Asthma: Classification, Pathophysiology and Treatment

Asthma: Classification, Pathophysiology and Treatment

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Asthma: Classification, Pathophysiology and Treatment

The article will help you to explain briefly every aspect of asthma. Let’s start with Asthma: Classification, Pathophysiology and Treatment

Asthma: Classification, Pathophysiology and Treatment
Asthma: Classification, Pathophysiology and Treatment


Asthma is a chronic inflammatory disease of the airways that is characterized by chronic airway inflammation and increased airway hyperresponsiveness toward various stimuli leading to symptoms of wheezing, cough, chest tightness, and dyspnoea.



  • Begins in childhood.
  • Family history is common. Asthmatic attacks are often preceded by allergic rhinitis, urticaria, or eczema.
  • A skin test with the antigen results in an immediate wheal-and-flare reaction, a classic example of the type I IgE-mediated hypersensitivity reaction.
  • Extrinsic (Allergic) Triggers: Dust, mites, Mould, Certain foods, Animal dander, Pollen.


  • In asthmatic subjects, the bronchial response, manifested as spasm, is much more severe and sustained.
  • Positive family history is uncommon.
  • Serum IgE levels are normal.
  • There are no associated allergies.
  • Viral infections of the respiratory tract (most common) and inhaled air pollutants such as sulfur dioxide, ozone, and nitrogen dioxide are the common causes.
  • Virus-induced inflammation of the respiratory mucosa lowers the threshold of the subepithelial vagal receptors to irritants.
  • The ultimate humoral and cellular mediators of airway obstruction (e.g., eosinophils) are common to both atopic and non-atopic variants of asthma.
  • Intrinsic (Non-Allergic) Triggers: Exercise, Infections (cold and flu), Cold or humid air, Intense emotions (ex. Stress), Medications (aspirin), Hormones, Air pollution, Fragrances and chemicals, Occupational irritants.

ETIOLOGY & TRIGGERS: Asthma: Classification, Pathophysiology and Treatment

  • Genetic factors.
  • Allergen exposure: house dust mites, household pets, grass pollen Atmospheric pollution: sulfur dioxide, ozone, cigarette smoke, perfume.
  • Dietary deficiency of antioxidants: Vit-E and selenium may protect asthma in children(fresh fruits and vegetables).
  • Occupational sensitizers: Isocyanates(from the industrial coating, spray painting).
  • Drugs: NSAIDs, B-blocker.
  • Cold air.
  • Exercise.
  • Emotion.


Asthma is a disease characterized by airway inflammation and episodic, reversible bronchospasm. It has two characteristic features:

1) Inflammatory changes in the airway.

2) Bronchial hyperreactivity to stimuli.

  • Antigens (pollen and house-dust mites) sensitize patients by stimulating the production of IgE-type antibodies, which remain either circulating in the blood or become attached to the mast cells of nasal or bronchial tissues and basophils.
  • On re-exposure, to the same antigen, the resulting antigen-antibody reaction in the early phase causes degranulation of the lung mast cells and releasing of the powerful bronchoconstrictor such as histamine, 5-HT, PGD2, and cysteinyl leukotrienes (LTB4, LTC4, and LTD4).
  • Lung mast cells also release ILs (IL-4, IL-5, and IL-13).
  • In the late phase of asthma, these mediators activate other inflammatory cells (eosinophils, basophils, and alveolar macrophages) which also release LTs and ILs.
  • Other mediators of inflammation, in the delayed phase, are adenosine (causing bronchoconstriction), neuropeptides ( causing mucus secretion and increase in vascular permeability, etc.
  • The normal tone of bronchial smooth muscle is influenced by a balance between parasympathetic, sympathetic, and non-adrenergic–non-cholinergic (NANC) mediator’s activity.


Symptoms of asthma:

  • Coughing.
  • Wheezing.
  • Dyspnoea.
  • Shortness of breath.
  • Chest tightness.

