LEPROSY (Hansen’s Disease)

• Causative Organism- Mycobacterium

leprae

• Affects mainly cooler parts of the body

• Skin, mouth, Respiratory Tract, eyes,

Peripheral nerves, Testis, etc

• Earliest --------Skin & Nerves

PATHOGENESIS Acid fast, obligate intracellular organism

Poor growth in culture, but grows in

armadillo, foot pad of mice

Virulence– cell wall properties

Cell mediated immunity– Lepromin Test

DIAGNOSIS

Split skin smears & nasal smears

AFB ( Ziehl – Neelson) stain

Fite Faraco Stain

Silver stain

• Bacteriological Index

• Morphological Index

Solid staining – Live

Fragmented / Beaded - Dead

• Paucibacillary – No Bacilli

• Multibacillary – Some or many Bacilli

TRANSMISSION

• ? Inhalation

• Direct Contact

• Maternofetal transmission

Classification

2 Main types ( polar forms);

a) Lepromatous – Low Immunity

b) Tuberculoid – High Immunity

Modified Ridley Jopling’s Classification• Indeterminate

• TT – Tuberculoid

• BT – Borderline Tuberculoid

• BB – Mid Borderline

• BL – Borderline Lepromatous

• LL -- Lepromatous

FEATURES TT LL

Skin Lesions Asymmetrical Symmetrical (Leonine Facies)

Nerve Involvement +, Sensory disturbance ++

Sensory disturbance

Foam Cells, ‘Grenz Zone’ +

Microscopy Tubercle, ‘Grenz Zone’ -ve

Bacilli load ‘Globi’ / cigarette pack

Few are seen

Immunity High Low

Lepromin Test + -

Tuberculoid Leprosy

Tuberculoid Leprosy:• Skin lesions

• Nerve lesionsAnaesthesia, Skin & muscle atrophy, Trophic ulcers, Contractures,etc

• MC – Ulnar, Radial, Common peroneal

• VII Cranial nerve Keratitis, Corneal ulcer

Lepromatous Leprosy:

• Widespread invasion of shwann cells, neural macrophages

• GlobiAggregates of foam cells filled with masses of AFB

• Macules, Papules,Nodules Leonine Facies

• Testes- Extensive destructionSterility

REACTIONS IN LEPROSY

Type I ( Reversal Reaction)• Upgrading Reaction• Downgrading Reaction

Type II ( Erythema Nodosum Leprosum)• Usually after chemotherapy• Occurs in LL• Tender nodules, Iridocyclitis, Lymph node involvement• Infiltration of neutrophils, Vasculitis• Responds to Treatment