Definition

Asthma is defined as a chronic inflammatory disorder of the airways characterized by reversible airway obstruction and bronchial hyperresponsiveness to various stimuli. This condition manifests clinically with recurrent episodes of wheezing, chest tightness, shortness of breath and coughing.

Asthma is a heterogeneous disease with various phenotypes, including allergic (IgE-mediated) asthma, non-allergic asthma, and exercise-induced asthma. The diagnosis of asthma typically involves spirometry to document variable expiratory airflow limitation and bronchial hyperresponsiveness.

Key History

Key Physical Exam

Classification Systems

• Daytime asthma symptoms < 2 times/week
• < 2 nocturnal awakenings/month
• PEF or FEV1 measurements when asymptomatic are within 80% of predicted normal range
• < 20% change in PEF during day
• Or asthma only with vigorous exercise or certain triggers, like viral infection or exposure to cats

• Daytime asthma symptoms > 2 times/week
• > 2 nocturnal awakenings/month
• PEF or FEV1 measurements when asymptomatic are within 80% of predicted normal range
• < 30% change in PEF during day

• Daily asthma symptoms
• > 1 nocturnal awakenings/week
• Asthmatic attacks that interfere with activity
• Daily need for bronchodilator medications (short or long-acting)
• PEF or FEV1 60–80% of predicted normal range

• Symptoms with minimal exercise
• > 2 nocturnal awakenings/week
• Asthma exacerbations occur frequently
• Require multiple asthma medications on a regular basis
• PEF or FEV1 < 60% of predicted normal range
• Widely varying PEF from day to day
• Lung function may consistently remain abnormal

A well-controlled asthmatic is one that has daytime symptoms no more than twice per week and no more than twice per month at night.

Differential Diagnosis

Diagnostic Testing

• Peak expiratory flow rate (PEFR)
• Spirometry
• Chest x-ray
• CBC
• Allergy testing
• Response to treatment

Clinical Risk

• Personal or family history of atopy
• Family history of asthma and allergies
• Asthmatic symptoms as a child

Back To Top

Treatment

Common text / literature recommendations include:

Current treatments for asthma are categorized into relievers and controllers, with the goal of managing symptoms and preventing exacerbations.

• Short-Acting Beta2-Agonists (SABAs): These are the first-line agents for rapid relief of acute bronchoconstriction. They act quickly to relax bronchial smooth muscle.

• Inhaled Corticosteroids (ICS): These make up the cornerstone of asthma management for their anti-inflammatory effects. They are recommended for all patients with persistent asthma to reduce airway inflammation and prevent exacerbations.


• Long-Acting Beta2-Agonists (LABAs): These are used in combination with ICS for better control of moderate to severe asthma. LABAs help in reducing symptoms and preventing nocturnal asthma.


• Leukotriene Receptor Antagonists (LTRAs): These are used as add-on therapy for patients with mild to moderate asthma who are not adequately controlled on ICS alone. They help in reducing inflammation and bronchoconstriction.


• Long-Acting Muscarinic Antagonists (LAMAs): Tiotropium is an example, used as an add-on therapy for patients with uncontrolled asthma despite ICS/LABA treatment.


• Biologics: These include monoclonal antibodies such as omalizumab (anti-IgE), mepolizumab, benralizumab, reslizumab (anti-IL-5), and dupilumab (anti-IL-4/IL-13). These are indicated for severe asthma with specific phenotypes such as eosinophilic or allergic asthma.


• Theophylline: This is a bronchodilator with some anti-inflammatory properties, used less frequently due to its narrow therapeutic window and side effects.

• Phosphodiesterase-4 (PDE-4) Inhibitors: These are being investigated for their anti-inflammatory properties but have shown inconsistent results in asthma management.


• Cytokine-Receptor Antagonists and Leukocyte-Suppressing Anti-Inflammatory Drugs (LSAIDs): These are under investigation and show promise as future treatments.

The National Asthma Education and Prevention Program (NAEPP) guidelines recommend a stepwise approach to asthma management, starting with ICS and adding LABAs, LTRAs, or biologics as needed based on the severity and control of the disease.

Complications

• Hypoxia
• Death

Pregnancy

Pregnant asthmatics with poorly controlled disease have a minimal increase in preterm birth, stillbirth, and low-birth-weight babies. Asthma improves in one-third of patients, stays the same in one-third, and worsens in one-third during pregnancy. The symptoms can be the same in pregnancy, but an increased concern for PE should also be considered.

Inhaled corticosteroids (ICS), long-acting beta2-agonists (LABAs), and short-acting beta2-agonists (SABAs) are generally considered safe for use during pregnancy, with some important considerations.

• ICS, particularly budesonide, are the preferred controller therapy for managing persistent asthma during pregnancy. Studies have shown that ICS use does not increase the risk of congenital malformations and is effective in maintaining asthma control, which is crucial for preventing maternal and fetal complications.


• SABAs such as albuterol are widely accepted as safe for acute symptom relief during pregnancy. They are effective in providing rapid bronchodilation and are recommended for managing acute exacerbations.


• LABAs, when used in combination with ICS, are also considered safe for pregnant women with moderate to severe asthma. Although the safety data for LABAs are less extensive than for ICS and SABAs, available studies support their use as add-on therapy to ICS for better asthma control.

Overall, the benefits of maintaining good asthma control with these medications outweigh the potential risks associated with their use during pregnancy. Poorly controlled asthma poses a greater risk to both the mother and fetus, including preeclampsia, preterm birth, and low birth weight. Therefore, it is essential to continue appropriate asthma management during pregnancy to ensure optimal outcome.

Back To Top