2. mycobacterial infection leprosy- dr. sinhasan, mdzah

History:

* * 1870 - Hansen ( Norway) :

….. Transmissible agent,

…… 1873 - Isolated Organisms,

* In vitro culture - NOT POSSIBLE

* Animal models - footpads of mouse,

- 9-banded armadillos

- Monkeys & Chimpanzees.

** Chronic infection,

* Caused by Mycobacterium leprae,

** Affects cooler parts:

… Skin,

… Upper respiratory tract,

… Superficial nerves,

… Eye,

… Testes;

Introduction:

Uncertain ,

Nasorespiratory tract,

Skin to skin ( uncommon ),

Man to man,

5 to 25% of wild armadillos (Louisiana)

To man ( ? Zoonosis ).

WHO ---- 5.5 Million Patients in the world,

Mainly in-- India,

-- Tropical Africa,

-- South America,

-- Southeast Asia,

-- Philippines,

-- South Pacific Islands.

Incidence:

60.9% of global cases,

57 / 10,000 ----- 1981,

5 / 10,000 ----- 2000,

High Incidence:

Bihar, UP, MP, Orissa, WB = 62%.

Incidence in India:

1966 -- Ridley & Jopling:

Immunologic, Pathologic, Clinical features-

* TT -- Tuberculoid,

* BT -- Borderline-tuberculoid,

* BB – Mid-borderline,

* BL -- Borderline-lepromatous,

* LL -- Lepromatous,

Indeterminate,

Pure Neuritic,

Lucio leprosy,

Histoid leprosy,

• PAUCIBACILLARY …--- Skin smear -- Negative;

• MULTIBACILLARY …--- Skin smear -- Positive;

Clinical Features:

Hypoesthetic skin lesions,

-- Nearly all have peripheral neuropathy,

Thickened Superficial Nerves,

-- 1 in 4 shows deformity,

A F B In Skin Smears;

Skin patches which

have normal feeling

are present from birth

cause itching

are silvery white, black, dark red coloured

show scaling

appear and disappear periodically

spread quickly

Pale white or slightly reddish patch

DEFINITE LOSS OF SENSATION IN THE PATCH

Signs of damage to nerves

definite loss of sensation in hands/feet

weakness of muscles of hands/feet/face

visible deformity of hands/feet/face

Defective Cell-Mediated Immunity:

Antigen-recognition by Helper T-cells

Interleukin --2

Interferon gamma -->Activation of macrophages.

Pathogenesis:

Examine skin

Check for patches

Test for sensation

Count the number of patches

Look for damage to nerves

How to diagnose leprosy

Tuberculoidleprosy:

- No free zone,

- Well formed epitheloid cell granulomas +

- AFBs: + or -

Lepromatous leprosy:

-Grenz (free) zone +

-No epitheloid cell granulomas,

-Foamy macrophages,

- Numerous AFBs- (globi, cigar bundle)

----Lepra cells/ Virchow cells.

Cutaneous Pathology:

Grenz Zone

Virchow Cells with Globi

Leprous orchitis:

--Sterility & Impotence

Osteitis & Periosteitis:

--Skeletal deformities (collapsed nose),

Nasal mucosa: Macrophage infiltration,

Eye: Lagophthalmos, Exposure keratopathy,

Trophic Ulcers.

Other organs affected:

Clinical Examination,

Split Skin Smear,

Histopathological Examination,

( Fites-Ferraco stain for AFB )

Diagnosis: .. To be done with Utmost caution,

.. And Confidentiality.

( Social stigma )

Multi-Drug Therapy,

Dapsone

Rifampin

Clofazimine

Chemoprophylactic drugs to contacts

Can be CURED COMPLETELY

Leprosy: Treatment

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