Asthma
Disease Details
Family Health Simplified
- Description
- Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways, leading to episodes of wheezing, shortness of breath, chest tightness, and coughing.
- Type
- Asthma is a complex, multifactorial disease influenced by both genetic and environmental factors. It does not follow a simple Mendelian pattern of inheritance. Instead, the genetic transmission of asthma is polygenic, meaning multiple genes contribute to the risk of developing the condition, often interacting with environmental triggers.
- Signs And Symptoms
- Asthma is characterized by recurrent episodes of wheezing, shortness of breath, chest tightness, and coughing. Sputum may be produced from the lung by coughing but is often hard to bring up. During recovery from an asthma attack (exacerbation), it may appear pus-like due to high levels of white blood cells called eosinophils. Symptoms are usually worse at night and in the early morning or in response to exercise or cold air. Some people with asthma rarely experience symptoms, usually in response to triggers, whereas others may react frequently and readily and experience persistent symptoms.
- Prognosis
- The prognosis for asthma is generally good, especially for children with mild disease. Mortality has decreased over the last few decades due to better recognition and improvement in care. In 2010 the death rate was 170 per million for males and 90 per million for females. Rates vary between countries by 100-fold.Globally it causes moderate or severe disability in 19.4 million people as of 2004 (16 million of which are in low and middle income countries). Of asthma diagnosed during childhood, half of cases will no longer carry the diagnosis after a decade. Airway remodeling is observed, but it is unknown whether these represent harmful or beneficial changes. More recent data find that severe asthma can result in airway remodeling and the "asthma with chronic obstructive pulmonary disease syndrome (ACOS)" that has a poor prognosis. Early treatment with corticosteroids seems to prevent or ameliorates a decline in lung function. Asthma in children also has negative effects on quality of life of their parents.
- Onset
- Asthma can onset at any age, though it often begins in childhood.
- Prevalence
- Asthma is a common chronic respiratory condition that affects approximately 1 in 13 people, or about 7.7% of the population in the United States. Globally, it is estimated that around 235 million people are affected by asthma. The prevalence can vary significantly based on factors like age, sex, ethnicity, and geographical location.
- Epidemiology
- In 2019, approximately 262 million people worldwide were affected by asthma and approximately 461,000 people died from the disease. Rates vary between countries with prevalences between 1 and 18%. It is more common in developed than developing countries. One thus sees lower rates in Asia, Eastern Europe and Africa. Within developed countries it is more common in those who are economically disadvantaged while in contrast in developing countries it is more common in the affluent. The reason for these differences is not well known. Low and middle income countries make up more than 80% of the mortality.While asthma is twice as common in boys as girls, severe asthma occurs at equal rates. In contrast adult women have a higher rate of asthma than men and it is more common in the young than the old. In 2010, children with asthma experienced over 900,000 emergency department visits, making it the most common reason for admission to the hospital following an emergency department visit in the US in 2011.Global rates of asthma have increased significantly between the 1960s and 2008 with it being recognized as a major public health problem since the 1970s. Rates of asthma have plateaued in the developed world since the mid-1990s with recent increases primarily in the developing world. Asthma affects approximately 7% of the population of the United States and 5% of people in the United Kingdom. Canada, Australia and New Zealand have rates of about 14–15%.The average death rate from 2011 to 2015 from asthma in the UK was about 50% higher than the average for the European Union and had increased by about 5% in that time. Children are more likely see a physician due to asthma symptoms after school starts in September.Population-based epidemiological studies describe temporal associations between acute respiratory illnesses, asthma, and development of severe asthma with irreversible airflow limitation (known as the asthma-chronic obstructive pulmonary disease "overlap" syndrome, or ACOS). Additional prospective population-based data indicate that ACOS seems to represent a form of severe asthma, characterised by more frequent hospitalisations, and to be the result of early-onset asthma that has progressed to fixed airflow obstruction.
- Intractability
- Asthma is generally not considered intractable. With proper management, including medications and lifestyle adjustments, many individuals can achieve good control over symptoms. However, some cases, known as severe asthma, can be more difficult to manage despite optimal treatment.
- Disease Severity
-
Asthma can vary in severity from mild to severe:
1. **Mild Intermittent:** Symptoms occur less than twice a week, with nighttime symptoms less than twice a month.
2. **Mild Persistent:** Symptoms occur more than twice a week but less than once a day, with nighttime symptoms more than twice a month.
3. **Moderate Persistent:** Daily symptoms with nighttime symptoms more than once a week, requiring daily use of quick-relief inhalers.
4. **Severe Persistent:** Symptoms throughout the day, with frequent nighttime symptoms, severely limiting daily activities.
