Asthma - Symptoms & Causes

No, there is no cure for asthma, but the symptoms can be controlled for a healthy lifestyle.

During sleep, airways shrink which adds a bit more resistance to the air entering and exiting our bodies. This results in coughing and further narrowing of the airways. The sinuses may then begin to drain, causing an asthmatic reaction.

Children below five years of age already have short, constricted bronchial tubes, and illnesses like head colds, chest colds, and other respiratory infections can irritate and constrict these already-sensitive airways.

There is no way to prevent asthma but it is possible to avoid severity of the disease by following a proper medication plan, keeping regular checks on vaccinations especially for influenza and pneumonia, monitoring the breathing regularly to detect early warning signs, and identifying and avoiding asthma triggers.

Risk factors of asthma include blood relation with an asthmatic person, active or passive smoking, being overweight, constant exposure to pollutants and harmful chemicals.

Asthma is preliminarily diagnosed through a test called spirometry. The patient is told to inhale deeply into a tube that is attached to a spirometer, and then to forcibly exhale through it to assess how well the lungs are functioning (pulmonary function).

Common asthma triggers include allergens (like pollen, dust mites, and pet dander), irritants (such as smoke and strong odors), respiratory infections, exercise, cold air, and stress. Each person with asthma may have different triggers, and identifying these is crucial for managing the condition.

In asthma, the airways produce excess mucus in response to inflammation. This thick, sticky mucus can clog the already narrowed airways, further obstructing airflow. The combination of mucus, inflammation, and bronchospasm creates the characteristic difficulty in breathing experienced by asthma patients.

Acute asthma symptoms, also known as asthma attacks or exacerbations, are sudden worsening of symptoms that can be severe and require immediate treatment. Chronic asthma symptoms are ongoing, milder symptoms that persist over time and require long-term management. Both types can significantly impact a person's quality of life.

The hygiene hypothesis suggests that a lack of early childhood exposure to certain microorganisms and parasites may increase susceptibility to allergic diseases, including asthma. This theory proposes that our increasingly clean environments may prevent the immune system from developing properly, leading to overreactions to harmless substances.

In asthma, the immune system overreacts to certain triggers, releasing chemicals that cause inflammation in the airways. This immune response leads to increased mucus production, swelling of the airway lining, and tightening of the muscles around the airways, all contributing to the characteristic symptoms of asthma.

Allergies and asthma are closely related. Many people with asthma have allergic asthma, where allergens trigger their symptoms. The same immune system overreaction that causes allergy symptoms can also trigger asthma symptoms. This connection is why managing allergies is often an important part of asthma control.

Nitric oxide plays a complex role in asthma. In normal lung function, it helps relax airway smooth muscles. However, in asthma, there's often an overproduction of nitric oxide, which can contribute to inflammation. Measuring exhaled nitric oxide levels is sometimes used as a non-invasive way to assess airway inflammation in asthma patients.

Air pollution can worsen asthma symptoms by irritating the airways and increasing inflammation. Particulate matter, ozone, and other pollutants can trigger asthma attacks and contribute to long-term airway damage. People with asthma are often more sensitive to changes in air quality and may need to take extra precautions on high-pollution days.

Many people with asthma experience worse symptoms at night or in the early morning. This is partly due to the body's circadian rhythm, which affects hormone levels and airway function. Understanding this pattern helps in timing medication doses and identifying potential nighttime triggers.

Obesity can worsen asthma symptoms and make the condition harder to control. Excess weight can put pressure on the lungs, making breathing more difficult. It also increases inflammation throughout the body, which can exacerbate airway inflammation. Weight loss is often recommended as part of asthma management for obese patients.

Airway remodeling refers to structural changes in the airways that occur over time in some people with asthma. This includes thickening of the airway walls, increased mucus gland size, and changes in the airway smooth muscle. These changes can lead to permanent narrowing of the airways and may not be fully reversible, even with treatment.

