• Definition
    • A chronic bacterial disease of the skin, peripheral nerves and the upper airway
  • One of the most feared diseases
  • Causal organism
    • M. Leprae
  • Early stage
    • painless depigmented patch

Differential diagnosis

  • Tinea vesicolor
  • Pityriasis rosea
  • Birth mark depigmentation
  • Granuloma multiforme
  • Psoriasis
  • Contact dermatitis
  • Avitaminosis B
  • Neurofibromatosis
  • Scleroderma
  • Xathomatosis

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Epidemiology

  • Infectious agent:
    • Mycobacterium leprae
      • acid fast bacilli
      • cannot grow in bacterial media/culture
      • Grow on
        • mouse foot pads
        • in nine banded armadillo
  • Occurrence
    • World prevalence 10-12 million
    • Prevalence rates >5 per/1000 rural tropics and subtropics
  • Endemic areas
    • SE Asia
    • South Asia
    • Philippines
    • Indonesia
    • India
    • Bangladesh
    • Pacific Islands
    • Tropical Africa
    • Latin America
  • Reservoir
    • Man is the only reservoir of proven significance
    • Feral Armadillos in Louisiana & Texas are affected
    • Naturally acquired leprosy Manageby monkey & chimpanzee
      • captured in  Nigeria and Sierra Leone\

Mycobacterium leprae

  • General
    • Acid fast
      • occurs in intracellular and extracellular
    • Occurs in clumps or bundles
      • globi
    • Affinity for
      • Schwann cells
      • cells of the reticulo- endothelial system
    • They remain dormant in various sites
      • can cause relapse
    • Leprosy is highly infectious disease
      • but low pathogenecity
  • Mode of transmission
    • Contact
      • not clearly established
        • Household
        • prolonged close contact
    • Droplet infection
      • Millions of bacilli are liberated daily
        • in the nasal discharge
          • remain viable for 7days in dried nasal secretions
        • Cutaneous ulcers also shed large amounts of bacilli
  • Incubation Period
    • 9 months – 20 years
      • average 4 years for tuberculoid
      • 3-5  years for lepromatous
    • Disease seen children <3 years
      • 50 cases so far
      • youngest: 2 1/2 month
  • Period of communicability
    • Infectivity is lost in most instances (continuous & regular treatment)
      • within 3 months
        • with Dapsone (DDS) or clofazimine
      • within three days
        • with rifampine
  • Susceptibility and resistance
    • Persistence and form of leprosy depend upon ability to develop cell mediated immunity
  • Lepromin test
    • Intradermal injection of autoclaved M.  Leprae & the presence or absence of induration at 28 days is called Mitsuda reaction
    • Reaction
      • lepromatous leprosy
        • -ve immune reaction
        • Mitsuda reaction
      • tuberculoid disease
        • +ve immune reaction
    • The test gives prognostic information but it is not diagnostic

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Intermediate lesion

  • Small macules
    • irregular
    • raised edge
    • pale skin lesions
    • anywhere on the body
      • Most common on
        • back
        • forearm
        • thighs
        • face
  • No sensory loss
  • Normal sweating
  • Pathology –non specific inflammatory reaction
  • 90% spontaneous recovery
    • may progress to any of the three later types
    • depending on the cell-mediated response
      • Tuberculoid leprosy
      • Lepromatous leprosy
      • Borderline leprosy 

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Tuberculoid leprosy

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  • Clinical features
    • One or more sensationless  asymmetrical macules with raised edges
      • In dark skins macules: depigmented
      • in pale skins macules: reddish
    • Affected nerves are thickened
      • ulnar
      • median
      • superficial radial
    • Loss of sweat
    • Loss of sensation
    • Wasting of muscles
  • Skin smear
    • -ve for M. leprae
  • Biopsy shows
    • epithelial granuloma with giant lymphocytes
    • scanty bacilli

