prevent asthma medicines from working well and may worsen asthma symptoms.

Be sure to tell your doctor about all of the medicines you take, including over-the-counter medicines.

Older adults may develop weak bones from using inhaled corticosteroids, especially at high doses. Talk with your doctor about taking calcium and vitamin D pills, as well as other ways to help keep your bones strong.

Pregnant women who have asthma need to control the disease to ensure a good supply of oxygen to their babies. Poor asthma control increases the risk of preeclampsia,  a condition in which a pregnant woman develops high blood pressure and protein in the urine. Poor asthma also increases the risk that a baby will be born early and have a low birth weight. 

Studies show that it is safer  to take asthma medicines during pregnancy than to risk having an asthma attack. 

You can consult with your doctor if you have asthma and are pregnant or planning a pregnancy. Your level of asthma control may get better or it may get worse while you are pregnant. Your healthcare team will check your asthma control often and adjust your treatment as needed.

 

Physical activity is an important part of a healthy lifestyle. Adults need physical activity to maintain good health. Children need it for growth and development. In some people, however, physical activity can trigger asthma symptoms. If this happens to you or your child, talk with your doctor about the best ways to control, so you can stay active in such conditions also.

 

The following medicines may help prevent asthma symptoms caused by physical activity: 

• Short-acting beta-2-agonists (quick-relief medicines) taken shortly before physical activity can last 2 to 3 hours and prevent exercise-related symptoms in most people who take them.
• Long-acting beta-2-agonists can be retain its effect for up to 12 hours. However, with daily use, they will no longer give up to 12 hours of protection. Also, frequent use of these medicines for physical activity might be a sign that asthma is poorly controlled.
• Leukotriene modifiers: These pills are taken several hours before physical activity. They can help relieve asthma symptoms brought on by physical activity.
• Long-term control medicines: Frequent or severe symptoms due to physical activity may suggest poorly controlled asthma and the need to either start or increase long-term control medicines that reduce inflammation. This will help prevent exercise-related symptoms.

 

A warm-up before any physical activity can be helpful as it will ease the transition from resting state to  active state. You also may want to wear a mask or scarf over your mouth when exercising in cold weather.

If you use your asthma medicines as your doctor directs, you should be able to take part in any physical activity or sport you choose.

 

Asthma may add to the risk of having problems during and after surgery. For instance, having a tube put into your throat may cause an asthma attack.

Inform your surgeon about your asthma beforehand. So, that the surgeon can take steps to control your risk involved by giving you asthma medicines before or during surgery.

 

 

Immunotherapy increases your immunity so as to increase your tolerance to the drugs suggested for treatment.[10]

Two types of immunotherapy are available: allergy shots and sublingual (under the tongue) tablets.

1. Allergy shots: If your asthma is triggered by an allergy, you should consider allergy shots. These are very effective in relieving allergy symptoms and in some cases can actually cure your allergy. The treatment, which can take several years, builds up immunity to your offending allergens (pollens, dust mite, pets, and mold). It works by injecting small amounts of the allergen in gradually increasing amounts over time. As the shots help the body build up a tolerance to the effects of the allergen in gradually increasing amounts over time. . This will eventually reduce the allergy or can even eliminate your allergy symptoms.[11]

2. Sublingual tablets: This type of immunotherapy was approved by the Food and Drug Administration in 2014. This method starts several months before allergy season begins, in this patients dissolve a tablet under the tongue daily. This treatment can continue for as long as three years. However, in patients with severe or uncontrolled asthma these medications should be avoided. Till now, this method has shown positive results in only a few allergens (certain grass and ragweed pollens), but it is a promising therapy for the future.

 

 

 

 

In addition to using maintenance medications, you can take steps each day to make yourself healthier and reduce your risk for asthma attacks. These include: 

• Eating healthier diet: Eating a healthy, balanced diet can improve your overall health, which may reduce the risks for asthma attacks. Research suggests that eliminating processed foods may cut down on the risk of an asthma attack.

• Maintaining a healthy weight: Asthma tends to be worse in overweight and obese individuals. Losing weight is healthy for your heart, your joints, and your lungs.

• Quitting smoking: Irritants such as cigarette smoke can trigger asthma. You also put yourself at greater risk for chronic obstructive pulmonary disease (COPD).

• Exercising regularly: Physical activities can trigger an asthma attack, but regular exercise may actually reduce the risk of breathing problems. Aerobic activity can strengthen your lungs and help you breathe better.

• Managing stress: Stress can be a trigger for asthma symptoms. Stress can also make stopping an asthma attack more difficult. 

 

• Get vaccinated for influenza and pneumonia. Staying current with vaccinations can prevent flu and pneumonia from triggering asthma flare-ups (aggravation of asthma). 

• Identify and avoid asthma triggers. A number of outdoor allergens and irritants, ranging from pollen and mold to cold air and air pollution,  can trigger asthma attacks.

 

 

In some cases, asthma can lead to a number of serious respiratory complications, including: 

• Pneumonia (infection of the lungs)
• A collapse of part or all of the lung
• Respiratory failure, where the levels of oxygen in the blood become dangerously low, or the levels of carbon dioxide become dangerously high.
• Status asthmaticus (severe asthma attacks that do not respond to treatment)[12]

 

 

Specialists 

• Pulmonologist/Lung Specialist
• Allergist/Immunologist