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Leprosy
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A chronic infectious disease caused by the bacteriumMycobacteriumleprae
It is mainly a Granulomatous disease affecting: peripheral nerves and
mucosa of the upper-respiratory tract
Granulomatous - refers to granulomas which are lesions of epithelioid
macrophages
Leprosy (Hansens Disease)
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A Little History
Gerhard Henrik Armauer Hansen wasa physician which first identified
Mycobacterium leprae as the cause of
leprosy in 1873
FYI
7/29/1841-2/12/1912
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A little taxonomy .
Kingdom Bacteria
Phylum Actinobacteria
Order Actinomycetales
Suborder Corynebacterineae
Family Mycobacteriaceae
Genus Mycobacterium
Species M. leprae
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Pathology
Gram-positive
Intracellular
Aerobic rod-shaped bacillus
With a waxy coating
M. leprae is unable to grow in vitro
This is thought to be due to the fact that it no longer has the genesneeded for independent growth
Because of its inability to grow on agar, nude mice and nine-banded
armadillos are used as animal models
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Clinical Features
Skin lesions, typically anaesthetic at the tuberculoid end ofthe spectrum
Thickened peripheral nerves
Acid-fast bacilli on skin smears or biopsy
Acid-fast is a property of Mycobacteria in which they aresistant to decolorization by acids during staining
This is a helpful diagnostic tool forM. tuberculosis andM.
leprae
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SymptomsTuberculoid Borderline
Tuberculoid
Borderline
Lepromatous
Borderline Lepromatous
Skin
Infiltrated
lesions
Defined plaques,
irregular plaques,
healing centers
Polymorphic,
partially raised
edges, satellites
Papules, nodules,
punched-out
centers
Diffuse
thickening
Diffuse thickening
Macular
lesions
Single, small Several, any
size
Multiple, all sizes,
bizarre
Innumerable,
small
Innumerable,
confluent
Peripheral
Nerve
lesions
Solitary, enlarged
nerves
Irregular
enlargement of
several large
nerves,
asymmetrical
patterns
Many nerves
involved
symmetrical
patterns
Late neural
thickening,
asymmetrical
anaesthesia
and paresis
Slow, symmetrical
glove-and-
stocking
anaesthesia
Note: Contrary to popular belief leprosy does not cause body parts to simply fall off
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Tuberculoid leprosy- Patients lymphocytes respond toM. leprae in vitro
- Skin tests with lepromin elicit a strong positive response
- They also have a Th1- type response producing interleukin-2 and intergerons-
- These strong cell-mediated responses clear antigens, but cause local tissuedestruction
Lepromatous leprosy- Patients in this case do not mount a normal cell mediated response to
M. leprae, and in fact their lymphocytes do not respond to M. leprae invitro
- They are also unresponsive to lepromin
- They have specific T cell failure and macrophage dysfunction, andproblems producing interleukin-2 and intergerons-
- But they do produce Th2-type cytokins
Immunology
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Social Aspect WHO reported that at the start of 2007 there were 224,717 reported
cases (from 109 countries and territories) In comparison with the number of new cases detected in 2006 which
was 259,017, the number of new cases fell by more than 40,019 cases
(a 13.4% decrease)
In the last five years, the global number of new cases has dropped on
average by 20% per year. Also Leprosy has been around since about 300BC
FYI
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Geographic Rage For Leprosy
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Transmission
The transmission of leprosy is thought to occur through the respiratory
track
Infected individuals discharge bacilli through their nose and a healthy
individual breaths them in
But it is important to note that the extract mechanism is not known
The main reservoir is humans
Risk group: children, people living in endemic areas, in poor
conditions, with insufficient diet, or have a disease that compromises
their immunity (ie HIV)
In the 19th century leprosy was believed to be a hereditary ailment
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Diagnosis
Is clinical, by finding signs of leprosy and supported with the use ofacid-fast bacilli smear or skin biopsy
But this is contingent on experienced histopathologist
What doctors typically look for include: anaesthesia of skin lesions,
and peripheral nerve thickening and tenderness
There is no serological test
Note: The genome has been sequenced
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Treatment & Management Chemotherapy
- First line drugs are rifampicin, dapsone, and clofazimine- The WHO recommends that if a patient test positive in an acid-fast
skin smear they should be treated for multibacillary disease
- The patients bacterial load decides length of treatment (6-24 months)
- Patients tend to improve quickly with minimal side-effects
- Second line drugs are ofloxacin and minocycline- Tripledrug combinations have been used in cases where a patient has
only a single lesion
- Leprosy is combated with multidrug therapy to reduce the chance ofdeveloping resistance
- Since in the 1960s resistance to dapsone developed
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Multibacillary (MB or lepromatous) is a 24-month treatment of rifampicin, clofazimine, and dapsone.
