Asthma, COPD, and Sinusitis Notes

Anatomy of the Respiratory System

• Upper & Lower Respiratory Tract:
  • Nasal cavity (filters, warms, and humidifies air)
  • Mouth (alternative air entry)
  • Pharynx (connects nasal cavity to larynx)
  • Larynx (protects airways and produces sound)
  • Trachea (main airway to lungs)
  • Bronchi (primary branches into lungs)
  • Bronchioles (smaller airway branches)
  • Alveoli (microscopic air sacs for gas exchange)
  • Lungs (primary respiratory organs)
  • Diaphragm (contracts to facilitate breathing)

Asthma

• Definition: Chronic condition characterized by airway inflammation and narrowing, leading to breathing difficulties, chest tightness, and wheezing.
• Triggers: Allergens (pollen, pet dander), air pollutants, respiratory infections, physical activity.
• Pathophysiology:
  • Airway Inflammation: Activated inflammatory cells (eosinophils, mast cells, T-lymphocytes) release cytokines and mediators, causing mucosal edema and excessive mucus secretion.
  • Bronchial Hyperreactivity: Heightened sensitivity of bronchial smooth muscle to stimuli, resulting in exaggerated bronchoconstriction in response to triggers.
  • Airway Obstruction: Constricted bronchioles impede expiratory airflow, increasing airway resistance, causing air trapping and wheezing.
  • Airway Remodeling: Persistent inflammation promotes subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia, leading to irreversible structural changes and lung function decline.
• Symptoms: Wheezing, coughing (especially at night or early morning), chest tightness, and shortness of breath (dyspnea). Symptoms worsen during physical exertion, emotional stress, or exposure to triggers.
• Causes:
  • Allergens: Pollen, dust mites, pet dander.
  • Irritants: Air pollutants, smoke, strong odors.
  • Exercise: Can trigger bronchospasm.
  • Infections: Viral or bacterial respiratory infections.
• Genetic Predisposition: Family history increases risk due to multiple gene variants.
• Environmental Factors: Allergens, air pollutants, tobacco smoke, respiratory viral infections.

Types of Drugs Used for Asthma

• Inhaled Corticosteroids (ICS)
  • Mechanism of Action: Suppress airway inflammation by inhibiting inflammatory cell activity and cytokine production.
  • Examples: Fluticasone, Budesonide.
  • Side Effects: Hoarseness, oral thrush, increased risk of pneumonia.
• Long-Acting Beta-Agonists (LABAs)
  • Mechanism of Action: Stimulate beta-2 adrenergic receptors on airway smooth muscle, causing prolonged relaxation and bronchodilation.
  • Examples: Salmeterol, Formoterol.
  • Side Effects: Tremors, headache, increased heart rate.
• Short-Acting Beta-Agonists (SABAs)
  • Mechanism of Action: Rapidly activate beta-2 adrenergic receptors, quickly inducing bronchodilation.
  • Examples: Albuterol, Levalbuterol.
  • Side Effects: Tremors, nervousness, headache.
• Leukotriene Modifiers
  • Mechanism of Action: Block leukotriene receptors or inhibit leukotriene synthesis, preventing leukotriene-induced inflammation and bronchoconstriction.
  • Examples: Montelukast, Zafirlukast.
  • Side Effects: Headache, abdominal pain, mood changes.
• Combination Inhalers
  • Mechanism of Action: Deliver both anti-inflammatory (ICS) and bronchodilatory (LABA) effects.
  • Examples: Advair, Symbicort.
  • Side Effects: Hoarseness, tremors, increased heart rate.
• Theophylline
  • Mechanism of Action: Inhibits phosphodiesterase enzymes, increasing cAMP in airway smooth muscle, leading to bronchodilation and anti-inflammatory effects.
  • Examples: Theo-Dur, Slo-bid.
  • Side Effects: Nausea, headache, insomnia.

Chronic Obstructive Pulmonary Disease (COPD)

• Definition: Progressive respiratory disorder characterized by persistent airflow limitation due to alveolar wall destruction and bronchial passage thickening.
• Airflow Obstruction: Leads to reduced gas exchange capacity and impaired lung function.
• Inflammation: Persistent inflammatory response in airways, lung parenchyma, and pulmonary vasculature, neutrophil-dominant, leading to structural remodeling.
• Symptoms: Progressive dyspnea, chronic productive cough with sputum, wheezing, chest tightness, frequent respiratory infections; worsen over time.
• Pathophysiology:
  • Chronic Inflammation: Irritants trigger immune cells, causing ongoing inflammation.
  • Tissue Breakdown: Inflammatory substances damage lung tissue, causing breakdown of air sacs and loss of elasticity.
  • Excess Mucus Production: Ongoing irritation increases mucus-producing cells, blocking smaller airways.
  • Airway Narrowing: Repeated damage causes thickening of airway walls.
  • These permanent changes result in permanent airflow blockage.
• Causes:
  • Smoking: Primary cause (80-90% of cases).
  • Second-hand smoke: Increases risk by up to 30%.
  • Occupational exposure: Dust, chemicals, and fumes.
  • Air pollution: Indoor and outdoor pollutants.
  • Genetic factors: Alpha-1 antitrypsin deficiency (about 1% of cases).

