Leprosy (Hansen's Disease) | Leprosy History, Causes, Classifications & Treatments - ASLPclick

 

Leprosy

-   Leprosy (Hansen’s disease)

Leper (Greek word) = scaly

Ø Distribution of Disease – in 1985, 122 countries were endemic for leprosy, but in 2000 leprosy was restricted to only 10 countries by using multidrug treatment eliminating of disease. Now the highest burden is concentrated in 6 countries i.e., India, Brazil, Myanmar, Madagascar, Nepal, and Mozambique. In India it is endemic in Bihar, U.P., Maharashtra, West Bengal, Orissa, Tamil Nadu, Andhra Pradesh, M.P., Jharkhand, Chhattisgarh, Uttarakhand etc.

Ø Agent Factors –

(i)  Agent – Mycobacteria leprae (acid fast bacilli).

(ii)  Source of infection – All patient of active leprosy.

(iii)  Portal of exit – Main portal of exit is nasal mucosa. Other are ulcerated or broken skin or sometimes intact skin (hair follicle)

(iv)  Infectivity – Highly infectious.

Ø Host Factors –

(i)  Age – In all age but predominant in infant and children.

(ii)  Sex – In both sexes but higher in male due to greater mobility.

(iii)  Migration – It was migrated from rural to urban areas.

(iv)  Immunity – Cell-mediate immunity is responsible for resistance to infection in some individuals.

Ø Environmental Factors –

(i)  Humidity favours the survival of M leprae.

(ii)  The poverty and related problems e.g., overcrowding, poor housing, lack of education, lack of personal hygiene etc. social factors favours the spread of disease.

(iii)  There is a social stigma of leprosy due to the deformities it can cause, so it is known as “social disease”

Ø Mode of Transmission –

(i)  Droplet infection by sneeze

(ii)  Direct (skin to skin) or indirect (contact with soil, fomites etc.) contact transmission.

(iii)  Some rare routes are breast milk from lepromatous mother to baby, by insect vectors or by tattoing needles.

Ø Classification of leprosy –

 

Indian	Ridly & Jopling	Madrid	WHO
Indeterminate	Tuberculoid (TT)	Indeterminate	Paucibacillary
Tuberculoid	Borderline tuberculoid (BT)	Tuberculoid	Multibacillary
Borderline	Borderline (BB)	Borderline
Pure neuritic	Lepromatous (LL)	Lepromatous

 

(i)  Indeterminate – Early cases with one or two vague hypopigmented macules and definite sensory impairment. The lesions are bacteriologically negative.

(ii)  Tuberculoid type – The cases with one or two well-defined lesions, which be flat or raised, hypopigmented or erythematous and are anaesthetic. The lesions are bacteriologically negative.

(iii)  Borderline type – Cases with four or more lesions which may be flat or raised, well or ill-defined, hypopigmented of erythematous and show sensory impairment or loss. The bacteriological positivity of these lesions is variable, without treatment, it usually progresses to lepromatous type.

(iv)  Lepromatous type – Cases with diffuse infiltration or numerous flat or raised properly defined, shiny, smooth, symmetrically distributed lesions. The lesions are bacteriologically positive.

(v)  Pure neuritic type - The cases of leprosy which show nerve involvement but do not have any lesion in the skin. These cases are bacteriologically negative.

-  Paucibacillary leprosy – 1-5 skin lesions

-  Multibacillary leprosy – more than five skin lesions.

 

Ø Clinical Features – 

    Leprosy is clinically characterized by one or more of the following cardinal features.

(i)  Hypopigmented patches.

(ii)  Partial or total loss of cutaneous sensation in the affected areas.

(iii)  Presence of thickened nerves

(iv)  Presence of acid-fast bacilli in the skin or nasal smears.

The signs of advanced disease are presence of nodules or limps especially in the skin of the face and ears, plantar ulcers, los of fingers or toes, nasal depression, foot drop, claw toes etc.

 

Ø Diagnosis –

1.  Family history and clinical examination (thickening of nerve, hypopigmented patches and loss of sensation).

2.  Bacteriological examination for presence of M. leprae in the smears of skin or nasal blow, and Ziehl-Neelsen staining for acid fast bacilli.