In terms of "nan," it is not a recognized term related to asthma severity. If this refers to "not a number" or "not applicable," it would imply missing or irrelevant data. Please clarify if more specific information is needed. - Healthcare Professionals
- Disease Ontology ID - DOID:2841
- Pathophysiology
- Asthma is the result of chronic inflammation of the conducting zone of the airways (most especially the bronchi and bronchioles), which subsequently results in increased contractability of the surrounding smooth muscles. This among other factors leads to bouts of narrowing of the airway and the classic symptoms of wheezing. The narrowing is typically reversible with or without treatment. Occasionally the airways themselves change. Typical changes in the airways include an increase in eosinophils and thickening of the lamina reticularis. Chronically the airways' smooth muscle may increase in size along with an increase in the numbers of mucous glands. Other cell types involved include T lymphocytes, macrophages, and neutrophils. There may also be involvement of other components of the immune system, including cytokines, chemokines, histamine, and leukotrienes among others.
- Carrier Status
- Asthma is not typically described in terms of "carrier status" because it is not a single-gene genetic disorder like cystic fibrosis or sickle cell anemia. Instead, asthma is a complex genetic condition influenced by multiple genes and environmental factors. Therefore, the concept of being a carrier of asthma does not apply.
- Mechanism
-
Asthma is a chronic inflammatory disorder of the airways characterized by recurrent episodes of wheezing, breathlessness, chest tightness, and coughing. The underlying mechanism involves airway inflammation, hyperresponsiveness, and reversible airflow obstruction.
**Mechanisms:**
1. **Airway Inflammation**: Persistent inflammation in the bronchial tubes due to infiltration of various immune cells like eosinophils, T lymphocytes (Th2 cells), mast cells, and macrophages.
2. **Airway Hyperresponsiveness**: Increased sensitivity of the airways to various stimuli such as allergens, exercise, cold air, or irritants.
3. **Airflow Obstruction**: Caused by bronchoconstriction, mucus hypersecretion, and structural changes in the airway walls (remodeling).
**Molecular Mechanisms:**
1. **Th2 Cell Activation**: The key immune response involves Th2 cells which release cytokines such as IL-4, IL-5, and IL-13. These cytokines promote:
- **Class Switching to IgE**: IL-4 and IL-13 induce B cells to produce IgE antibodies, which sensitize mast cells.
- **Eosinophil Recruitment and Activation**: IL-5 is crucial for the growth and activation of eosinophils, contributing to airway inflammation and damage.
2. **IgE-Mediated Mast Cell Activation**: Allergen exposure leads to cross-linking of IgE on mast cells, causing degranulation and release of histamine, leukotrienes, and other mediators of inflammation, leading to bronchoconstriction and airway hyperreactivity.
3. **Airway Remodeling**: Chronic inflammation can lead to structural changes in the airway, including increased smooth muscle mass, subepithelial fibrosis, and angiogenesis. Growth factors and pro-inflammatory cytokines like TGF-β and IL-13 contribute to these changes.
Understanding these mechanisms is critical for developing targeted therapies and managing asthma effectively. - Treatment
-
Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways. Treatment aims to control symptoms, reduce flare-ups, and improve lung function. Key treatments include:
1. **Quick-Relief Medications**:
- **Short-Acting Beta Agonists (SABAs)**: These bronchodilators, such as albuterol, provide rapid relief by relaxing airway muscles during an asthma attack.
2. **Long-Term Control Medications**:
- **Inhaled Corticosteroids**: These reduce inflammation in the airways and are the most effective long-term control for persistent asthma.
- **Long-Acting Beta Agonists (LABAs)**: Used in combination with inhaled corticosteroids to help control symptoms.
- **Leukotriene Modifiers**: Oral medications that help control asthma by blocking substances in the body that cause inflammation.
- **Combination Inhalers**: These contain both inhaled corticosteroids and LABAs for better control.
3. **Biologic Therapies**: These are injectable medications for severe asthma targeting specific pathways in the immune response. Examples include omalizumab, mepolizumab, and benralizumab.
4. **Theophylline**: An oral bronchodilator used less commonly due to potential side effects.
**Non-Pharmacologic Strategies**:
- **Trigger Avoidance**: Identifying and avoiding allergens and irritants that can trigger asthma symptoms.
- **Regular Monitoring**: Using a peak flow meter to monitor lung function and adjust treatment as needed.
- **Asthma Action Plan**: A personalized plan created with a healthcare provider to manage symptoms and exacerbations.
Always consult with a healthcare provider for personalized management and treatment options. - Compassionate Use Treatment
-
Compassionate use treatments and off-label or experimental treatments for asthma can provide options for patients who do not respond well to standard therapies. Some of these include:
1. **Monoclonal Antibodies (Biologics)**: These drugs, such as dupilumab, mepolizumab, reslizumab, and benralizumab, target specific inflammatory pathways involved in asthma and have been used experimentally for severe cases.