Paucibacillary (PB or tuberculoid) is a six-month treatment of rifampicin and dapsone.
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Treatment & Management New Nerve Damage
- Patients with motor or sensory loss of 6 moths or less should receive a 6 monthtreatment of corticosteroids (a treatment for type 1 reactions)
Patient Education
- It is very important since within a few days of starting chemotherapy sincepatients will no longer be infectious and can live a normal life
- Currently there are few leper colonies left- Also care of limbs is very important
Preventing Disability
- Nerve damage produces anaesthesia, dryness and muscle weakness which inturn causes misuse of affected limbs causing ulceration and infection, leading
to deformity- Dryness can lead to skin cracking and ultimately infection
- Treatment involves soaking and applying oil- based creams to affected areas,also physiotherapy can help prevent contractures, muscle atrophy and overstretching of muscles
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Treatment & Management Immune-Mediated Reactions
- Type 1 reactions occur in borderline leprosy- Type 1 reactiondelayed hypersensitivity occurring at site of localizedM.
leprae antigens
- Skin lesions appear and are erythematous, and peripheral nerves becometender and painful
- Loss of nerve function can be sudden (ie foot-drop)
- Type 2 reactions occur in borderline lepromatous and lepromatous cases- Type 2 reactionerythema nodosum leprosum (ENL) results from immune
complex deposition
- The main symptoms are malaise, fever, and crops of small, pink nodules onface and limbs, and ENL may continue for years
- Management procedures include : control inflammation, pain, treat neuritis,
and halt eye damage
Vaccines
there currently isnt a vaccine against leprosy, but there are trials investigatingthe effectiveness of the BCG vaccine
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DiscussionThalidomide (Thalomid). This drug was originally developed as a sedative and
morning-sickness pill but was subsequently found to cause severe birth
defects; the Food and Drug Administration then banned it. Under the newregulations there are a number of restrictions on its use:
1. It can be used only for the treatment of erythema nodosum leprosum.
2. Doctors who prescribe the drug and pharmacists who dispense it mustregister with
Celgene, the company that produces it.
3. Women must have a negative pregnancy test 24 hours before taking thedrug.
4. Women must get weekly pregnancy tests during the first month oftreatment. Thereafter they
must get once-a-month pregnancy tests.
5. All thalidomide users must enroll in a registry at Boston University that
will record anypregnancies that occur and their outcomes.
6. All male patients must use condoms during sexual intercourse because thedrug is found in
semen.
http://www.kcom.edu/faculty/chamberlain/Website/tritzid/leprosy.htm
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Discussion
1) First of all lets assume that areas with highconcentrations of Leprosy could afford
Thalidomide in addition to their basic
treatment. What are the moral problems
with its prescription? What are some of the
additional problems that might arise if the
above regulations aren't followed?
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Discussion
2)What could explain such a drop in new Leprosy cases? Considering
the expense and length of treatment, not knowing the mode of
transitions and the fact that most areas that are affected are still
developing.
Free MDT,Reducing disease burden,
Preventing disability, Changing
the negative image, Working
with local governments and
agencies
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I got this off the net, I hope it helps, if anyone has any questions please email me.Can leprosy cause limbs to fall off?Leprosy does not cause flesh to rot and fingers and toes to drop off. In the past, limbs that have been damaged
because the person cannot feel pain have sometimes had to be amputated. Now that the disease can be detectedearly and cured completely, the need to amputate is very rare.
Who can get leprosy?Susceptibility: About 90% of the population is not susceptible to infection. Children are more susceptible than adults.Immunologic and epidemiologic studies suggest that only 10-20% of those exposed to M. lepraewill develop signs
of indeterminate Hansen's disease; only 50% of those with indeterminate disease will develop full-blown clinical
leprosy. Spontaneous healing also has been reported in tuberculoid leprosy.Host immunity: Where host cell-mediated immunity functions perfectly, organisms are routed and no diseasedevelops. If the individual has good immunity, organisms are contained and TT disease occurs. In subjects with
moderate immunity, a battle occurs and results in borderline types of leprosy. In persons with poor immunity, LL
occurs.