LEPROSY
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Leprosy I
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Introduction
Epidemiology
Bacteriology
Classification
Clinical features
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Leprosy II
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Reactions
Diagnosis
Treatment
Rehabilitation
Introduction
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Chronic granulomatous disease
Caused by Mycobacterium leprae
Mainly involves the peripheral nerves and skin
Other organs may involve:
Mucosa of mouth
Upper respiratory tract
Eyes
Bones
Testes etc
Historical aspect of leprosy
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Oldest disease known to mankind
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Word leper comes from Greek word “scaling”
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Earliest description from India in 600BC
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Kustha Roga & attributed punishment or curse of God
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M. leprae discovered in 1873 by Armauer Hansen
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Referred as Hansen’s disease
Epidemiology
Distribution
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Prevalence
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Wide distribution world-wide
Out of 122 countries, only 2 countries still have to
reach the elimination goal
Brazil and East Timor
Leprosy status in districts
March 2010
59 Districts with Prevalence rate less than 1 per 10,000
16 Districts with PR more than 1 per 10,000
Cases under treatment
at the end of the year
Year 2004-2010
Bacteriology
Lepra bacilli
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Obligate intracellular Gram positive and acid fast bacilli
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Short, thick, pink stained rods
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Size: 5 X 0.5 
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Arrangement: Single or in cigar-shaped bundles or in “globi”
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Affinity for Schwan cells & cells of R-E system
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Cannot grow in vitro but can grow in
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mice and
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nine banded armadillos
The Leprosy Bacteria
Reservoir of infection
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Main reservoir: Human being
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Lepromatous case> Non lepromatous cases
Animal reservoirs
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9-banded armadillos
Chimpanzees
Mangabey monkeys
Portal of exit
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Major portal of exit: Nose
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LL cases harbour millions of M. leprae in their nasal
mucosa
Ulcerated or broken skin of bacteriologically positive
cases
Mode of transmission
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Transmission by inhalation
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Droplet infection
Transmission by contact
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Skin to skin contact with infectious cases
Skin contact with soil & fomites
Incubation period
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Long incubation period
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Ranged: 6 months-40 years or more
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Average: 2-5 years
Environmental factors
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Humidity favors survival of M. leprae in environment
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M. leprae remain viable in
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Dried nasal secretions for 9 days
Moist soil at room temperature for 46 days
Overcrowding & lack of ventilation within households
Social factors
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Often called a “social disease”
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Social factors:
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Poverty
Poverty related circumstances
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Overcrowding
Poor housing
Lack of personal hygiene
CLASSIFICATION OF
LEPROSY
IMPORTANCE OF CLASSIFICATION
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Identify the infectious cases – Epidemiological
importance - Principal targets for treatment
Identify the patients likely to develop the deformities
and determine the prognosis
Frame the line of treatment
Helpful in planning and evaluation of leprosy control
activities
Ridley-Jopling 1966
(Research purposes)
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Most widely accepted
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Based on clinical, bacteriological, immunological
and histopathological parameters, which divide
the leprosy into five recognizable groups
Exhibits a spectral disease with varied clinical
characteristics due to varied host immune
response to bacilli
RIDLEY-JOPLING
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Tuberculoid (TT)
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Borderline Tuberculoid (BT)
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Borderline Borderline (BB)
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Borderline Lepromatous (BL)
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Lepromatous (LL)
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Indeterminate leprosy
Immunity in leprosy
LL - multibacillary state with
multiple lesions due to low
immune response
(+)
TT -paucibacillary
state, few lesions due
to high immune
response
(-)
LLHD
BLHD
BBHD
BTHD
TTHD
Contd..