Diagnosing and Treating Asthma and COPD

• Initial Assessment: Physical examination, detailed medical history.
• Diagnostic Tests: Spirometry, peak flow monitoring.
• Treatment Plan: Tailored medication regimens.
• Ongoing Management: Regular follow-ups to adjust treatment.
• Diagnosis:
  • Asthma: Physical exam, pulmonary function tests, allergy testing.
  • COPD: Physical exam, pulmonary function tests, chest X-ray.
• Treatment:
  • Asthma: Inhalers, oral medications, allergy avoidance.
  • COPD: Bronchodilators, inhaled corticosteroids, pulmonary rehabilitation.

Medication Treatment for COPD

• Bronchodilators:
  • Short-acting (salbutamol, ipratropium): Quick relief for 4-6 hours.
  • Long-acting (tiotropium, salmeterol): Maintain airway dilation for 12-24 hours.
  • Administered via metered-dose inhalers or dry powder devices.
• Corticosteroids:
  • Reduce airway inflammation in moderate-to-severe COPD (fluticasone, budesonide).
  • Often combined with bronchodilators (Seretide, Symbicort).
  • Administered twice daily.
• Phosphodiesterase-4 Inhibitors:
  • Roflumilast (Daxas): Reduces exacerbations in severe COPD with chronic bronchitis.
  • Taken as a once-daily oral tablet.
  • Added to Malaysian Ministry of Health Drug Formulary in 2018.
  • Side effects: nausea and weight loss.
• Supplemental Oxygen:
  • Prescribed when blood oxygen levels fall below 88% saturation.
  • Delivered via nasal cannula at 1-3 liters per minute.
  • Improves survival when used >15 hours daily.

Asthma and COPD MCQ Tutorial

• Which of the following is the primary trigger for asthma symptoms?
  • Correct Answer: Viral upper respiratory tract infections
• Which statement best differentiates COPD from asthma?
  • Correct Answer: COPD is usually irreversible, while asthma is largely reversible.
• Which is considered a first-line maintenance treatment for COPD?
  • Correct Answer: Long-acting muscarinic antagonists (LAMA)
• Which is NOT a common symptom of asthma?
  • Correct Answer: Chronic productive cough with sputum
• Pathophysiology: Which inflammatory cell is most associated with asthmatic airway inflammation?
  • Correct Answer: Eosinophils
• Medications: Fluticasone and budesonide belong to which drug class?
  • Correct Answer: Inhaled corticosteroids
• Diagnosis: A reduced FEV1/FVC ratio that doesn't improve with bronchodilators suggests what condition?
  • Correct Answer: COPD
• Comorbidities: Sinusitis in COPD patients may lead to what complication?
  • Correct Answer: Exacerbation of respiratory symptoms
• Treatment: Which therapy is appropriate for both severe asthma and COPD?
  • Correct Answer: Pulmonary rehabilitation

Sinusitis

• Definition: Inflammation of the sinuses, air-filled cavities in the bones of the face, caused by viral, bacterial, or fungal infection.
• Symptoms: Facial pain, pressure, headache, congestion, runny nose (worse when bending over or lying down).
• Duration:
  • Acute: Lasts for a few weeks.
  • Chronic: Lasts for more than 12 weeks; often occurs in individuals with asthma or COPD.
• Pathophysiology:
  • Inflammation: Pathogens, allergens, or irritants compromise the mucociliary clearance system.
  • Mucosal Edema: Swelling blocks narrow sinus ostia, preventing proper drainage.
  • Mucus Stasis: Trapped secretions create an environment for bacterial growth.
  • Inflammatory Response: Neutrophils and cytokines intensify inflammation, causing pressure and pain.
• Signs and Symptoms:
  • Facial Pain and Pressure: Concentrated over affected sinuses; intensity increases when bending forward or lying down.
  • Nasal Symptoms: Thick yellow-green discharge (bacterial infection), congestion.
  • Headache and Referred Pain: Frontal sinusitis causes forehead pain; maxillary inflammation creates toothache-like sensations.
  • Systemic Manifestations: Fever (acute bacterial cases), fatigue, and malaise.

Diagnosis of Sinusitis

• Clinical Assessment: History and examination of facial tenderness, nasal congestion, and discharge patterns.
• Diagnostic Imaging: CT scans reveal sinus opacification, mucosal thickening, and obstruction of sinus drainage pathways.
• Nasal Endoscopy: Direct visualization of nasal passages and sinus openings to identify inflammation, polyps, or structural issues.
• Culture Studies: Aspirates from infected sinuses identify specific pathogens and guide targeted antimicrobial therapy.

Managing Sinusitis

• Nasal Sprays: Decongestants and corticosteroids reduce inflammation and mucus.
  • Examples: Iliadin (xylometazoline) or Nasonex (mometasone furoate).
  • Side effects: dryness, burning, and headache.
• Antibiotics: Eliminate bacterial pathogens and help worsen asthma and COPD symptoms.
  • Examples: Klacid (clarithromycin) or Zinnat (cefuroxime).
  • Side effects: diarrhea, nausea, and rash.
• Humidifiers: Add moisture to the air to thin mucus.
• Nasal Rinse:
  • Sterimar (isotonic sea water) flushes out mucus and irritants.

Improving Quality of Life: Integrated Approaches

• Lifestyle Modifications: Quitting smoking, avoiding irritants, managing stress.
• Regular Exercise: Strengthen respiratory muscles.
• Nutrition: Healthy diet rich in fruits, vegetables, and whole grains.