Asthma – Causes, Symptoms, Diagnosis & Treatment

According to Medscape, 24 million are affected in the US which include estimated 7 million children. Asthma is one of the leading conditions causing a huge cost burden to American healthcare. The economic impact of asthma in inflation-adjusted 2013 dollars has grown from over $10 billion in 1990 to over $60 billion in 2007.

Causes:

Various causes such as ones below can cause asthma.

• Allergens from dust, animal fur, cockroaches, mold, and pollens from trees, grasses, and flowers
• Irritants such as cigarette smoke, air pollution, chemicals or dust in the workplace, compounds in home décor products, and sprays (such as hairspray)
• Medicines such as aspirin or other nonsteroidal anti-inflammatory drugs and nonselective beta-blockers
• Sulfites in foods and drinks
• Viral upper respiratory infections, such as colds
• Physical activity, including exercise

Pathophysiology:

The pathophysiology of asthma exhibits airway inflammation, intermittent airflow obstruction, and bronchial hyperresponsiveness (bronchospasm).

At times, smooth muscles of airway (trachea and bronchi) get inflamed causing the narrowing of the lumen of airway. Overreaction of mast cells and eosinophils (part of immune system) play an important role in the regulation of airway inflammation through the release of numerous cytokines (small proteins for cell signaling).

Along with that, bronchospasm (or bronchial spasm) is the constriction of airway muscles almost closing the lumen and excessive production of mucus leading to difficulty in breathing and asthma attack.

Pathways of different forms of Asthma

Symptoms (Sx):

Wheezing – A whistling sound heard when breathing in or out.

Coughing – A cough that may not go away and often occurs or worsens at night or early morning.

Chest Tightness – Feeling as if something is squeezing or sitting on your chest.

Shortness of Breath – Feeling as though you can’t catch your breath. You may feel as though you are breathless.

Asthma Triggers such as allergens, irritants, or conditions may cause your symptoms to worsen. Symptoms can get worse at night due to low levels of Cortisol causing the airways to constrict, Sinus infection or Heartburn (GERD/Esophagitis Reflux).

During pregnancy, some women find that their asthma improves, while others find it worsens or stays the same.

Some medicines can trigger asthma symptoms. These medicines include aspirin, cold medicines, nonsteroidal pain relievers (for example, ibuprofen and naproxen sodium), and even some eyedrops used to treat glaucoma.

Diagnosis (Dx):

When patient informs the doctor of Asthma symptoms, before declaring the diagnosis, the doctor tests to prove the symptoms are backed by the exams.

One of the tests is taken by the patient in writing scoring the overall value of life affected by asthma. You can take this test here: http://www.asthma.com/additional-resources/asthma-control-test.html

Asthma Control Test

For asthma, 2 main tests are performed. One, to see for airflow obstruction and bronchospasm and second to see if the airway smooth muscles have inflammation.

I. Spirometry:

For airway obstruction and bronchospasm, Spirometry (lung function test) with postbronchodilator (albuterol) response should be obtained as the primary test to establish the asthma diagnosis.

Along with that, Exhaled Nitric Oxide (FeNO) test is performed to see if patient’s airway muscles are inflamed. Normal value for FeNO is 30ppb. During inflammation, higher-than-normal levels of nitric oxide (NO) are released from epithelial cells of the bronchial wall. The concentration of NO in exhaled breath, or fractional exhaled nitric oxide (FeNO), can help identify airway inflammation, and thereby support a diagnosis of asthma.

Spirometer for Pulmonary Function Test

Spirometry test results

PFT results

Bronchial Restriction: This can be determined by looking at the FVC reading.

If FVC reading = 80+ (normal), 60-79 (mild), 45-59 (moderate), <45 (severe)

Bronchial Obstruction: This can be determined by looking at the FEV1/FVC

If FEV1/FVC = 80+ (normal), 65-79 (mild), 45-65 (moderate), <45 (severe)

II. FeNO Test:

Along with that, Exhaled Nitric Oxide (FeNO) test is performed to see if patient’s airway muscles are inflamed. Normal value for FeNO is 30ppb. During inflammation, higher-than-normal levels of nitric oxide (NO) are released from epithelial cells of the bronchial wall. The concentration of NO in exhaled breath, or fractional exhaled nitric oxide (FeNO), can help identify airway inflammation, and thereby support a diagnosis of asthma.

Treatment:

Depending on the results taken above, appropriate Asthma Management Plan is devised by your doctor. Treatment focuses highly on controlling the symptoms and improving the quality of patient’s life. According to Medscape, medical care includes treatment of acute asthmatic episodes and control of chronic symptoms, including nocturnal and exercise-induced asthmatic symptoms. Pharmacologic management includes the use of control agents such as inhaled corticosteroids, inhaled cromolyn or nedocromil, long-acting bronchodilators, theophylline, leukotriene modifiers, and more recent strategies such as the use of anti-immunoglobulin E (IgE) antibodies (omalizumab). Relief medications include short-acting bronchodilators, systemic corticosteroids, and ipratropium.