LEPROSY/HANSENS DISEASE

Question 1

What is the causative organism of leprosy?

Answer 1

Mycobaterium Leprae

Question 2

What is Leprosy?

Answer 2

This is a slowly progressive infection caused by M. leprae that mainly affects the skin and peripheral nerves. Other tissues affected include; nasal mucosal, upper respiratory tracts ant the eyes.

It is a disease of antiquity

Despite its low communicability, leprosy remains endemic among people living in several lower income tropical nations. Subtropical Asia, Africa, South America, some pacific countries and in some part of the USA.

It is a chronic granulomatous reaction.

Question 3

What is the best temperature for proliferation?

Answer 3

It proliferates best at 32° to 34°C, the temperature

Question 4

What relationship does it have with the host?

Answer 4

It is an obligate intracellular acid fast bacillus.

Question 5

When can it be grown and what is it’s incubation period?

Answer 5

It can be grown in the foot pad of mice and nine banded Armadillo
It has long incubation period(2-5years)

Question 6

MODE OF TRANSMISSION

Answer 6

Transmission by Inhalation(Droplets infection)
Transmission by contact(skin to skin contact with infectious cases and contact with the soil)

Question 7

Classification of leprosy

Answer 7

1. By pathology (Ridley-Jopling Classification)
2. By number of bacilli in tissue of affected individuals (W.H.O CLASSIFICATION)

Question 8

Types of leprosy under Ridley-Jopling Classification

Answer 8

Tuberculoid
Borderline Tuberculoid
Borderline borderline
Borderline lepromatous
Lepromatous

Question 9

Types of leprosy according to W.H.O CLASSIFICATION

Answer 9

Paucibacillary L: few bacilli (seen in TL)
Multibacillary L: more bacilli (seen in LL)

Question 10

PATHOGENESIS of leprosy

Answer 10

This is dependent on the type.
Tuberculoid is characterized by formation of chronic granulomatous lesion
The Lepromatous is mostly via Th2 responses with production of antibodies against PG-1 protein of the bacillus.
Lepra reactions(Type 1 and type 2)

Question 11

Discuss Tuberculoid leprosy

Answer 11

If a patient has a competent immune system a strong cell mediated immune response is elicited
And the nerve is invaded by lymphocytes and histiocytes (macrophages).
The histocytes become fixed epitheloid cells which lead to nerve destruction.
This is the picture seen with tuberculoid leprosy.

Question 12

Lepromatous leprosy

Answer 12

If on the other hand there is a poor cell mediated response,

The bacilli which enter the Schwann cells multiply unchecked and enter into the perineural cells and then destroy the nerves.

The bacilli are ingested by histocytes which instead of becoming fixed epitheloid cells become wandering macrophages and allow the bacilli to multiply within them while travelling to other nerves and tissues via blood, lymph and tissue fluid.

These swollen macrophages packed with bacilli are known as lepra cells and are called globi when seen in skin smears or biopsies.

Question 13

Intermediate forms of leprosy

Answer 13

Borderline tuberculoid (BT), Borderline borderline (BB) and Borderline Lepromatous (BL) fall between
The immune competence is greater at BT than at BL.

TT --> BT --> BB ---> BL ---> LL.

Question 14

Clinical features of leprosy

Answer 14

Macular/plagues and nodular hypopigmented skin lesion with hypoaesthesia.
Enlarged nerve trunks
Testicular atrophy
Osteomyelitis
Collapsed nasal bridge
Renal amyloidosis
Nasal congestion
Most remarkable is the enormously wide variation in the clinical presentation. In some the disease
Involves only one peripheral nerve (mono-neutris), cause a single skin blemish in TT
Produces countless nodules and other types of skin lesions with polyneurihis, damage of vital organism like eyes, larynx, testes and bones in LL
These variations are not due to organisms of varying pathogenicity but to the immune status of the infected person.

Question 15

Discuss Tuberculoid Leprosy (TT)
Type of nerve damage

Answer 15

Nerve damage is early and localized.
Report early for medical examination.
May have neural or dermal symptoms.
Both often mixed

Question 16

What are the symptoms of neural TT?

Answer 16

Pain,
Anesthesia,
Tingling,
Muscle weakness
Paralysis

Question 17

What are the symptoms of dermal leprosy?

Answer 17

Usually accompanies the neural lesion
Easier to diagnose as leprosy
i.e. skin + nerve defect = leprosy.
Usually single but may be 2 or 3.
Usually a plaque any where except warmer parts of the body e.g. hairy scalp, axillae, groins and perineum
Usually anaesthetic
Hair growth is deficient or absent over the lesion.
Loss of sweating.
A thickened nerve is usually present in the vicinity.

Question 18

Discuss neve damage and symptoms of Lepromatous Leprosy (LL)

Answer 18

Nerve damage is late and generalized.
Usually report late for medical because they tend to be asymptomatic and early skin lesions are non-specific.

First symptoms
Usually nasal stuffiness with crust formation and blood stained discharge
Oedema of legs.
Skin lesions may be macules, nodules, or papules.
Macules may be coppery or hypopigmented
Are multiple, bilateral and Symmetrical.
Face, arms, buttocks and legs are principally involved but trunk may be too
Thickening and modulation of ears occur early.
Thinned eyebrows and eyelashes.
Chronic leg oedema.

Question 19

What happens when LL progresses?

Answer 19

With progression -
Thickening of skin of forehead–> leonine facies.
Eyebrows & lashes are lost
Nose collapses.
Hoarse voice.
Loose or loss of upper incisors.
Bilateral insensitivity of limbs- glove & stocking anesthesia.
Icthyosis (thighs legs and arms).
Nerve damage in Eyes, bones, kidneys, testes.

Question 20

How can leprosy be diagnosed?
Name the different kinds of tests

Answer 20

Lepromin test(intradermal inoculation of killed M.Leprae)
Strongly positive responses measures more than 5mm in TT and BT, while it is negative in LL.
The reaction may be early(Fernandez) or late(Mitszuda)
Skin biopsy
Slit smear
Serology( Anti-PGL-1)
Polymerase chain reaction

Question 21

How is leprosy treated?

Answer 21

Its now a curable disease
Treatment is by multidrug therapy
Paucibacillary leprosy(Dapsone with rifampicin for 6months
Multibacillary leprosy is treated with Dapsone, clofazimine and rifampicin for one year.