Leprosy & Poliomyelitis

• 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

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

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

• 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

• 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

• 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

• 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