Allergies and Respiratory Infections Quiz

Overview of Asthma

• Affects all ages, most notably children; gender ratio shifts from M>F in childhood to F>M in adult onset.
• Consists of three components: airway inflammation, hyperresponsiveness, and limitation (obstruction) which is often variable and reversible.

Inflammation in Asthma

• Involved cells:
  • Mast cells, basophils, eosinophils, macrophages.
  • Epithelial cells, endothelial cells, smooth muscle cells, goblet cells, myofibroblasts.
• Key mediators:
  • Histamine, platelet-activating factor (PAF), prostaglandins (D2, D4, E4, C4), IL-5, IL-13, leukotrienes, IgE.

Airflow Limitation and Remodeling

• Airflow restriction is generally reversible.
• Causes of fixed airway narrowing:
  • Bronchoconstriction from smooth muscle contraction.
  • Edema due to increased blood vessel permeability.
  • Increased secretions from goblet cells.
  • Structural changes: fibrosis, smooth muscle hypertrophy/hyperplasia, goblet cell hyperplasia with cilia loss.

Hyperresponsiveness

• Severity of asthma ranges from mild to severe.
• Triggers include dust mites, cockroaches, pollution, respiratory infections, tobacco, NSAIDs/aspirin, beta blockers, exercise, GERD, and pet dander.

Risk Factors

• Genetic predisposition: atopy and high IgE levels.
• Environmental influences: pollution and allergens.
• Infections: particularly viral and atypical bacterial.
• Obesity, race, and gender also play roles.

Clinical Features

• Symptoms often worsen at night and in the early morning: recurrent cough, wheezing, chest tightness, breathlessness.
• Physical exam signs include tachycardia, tachypnea, pulsus paradoxus, prolonged expiration phase, and accessory muscle use.
• Conditions indicating higher asthma probability: eczema and nasal polyps.

Differential Diagnosis (DDx)

• Conditions to consider:
  • Laryngospasm, cardiac asthma, COPD, upper airway obstruction, anemia, obesity, left ventricular (LV) dysfunction, bronchiectasis.

Laboratory Investigations

• Lung function tests:
  • Peak expiratory flow, spirometry with bronchodilator reversibility, bronchial challenge test.
• Blood tests:
  • Complete blood count (CBC), IgE levels, and radioallergosorbent testing (RAST).
• Imaging:
  • Chest radiograph for hyperinflation or pneumonia exclusion, CT scan for bronchiectasis.
• Exhaled nitric oxide (FeNO) testing: indicates eosinophilic inflammation.

Management Goals

• Control symptoms, maintain normal activity, ensure adequate pulmonary function, prevent exacerbations, minimize medication side effects, and prevent mortality.

Components of Severity

• Symptoms categorized as intermittent, mild persistent, moderate persistent, or severe persistent.
• Severity affects treatment approach and medication.

Asthma Control Levels

• Classified as controlled, partly controlled, or uncontrolled based on daytime symptoms, activity limitations, nocturnal symptoms, need for rescue medication, and lung function measures.

Diagnosis and Evaluation

• Assessment requires symptom evaluation, lung function measurement, inhaler technique checks, dose adjustments, and self-management plans.

Treatment Options

• Regular preventer medications, short-acting beta agonists (SABAs) for relief, adjustment of treatment based on patient response.
• Preferred treatments may include high-dose SABA/SAMA, and systemic steroids.
• Intubation and mechanical ventilation may be necessary for impending respiratory failure.

Signs of Severity in Asthma Attacks

• Mild: breathlessness while walking, sentences spoken, alert, normal respiratory rate.
• Moderate: breathlessness at rest, phrases only, increased respiratory rate.
• Severe: breathlessness limits conversation, agitated, >30/min respiratory rate, loud wheezing, unable to recline, possible bradycardia.

Respiratory Failure Indicators

• Increasing obstruction may lead to serious conditions; respiratory arrest is a life-threatening event requiring immediate intervention.

Test your knowledge on common allergens and their relationship to respiratory infections. This quiz covers various pollutants including dust mites, cockroaches, and the impact of tobacco. Enhance your understanding of how different substances affect respiratory health.