Cold air can trigger asthma symptoms by cooling and drying the airways. This can cause the airway muscles to contract and lead to increased mucus production. Additionally, cold air often contains less moisture, which can further irritate the airways. Understanding this mechanism helps in developing strategies to prevent cold-induced asthma attacks.

GERD and asthma often coexist and can exacerbate each other. Acid reflux can irritate the airways and trigger asthma symptoms. Conversely, asthma can worsen GERD by changing pressure relationships in the chest and abdomen. Managing GERD can sometimes lead to improvements in asthma symptoms.

Inhaled corticosteroids work by reducing inflammation in the airways. They suppress the immune response that causes swelling and mucus production, making the airways less sensitive to triggers. This helps prevent asthma symptoms and reduces the frequency and severity of asthma attacks over time.

Bronchodilators are medications that relax the muscles around the airways, helping to open them up and improve airflow. There are two main types: short-acting bronchodilators for quick relief of symptoms, and long-acting bronchodilators for ongoing control. They work by binding to receptors on airway smooth muscles, causing them to relax.

Asthma is unique because it involves both inflammation and reversible airway obstruction. Unlike chronic obstructive pulmonary disease (COPD), asthma symptoms can often be completely reversed with proper treatment. Asthma also tends to have triggers that cause sudden flare-ups, whereas other respiratory conditions may have more constant symptoms.

The "early phase" response occurs within minutes of exposure to a trigger and involves the rapid constriction of airway smooth muscles. The "late phase" response happens hours later and is characterized by increased inflammation and mucus production. Understanding these phases helps in developing targeted treatments for both immediate and long-term symptom management.

Bronchial smooth muscles surround the airways. In asthma, these muscles can become hypersensitive and contract excessively in response to triggers. This contraction, known as bronchospasm, narrows the airways and makes breathing difficult. Many asthma medications work by relaxing these muscles to open up the airways.

Exercise-induced asthma, or exercise-induced bronchoconstriction, is triggered specifically by physical activity. It occurs when the airways narrow in response to the increased breathing rate and dry, cool air associated with exercise. While it shares similar symptoms with other forms of asthma, it is uniquely tied to physical exertion.

Extrinsic (allergic) asthma is triggered by allergens and involves an IgE-mediated immune response. Intrinsic (non-allergic) asthma is not caused by allergens and its triggers are often less clear. It may be related to viral infections, exercise, or stress. Understanding this distinction can help in tailoring treatment approaches.

Anti-IgE medications, such as omalizumab, work by binding to and neutralizing IgE antibodies in the blood. IgE plays a crucial role in allergic reactions, including those that trigger asthma. By reducing free IgE, these medications can decrease the allergic response and improve asthma control in people with severe allergic asthma.

Eosinophils are white blood cells that play a significant role in the inflammation associated with asthma. In some types of asthma, there's an increase in eosinophils in the airways. Newer biologic treatments for severe asthma specifically target pathways that reduce eosinophil numbers or activity, helping to decrease inflammation and improve symptoms.

Thunderstorm asthma is a phenomenon where a thunderstorm triggers a sudden and severe asthma attack in multiple people simultaneously. It occurs when the storm's downdrafts carry pollen grains to ground level, where they rupture due to moisture and release tiny allergenic particles. These particles can penetrate deep into the lungs, potentially causing severe asthma attacks in susceptible individuals.

Viral respiratory infections, such as the common cold, can trigger asthma attacks and worsen symptoms. These infections cause additional inflammation in the airways, making them more sensitive to other triggers. For many people with asthma, catching a cold can lead to a significant exacerbation of their condition.

Beta-2 agonists are a type of bronchodilator that work by binding to beta-2 receptors on airway smooth muscle cells. This binding causes the muscles to relax, widening the airways and improving airflow. They provide quick relief of symptoms but don't address the underlying inflammation in asthma.

Leukotrienes are inflammatory molecules produced by the immune system that contribute to airway constriction and increased mucus production in asthma. Leukotriene modifiers are medications that block the action of these molecules, helping to reduce inflammation and improve asthma control.