Lepromatous leprosy

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  • Clinical features
    • Numerous symmetrical distributed, macular, plaque form/nodular skin lesions
      • Leonine facies
        • lion face
      • Skin thickened by infiltration
      • Swelling of nose, ear and lips
    • Proliferation of infection in mucous membranes
      • causes nasal congestion & keratitis
      • Nasal discharge, painful eyes
    • Peripheral neuritis
      • complicated by neuropathies ulcers on limbs
      • lead to disfiguration and disability
    • Loss of sensation, pain and temperature
    • Neuropathic ulcers on
      • hands, feet
      • with loss of fingers and toes
    • Painless burns or ulcers
      • Secondary infection
    • Facial nerve palsy
    • Testis & lymph nodes may be damaged
    • Generalized systemic symptoms
      • fever
  • Skin smear highly +ve for bacilli
  • Immune response highly -ve (Mitsuda reaction)

Borderline leprosy

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  • between tuberculoid & lepromatous
  • Mixed clinical features
    • Skin lesions often raised ring shaped lesions
      • with normal or slightly reduced sensation
    • Peripheral nerves may be thickened

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Clinical manifestations

  • Signs of peripheral nerves involvement
    • Skin lesions
      • Test for light touch, pin prick & temperature discrimination
      • Hyperesthesia & anesthesia
    • Peripheral nerves
      • Bilateral palpation of peripheral nerves for enlargement and tenderness
        • ulnar at elbow
        • peroneal nerve at head of fibula
        • great auricular nerve
    • Muscles
      • Paralysis
      • muscle wasting
    • Trophic ulcers

Diagnosis

  • Clinical examination
    • Examination of
      • skin
      • nerves
      • pain sensation
      • sweating
      • motor functions
      • nerve thickening
  • Laboratory Examination
    • Skin slit smears
      • Skin is slit without drawing blood
      • smear taken & stained for bacilli
        • usually from ear lobes
      • The quantity and the morphology is measured
    • Skin biopsy
      • of lesion edge/nerve
    • Mitsuda reaction (Not diagnostic)
      • Skin test with lepromin
        • made from autocalved Mycobacterium leprae
      • Granulomatous nodule after 28 days in tuberculoid and some boderline cases
      • Healthy persons may show a positive Mitsuda reaction
      • If no reaction –> lepromatous leprosy

Treatment

Multidrug therapy (MDT)

  • Combinations of
    • Rifampicin
      • urine slightly reddish for few hours
    • Clofazimine
      • brownish black discoloration
      • drness of skin
    • Dapsone
      • allergic reaction towards sulpha drugs
        • itchy skin rashes
        • exfoliative dermatitis
      • do not give to patients who are allergic
  • May develop drug resistance if only 1 drug used

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Reactions in leprosy

Non-Lepromatous lepra reaction (Type 1 lepra reaction)

  • Seen following treatment of boderline leprosy
    • Type 4 delayed hypersensitivity reaction
  • Last for few days to several weeks
  • Reactions
    • Acute inflammation of preexisting borderline lesion
    • Skin lesions become swollen and erythematous
    • Neurological lesions
      • ulnar nerve palsy may occur abruptly
    • Both upgrading or reversabile reaction
      • more tuberculoid or more lepromatous

Erythema Nodosum Leprosum (Type 2 lepra reaction)

    • Humeral antibody response to antigen antibody complex
      • type III hypersensitivity reaction
    • systemic manifestations
      • Fever
    • Athralgia
    • Painful subcutaneous erythematous nodules
    • Iritis

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Prevention & control of leprosy

  • Primary prevention
    • Health promotion
    • improve housing standards
    • standard of living
    • BCG (Limited protection)
  • Secondary prevention
    • Early diagnosis & treatment
    • WHO-Multi drug treatment
      • follow up 5 years,
      • Tuberculoid – 6 months
      • Borderline & lepromatous – 2 years
  • Tertiary prevention
    • Disability limitation
    • Care of the hands, feet, neuropathy and loss of sight
    • Rehabilitation
      • Restoration of function
      • Deformities, loss of limbs fingers, nose etc

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Poliomyelitis

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  • Definition
    • An acute viral infection
      • with severity ranging from inapparent infection to non-specific febrile illness, aseptic meningitis, paralytic disease and death
    • Minor illness includes (if the disease progresses)
      • fever
      • malaise
      • headache
      • nausea
      • vomiting
    • Severe illness includes
      • muscle pain
      • stiffness of neck
      • stiffness back with/without paralysis
    • The site of paralysis depends upon the location of the nerve cell destruction in the spinal cord/the brain stem
  • Infectious agent
    • Polio virus Type 1
      • Brunhilde
      • most commonly seen in epidemics
    • Type 2
      • Leon
    • Type 3
      • Lansing (genus Enterovirus)

