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Leprosy (Hansen's Disease)

S-2-Pathophysiology
2 min read

  • Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae, which primarily affects the skin, peripheral nerves, respiratory system, and eyes.

  • It has a long incubation period, sometimes taking years to manifest symptoms.

Leprosy (Hansen's Disease)
Leprosy (Hansen's Disease)

Signs and Symptoms

Early Signs

  • Skin Lesions: Pale or reddish patches that are numb to touch.

  • Numbness: Loss of sensation in affected areas.

  • Muscle Weakness: Often in the hands and feet.

Progressive Symptoms

  • Thickened Skin: Nodules and thickened dermal areas.

  • Eye Problems: Reduced blinking reflex, dryness, potential blindness.

  • Ulcers: Chronic skin ulcers, especially on the soles of the feet.

  • Deformities: Claw-like hands or drop foot due to nerve damage.

  • Loss of Eyebrows and Eyelashes: Common in advanced cases.

Types of Leprosy

Based on the Ridley-Jopling Classification:

1) Tuberculoid Leprosy (TT)

  • Few skin lesions, high nerve involvement, strong immune response.

2) Borderline Tuberculoid Leprosy (BT)

  • Intermediate between tuberculoid and borderline lepromatous.

3) Borderline Borderline Leprosy (BB)

  • Intermediate form with more lesions and moderate immune response.

4) Borderline Lepromatous Leprosy (BL)

  • Numerous lesions, weaker immune response.

5) Lepromatous Leprosy (LL)

  • Many skin lesions and nodules, poor immune response, more severe.

Etiology

  • Causative Agent: Mycobacterium leprae.

  • Transmission: Likely through prolonged close contact with an untreated person, possibly via respiratory droplets.

Pathogenesis

  • Entry: M. leprae enters the body, possibly through the skin or respiratory tract.

  • Spread: Bacteria preferentially infect peripheral nerves, skin, upper respiratory tract, and eyes.

  • Immune Response: Depending on the host's immune response, the disease can manifest as either paucibacillary (limited) or multibacillary (widespread).

Treatment

1) Multidrug Therapy (MDT)

  • Paucibacillary Leprosy: Dapsone and rifampicin for six months.

  • Multibacillary Leprosy: Dapsone, rifampicin, and clofazimine for 12 months.

2) Supportive Care

  • Physical Therapy: To prevent deformities and manage neuropathy.

  • Surgical Interventions: To correct deformities and manage chronic ulcers.

  • Eye Care: Regular check-ups to prevent blindness.

Prevention:

  • Early Diagnosis and Treatment: To reduce transmission.

  • Contact Tracing and Screening: Of household contacts.


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