Asthma Overview and Causes

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Questions and Answers

Which risk factors for asthma are considered non-modifiable?

Air pollution

Allergen exposure

Obesity

Family history (correct)

What is the pathophysiological process that leads from inhaled allergens to bronchoconstriction?

T cell activation and cytokine release

Direct bronchial irritation and swelling

Alveolar inflammation and edema

Th2 activation and IgE production (correct)

In which group is asthma more prevalent in childhood?

Neither group, asthma is rare in childhood

Males (correct)

Females of all ages

Both genders equally

What are common intermittent symptoms of asthma?

Chest tightness and coughing Signup and view all the answers

What can severe asthma exacerbations potentially lead to?

Respiratory acidosis due to CO2 retention Signup and view all the answers

What is a significant consequence of chronic inflammation in asthmatic patients?

Structural changes in the airways Signup and view all the answers

Which of the following is NOT considered a non-modifiable risk factor for asthma?

Exposure to air pollution Signup and view all the answers

What role do eosinophils, neutrophils, and basophils play in the late phase response of asthma?

They contribute to mucus hypersecretion. Signup and view all the answers

How does obesity influence the risk of developing asthma?

Due to the effects of pro-inflammatory mediators from adipose tissue Signup and view all the answers

Which factor is a known risk for developing asthma later in life?

Exposure to RSV in childhood Signup and view all the answers

What is mucus hypersecretion in the context of asthma typically associated with?

Increased airway hyperresponsiveness Signup and view all the answers

Which of the following accurately describes airway remodeling associated with uncontrolled asthma?

Subepithelial fibrosis and smooth muscle hypertrophy Signup and view all the answers

Which allergen is a recognized trigger for asthma attacks?

Dust mites Signup and view all the answers

What is the most common trigger for asthma attacks?

Environmental allergens Signup and view all the answers

Which immune response component is activated when inhaled allergens are processed?

Dendritic cells Signup and view all the answers

What role do Th2 cells play in the development of asthma?

Producing IgE antibodies Signup and view all the answers

What physiological response occurs during the early phase response of asthma?

Degranulation of mast cells Signup and view all the answers

What is a common effect of histamine and leukotrienes in asthma?

Bronchoconstriction Signup and view all the answers

Which of the following is not a factor contributing to asthma development?

Nutritional deficiencies Signup and view all the answers

What happens to smooth muscle in the airways during an asthma attack?

It constricts rapidly Signup and view all the answers

What are the consequences of increased vascular permeability during an asthma attack?

Increased mucus secretion Signup and view all the answers

Study Notes

Asthma

Asthma is a chronic inflammatory disorder of the airways, causing variable airflow obstruction, bronchial hyperresponsiveness, and airway remodeling. It is often reversible with treatment.

Most Likely Causes

Inhaled Allergens (Environmental Triggers): Common triggers include dust mites, pollen, pet dander, mold, and cockroach droppings.
Air Pollutants and Irritants: Exposure to air pollution, tobacco smoke, strong odors, and chemical irritants can trigger asthma.
Genetic and Environmental Interactions: A genetic predisposition combined with environmental exposure increases asthma risk.
Respiratory Infections: Viral infections (like RSV and rhinovirus) in childhood can increase asthma risk.

Pathophysiology

Sensitization and Initial Immune Response: Inhaled allergens are processed by antigen-presenting cells (APCs), like dendritic cells, in the airways. APCs present allergens to naive T-helper cells (Th0), which differentiate into Th2 cells that secrete cytokines. IL-4 stimulates B cells to produce IgE antibodies specific to the allergen. IgE antibodies bind to mast cells, sensitizing them.
Early Phase Response: Upon re-exposure, mast cells degranulate, releasing histamine, leukotrienes, and prostaglandins. These cause bronchoconstriction, vasodilation, increased vascular permeability (leading to mucus secretion), and airway swelling. This rapidly causes wheezing, shortness of breath, and chest tightness.
Late Phase Response (4-8 Hours After Initial Exposure): Eosinophils, neutrophils, and basophils are recruited to the inflammation site, along with additional pro-inflammatory cytokines and cytotoxic mediators.

Airway Remodeling

Chronic Inflammation: Uncontrolled asthma can lead to structural changes in the airways. Smooth muscle hypertrophy, goblet cell hyperplasia, and deposition of extracellular matrix proteins (subepithelial fibrosis) stiffens the airway wall. This makes the airways hyperresponsive to irritants, perpetuating the cycle.

Disease Transmission

Not transmissible. It is a non-communicable chronic disease.

Risk Factors (Modifiable)

Allergen Exposure: Exposure to common allergens like pollen, dust mites, animal dander, and mold.
Air Pollution: Exposure to air pollutants.
Occupational Exposure: Exposure to chemical irritants and fumes in certain workplaces.
Respiratory Infections: Viral infections in childhood (e.g., RSV, rhinovirus).
Smoking: Active and passive smoking in childhood.
Obesity: Obesity linked to pro-inflammatory mediators from adipose tissue.
Diet: Diets low in antioxidants, omega-3 fatty acids, and fruits/vegetables could increase risk.

Risk Factors (Non-Modifiable)

Genetic Factors: Family history of asthma, eczema, and allergic rhinitis.
Age: Childhood exposure to allergens and infections.
Sex: Males at greater risk in childhood, females in adulthood.
Ethnicity: Some studies show higher rates among certain groups.

Clinical Manifestations

Intermittent Symptoms: Wheezing, shortness of breath, chest tightness, and cough that worsen at night, early morning, or upon exposure to triggers.
Airway Obstruction: Difficulty exhaling, air trapping in the alveoli, prolonged expiratory phase, and reduced lung capacity.
Hyperinflation of the Lungs: Dyspnea (shortness of breath), and use of accessory muscles.
Severe Asthma Exacerbations: Respiratory acidosis due to CO2 retention, potentially life-threatening.

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Description

This quiz covers the basics of asthma, focusing on its pathophysiology and the most common causes. Learn about environmental triggers, the role of genetics, and how respiratory infections can influence asthma development. Test your knowledge and understanding of this chronic inflammatory disorder.