Makindo Medical Notes

📖 About

• 🦠 Caused by Mycobacterium leprae → an obligate intracellular, aerobic, acid-fast bacillus.
• 👥 Transmission: mainly human-to-human (likely via respiratory route).
• 🌱 Chronic granulomatous disease affecting nerves and skin.

🧬 Aetiology

• Lives in phagolysosomes of macrophages and vacuoles of Schwann & endothelial cells.
• Risk ↑ with age and close contact with infected individuals.
• Cannot be cultured in vitro → grows in mouse footpad & nine-banded armadillos.
• 🐢 Extremely slow growth: doubling time ≈ 13 days.

🌍 Epidemiology

• ~4 million cases worldwide.
• 🇮🇳 70% in India; also Brazil, Indonesia, Mozambique, Madagascar, Tanzania, Nepal.

🩺 Clinical Forms

• Tuberculoid / Paucibacillary (Strong CMI → elimination of bacilli):
  • Incubation: 2–5 years.
  • ≤5 skin lesions; usually negative smears.
  • Few hypopigmented anaesthetic patches; localised nerve involvement.
• Lepromatous / Multibacillary (Weak CMI → uncontrolled bacilli):
  • Incubation: 8–12 years.
  • ≥6 lesions, skin smear often positive.
  • Diffuse papules, nodules → “leonine facies.”
  • Nasal discharge sheds bacilli → spreads infection.
  • Haematogenous spread to skin, nerves, organs.
  • Thickened peripheral nerves (ulnar, median, radial, facial).

🧭 Ridley–Jopling Classification

• LL → Lepromatous (low CMI, high bacterial load).
• BL → Borderline lepromatous.
• BB → Borderline borderline.
• BT → Borderline tuberculoid.
• TT → Tuberculoid (high CMI, low bacterial load).

🔎 Investigations

📋 Summary of Clinical Types

💊 Drugs Used

💡 Teaching Pearl: Leprosy spectrum depends on host immunity. Strong CMI → tuberculoid (few lesions, low bacilli). Weak CMI → lepromatous (diffuse, nodules, high bacilli).