Airway Hyperresponsiveness - Causes, Symptoms, Diagnosis, Treatment

Introduction:

Lungs are the respiratory organ of the body, present in the chest wall. Airway hyperresponsiveness (AHR) is an abnormal condition affecting a person's air passage. In AHR, the lungs' airways become highly sensitive and narrow in response to certain stimuli. Narrowing of the airway makes breathing difficult. AHR can lead to various respiratory problems, such as asthma and chronic obstructive pulmonary disease (COPD).

What Are the Causes of Airway Hyperresponsiveness?

The exact cause of AHR is unknown, but it is believed it occurs due to a combination of genetic and environmental factors. The causes of AHR are given as follows:

• Genetics - Genetic variations associated with increased risk of developing AHR. Studies have identified several genes associated with an increased risk of asthma and other respiratory conditions. Still, the exact mechanisms are not unknown.

• Environmental factors - Certain environmental factors are associated with the development of AHR. Some of the most common environmental factors include the following-

1. Allergens - Exposure to specific allergens such as dust, pollens, and animal dander can lead to inflammation in the airways of patients.

2. Inflammation - Chronic inflammation causes the narrowing of the airways, and the airways become more sensitive to triggers.

3. Smoking - Tobacco smoke can irritate the airways and increase the risk of AHR.

4. Occupational Exposure - Certain chemicals and irritants are also responsible for it.

5. Air Pollution - Air pollution, produced from smog and diesel, can irritate the airways.

6. Other Underlying Conditions - Various underlying conditions, such as obesity, are associated with it.

What Are the Symptoms of Airway Hyperresponsiveness?

Symptoms of AHR depend on the person and the severity of the condition. The common symptoms of AHR include the following:

• Wheezing - It is a high-pitched whistling sound during breathing, usually heard when breathing out.

• Chest Tightness - A tightness in the chest during breathing makes breathing difficult.

• Shortness of Breath - Difficulty breathing or feeling like a person can not catch their breath.

• Coughing - A persistent or recurrent cough that worsens at night or in the early morning.

• Fatigue - A person may feel tiredness or weakness due to difficulty breathing.

• Rapid Breathing - The breathing rate becomes faster than usual.

• Trouble Sleeping - The person feels difficulty sleeping due to coughing, chest tightness, and shortness of breath.

• Chest Pain - A feeling of pain or discomfort in the chest. Sometimes people mistake it for a heart attack.

• Rapid Heartbeat - The heartbeat becomes faster than normal, known as tachycardia.

• Bluish Discoloration of the Lips and Face - Lips, face, and extremities become blue due to a lack of oxygen supply to the body's tissues.

• Difficulty Speaking - Difficulty in speaking due to shortness of breath or the presence of tightness in the chest.

• Difficulty Performing Physical Activities - People finddifficulty in performing physical activities, including playing sports, going for a walk, or climbing stairs.

What Are the Diagnosis of Airway Hyperresponsiveness?

Diagnosis of AHR typically involves a combination of tests. The diagnostic methods used to identify AHR are as follows:

• Physical Examination - A healthcare professional heard the sounds of the lungs with a stethoscope to detect abnormal sounds such as wheezing. Doctors also examine the chest to check the signs of increased breathing effort. These signs include using accessory muscles, chest retractions, and flaring nostrils.

• Lung Function Tests - Spirometry is the most common lung function test used to diagnose AHR. This test measures the air a person can inhale and exhale and detect any airways narrowing. Spirometry also measures peak flow measurement (a simple test that measures the maximum speed of air exhaled). It can also be used to monitor the severity of AHR.

• Breathing Tests - Methacholine challenge test involves inhaling a substance that causes the constriction of the airways and then measures how much the airways have narrowed in response. This test helps diagnose AHR in people who have not been diagnosed with asthma.

• Allergy Testing - Skin or blood tests helps in the detection of any allergies that are responsible for AHR.

• Chest X-ray or CT (Computed Tomography) Scan - These imaging tests are done to check for any structural abnormality in the lung.

What Are the Treatment of Airway Hyperresponsiveness?

Treatment for AHR aims to reduce symptoms and improve the functional capacity of the lung. The treatment options that may be used for AHR include the following:

• Inhaled Bronchodilators - These medications relax the muscles in the airways and help open them up, which helps in making breathing easier. These medications are typically used as a "reliever" medication. These are taken when symptoms occur. Examples of inhaled bronchodilators such as Albuterol, Levalbuterol, and Terbutaline.

• Inhaled Corticosteroids - These medications help reduce inflammation in the airways. They are typically used as a "controller" medication. These medications are taken regularly to prevent symptoms. Examples of inhaled corticosteroids include Fluticasone and Budesonide.

• Oral Corticosteroids - These medications used in severe cases of AHR, typically used when inhaled medications alone, are insufficient to control symptoms. These are given for a short period. These drugs also have many potential side effects. Therefore, they should always be used under medical supervision.

• Leukotriene Modifiers - These medications block the action of leukotrienes (chemicals produced by the body that can cause inflammation in the airways). Examples include Montelukast and Zafirlukast.

• Immunomodulators - These medications can target the underlying cause of AHR, such as allergic reactions. Examples include Omalizumab and Mepolizumab.

• Lifestyle Changes - In addition to medication, lifestyle changes help manage AHR. Avoid trigger factors, such as cigarette smoke and allergens. These measures can reduce the likelihood of an exacerbation of the condition. Regular exercise also helps to improve lung function and overall health.

Conclusion:

Airway hyperresponsiveness is characterized by the airways' narrowing, which makes breathing difficult. A combination of genetic and environmental factors is responsible for its occurrence. AHR is a progressive condition, meaning symptoms become more severe over time if left untreated. Therefore, it is essential to consult a healthcare provider to monitor the condition and take treatment as necessary. The healthcare professional will diagnose adequately and make an appropriate treatment plan. The treatment plan for AHR depends on the patient's condition and the severity of the condition. Making an individualized treatment plan and monitoring the condition regularly is essential. Regular follow-up appointments with a healthcare provider are necessary to monitor the condition and to adjust the treatment plans whenever necessary.