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Borderline forms (BB, BT and BL) lie between these
two poles and are immunologically unstable, tending
to move towards one of the polar forms
(+++)
Immunology & bacteriology in
leprosy (spectrum)
(+++)
Bacilli
(++)
Bacilli
Immunity
(++)
Immunity
(+)
(+)
(-)
(-)
LLHD
WHO Classification
Clinical Feature
on
Skin Lesion
Pauci bacillary
Leprosy
PB
Including macular flat 1 to 5 lesion
lesion, papules &
nodules
Asymmetrical
distribution
Definite
sensation
loss of
Multi Bacillary
Leprosy
MB
More
than 5 lesion
Symmetrical
distribution
Loss
of sensation
may or may not be
present
W H O classification
(For chemotherapy – M. leprae)
Paucibacillary
 Indeterminate - I
 Tuberculoid – TT
 Borderline Tuberculoid – BT
 If any of these have positive
bacterial index they should be
classified as multibacillary
for multidrug therapy
Multibacillary
 Mid borderline – BB
 Borderline Lepromatous –
BL
 Lepromatous – LL
 All smear positive cases
Clinical Feature
Indeterminate Leprosy
 Earliest & transitory stage
 Hypopigmented macule with indistinct margins
Indeterminate Leprosy
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If untreated may progress towards tuberculoid,
borderline or lepromatous leprosy
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Spontaneous regression may occur
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Usually negative for skin smear for AFB
TUBERCULOID LEPROSY
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Single or a few lesions
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Asymmetrically distributed on trunk and limbs
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Sharply defined, dry, erythematous or
hypopigmented, anesthetic macules or plaques
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One or two nerves may be enlarged near the skin
lesion
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SS for AFB: Negative
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Lepromin test may be strongly positive
Tuberculoid Leprosy
Borderline Tuberculoid
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Single or multiple, asymmetrically distributed
Macules or plaques of variable sizes with welldefined margins & satellite lesions
Peripheral nerves enlarged asymmetrically
Sensation: hyposthesia
SS for AFB: may be seen
Lepromin test may be weakly positive
Borderline
tuberculoid
Borderline Borderline
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Multiple erythematous macules & plaques
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Various sizes and shapes with punched out centre and
ill defined slopping outer margin
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Tend to be symmetrical
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Nerves may be asymmetrically enlarged
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Sensation:+/-
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SS for AFB: seen +/-
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Lepromin test-usually negative, may be doubtful
Borderline Borderline
Borderline Lepromatous
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Numerous, symmetrically distributed lesions
Hypopigmented or erythematous irregularly
shaped maculopapules, infiltrative nodules, or
plaques, with smooth surfaces & ill defined
borders, sloping outwards
Nerves may be symmetrically or asymmetrically
enlarged
Sensation:+/SS for AFB: numerous seen
Lepromin test -negative
Borderline Lepromatous
Lepromatous Leprosy
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Numerous macules, plaques, nodules or diffusely
infiltrated lesions, symmetrically distributed on face,
trunk and extremities with ill-defined margin which
may be slightly hypopigmented or erythematous
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Symmetrical nerve enlargement is seen
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Sensation: normal
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SS for AFB: numerous seen
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Lepromin test - negative
Lepromatous Leprosy
Ear lobes thickens
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diffuse thickening of the skin, with loss of
hair (eyebrows and eyelashes).
saddle nose deformity
 leonine
facies
General Findings
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Eye The anterior chamber can be invaded in
LL with resultant glaucoma and cataract
formation. Iritis/Iridocyclitis
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Testes May be involved in LL with resultant
hypogonadism.
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Systemic involvement – Respiratory, Bones,
Kidneys, Lymph glands, etc.
Nerve involvement in
Leprosy
M. Leprae : superficial nerve involvement
W Britton
Nerve Involvement
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Neural involvement leads to muscle weakness,
muscle atrophy, severe neuritic pain, and
contractures of the hands and feet.
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Ulnar nerve commonly involved
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Examination for sensations of hot and cold , pain
and fine touch
Nerve palpation
Face
Facial Nerve
 Lagophthalmos
 Facial droop
Trigeminal Nerve
 Corneal anaesthesia
Nerve damage – upper
limb
Ulnar
S Anaesthesia medial 1/3 palm
M Claw ring and little fingers
A Dryness medial 1/3 palm
Median S Anaesthesia lateral 2/3 palm
M Claw mid + index + loss Opposition
A Dryness lateral 2/3 palm
Radial
S Anaesthesia dorsum hand
M Wrist drop
Nerve damage – lower limb
Lateral (common) Popliteal
 Foot drop
Posterior Tibial
S Sole anaesthesia
M Claw Toes
A Dryness in sole
Classification of leprosy