As per the severity of the attack; it is classified as:

Mild asthma attack: Asthma: Classification, Pathophysiology and Treatment

  • Cough.
  • Wheezing.
  • Mild difficulty breathing during normal activities.
  • Difficulty sleeping.
  • The peak expiratory flow rate (PEFR) is 70 to 90%.

Moderate asthma attack:

  • Severe cough.
  • Moderate wheezing.
  • Shortness of breath.
  • Chest tightness.
  • Usually worsens with exercise.
  • Inability to sleep.
  • Nasal congestion.
  • PEFR is 50 to 70 %.

Severe asthma attack:

  • Severe wheezing.
  • Severe dyspnoea.
  • Inability to speak in complete sentences.
  • Inability to lie down.


  • Rib retractions: ribs are visible during each breath.
  • Nasal flaring: nostrils open wide during each breath.
  • Use of accessory muscles: neck muscles are prominent during each breath.
  • Chest pain: Sharp, chest pain when taking a breath, and coughing.


  • PEFR is <50%.
  • Confusion.
  • Rapid pulse.
  • Fatigue.
  • Tachycardia.
  • Hyper-resonant percussion note.
  • Expiratory rhonchi, expiration>inspiration.

SILENT CHEST: No findings when asthma is under control or b/w attacks.

INVESTIGATIONS: Asthma: Classification, Pathophysiology and Treatment

Lung function tests/ pulmonary function tests:

  • Spirometry– estimate degree of obstruction – ↓FEV1, ↓FEV1/FVC, ↓PEF.
  • Blood tests: shows an increase in the number of eosinophils in peripheral blood.
  • Sputum tests: It is a more useful diagnostic tool showing the presence of large numbers of eosinophils in the sputum.
  • Chest X-ray: There are no diagnostic features of asthma on the chest X-ray. It may be helpful in excluding a pneumothorax, which can occur as a complication of asthma.
  • Skin-prick tests (SPT): They should be performed in all cases of asthma to help identify allergic causes.

Asthma: Classification, Pathophysiology and Treatment


  • Chronic obstructive pulmonary disease (COPD).
  • Congestive heart failure.
  • Pulmonary embolism.
  • Laryngeal dysfunction.
  • Mechanical obstruction of the airways (benign and malignant tumors).
  • Pulmonary infiltration with eosinophilia.
  • Diffuse parenchymal lung diseases.
  • Vocal cord dysfunction.


  • Pneumonia (infection of the lungs).
  • Respiratory failure.
  • Status asthmaticus.
  • Pneumothorax.


  • Maintain pulmonary function as close to normal as possible.
  • Avoid adverse effects from asthma medications.
  • Prevent asthma mortality.

General Measures: Asthma: Classification, Pathophysiology and Treatment

  • Advice diets are higher in vitamins C and E, magnesium, and omega-3 fatty acids.
  • Avoid seafood that may become allergens.
  • Exercise: short, intermittent periods of exertion.
  • Stop smoking.
  • Reassure the patient, as anxiety worsens respiratory distress.
  • Keep the patient in an upright position.

Medicinal Therapy:

  • Start oxygen 50-60 % initially, and continue until the patient is better and not dyspnoeic.
    Nebulized with salbutamol or Terbutaline for immediate relief. Salbutamol 5 mg (1 ml with 1 ml normal saline) stat. Repeat the dose at 15 mins if required during the first hour. Hourly for the next few hours till the bronchospasm is controlled.
  • Secure I/V Inj. Hydrocortisone 200mg I/V stat routinely given to all severe cases than 6 hourly.
  • Antibiotic if there is evidence of infection.
  • Adequate hydration and mucolytics.

Asthma: Classification, Pathophysiology and Treatment


  1. Arsenic album.
  2. Spongia Tosta.
  3. Blatta Orientalis.
  4. Sambucus nigra.
  5. Nux vomica.
  6. Antimonium Tart.
  7. Dulcamara.
  8. Natrum sulph.

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