MYCOBACTERIUM LEPRAE

Mycobacterium Leprae Definition -

• A gram-positive, acid-fast, obligate intracellular parasite.

Causes -

• It primarily affects the skin, mucous membranes, and peripheral nerves.
• It is highly contagious through respiratory droplets.

Types -

• Tuberculoid (TT)
  • Characterized by low bacterial load and strong immune response.
  • Lesions are few and small, with little or no involvement of nerves.
• Lepromatous (LL)
  • Characterized by high bacterial load and poor immune response.
  • Lesions are numerous and widespread, with significant nerve involvement.
• Borderline (BB)
  • Characterized by intermediate bacterial load and immune response.
  • Lesions are varied in number and size, with moderate nerve involvement.
• Borderline-tuberculoid (BT)
  • Shows characteristics of both TT and BB.
• Borderline-lepromatous (BL)
  • Shows characteristics of both LL and BB.

Pathogenesis - → Mycobacterium Leprae enters the body through respiratory droplets. → It multiplies within the macrophages of the respiratory tract. → It spreads to the skin and peripheral nerves through the bloodstream. → It causes damage to the skin and nerves by inducing inflammation and tissue destruction.

Morphology -

• Bacilli are slender, rod-shaped, and acid-fast.
• They are 3-4 μm in length and 0.2-0.5 μm in width.
• They have a thin, transparent capsule.

Clinical Features -

• Skin lesions (macules, papules, nodules, plaques)
• Nerve involvement (numbness, tingling, pain, muscle weakness)
• Eye involvement (keratitis, uveitis, conjunctivitis)
• Systemic involvement (fever, weight loss, fatigue)

Complications -

• Disfigurement and disability
• Blindness and vision loss
• Nerve damage and paralysis
• Organ damage and failure

Diagnosis -

• Clinical examination and history
• Skin smear and biopsy
• Blood tests (ELISA, PCR)
• Slit-skin smear

Management -

• Multidrug therapy (MDT)
• Includes rifampicin, dapsone, and clofazimine
• Duration of treatment is 6-12 months
• Monitoring for side effects and drug resistance

Memory Trick: "Mother's Little Baby Eats Rice And Peas"

• M (Mother) - Macule
• L (Little) - Lesion
• B (Baby) - Bacillus
• E (Eats) - Enters
• R (Rice) - Respiratory
• A (And) - And
• P (Peas) - Peripheral nerves

Life Cycle:

1. Mycobacterium Leprae enters the body through respiratory droplets.
2. It multiplies within the macrophages of the respiratory tract.
3. It spreads to the skin and peripheral nerves through the bloodstream.
4. It causes damage to the skin and nerves by inducing inflammation and tissue destruction.