Epidemiology

  • Occurrence
    • Worldwide
    • disease of children & adolescents
  • Reservoir
    • Man only
      • people with inapparent infections
  • Mode of transmission
    • Direct contact through close association
    • Rare instances – fecaloral route
  • Incubation period
    • 7-14 days of paralytic cases
    • Range 3-35 days

Susceptibility and resistance

  • Susceptibility to infection is general
  • paralytic infections are rare
  • Lifelong specific immunity
    • immunisation at birth
    • Infants born to immune mothers have transient passive immunity Injections of other vaccines may provoke paralysis
    • Second attacks are rare
      • due to different type of polio virus
  • Tonsillectomy increases the risk of bulbar involvement
  • Strenuous exercise is known to make the paralysis worse in the exercised limb
    • during the prodromal phase
  • Statistics
    • 90% have no or almost no symptoms/indistinguishable from influenza
    • 9% have non-paralytic polio
    • 1% have spinal/bulbar polio
      • 10% die
      • 50% recover fully
      • 40% are left with only partial recovery/permanent paralysis
    • 0.4% of permanent paralysis,
      • 1 or both lower limbs
    • 0.01%
      • Quadriplegia
      • respiratory paralysis

    Pathophysiology of polio

    • Polio is generalized infection
      • which may involve the whole body including muscles, liver spleen, and gastrointestinal system
    • Anterior horn cells are chiefly affected
      • Degeneration & loss of Nissls granules
        • uptil complete disappearance of the cells
      • This results in the lower motor neuron paralysis
        • with asymmetrical paralysis & normal sensation
        • Paralysis occurs in small proportion & may be minimal to severe
        • Paralysis may cause shortening & decrease diameter of the bones
      • Most common muscles involved
        • extensor of hips
        • extensor of knees
        • dorsiflesion of ankles
        • deltoid
        • triceps
        • thenar muscles
        • respiratory muscles
        • spinal muscles
    • Bulbar paralysis
      • Pharyngeal paralysis
        • inability to swallow food, drinks and own secretions
        • inability to cough and difficulty in speaking
    • Respiratory paralysis
      • Respiratory muscles rare
      • Intercostal muscles
        • Anterior horn cells of the thoracic region
      • Diaphragm
        • Anterior horn cells of mid cervical
    • Fibrillations of muscles
      • Paralyzed muscles show fine ripples of contractions

    Diagnosis of polio

    • Clinical examination
      • confirmation of sudden onset of acute flaccid paralysis (AFP)
        • with no loss of sensation
    • Laboratory culture (stool)
      • isolate virus
        • 100% isolation of virus within 2 weeks of onset
          • WHO criteria for certification of polio free
        • 50% within three weeks of onset
        • 25% within 6 weeks

    Prevention of polio

    • Primary prevention
      • Health education
      • Oral polio virus vaccine (OPV)
        • Live attenuated Sabin Vaccine
        • OPV given in Malaysia in
          • 2nd month
          • 3rd month
          • 5th month
        • Booster
          • 18 months
          • standard 1
      • Intramuscular injection
        • Salk Vaccine
    • Secondary Prevention
      • Early diagnosis and prevention
        • Spinal polio and bulbar polio
      • Disability limitation
        • avoid factors that potentiate paralysis
        • eg. operations, injections & strenuous exercise
      • Prevention of deformities & contractures (of bone?)
    • Tertiary prevention (Rehabilitation)
      • Surgery on contractures
      • equinus foot
      • wheel chair for the disabled

    Eradication of polio

    • Polio transmission is now  limited to about 9 countries
      • Afghanistan
      • Pakistan
      • India
      • Angola
      • Congo
      • Nigeria
      • Somalia
      • Ethiopia
      • Sudan
    • Eradication is possible because the virus affects only humans
      • no animal reservoir
      • no long term carriers
      • virus cannot survive outside the human body for long
    • Acute flaccid paralysis (AFP) is being carried out all countries that have declared free of polio
    • Malaysia is free of polio
  • 4 COMMENTS

    1. That one of the best paper on leprosy. As, I am medical student at Westminster university. I am suppose to do a poster on leprae due next week, can I have permission to use one your diagram in my presentation?
      antoine

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