Leprosy Dr Ali Farhan 21 sept University -Reduced.pdf

Leprosy
Dr/Ali Farhan
1 Leprosy Dr Ali Farhan 21 sept University - 10 December 2022

Definition
❖Leprosy (Hansen's disease) is a chronic
infectious disease caused by
Mycobacterium leprae. It mainly affects
the peripheral nerves &skin. It also
affects, muscles, eyes, bones, testes and
internal organs.
❖Mycobacterium leprae was discovered by
Gerhard Henrik Hansen in 1873.

Bacteriology
❖It is an acid-fast bacillus stained with
Ziehl-Neelsen , Fite .
❖measuring 1 to 8 microns in length by 0.3
microns in diameter.
❖It is an obligate intracellular parasite that
divides every 12-13 days in histiocyte and
schwann cells .

Bacteriology
❖The capsule of lepra bacilli
contains a phenolic glycolipid 1
(PGL1).
❖The optimal temperature for growth
for lepra bacilli is 30-33 centigrade.
❖and thus has a preference for
cooler regions of the body (e.g. the
nose, testicles and ear lobes) .
❖Affinity for macrophages and
Schwann cells.

Bacteriology...
❖Incubation Period varies widely,
from months to over 30 years, but it
is usually 4–10 years.
❖leprosy primarily affects humans, it
can be found or reproduced in
armadillos, monkeys and mice.
❖incidence occurs in individuals
between 10–15 and 30–60 years .

• spread predominantly via nasal and oral droplets from the
bacilliferous patient and much less often from
• eroded skin..
‣ Every 1cc of nasal secretion contain 1-2 millions lepra
bacilli .
‣ Even after 1–7 days, the bacillus is still viable in dried
secretions
• Inoculation is via
‣ the nasal mucosa.
‣ breaks in the skin barrier.
Mode of Spread:

• with more than 10 million patients on the
registry during the 1980s.
• WHO Start multidrug therapy in 1982.
• leprosy prevalence was markedly reduced by
more than 85% although the new case
detection rate has remained relatively stable
at more than 200,000 worldwide for almost
10 years .
EPIDEMIOLOGY

• The WHO in 1998 defined a case of leprosy as a person
having one or more of the following features and who has
yet to complete a full course of treatment:
❖Hypopigmented or reddish skin lesion(s) with definite
loss of sensation.
❖Involvement of peripheral nerves as demonstrated by a
definite thickening with loss of sensation.
❖Skin smear positive for acid fast bacilli (AFB).
Definition of a Case of Leprosy

Tuberculoid With a
Predominantly Th1
Response
Classification
Lepromatous With
a Predominantly
Th2 Response
Borderline Group
Based upon the
clinicopathologic findings,
which reflect the
degree/type of immunity

Ridley and Jopling Classification
• 1966, Ridley and Jopling
proposed a 5-group
classification system
based on clinical,
histopathologic, and
immunologic criteria

LL
TT
BB
BL
BT
BL

immunologic spectrum of leprosy

WHO created an operational system
paucibacillary,
single-lesion leprosy
paucibacil-lary
leprosy (two to five
skin lesions)
multibacillary
leprosy (more than
five skin lesions)
This simplified classification is based solely on
the number of cutaneous lesions, independent
of their size, location or histologic features.

❖Indeterminate leprosy is believed to be the
very first sign of infection with the leprosy
bacillus.
❖It usually manifests as a solitary macular
skin lesion that is vaguely defined and
either erythematous or hypopigmented.
❖Patients with indeterminate leprosy may
clear spontaneously or progress to one of
the other three types of leprosy.
Indeterminate leprosy

Tuberculoid Leprosy
❖Patients with tuberculoid leprosy have
a high degree of immunity against M.
leprae and have few skin lesions and
few organisms in their skin..

Tuberculoid Leprosy
❖1-5 hypopigmented well defined
macules or plaques.
❖The lesions are dry, hypoanesthetic
or anesthetic with loss of sweating
and hair.
❖Peripheral nerve trunks are not
involved, but nerve feeding the
patch may be thickened.
❖Patients with tuberculoid leprosy
have a high degree of immunity
against M. leprae and have few skin
lesions and few organisms in their
skin.

