Asthma

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Asthma

Overview

Asthma is a condition in which the airways become narrow and produce extra mucus. Due to this, it becomes difficult to breathe and the person has wheezing, coughing and shortness of breath. In some individuals, asthma occurs as a minor disease. In others, it becomes a major problem which interferes with daily activities and can lead to a life-threatening asthma attack. Asthma is not curable, but its symptoms can be controlled.

Asthma is present worldwide. About 5% to 10% of people suffer from asthma. About 300 million people suffer from asthma worldwide, and 250,000 annual deaths are caused due to asthma.

Normally, when the person breathes, air goes through the nose and fills the lungs. There are very small air passages in the lungs which help deliver oxygen from the air to the bloodstream. When the lining of air passages swell with mucus, the muscles tighten and asthma symptoms occur. The mucus gets collected in the airways decreasing the passage of air. This lead to the coughing and tightness in the chest that is typical of an asthma attack.

Causes

  • Asthma triggers
  • Exposure to various allergens and irritants will trigger asthma. Asthma triggers are usually :
  • Airborne substances like pollen, dust mites, particles, mold spores, and pet dander.
  • Respiratory infections like that of a common cold
  • Cold air
  • Exercise or physical activity
  • Irritants like smoke and air pollutants
  • Certain medications like aspirin, beta blockers, naproxen (Aleve) and ibuprofen (Motrin IB, Advil, others)
  • Stress and strong emotions
  • Preservatives and Sulfites added to various types of beverages and foods like dried fruit, shrimp, beer, processed potatoes and wine.
  • Gastro esophageal reflux disease (GERD) is a condition in which acids from the stomach go back into the throat.

Symptoms

The signs and symptoms of asthma are

  • Shortness of breath,
  • A cough that worsens at night
  • Wheezing with exhalation (a high-pitched whistling sound due to turbulent airflow through narrow airways).
  • Many patients also report chest tightness.
  • The symptoms are usually episodic, and individuals with asthma can go for long periods of time without any symptoms.
  • Common triggers for asthmatic symptoms include exposure to allergens (dust mites, pets, molds, cockroach, and pollens), viral infections and exercise.
  • Many of the signs and symptoms of asthma are usually nonspecific and are also seen in other conditions also. Symptoms that might suggest conditions other than asthma are the presence of associated symptoms (such as palpitations, chest discomfort, fatigue, and lightheadedness), new symptom onset in older age and lack of response to appropriate medications for asthma.
  • The physical examination of a patient with asthma may reveal wheezing, increased heart rate, increased respiratory rate and the effort required for respiration.
  • Individuals use accessory muscles to breathe, and breath sounds are usually diminished. Usually, the blood oxygen level remains normal. Low blood oxygen level is a dangerous sign signifying respiratory failure.

Risk factors

The risk factors that increase the chances of asthma are as follows:

  • Individuals with a blood relative with asthma such as a parent or sibling
  • Allergic conditions like allergic rhinitis (hay fever) or atopic dermatitis
  • Overweight
  • Smoking and exposure to second-hand smoke
  • Exposure to exhaust fumes or other types of pollution
  • Exposure to occupational triggers like chemicals used in hairdressing, farming, and manufacturing.

Diagnosis

History and physical examination are very important in diagnosing asthma. The person usually has a history of allergic rhinitis or other allergic conditions, wheezing, coughing and difficulty breathing, with exercise or during the night. There may also be a tendency toward respiratory infections or bronchitis. Typically improvement with medications is suggestive of asthma.

Diagnostic procedures which are used in the diagnosis of asthma are:

  • Spirometry is used to measure the functioning of a lung as the person breathes into a tube. If the person’s lung functioning improves after administration of a bronchodilator like albuterol, this will confirm the diagnosis of asthma. It is important to note, however, that normal lung function testing does not rule out the possibility of asthma.
  • Measurement of exhaled nitric oxide (FeNO): It is performed by a simple breathing exercise. Increased levels of exhaled nitric oxide suggest “allergic” inflammation that is seen in asthma.
  • Skin testing for common aeroallergens: The presence of sensitivities to environmental allergies increases the likelihood of asthma. Skin testing is useful to detect allergies to environmental substances.
  • Methacholine challenge test detects hyper-responsiveness of the airway. The tendency of the breathing tubes to narrow in response to irritants is called hyper-responsiveness. Negative methacholine indicates asthma least likely.
  • Sputum eosinophils is another marker for “allergic” inflammation seen in asthma.
  • Chest imaging may show hyperinflation. Tests to rule out other conditions like cardiac testing is also used in certain cases.
  • Blood testing helps differentiate the types of asthma. Blood tests help to know the level of allergic antibody (IgE) or specialized white blood cells called eosinophils, that are associated with allergic or extrinsic asthma.

