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leprosy. definition : A chronic infectious disease caused by mycobacterium leprae, With neurologic and cutaneous lesions. leprosy. leprosy. the infectious agent : mycobacterium leprae stained red with acid-fast stain , contains o-diphenoloxidase
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definition: A chronic infectious disease caused by mycobacterium leprae, With neurologic and cutaneous lesions.
the infectious agent: mycobacterium leprae stained red with acid-fast stain, contains o-diphenoloxidase breed one generation a 13-14days
M.lepraein nasal secretion of patients, after drying ex vivo→still alive for 2-9 days, Keep alive 3-4 weeks 0℃,inactivation after boiled 8', lose productivity after deposed to sunlight for 2-3h。
epidemiology: (1)infectious agent:leper(lepromatous type) (2)route of transmission:damaged skin、mucosa,direct contact,droplet spread. (3)herd suseptibility:natural acquired immunity. (4)epidemic condition:clustering distrubition,endemic
pathogenesis: Toxicity of M.leprae high:no invasion/autotherapy Organism resistance medium :TT low:Borderline none:LL(infectious) Cytoimmunity hypofunction
pathology: The pathological changes mainly occur in dermis and peripheral nerve. Tuberculoid type: tuberculoid type structure.hair follicle、coil gland、 sebaceous gland、blood vessel and nerve damaged. LL: focus of infection contains lepra cell(foam cell) histiocytic infiltrate around vessels.
Clinical features: Incubation:2-5years(3moths-10years) 1、 skin lesions: 2、 peripheral nerve syptoms
1、 skin lesions: 1.diversification of lesions 2.appendages of the skin involvement:pelage、sweat glands、sebaceous follicle 3.skin nerve terminal→superficial sensation dysesthesia 4.found M.leprae(especially LL、borderline type)
2、peripheral nerves symptoms: Pure neural leprosy spindle-shaped swelling 、nodules or uniformly enlargement can be found,often felt painful or tenderness. 1. anesthesia: 2. dyscinesia,muscular atrophy,palsy ulnar N→little finger and fourth finger contractures,hypothenar…claw hand median N→thenar eminence…ape hand radial N→wrist drop/mallet finger common peroneal N→foot drop facial N→facial paralysis 3. disturbance of trophicity 4. dyshemia
little finger and fourth finger contractures,hypothnar…claw hand
Spectrum classification: 1. Tuberculoid (TT) 2. Borderline tuberculoid (BT) 3. Borderline (BB) 4. Borderline lepromatous(BL) 5.Lepromatous(LL) 6.Early and indeterminate leprosy
1. tuberculoid(TT): High resistance, the evolution is slow, Without internal organs involvement, lesions are limited。 bacilli(-),lepromin test(+), Test for cellular immunity shows normal. Typical lesions,superficial sensation disturbance, Nerve trunk is enlarged and stiff。
2. Borderline tuberculoid(BT): Numerous lesions, dissymmetric,the edges of lesions are well defined borderline, Peripheral nerve involvement more than TT, fewer internal organs involvement, Bacilli + - ++,lepromin test weakly(+)-(-)in advanced stage, comparatively low cytoimmunity.
3. Borderline(BB): Lesions polymorphism、multi-color、macule like infiltration and nodules. Lesions are generalized and asymmetrical,internal organs involvement. Bacilli +++→++++,lepromin test(-). Cytoimmunity between TT and BT
4. Borderline lepromatous(BL): Diffuse infiltration、macula、plaque/nodule Peripheral nerve trunk involvement ,asymmetrical: Nerve enlarged、tender,madarosis bacilli++++ - +++++,lepromin test(-)in advanced stage,cytoimmunity test(-).
5.Lepromatous(LL): very low resistance, developing fast, lesions are numerous,symmetrical. bacilli(+).
6.Indeterminate leprosy: nonage,hypopigmented macule,superficial sensory disturbance,slight peripheral involvement. Usually bacilli(-)or only a few(+) Leromin test most(+)in advanced stage
Reactional leprosy: acute or subacute symptoms abrupt onset in the course of disease,it is an allergic phenomenon.
Lepromin test: lepromin 0.1ML 48h(nonage〕3W(advanced stage)pratical value in late phase response: 1 (+)means high resistance 2 Useful to classify a given case
diagnosis and differential diagnosis 1 lesions with superficial sensory disturbance or only anhidrosis, or only an anesthsia area. 2 peripheral nerve trunk or cutaneous nerve enlargement; 3 lesions or histology section found M.leprae; 4 Specific changes in histopathology if there are 2 or over 2 items accord with above 4 items, the leprosy can be diagnosed.
treatment: 1 sulfone: dapsone(DDS) acedapsone (DADDS) 2 rifampicin 3 clofazimine 4 protionamide ethinamide drugs above should be used in trigeminy treatment