Borderline Leprosy
❖Dimorphous leprosy, also known as
borderline leprosy,
❖ shows features intermediate between
tuberculoid and lepromatous leprosy.
❖It is a less stable form of leprosy, and
its clinical features and immune status
may change over time.
❖If dimorphous leprosy develops more
features of lepromatous leprosy, it is
referred to as dimorphous-
lepromatous. If it develops features of
tuberculoid leprosy, it is called
dimorphous-tuberculoid

Lepromatous Leprosy
❖the form with the least cellular immunity
and greatest number of bacilli.
❖characterized initially by multiple, poorly
defined, erythematous macules, papules,
nodules and plaques.

Lepromatous Leprosy
❖Lesions are widespread, and symmetric .
❖Infiltration of the skin of the forehead can
lead to a leonine facies ,madarosis, saddle
nose.

madarosis
saddle nose.

Clinical Features of Leprosy Skin Lesions
CUTANEOUS LESIONS TUBERCULOID DIMORPHOUS LEPROMATOUS
Number Few Many Numerous
Size Large Large and small Small
Symmetry Asymmetrical Symmetrical Symmetrical
Sensation Anesthetic Variable Variable
Surface Rough, scaly Rough, scaly Smooth
Edge Sharp Sharp Vague
Bacilli in skin lesion
Cellular immunity
Operational Paucibacillary 1-5 Multipacillary > 5

DIAGNOSIS
❖History & clinical examination.
❖Slit Skin Smear (SSS)
❖Biopsy.
❖PCR.
❖Serologic assays for anti-PGL antibodies.

DIAGNOSIS

DIAGNOSIS
Radial
ULNAR
MEDIAN

DIAGNOSIS
Posterior Tabial
Lat
Popletial

DIAGNOSIS
❖tissue smear from the skin and staining with
modified Ziehl-Neelsen stain.
❖_ 1 to 10 bacilli in 100 fields -1 +
❖_ 1 to 10 bacilli in 10 fields -2 +
❖_ 1 to 10 bacilli in an average field -3 +
❖_ 10 to 100 bacilli in an average field -4+
❖ _ 100 to 1000 bacilli in an average field -5 +
❖ _ Clumps and globi in an average field -6+
Slit Skin Smear (SSS)

DIAGNOSIS
❖PCR.
• 36 kDa proline-rich antigen, Ag85B)
❖Serologic assays for anti-PGL antibodies.
• monitor the response to treatment, and predict leprosy
reactions.

DIAGNOSIS
❖Lepromin is prepared from M.leprae
and used as skin test antigen.
❖Lepromin is strongly positive in TT
Hansen and gradually decreases
across the spectrum and becomes
negative in LL Hansen.
Lepromin Skin Test

Treatment
Daily Monthly Duration
Paucibacillary
1-5 lesions
Dapsone (100mg)
Rifampin
(600 mg)
6 Months
Multibacillary
>5 lesions
Dapsone (100 Mg)
Clofazimine (50 Mg)
Rifampin (600 Mg)
& Clofazimine (300 Mg)
12 Months

REACTIONS IN LEPROSY
❖Reactions are acute episodes of hypersensitivity
reactions due to fluctuations in the immune status of
a leprosy patient.

Type 1 – Reversal reaction
Type 2 – Vasculitis
(erythema nodosum
leprosum)
Leprosy category Borderline (BT, BB, BL) Lepromatous and BL
Pathogenic process type IV hypersensitivity
reaction
type III or immune complex
Clinical
characteristics
• Increased inflammation in skin
lesions.
• Emergence of “new” skin lesions.
• Acute nerve pain or tenderness .
Nodular skin lesions • Fever,
myalgias, malaise • Severe joint
swelling and pain • Iridocyclitis •
Lymphadenitis •
Hepatosplenomegaly • Orchitis •
Glomerulonephritis
Treatment
Prednisone Thalidomide

E N L

Complications
❖ ulnar claw hand.

Complications

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