Treatment

The goals for treating asthma are

  • Control symptoms adequately
  • Risk of future exacerbations is minimized
  • Normal lung function is maintained
  • Normal activity levels are maintained
  • Medication should be used in the least required amount with minimal side effects.
  • Most effective anti-inflammatory agents are the inhalation corticosteroids (ICS) which are used for the treatment of asthma and are considered as first-line. ICS is recognized as very effective in decreasing the risk of asthma exacerbations. The combination of an ICS and long-acting bronchodilator (LABA) has a significant beneficial effect on improving asthma control.

Asthma medications that are used most commonly include the following

  • Short-acting bronchodilators (Albuterol) help to quick relief and can be used in conjunction with exercise-induced symptoms.
  • Inhaled steroids (budesonide, fluticasone, mometasone, beclomethasone, flunisolide,  ciclesonide)  are first-line anti-inflammatory therapy.
  • Long-acting bronchodilators (formoterol, salmeterol, vilanterol)is added to ICS as additive therapy.
  • Leukotriene modifiers zafirlukast, (montelukast, zileuton) serve as anti-inflammatory agents.
  • Anticholinergic agents (ipratropium bromide, tiotropium)  can help decrease sputum production.
  • Anti-IgE treatment (omalizumab) can be used in allergic asthma.
  • Anti-IL5 treatment (mepolizumab, reslizumab) can be used in eosinophilic asthma.
  • Chromones (cromolyn, nedocromil) stabilize mast cells (allergic cells) but are rarely used in clinical practice.
  • Theophylline helps in bronchodilation (open the airways) but is rarely used in clinical practice due to an unfavorable side-effect profile.
  • Systemic steroids (prednisone, prednisolone, methylprednisolone [Solu-Medrol, Medrol, dexamethasone) are the anti-inflammatory medicines which are used to treat asthma exacerbations but has many side effects.
  • Monoclonal antibodies will be available within the next couple of years for treating asthma.
  • Immunotherapy or allergy shots decrease the use of medication in allergic asthma.
  • Asthma medications are administered via inhalers or nebulized solution. Smoking cessation or minimizing exposure to smoke is essential in treating asthma. Treating conditions like allergic rhinitis and gastroesophageal reflux disease (GERD) improve asthma control. Vaccinations for influenza and pneumonia are given to prevent asthma exacerbations.
  • Though many patients with asthma are treated as outpatients, severe exacerbations are managed in the emergency department. These patients require supplemental oxygen, administration of systemic steroids, bronchodilators like a nebulized solution. Patients with poor outcomes are referred to a specialist (pulmonologist or allergist).

The patient is referred to a pulmonologist

  • If the person has any history of multiple hospitalizations for asthma or ICU admission.
  • History of multiple admission in the emergency department
  • History of use of systemic steroids for asthma frequently
  • Symptoms with no relieve with medications
  • Significant allergies causing poorly controlled asthma.

Prevention

  • One cannot prevent asthma: However, the person can have a better living with the condition if few steps are taken.
  • Follow the asthma action plan: With the help of doctor and also the health care team, medications are used to manage an asthma attack. Asthma is an ongoing illness which requires regular monitoring and treatment.
  • Get vaccinated for influenza and pneumonia: Vaccinations for flu and pneumonia are given to prevent asthma flare-ups.
  • Identify and avoid asthma triggers: A number of allergens and irritants ranging from pollen to air pollution will trigger asthma attacks.
  • Monitor your breathing: The home peak flow meter is used to measure and record the peak airflow. Coughing, Wheezing or Shortness of breath is recognized as warning signs of an attack, and immediate actions should be undertaken.
  • Identify and treat attacks early: The person is less likely to have a severe attack if attacks are detected and treated early. When your peak flow measurements decrease it is an alert of an oncoming attack. Take your medications as instructed and immediately stop any activity that may have triggered the attack. If your symptoms don’t improve, get medical help as directed in your action plan.
  • Take the medication as prescribed: Just because asthma seems improving, never change medication without doctor opinion. It’s a good idea to carry the medications for every medical visit so that the doctor will double-check the use of medications correctly and help in taking the right medication.
  • Pay attention to increase use of the quick-relief inhaler: If the person finds increased use of quick-relief inhaler like albuterol, it indicates that asthma is not under control. The doctor will adjust the treatment.