3.  Mouse foot pad culture of M. leprae.

4.  Histamine test - I/D injection of 0.1 ml (1:1000) solution of histamine in hypopigmented patches. In healthy person, it gives rise to a wheel surrounded by an erythematous flare within few minutes. In the cases of leprosy by an erythematous flare within few minutes. In the cases of leprosy flare response is lost because nerve supply is damaged in that area.

5.  Biopsy - for confirmation and classification of disease

6.  Immunological test.

(A)  Tests for detecting Cell Mediate Immunity (CMI) -

(i)  Lepromin test - it is a performed by injecting I/D injection of 0.1 ml of lepromin into the inner aspect of the forearm. There are two types of positive reaction.

· Early Reaction (Fernandez reaction) – an inflammatory response develops within 25 to 48 hours and disappears after 3 to 4 days. The sign is redness and induration of site more than 10 mm. it shows that person is exposed to infection previously.

 

· Late Reaction (Mitsuda reaction) – the reaction starts 7-10 days and reaches its maximum in 3 or 4 weeks. The test is read at 21 days when nodule in maximum. If nodule is more than 5 mm, the reaction is positive. It indicates cell mediate immunity.

Lepromin test is not a diagnostic test because it shows both false positive and false negative results. It is used to evaluate the immune status (CMI) of leprosy patient, to confirm the classification of case and to estimate the prognosis of cases.

(ii)  LTL and LMIT (Lymphocyte Transformation Test and Leucocyte Migration Inhibition Test) – They are used to detect subclinical cases and CMI of patients.

 

(B) Tests for Humoral Responses to M. leprae –

These tests are expected to have value in detecting subclinical infections, preclinical manifestations and follow-up efficacy of drug treatment.

(i)  FLA-ABS test (Fluorescent Leprosy Antibody Absorption Test).

(ii)  Test for the presence of monoclonal antibodies.

(iii)  ELISA

Ø Leprosy Control –

1. Medical measures –

(i)  Estimation of the problem (by epidemiological surveys).

(ii)  Early case detection by contact survey, group survey and mass survey.

(iii)  Multidrug therapy (MDT) – WHO recommendation for adults are :

For Multibacillary leprosy (12 month) –

Rifampicin- 600 mg once monthly, given under supervision. Dapsone (DDS)- 100 mg daily, self-administered.

Clofazimine- 300 mg once monthly, supervised and 50 mg daily, self administered.

For Paucibacillary leprosy (6 months) –

Rifampicin- 600 mg, once monthly, given under supervision. Dapsone- 100mg daily, self-administered.

Ø Lepra Reaction – During the course of leprosy, immunologically mediated episodes of acute and subacute inflammation known as lepra reaction may occur. Because peripheral nerve trunks are often involved, unless reactions are promptly and adequately treated (using tapering dose of prednisolone for 10 weeks starting from 40 mg) such episodes can result in permanent deformities.

(iv).Surveillance – after the completion of treatment paucibacillary cases are examined at least once a year for a minimum 2 years and multibacillary cases once a year for a minimum 5 years

(v) Immunoprophylaxis – BCG vaccine can provide some protection against leprosy, others are under determined.

(vi) Chemoprophylaxis – Dapsona and acedapsona are useful but their applicability is still to be determined.

(vii) Treatment of Deformities – Prevention and treatment of following deformities:-

Face – Mask face, facies leonine, lagophthalmos, loss of eye brows and eyelashes, corneal ulcers and opacities, perforated nose, depressed nose, ear deformities etc.

Hand – Claw hand, wrist-drop, ulcers, absorption of digits, thumb-web contracture, hollowing of the interosseous spaces and swollen hand etc.

FEET – Plantar ulcers, foot-drop, inversion of the foot, clawing of the toes, absorption of the toes, collapsed foot, swollen foot and callosities etc.

 

Ø Others – Gynecomastia, perforated palate etc.

(Viii) Rehabilitation – The cheapest and surest method is to prevent physical deformities and social and vocational disruption by early diagnosis and treatment.

(ix) Health Education – Education about the characteristics of disease, regular treatment and leprosy control programme.

(2)  Social Support – e.g. assistance to the patient to travel to and from the clinic, help to the needy families in term of food grains, cloths, care of children and their education and job placement, slum improvement and abolishing the social evil of beggary.

(3)  national leprosy eradication programme.

(4)  Evaluation of programme.