This lecture is on Pathology of asthma for nurses. This lecture is prepared for sem 4 nursing students. It includes, etiopathogenesis, gross morphology and microscopic morphology and diagnosis of asthma. It describes charcot leyden crystals and Cruschman spiral.
2. DEFINITION
Disease of airways that is characterized by increased
responsiveness of the tracheobronchial tree to a variety of stimulus
leading to spasmodic narrowing of the air passage.
4. EXTRINSIC ASTHMA
Also called allergic asthma
Begins in childhood
Family history present of allergic diseases
Hypersensitivity to allergens
Allergens like, dust, pollens, animal danders etc.
Occupational asthma is a variant of extrinsic asthma in
which fumes, gases and organc substances inhaled by
the person causes asthma.
Increased levels og Ig E in serum
Positive skin tests for allegerns
6. Occurs by Ig E mediated hypersensitivity reaction occurring in 2 stages
Acute immediate response Late phase reaction
7. 1) ACUTE IMMEDIATE RESPONSE
Initiated by Ig E sensitized mast cells
Mast cells on degranulation releases cell mediators like
histamine, prostaglandins, leukotrienes etc.
Bronchoconstriction occurs due to inflammatory reaction
Oedema
Hypersecretion of the mucus occurs
Eosinophils and neutrophils accumulates
8. 2) LATE PHASE REACTIONS
Follows acute immediate response.
Responsible for prolonged effect of asthma
Excessive mobilization of blood leucocytes including
basophils leads to release of further cell mediators
thus taking time to heal.
Inflammatory injury occurs.
9. INTRINSIC ASTHMA
Also called idiosyncratic or non atopic asthma
No family history of asthma
No known allergens
Negative skin tests for allergens
Normal serum IgE levels
Usually occurs in adults
Occurs after a upper respiratory tract infection caused
by a virus
Patient becomes hypersensitive to drugs.
Aspirin sensitive asthma
11. MIXED ASTHMA
Patient does not clearly fits into any classification
Asthma which occurs as a result of cold, exercise, emotional stress etc falls under this category
12. EXERCISE INDUCED ASTHMA
Occurs 5 to 20 min of exercise
Slight chest pain to severe cough and wheezing may occur
Shortness of breath
14. MICROSCOPIC MORPHOLOGY
Mucus plugs contains normal or degenerated respiratory epithelium
This twists into spirals called as the CRUSHMAN’S SPIRALS
Sputum contains eosinophils
Diamond shaped crystals derived from eosinophils are also seen in sputum called as the CHARCOT-
LEYDEN CRYSTALS
Thick wall of the bronchi
Submucosal edema
Inflammatory infiltrate of lymphocytes, plasma cells and eosinophils
Too much eosinophils
Hypertrophy of mucosal glands
Hypertrophy of smooth muscles of the bronchi
15.
16. Epithelial shedding
Exudative inflammatory process and sloughing of epithelial cells into the airway impairs
mucociliary transport
Bronchial glands increases in size and number
17. CLINICAL FEATURES
Acute attacks with symptom free periods
Attacks of dyspnea
Cough
Wheezing
Lasts from minutes to hours
Use of accessory muscles
Tachypnea
Tachycardia
Hyperesonance
19. STATUS ASTHMATICUS
Life threatening emergency
Occurs when bronchospasms does not get relived by conventional medications
Can lead to worsening of acid base balance, hypoxemia respiratory arrest etc.
20. Diagnostic studies
History and physical examination
Pulmonary function test
Chest x ray
Arterial blood gas
Oximetry
Allergy testing
Blood levels of eosinophils
Sputum culture and sensitivity
Spirometry – Patient demonstrates lung capacity by blowing air into the incentive spirometer
Methacholine challenge- patient breathes in increasingbamounts of methacholine andperforms
spirometry after each dose.
21. TREATMENT
Long term control medications
1) Corticosteroids
Inhaled form
Systemic steroids
2)Cromolyn sodium
Anti inflammatory agents
3)Long acting beta blockers- relaxes airway smooth muscles
4)Methylxanthines- bronchodilator
5)Leukotrine modifiers- reduces leukotriene
22. QUICK RELIEF MEDICATIOSN
1) Short acting beta 2 antagonists- relaxes airway smooth muscles and increase in airflow
2) Anticholinergics- bronchodilator
3) Systemic steroids