2. **Fevipiprant**: An oral drug that targets the prostaglandin D2 receptor 2 (DP2), this drug is in the experimental stage and has shown promise in reducing asthma symptoms and exacerbations.
3. **Tezepelumab**: This monoclonal antibody targets thymic stromal lymphopoietin (TSLP) and has shown efficacy in clinical trials for severe asthma.
4. **Bronchial Thermoplasty**: A non-drug treatment, this procedure involves heating the airways with a thermal probe to reduce smooth muscle mass, thereby decreasing the frequency and severity of asthma attacks. It is considered for severe asthma that is not controlled by medications.
These treatments are generally considered when conventional medications, such as inhaled corticosteroids and long-acting beta-agonists, are insufficient in managing the disease. Always consult a healthcare professional to discuss the appropriateness and potential risks of these treatments. - Lifestyle Recommendations
-
**Lifestyle Recommendations for Asthma:**
1. **Avoid Triggers:**
- Identify and limit exposure to allergens like pollen, dust mites, pet dander, and mold.
- Avoid tobacco smoke and other air pollutants.
2. **Healthy Diet:**
- Maintain a balanced diet rich in fruits, vegetables, and whole grains.
- Avoid foods that are known allergens or that trigger asthma symptoms.
3. **Regular Exercise:**
- Engage in regular physical activity to improve lung function, but consult a healthcare provider for tailored advice.
- Warm-up adequately and take preventive medication if exercise induces asthma.
4. **Weight Management:**
- Maintain a healthy weight, as obesity can exacerbate asthma symptoms.
5. **Stress Management:**
- Practice relaxation techniques like yoga, meditation, or deep-breathing exercises to reduce stress, which can trigger asthma.
6. **Home Environment:**
- Use air purifiers to reduce indoor allergens.
- Ensure good ventilation and humidity control in your living space.
7. **Medication Adherence:**
- Take prescribed asthma medications regularly as directed by your healthcare provider.
- Keep a quick-relief inhaler accessible at all times.
8. **Educate Yourself:**
- Understand your asthma action plan and recognize early signs of an asthma attack.
- Get regular medical check-ups to monitor your condition.
These lifestyle adjustments can help manage asthma and improve overall quality of life. - Medication
- Medications used to treat asthma are divided into two general classes: quick-relief medications used to treat acute symptoms; and long-term control medications used to prevent further exacerbation. Antibiotics are generally not needed for sudden worsening of symptoms or for treating asthma at any time.
- Repurposable Drugs
-
Repurposing drugs for asthma involves using medications that were originally developed for other conditions but have shown potential in treating asthma symptoms. Some examples include:
1. **Statins**: Commonly used to lower cholesterol, statins have anti-inflammatory properties that may be beneficial in asthma management.
2. **Macrolide Antibiotics**: Drugs like azithromycin have anti-inflammatory and antimicrobial effects that may help in treating severe asthma.
3. **Antifungal Medications**: Itraconazole and other antifungals can be repurposed for asthma, particularly in patients with allergic bronchopulmonary aspergillosis (ABPA).
These repurposing options are being actively researched to determine their efficacy and safety in the treatment of asthma. - Metabolites
- Asthma is characterized by airway inflammation and hyperreactivity. Key metabolites associated with asthma include leukotrienes, prostaglandins, and cytokines like IL-4, IL-5, and IL-13. These metabolites play roles in promoting inflammation, bronchoconstriction, and mucus production, which are hallmark features of asthma.
- Nutraceuticals
-
Nutraceuticals, which include vitamins, minerals, and other dietary supplements, have been explored for their potential benefits in managing asthma. Some of these nutraceuticals include:
1. **Omega-3 Fatty Acids**: Found in fish oil, they possess anti-inflammatory properties that may benefit asthma patients by reducing airway inflammation.
2. **Vitamin D**: Adequate levels of Vitamin D have been associated with better asthma control and fewer exacerbations, possibly due to its immune-modulating effects.
3. **Magnesium**: This mineral may help relax bronchial muscles, thus improving airflow and reducing symptoms.
4. **Antioxidants**: Vitamins C and E, and other antioxidants may protect against oxidative stress, which can exacerbate asthma symptoms.
Patients should consult healthcare professionals before starting any nutraceutical regimen for asthma management. - Peptides
-
Peptides are short chains of amino acids and have been studied for their potential role in asthma treatment. They can modulate immune responses and reduce inflammation, offering a novel approach to therapy.
Nanotechnology (nan) in asthma focuses on enhancing drug delivery systems. Nano-sized particles can improve the precision and effectiveness of asthma medications, reduce side effects, and offer targeted treatment options.