Bronchial Spasm: Etiology, Diagnosis, and Management

Introduction

Bronchial spasm is also referred to as bronchospasm. It happens when the muscles in the walls of the bronchi tighten. It causes breathing difficulties and results in hypoxia. It usually occurs in individuals with respiratory diseases like asthma or COPD (chronic obstructive pulmonary disease). It can also occur due to various factors.

What Is Bronchial Spasm?

The trachea (windpipe), which is the main airway, branches off into the right and left bronchi. The bronchus further divides into smaller branches. The smallest branches that lead to the air sacs in the lungs are called bronchioles. The bronchioles are lined with smooth muscle layers, which help in bronchodilation and bronchoconstriction. Bronchial spasm denotes a sudden constriction of the smooth muscles that line the bronchioles. It limits the amount of oxygen in the body and results in breathing difficulties. Children, especially infants, are more susceptible to bronchospasm, but it can affect people of any age.

Development of Bronchospasm

The anaphylatoxins stimulate mast cells or basophils. The mast cells release histamine, cysteinyl-leukotrienes, and prostaglandins to cause bronchoconstriction. The mast cells also release cytokines to cause inflammation. This stimulus causes constriction and inflammation of the airways resulting in the narrowing of the airways. The stimulation of smooth muscles of the bronchioles causes hyperresponsiveness. Airway obstruction results in increased resistance to airflow. This decreases the expulsion of air and results in hyperinflation. This increases the work of breathing. These changes increase mucus production, reduce the amount of oxygen available to the body, and result in coughing, breathlessness, and hypoxia.

Etiology of Bronchial Spasm

It can be caused by various factors, which include:

• Bacterial, viral, or fungal infections of the airway.

• Lower respiratory tract disorders like asthma, chronic obstructive pulmonary disease, and emphysema.

• Dust, pollen, pet dander, and other allergens.

• Anaphylaxis

• Foreign body aspiration.

• Exercise-induced bronchospasm.

• Chemical fumes or other irritants.

• Cold temperatures.

• Smoking.

• Topical decongestants like Oxymetazoline and Phenylephrine.

• Pilocarpine and beta blockers can cause bronchospasm as a side effect.

• Breathing tubes during general anesthesia can cause bronchospasm.

Living With Bronchospasm

Bronchial spasm is scary and can cause life-threatening experience. It causes symptoms like:

• Tightness in the chest.

• Shortness of breath.

• Wheezing.

• Coughing.

• Prolonged expiration.

• Diminished breath sounds.

• Increases airway pressures in ventilated patients.

• Tiredness.

• Dizziness.

Are Bronchospasm, Laryngospasm, and Asthma the Same?

Bronchospasm, laryngospasm, and asthma affect breathing. However, they are different conditions.

Bronchospasm vs. Laryngospasm

Bronchospasm affects the bronchi and bronchioles. Laryngospasm affects the vocal cords.

Bronchospasm causes constriction of the smooth muscles lining the bronchioles. Laryngospasm causes sudden closure of vocal cords and obstructs the flow of air into the lungs.

Bronchospasm vs. Asthma

Asthma causes symptoms like bronchospasm. Asthma causes bronchospasm as a symptom, but bronchospasm does not cause asthma. Asthma and bronchospasm are caused due to irritation and inflammation of the airways.

Complications of Bronchospasm

Bronchospasm causes sudden constriction. An episode of bronchial spasm lasts between seven and fourteen days. It can cause serious complications if left untreated. Air trapping from obstruction caused by bronchospasm results in pneumothoraces and pneumomediastinum. It leads to respiratory distress and respiratory failure with hypoxia and hypercapnia. Respiratory arrest lasting for more than five minutes damages vital organs like the brain. Brain injury lasting for more than five minutes can result in death. Bronchospasm usually presents as wheezing. Timely intervention is important to prevent serious complications.

Diagnosis of Bronchospasm

The diagnosis of bronchospasm is based on the presentation of symptoms. Following tests are performed to assess lung function. This include:

• Pulse Oximetry - A pulse oximeter device is placed on the finger to measure the oxygen saturation in the blood.

• Spirometry - A spirometer is a device with a breathing tube. It measures the force of air breathed in and out of the tube.

• Lung Volume Assessment - This test is done to measure the amount of air that the lungs can hold.

• Lung Diffusion Capacity - This test uses a breathing tube through which the patient breathes. This measures how well the oxygen is diffused between the lungs and the blood.

• Arterial Blood Gas Test - This test measures the amount of oxygen and carbon dioxide in the blood. It is also used to measure the pH (potential of hydrogen) level of blood.

• Eucapnic Voluntary Hyperventilation - This test is performed to diagnose exercise-induced bronchospasm. The patient is asked to breathe in a mixture of oxygen and carbon dioxide, and this mimics breathing during exercise. If it causes a negative impact on the lungs, it denotes the presence of exercise-induced bronchospasm.

• Radiographic Imaging - Radiographs are not routinely performed. Chest X-rays and CT (computed tomography) scans may be performed to diagnose lung infections and other problems like pneumothorax, pneumonia, and atelectasis.

Management of Bronchospasm

Bronchospasm is usually managed with bronchodilators. Severe cases are treated with steroids to reduce inflammation in the airways. The treatment includes the following:

• Short-Acting Bronchodilators - Terbutaline, Salbutamol, and Levosalbutamol are the commonly used short-acting bronchodilators. They offer rescue relief from symptoms. Short-acting bronchodilators widen the airways in a few minutes, and this effect lasts up to six hours.

• Long-Acting Bronchodilators - Formoterol and Salmeterol are the commonly used long-acting bronchodilators. They do not offer immediate relief. The effect occurs after a long time but lasts for up to 12 hours. Anticholinergic agents are other forms of long-acting bronchodilators. They are available as short-acting agents (Ipratropium) and long-acting agents (Tiotropium, Umeclidinium, and Aclidinium).

• Steroids - Inhalational steroids are given to reduce the inflammation of the airways. Severe cases of bronchospasm require intravenous treatment with steroids.

If bronchospasm is due to respiratory tract infections or allergic reactions, specific treatment is given to manage such conditions. There are no home remedies available for the treatment of bronchospasm. If the individual has already been diagnosed with bronchospasm and has been using short-acting inhalers, then this can be used on the occurrence of another episode.

Conclusion

Bronchospasm is a common respiratory condition. It is a treatable disease that cannot be prevented. It is a common symptom in respiratory conditions like asthma and COPD. It can cause life-threatening symptoms and complications. If left untreated, it results in serious complications. Early diagnosis and treatment is important to prevent the risk of complications. It is important to consult the physician on experiencing symptoms like breathing difficulty.