Related Subjects:
|Red blood cells
|White blood cells
|Lymphocytes
|Platelets
|Cryoprecipitate
|Fresh Frozen Plasma
|d Blood Cell Maturation
🧾 About Leukotrienes
- 🧪 Leukotrienes are lipid mediators derived from arachidonic acid via the lipoxygenase pathway in leukocytes.
- 🌡️ They play a central role in allergic and inflammatory reactions.
- 💧 Increase vascular permeability → oedema and tissue swelling.
- 🧲 Act as chemoattractants, drawing neutrophils & eosinophils to sites of inflammation.
- 🌬️ Leukotriene D4 = “slow-reacting substance of anaphylaxis (SRS-A)” → potent bronchoconstrictor & intestinal smooth muscle contraction.
- 🤧 They also ↑ mucus production → key contributor to bronchial asthma pathophysiology.
📖 Clinical Relevance
- 🔥 In asthma, leukotrienes drive bronchospasm, mucus plugging, and airway oedema.
- 🤒 In allergic rhinitis, they mediate nasal congestion, sneezing, and mucus hypersecretion.
- 💊 Leukotriene receptor antagonists (LTRAs, e.g. montelukast, zafirlukast) block cysteinyl-leukotriene receptors → useful in asthma and allergic rhinitis.
- ⚕️ 5-lipoxygenase inhibitor (zileuton) reduces leukotriene synthesis but is less commonly used (liver monitoring required).
🧩 Pathophysiology in Asthma
🌬️ Triad of leukotriene effects in asthma:
1️⃣ Bronchoconstriction → wheeze, breathlessness
2️⃣ Mucus hypersecretion → sputum plugging
3️⃣ Vascular leak → airway oedema
🧪 Exam / OSCE Tips
- ❓ Leukotriene D4 = SRS-A (slow reacting substance of anaphylaxis).
- ❓ Unlike prostaglandins (can cause bronchodilatation), leukotrienes cause bronchoconstriction.
- 💊 LTRAs are add-on therapy in asthma (esp. exercise-induced or aspirin-sensitive asthma).
- 🧲 Remember: they recruit eosinophils (hallmark of allergic airway inflammation).
📚 References
- Kumar & Clark’s Clinical Medicine, 10th edition.
- BNF – Leukotriene receptor antagonists.
- British Thoracic Society / SIGN Asthma Guidelines.
