Asthma

By Talsk Research's Physician Group

Overview

Asthma is a medical condition that affects the respiratory system and causes difficulty in breathing. Certain factors cause inflammation or swelling of the mucosal lining of the tubes resulting in excessive and thicker mucus secretions narrowing the airways. When people with the hyper responsive airways are exposed to triggering factors, the muscles around the breathing tubes tighten further narrowing the air passages. This results in less air flowing in and out of the lungs, causing wheezing, shortness of breath, chest tightness and coughing which is usually referred to as an asthma attack. It may be mild and go away on its own or after self treatment with an asthma medicine. Other times, symptoms continue to get worse and may need immediate medical attention.

Asthma most often starts in childhood but can affect persons of all age groups. It is not a contagious disease. Frequent asthma attacks can be debilitating and frightening and at times life threatening when a severe attack is not promptly treated. When not properly controlled, it can interfere with work and activities of daily living. Studies have also shown that there is a global increase in the burden of the disease among both children and adults, and this may be due to the change in lifestyles and increase in atmospheric pollution. The condition can be kept under check by avoiding the triggering factors, whenever possible, and taking medicines best suited for your problem, as prescribed by a physician.

Causes

Though the exact cause of asthma is not known, asthma can be triggered by many factors. Studies have shown combinations of genetic and environmental factors early in life interact to cause asthma. These factors include:

• An inherited tendency to develop allergies called ‘atopy’

• Parents who have asthma

• Exposure to airborne allergens such as house dust mites, cockroaches, cat, or dog dander.

• Some respiratory infections that affect children can make them prone to asthma later in life.

• Viral infections that might affect the immune system can lead to asthma-like conditions

• Irritants like tobacco and smoke

About half the adults with asthma have another allergy-related condition and there are various factors that can trigger asthma and these include:

• Allergies to airborne substances such as tree, grass, and weed pollen are extremely common

• Mold or damp conditions, house dust mites, chemicals in flooring material, dust trapped in carpets are also common culprits

• Cockroach droppings or body parts are one of the major asthma triggers and may reduce lung function even in people without a history of asthma

• Allergies due to foods like eggs, cow’s milk, peanuts, soy, wheat, fish, shrimp, and shellfish can sometimes be very severe

• Allergies due to preservatives like sodium bisulfite are hard to identify

• Exercise induced asthma is common where strenuous exercise can cause a reactive narrowing of the breathing tubes

• Indigestion or Acid Reflux disease can cause or exacerbate asthma when stomach acids travel back from the stomach into the food pipe, and if the acid reaches into the throat or breathing tubes, the irritation and swelling can trigger an asthma attack

• Active or passive smoking, viral or bacterial infection of lungs irritate the airway lining and can cause asthma.

• Cold air, changes in temperature, and humidity can also trigger an attack

• Various substances found in the workplace can lead to breathing difficulties, which is called occupational asthma. Some of the irritants which trigger asthma in workplaces include wood dust, pesticides, and asbestos

• Odors from perfumes, talc powders, incense, spray deodorant, and hairsprays can trigger an attack

• Some common medications such as aspirin can cause allergic asthma reaction.

However, it is important to remember that asthma is different from person to person, and some of the triggers listed above may not affect all, and those that do affect may not be on the list.

Risk Factors

There are various risk factors that predispose one to asthma and they include:

• Hereditary or genetic predisposition

• Personal history of allergies such as hay fever

• Gender - Men are affected more than women

• Ethnicity - African-Americans are affected more than Caucasians

• Tobacco smoking - Both active and passive

• Bacterial or viral infections of the lung

• Obesity

• Stressful situations and anxiety

• Low birth weight

• Hormonal fluctuations or changes in hormone levels may play a role in the severity of asthma in women.

• Occupational exposure to certain chemicals increases the risk for asthma which explains the high incidence in certain occupations like farmers, laboratory workers, miners.

Symptoms

Common symptoms include:

• Shortness of breath or difficulty in breathing

• Frequent cough, especially at night

• Feeling tired or weak when exercising

• Wheezing or coughing after exercise

• Chest tightness

• Anxiety

• Fast heartbeat

• Excessive sweating

• Cold or allergies (sneezing, runny nose, nasal congestion, and sore throat)

• Trouble sleeping

Serious symptoms such as extreme difficulty to breathe or even inability to breathe need emergent treatment. Other symptoms that warrant an emergency call include bluish color to the lips and face, severe anxiety, fast heartbeat, excessive sweating, and decreased level of consciousness such as drowsiness or confusion.

Diagnosis

A detailed history and physical examination by the doctor should be the starting point for diagnosis of asthma. The doctor may include one or more of the following tests to aid in the diagnosis.

• Allergy skin tests - to identify the offending allergens which may trigger/cause asthma

• Blood tests - to measure eosinophil count (a type of white blood cell) and IgE (a type of immune system protein), which are increased if there are allergies

• Sputum (phlegm) test - fluid coughed up from the lungs examined under the microscope to check for bacteria

• Lung function tests - A device called spirometer used to check how quickly you can breathe out, evaluating your lung function and capacity. The tests may be repeated after inhaler treatments to check for improvement to help confirm the diagnosis of asthma.

