Expiratory Wheezing - Types and Treatment

Introduction:

Wheezing is a high-pitched whistling sound produced while exhaling when the airway is partially blocked. Wheezes can often be heard with the help of a stethoscope, whereas some wheezes can also be heard by ear without using a stethoscope. According to Bernoulli's principle, whenever air is forced to pass through a narrowed airway, it produces a superior high-pitched sound known as wheezing.

Narrowing of the airways can be due to various reasons, such as:

• Bronchospasm or constriction of the muscles of the airways.

• Mucus secretions in the airways.

• Swelling of the lining epithelium of the airways.

• Inhalation of foreign bodies.

• Abnormal proliferation of cells in the airways.

What Can Cause Wheezing?

Conditions that can cause wheezing are

1. Asthma: Bronchial asthma is a chronic inflammatory disease characterized by hyperresponsiveness of the tracheobronchial smooth muscle to a variety of stimuli, resulting in the narrowing of the airways along with increased secretion, mucosal edema, and mucus plugging. This makes it difficult for the air to flow easily through the airways, and it becomes difficult to breathe. Asthma can present as:

• Cough typically occurs at night or early morning.

• Difficulty in breathing.

• Chest tightness.

• Wheezing.

2.Allergic Reactions: Exposure to allergens, such as pollen grains, dust, food, and pet dander, often causes constriction of the airways.

3.Airway Obstruction: Due to airway obstruction due to weak lungs or certain condition.

4.Anaphylaxis: It is a life-threatening allergic reaction that occurs due to sudden exposure to certain substance and shows symptoms within minutes.

5. Chronic Bronchitis:The inflammation of the lining epithelium of the bronchi characterizes chronic bronchitis. It is a condition in which sputum production for more than three months per year for more than two consecutive years due to hyperplasia of the mucous gland located in the submucosal layer of the bronchial tubules.

6. Bronchiolitis: It is the inflammation of the bronchioles, often causing congestion, particularly in children.

7. Chronic Obstructive Pulmonary Diseases (COPD): A chronic inflammatory lung disease that results in irreversible airflow obstruction from the lungs. The leading cause of COPD is prolonged cigarette smoking. Other factors that play a role in the development of COPD are genetic disorders such as alpha 1 antitrypsin deficiency and occupational hazards due to long-term exposure to obnoxious chemical fumes, vapors, and dust particles which can inflame the lung parenchyma. The enzyme alpha 1 antitrypsin is produced by the liver and secreted into the bloodstream to protect the lungs. The enzyme helps inhibit the elastase enzyme; therefore, all the elastin is broken down. COPD mainly consists of two disorders: chronic bronchitis and emphysema. These two conditions can co-occur and can vary in severity.

8. Cystic Fibrosis: It is an autosomal recessive disorder that causes sticky, thick, hyper-viscous mucus to build up in the lungs. This mucus secretion is not removed; the secretions plug up ducts and the airways, leading to difficulty breathing and increasing the risk of infections. It is a defect in the cystic fibrosis transmembrane regulator (CFTR) gene. The CFTR is an epithelial anion channel in the alveolar ducts that facilitates the transfer of chloride and bicarbonate ions along with water to pass through it.

8. Inflammatory Cells: such as macrophages and polymorphonuclear cells, which release elastase and cause elastolysis and emphysema. A characteristic feature of emphysema is the barrel chest which is a rounded and enlarged chest appearance due to hyperinflation. Typically, the anteroposterior to transverse ratio is 5:7 or 1:2, but in the case of emphysema, it becomes 1:1 due to hyperinflation.

11. Smoking: Inhalation of the chemicals from the smoke can often cause activation of the inflammatory mediators, leading to the narrowing of the airways.

12. Respiratory syncytial virus (RSV): It is the most common type of viral infection affecting the lungs and the respiratory tract in small children below the age of two years. It often leads to bronchiolitis. In most cases, the disease is self-limiting and gets cured within one to two weeks.

13. Gastroesophageal reflux disease (GERD): It is a digestive disorder in which acid or bile irritates the food pipe.

14 Obstructive Sleep Apnea: It is the most common type of sleep-related breathing disorder. The condition occurs as the throat muscles relax, blocking the airways during sleep. A typical sign of obstructive sleep apnea is snoring loudly, especially if snoring is interrupted by periods of silence. Other signs of obstructive sleep apnea include awakening with dry mouth, abrupt awakening, gasping or choking, morning headache, and excessive daytime sleep.

What Are the Types of Wheezing?

Wheezing can be of two types:

• Inspiratory wheezing is less common and occurs during inhalation. It is more common in asthma patients.

• Expiratory wheezing is more common because the airways narrow down more during expiration or breathing out and often reflects mild airway blockage. Often the expiratory wheezing is so loud that it can be easily heard on its own.

• If wheezing is heard during inspiration and expiration, it reflects a more severe breathing problem. In acute asthma, inspiratory wheezing accompanies expiratory wheezing.

How to Treat Expiratory Wheezing?

Whether expiratory or inspiratory, managing wheezing depends on managing the underlying causes. Symptomatic relief can be achieved by administering oxygen. Usually, humidified oxygen can be administered, which is beneficial for patients with heavy mucus plugs in the small, distal airways. Other methods of providing symptomatic relief include nasopharyngeal suctioning and increased intravenous fluid administration. Medications that may help in providing symptomatic relief as well as treating the underlying causes are:

• Bronchodilators: Drugs that relax the tubules' muscles and dilate the airways, such as short and long-acting beta-agonists and anticholinergics.

• Corticosteroids: Drugs that help to reduce the inflammation of the airways.

• Combined Inhalers: Bronchodilators and corticosteroids combined as one inhaler.

• Antibiotics: Drugs to fight against bacterial infection.

• Mucolytics: Helps in lysis or breaking down the secretions such as guaiphenesin.

Even steam inhalation, exercises like pursed lip breathing and belly breathing exercises, using HEPA (high-efficiency particulate absorbing) filters, and avoiding smoking can reduce wheezing.

Conclusion:

Wheezing can occur during inhalation or exhalation. Asthma and airway inflammation are the most common causes of this symptom, but wheezing can be a characteristic sign of a severe respiratory condition. It can accompany other breathing difficulties, which may require immediate medical attention.