Asthma

Definition

Asthma is inflammation and narrowing of the airways (called the bronchial tubes).

Causes

The cause of asthma is not known, although it does seem to run in some families. Current research implicates environmental respiratory exposures in a genetically and biologically predisposed individual. Possible triggers of an asthma attack in a person with asthma include:

• Exercise
• Cold weather
• Viral illness
• Sinusitis
• Gastroesophageal reflux disease (GERD)
• Sulfites used in dried fruits and wine
• Medications, such as aspirin, ibuprofen, and beta-blockers
• Exposure to irritants or allergens, including:
  
  • Cigarette smoke, smoke from a wood-burning stove
  • Pet dander
  • Dust
  • Chemicals
  • Mold and mildew
  • Pollen
  • Smog or air pollution
  • Perfumed products

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

• Living in a large urban area
• Regularly breathing in cigarette smoke (including second-hand smoke)
• Regularly breathing in industrial or agricultural chemicals
• A parent who has asthma
• History of multiple respiratory infections during childhood
• Low birth weight
• Being overweight
• Gastroesophageal reflux disease (GERD)

Symptoms

Symptoms include:

• Wheezing
• Tightness in the chest
• Trouble breathing
• Shortness of breath
• Cough
• Chest pain
• Self-limited exercise, difficulty keeping up with peers

Diagnosis

The doctor will ask about your symptoms and medical history and perform a physical exam:

Tests may include:

• Peak flow examination—blowing quickly and forcefully into a special instrument that measures your output of air
• Pulmonary function tests (PFTs)—breathing into a machine that records information about the function of your lungs
• Bronchoprovocation tests—lung function tests performed after exposure to methacholine, histamine, or cold or dry air, which can cause narrowing of the airways in susceptible people; this test helps confirm asthma in unclear cases, but is not often used in a general practice setting.
• Exhaled nitric oxide (a marker of airway inflammation)—to confirm the diagnosis and manage medications
• Allergy tests —usually skin or sometimes blood tests to find out if allergies are causing your symptoms

Treatment

The treatment approach to asthma is four-fold: regular assessment and monitoring, control of contributing factors (including treatment of concurrent medical conditions such as gastroesophageal reflux and sinusitis), patient education, and medications. Often, you'll need to take more than one type of medication.

Asthma medications include:

Prevention

There are no guidelines for preventing asthma because the cause is not known. However, you can help prevent asthma attacks by avoiding substances that trigger the attacks. Some general guidelines include:

• Keep windows closed.
• Consider getting HEPA filters for your heating/cooling system and your vacuum cleaner.
• Keep the humidity down in your house.
• Avoid strenuous outdoor exercise during days with high air pollution, a high pollen count, or a high ozone level.
• Get a yearly flu shot .
• Treat allergies and sinusitis.
• Don't smoke.
• Avoid breathing in chemicals or second-hand smoke.
• Don't use a wood-burning stove regularly.
• Consider getting allergy shots, if allergies trigger your asthma attacks.
• Talk to your doctor about an appropriate level of exercise for you.
• Talk to your doctor about how to track your asthma, so you can identify and treat flare-ups immediately.