Makindo Medical Notes

📖 About

• Angioneurotic Oedema (Angioedema): Sudden, transient swelling of the deeper dermis, subcutaneous tissue, or mucosa.
• Can be allergic (histamine-mediated) or due to C1-esterase inhibitor (C1-INH) deficiency (hereditary or acquired).
• Commonly involves the lips, tongue, face, and airway, risking life-threatening obstruction.
• May also affect the gastrointestinal tract (abdominal pain, vomiting) or extremities.

🩺 Clinical Features

• With urticaria: Usually allergic, histamine-mediated, often linked with anaphylaxis.
• Without urticaria: Suggests C1-INH deficiency (hereditary/acquired angioedema).
• Swelling develops over hours and resolves over 24–72 hours.
• Airway involvement → stridor, voice change, respiratory distress (medical emergency 🚨).
• Abdominal attacks may mimic an “acute abdomen.”

🧬 Causes

• Idiopathic – no identifiable trigger.
• Allergic/Drug-related – food (shellfish, nuts), medications (ACE inhibitors, NSAIDs, statins).
• Hereditary Angioedema (HAE) – C1-INH deficiency or dysfunction (autosomal dominant).
• Acquired C1-INH deficiency – associated with autoimmune disease (e.g., SLE) or lymphoproliferative malignancies (lymphoma, myeloma).

⚠️ Management

• Airway first – involve anaesthetics/ICU early if obstruction risk.
• Adrenaline (IM) 0.3–0.5 mL of 1:1000 if features suggest anaphylaxis (hypotension, urticaria, bronchospasm).
• Antihistamines & steroids: Useful in allergic angioedema but ineffective in C1-INH deficiency.
• C1-INH concentrate (or bradykinin antagonist, e.g., icatibant) = treatment of choice in hereditary/acquired cases.
• Tranexamic acid: May reduce attack frequency in hereditary angioedema (especially prophylaxis).
• IV hydrocortisone (100–200 mg) – used in allergic-mediated cases; not effective in HAE.

💡 Key Exam Pearl:
- Urticaria present → think allergic/anaphylaxis (histamine-mediated, responds to antihistamines/steroids).
- Urticaria absent → think hereditary/acquired angioedema (C1-INH deficiency, no response to antihistamines/steroids).