Stress can worsen asthma symptoms through several mechanisms. It can lead to rapid, shallow breathing that irritates the airways. Stress also affects the immune system and can increase inflammation throughout the body, including in the airways. Additionally, stress may cause people to neglect their asthma management routines.

Airway hyperresponsiveness refers to the tendency of the airways in people with asthma to react more strongly to various stimuli compared to those without asthma. This heightened sensitivity can cause the airways to narrow excessively in response to triggers that wouldn't affect a person without asthma, leading to characteristic symptoms.

Inhaled corticosteroids are delivered directly to the airways, allowing for high local concentrations with minimal systemic side effects. They're used for long-term control. Oral corticosteroids affect the entire body and are typically used for short periods to manage severe asthma exacerbations due to their potential for significant side effects with long-term use.

The airway epithelium, the layer of cells lining the airways, plays a crucial role in asthma. In asthma, this barrier can become damaged and dysfunctional, leading to increased permeability to allergens and irritants. The epithelium also produces inflammatory mediators that contribute to the overall inflammatory response in asthma.

The "united airway disease" concept suggests that upper and lower airway diseases, such as allergic rhinitis and asthma, are interconnected and part of a single inflammatory process. This understanding emphasizes the importance of treating both upper and lower airway symptoms for optimal asthma management.

LAMAs work by blocking muscarinic receptors in the airways, which helps to relax airway smooth muscles and reduce mucus secretion. Unlike beta-2 agonists, which stimulate receptors to open airways, LAMAs block the action of acetylcholine, a neurotransmitter that causes airway constriction. They're often used as an add-on therapy for patients whose asthma is not well-controlled with other medications.

Vitamin D plays a role in immune system function and may help reduce airway inflammation. Some studies suggest that vitamin D deficiency is associated with increased asthma severity and poorer control. While more research is needed, maintaining adequate vitamin D levels may be beneficial for some asthma patients.

The lung microbiome, the community of microorganisms living in the airways, may play a role in asthma development and severity. An imbalance in the microbiome (dysbiosis) could contribute to airway inflammation and hyperresponsiveness. Understanding the lung microbiome may lead to new therapeutic approaches for asthma in the future.

AERD, also known as Samter's Triad, is a chronic condition characterized by asthma, recurrent nasal polyps, and sensitivity to aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs). In people with AERD, taking these medications can trigger severe asthma attacks. Understanding this condition is crucial for proper management of affected individuals.

Pregnancy can have variable effects on asthma, with some women experiencing improvement and others worsening of symptoms. Hormonal changes and the growing uterus putting pressure on the diaphragm can impact breathing. Proper asthma control during pregnancy is crucial for the health of both mother and baby, and may require adjustments to medication regimens under medical supervision.

IL-5 is a cytokine that plays a key role in the production and activation of eosinophils, which contribute to airway inflammation in asthma. IL-5 inhibitors are biologic medications that block the action of IL-5, reducing eosinophilic inflammation. These drugs can be effective in treating severe eosinophilic asthma that doesn't respond well to standard treatments.

Occupational asthma is caused or worsened by exposure to specific substances in the workplace. It can develop in people with no prior history of asthma or exacerbate pre-existing asthma. Unlike other forms of asthma, symptoms may improve when away from work and worsen during work hours. Identifying and avoiding the occupational trigger is crucial for management.

Asthma phenotypes refer to distinct subgroups of asthma based on clinical characteristics, triggers, and underlying mechanisms. Examples include allergic asthma, exercise-induced asthma, and eosinophilic asthma. Identifying a patient's specific phenotype can help in tailoring more effective, personalized treatment approaches.

Beta-blockers, commonly used to treat heart conditions, can potentially worsen asthma symptoms in some patients. They work by blocking beta receptors, including those in the lungs that help keep airways open. This can lead to bronchoconstriction. However, some newer, more selective beta-blockers may be safer for people with asthma.