• Chest X-ray - to check the breathing tubes and lungs

• Electrocardiogram - A tracing of your heartbeats to check the strain on your heart

• Computerized tomography - An imaging method to check for any foreign substance or obstruction in your breathing tubes and lungs

• Magnetic resonance imaging - An advanced technique to check for any obstruction of airways or other diseases that may be contributing to the narrowing of airways

According to the frequency and severity of the condition patients with asthma are categorized as follows:

• 30% of affected patients have mild, intermittent (less than two attacks a week) symptoms of asthma with normal breathing tests

• 30% have mild, persistent (two or more attacks a week) symptoms of asthma with normal or abnormal breathing tests

• 40% have moderate or severe, persistent (daily or continuous) symptoms of asthma with abnormal breathing tests

This classification aids in the management of the disease as it is easier to set up individual treatment plans.

Treatment

Depending on your condition, your physician may treat your asthma through any of these measures:

• Quick-relief or rescue medicines such as short acting bronchodilators (e.g. proventil) are used to reduce symptoms of coughing, shortness of breath, wheezing or a tight feeling in the chest. Their effect is immediate as they relax the muscles around the breathing tubes thus widening the airways but may last only a few hours. They are also used a few minutes before exercise for preventing exercise induced asthma. They can be used as oral medications but inhalers are predominantly used due to local and immediate action with minimal side effects.

• For severe asthma attacks and in pediatric patients who cannot use inhaler properly the same medicines can be used in a nebulizer or a breathing machine, which is used in hospital settings but can also be used at home.

• Long acting bronchodilators are used to provide relief for at least 12 hrs and are usually used on a regular basis along with steroid inhalers (e.g. advair) to control moderate to severe asthma by decreasing the inflammation of the mucosal lining of the airways.

• Oral corticosteroids such as predinisone are generally reserved for severe acute attacks not responding well to the inhaler treatments. The goal is to use the corticosteroids as minimum as possible due to their undesirable side effects.

• Peak flow meters are usually provided to the patients with asthma which can help them manage the disease well. If a person is aware of his or her peak flow then they can assess the severity of an asthma attack and tailor their treatment accordingly. A drop in the peak flow can alert a person even before he or she experiences any symptoms.

Prevention

• Following the clinician’s instructions carefully and using the inhalers properly and keeping an asthma diary to note the peak flow, symptoms, triggering factors, medicines used will help manage this condition very effectively.

• Arming yourself with information and knowing your triggering factors is the main defense against this condition

• Identifying and avoiding allergens that trigger the symptoms at home and work environments (staying indoors during high pollen counts, avoiding activities on fresh cut grass etc) whenever possible is very effective to prevent asthma attacks

• The following measures can be taken to decrease the concentration of the allergens

• The house should be free of mold or dust

• Home air filtration systems reduce irritants which could trigger sneezing or wheezing

• Doors and windows should be closed during the seasons when pollen counts are at the highest, such as spring

• A dehumidifier might help maintain humidity in the house

• Bed sheets and blankets should be washed every week in hot water. Replace carpeting with wooden floors wherever possible.

• If pet dander is a triggering factor then measures are to be taken to decrease contact with the pet.

• Avoiding exposure to tobacco smoke is of paramount importance

• Regular exercise and active lifestyle help curb asthma attacks. If exercise induced asthma is an issue a short acting bronchodilator such as proventil can be used 20 minutes before exercise to prevent an exercise induced attack

• Food related allergic asthma can be prevented by paying attention to food labels and knowing the ingredients when eating out

• Adequate precautions like wearing woolen clothing or jackets in cold weather will help prevent asthma attacks in winter

• A flu shot is highly recommended for people with asthma as they have a higher risk of pneumonia if they are infected with the flu virus.

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References

• Centers for Disease Control and Prevention

http://www.cdc.gov/asthma/

• National Heart Lung and Blood Institute

http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/

• National Institutes of Health

http://www.nlm.nih.gov/medlineplus/asthma.html

• American Lung Association

http://www.lungusa.org/lung-disease/asthma/

• American College of Allergy, Asthma, & Immunology

http://www.acaai.org/

• University of Maryland Medical Center

http://www.umm.edu/altmed/articles/asthma-000015.htm

• Centers for Disease Control and Prevention

http://www.cdc.gov/asthma/

• United States Environmental Protection Agency

http://www.epa.gov/asthma/

• Mayo Foundation for Medical Education and Research

http://www.mayoclinic.com/print/asthma/DS00021/METHOD=print&DSECTION=all

• Johns Hopkins Health Alerts

http://www.johnshopkinshealthalerts.com/symptoms_remedies/asthma/73-1.html#4

• MD Consult

http://www.mdconsult.com/das/patient/body/280851038-3/1202850940/10041/9385.html

All information provided above is for basic awareness and education purposes only and should not be used for diagnosis or treatment of any medical condition under any circumstance. Please consult a licensed medical professional for these purposes. In case of medical emergency please call 911.

Copyright 2011 Talsk Research Inc. All rights reserved.