Pathology of Asthma

What is Asthma?

Asthma is a disorder of the lungs that causes intermittent symptoms. In the airways there is:

  • Swelling or inflammation, specifically in the airway linings
  • Production of large amounts of mucus that is thicker than normal
  • Narrowing because of muscle contractions surrounding the airways
The symptoms of asthma include:
  • Feeling short of breath
  • Frequent coughing, especially at night
  • Wheezing (a whistling noise during breathing)
  • Difficulty breathing
  • Chest tightness
How does asthma affect breathing?

Asthma causes a narrowing of the breathing airways, which interferes with the normal movement of air in and out of the lungs. Asthma involves only the bronchial tubes and does not affect the air sacs or the lung tissue. The narrowing that occurs in asthma is caused by three major factors: 

  1. Inflammation: The most important factor causing narrowing of the bronchial tubes is inflammation. The bronchial tubes become red, irritated, and swollen. This inflammation occurs due to release of chemical mediators in response to an allergen or irritant and results in thickening of the walls of the bronchial tubes and narrow airways.
  2. BronchospasmThe smooth muscles of the bronchii could contract painfully and involuntarily, as a response to multiple chemical mediators. This condition is largely reversible by bronchodilators though.
  3. Hyperreactivity: In patients with asthma, the airways become highly sensitive (hyper-responsiveness) to triggers such as allergens, irritants, and infections.
Developing Asthma

There are situations within ourselves, called endogenous factors, which help develop asthma. Some things you can change, some things you can’t – but it is good to be aware of them. 

  1. Genetic predisposition to have asthma has been well documented. There is a 30 percent chance of the child having asthma if one parent is asthmatic - and 70 percent chance if both parents are.
  2. Atopy, or allergic hypersensitivity to various allergens including pollen, dust, animal hairs, etc.
  3. Obese people are more likely to have asthma.
  4. Gender: In childhood, asthma is twice more common in boys than in girls. In adults the prevalence of asthma is more in women though.
Asthma Causes and Triggers

People with asthma have very sensitive airways that react to many different things in the environment called "asthma triggers." Contact with these triggers cause asthma symptoms to start or worsen. The following are common triggers for asthma:

  • Infections such as sinusitis, colds, and flu
  • Allergens such as pollens, mold spores, pet dander, and dust mites
  • Irritants such as strong odors from perfumes or cleaning solutions, and air pollution
  • Tobacco smoke
  • Exercise (known as exercise-induced asthma)
  • Weather; changes in temperature and/or humidity, cold air
  • Strong emotions such as anxiety, laughter or crying, stress
  • Medications, such as aspirin-sensitive asthma
How is asthma diagnosed?
  1. Episodic breathing difficulty
  2. Chest tightness
  3. Cough and wheezing

Appearance of symptoms on exposure to potential environmental triggers and a confirmatory family history are helpful in making the diagnosis. In some patients, particularly in children, longstanding cough may be the predominant feature, known as cough variant asthma. 

Treatment

The goal of asthma treatment is to achieve and maintain good control over the illness. There are two types medicines for asthma – those which prevent asthma attacks are called as controllers and those that give relief during an attack of asthma are called as relievers.

  • Controllers are to be taken daily on a long term basis to keep asthma under control. Inhaled corticosteroids are the most effective controllers currently available.
  • Relievers are used on an ‘as-needed’ basis to get quick relief from symptoms. Rapid acting Beta 2 Agonists are the medications of choice for relief. Other medicines used in the treatment of asthma include Leucotriene modifiers, Theophilline, anticholinergics and cromones.

Asthma treatment can be administered in different ways – inhalation, orally or by injections. The advantage of inhalations is that the drugs are delivered directly into the airways, producing higher local concentrations with significantly less side effects. 

Additional Tips
  • Try to identify your asthma triggers and avoid them. Steer clear of allergens, irritants and pollutants in the air, and respiratory infections.
  • Eat herbs and spices like rosemary, sage, oregano, ginger and turmeric in your cooking.
  • Eat at least two servings of cold water fish like salmon, cod, mackerel, and herring a week. You can also take omega-3 supplements after consulting your doctor.
  • Include more fresh fruits and vegetables in your diet. Nutrients like magnesium, selenium beta-carotene, and vitamins C and E can help improve lung function.
  • Avoid eating processed and packaged foods with artificial food additives and preservatives. The chemicals may trigger asthma attacks.
  • Restrict your intake of milk and dairy products if you are allergic to milk proteins or have lactose intolerance due to lactase deficiency. Those who do not suffer from these problems, however, can take milk as the fats in whole milk tend to have a protective effect against asthma symptoms. 

SOURCE: Adapted from an article by Dr. Rajeev Moge