Hansen’s Disease

HistoryDefinition: Leprosy is a chronic systemic disease

caused by Mycobacterium leprae manifesting as development of specific granulomatous or neurotrophic lesions in the skin, mucous membrane, eyes nerves, bones and viscera.

Oldest infection known to mankind

Synonyms: Hansen’s disease, ‘Kushtha roga’

Transmission of LeprosyRespiratory route: inhalation of bacilli-laden

droplets

Cutaneous: skin to skin contact

GIT : ingestion of food

Intradermal : inoculation by tattoos } Not Yet Proven

Epidemiological factorsOccurs at all age groupsPeak age of onset : Between 10 – 20 yearsMales > FemalesChildren most susceptibleImmune status ( host resistance)OvercrowdingLow socioeconomic status

Immunity and Leprosy

Host resistance ExcellentGood

Fair

Poor Very poor

Clinical manifestationNo infectionSubclinical infection with spontaneous regression Indeterminate, pure neuritic,tuberculoidMid-borderline,borderline-lepromatous

Lepromatous

Mycobacterium LepraeObligate, intracellular, acid-fast bacillus Affinity for skin, nerves and muscle tissue Found in macrophages, histiocytes and Schwann

cells. Non cultivable Grown in animal modelsClosely resembles M.tuberculosis, but less acid-

fast. Multiplies in 11-13 days.

Classification

The Ridley Jopling classificationIndeterminateTuberculoidBorderline: borderline-tuberculoid,

mid-borderline, borderline-lepromatous

LepromatousPure neural, Maculoanaesthetic - Indian classification

ClassificationPaucibacillary Leprosy(PB): Indeterminate leprosy (I) Tuberculoid leprosy (TT) Borderline tuberculoid (BT) Pure neuritic (PN)* Multibacillary Leprosy(MB): Midborderline leprosy (BB) Borderline lepromatous (BL) Lepromatous leprosy (LL) * Asymmetric nerve involvement with no skin lesion

and usually of tuberculoid origin.

Tuberculoid (TT) Single or few, asymmetrical, well-defined,

erythematous or copper-coloured patches Sensations - Absent Nerves - thickened, presence of feeding nerves,

abscesses Skin smears - Negative Lepromin test - Strongly positive Course - Relative benign and stable, with good

prognosis.

Borderline leprosy

Common type of leprosy Subdivided into BT, BB & BL. Course - Unstable with variable prognosis , may

progress to sub-polar LL leprosy. Most prone to reactions. Lepromin test -Negative ,weakly positive in BT.

Borderline Tuberculoid (BT) Few asymmetric, hypopigmented or skin coloured

macules, plaques with ill defined marginsPresence of satellite lesion near the advancing

margin of patchSensory impairment - MarkedNerve involvement - Marked and asymmetrical

Midborderline leprosy (BB)Unstable form, reactions frequent Annular lesions with characteristic punched out

appearance (inverted saucer shaped) Sensory impairment - Moderate. Nerve involvement - Marked and asymmetrical.

Borderline lepromatous leprosy (BL)Multiple shiny macules, papules, nodules and

plaques with sloping edges Sensory impairment - SlightNerve involvement - Widespread and less

asymmetrical. Glove & stocking hypoaesthesia

Lepromatous leprosyHypopigmented, erythematous or coppery, shiny

macules, papules, nodules Lesions symmetrically distributed, small, multiple,

shiny with normal or mild sensory loss Leonine facies: Infiltration of skin with nodules, loss

of eyebrows and eyelashes Nerve involvement symmetrical; glove & stocking

anaesthesia Lepromin test - Negative

Indeterminate leprosyAsymmetrical, single /multiple hypopigmented, or

faintly erythematous and ill-defined macules.Sensation - Normal or slightly impairedPeripheral nerves - NormalSkin smears - NegativeLepromin test - Unpredictable and variableCourse - Usually self limiting ,may progress to

other forms of leprosy.

Pure Neuritic leprosyNeuritic manifestations -Tingling, heaviness and

numbness, paresis, hypotonia, atrophy, claw hand and toes, wrist-drop, foot-drop.

No skin lesion.Other changes-Anhidrotic, dry glossy skin, blisters,

neuropathic ulcers, decalcification, bone resorption.

Pure Neuritic leprosyLepromin test -Slightly positive.Course-Spontaneous regression or progression to

TT leprosy.Silent neuritis (silent neuropathy) Sensory or motor impairment without skin signs of

reversal reaction or ENL ,tenderness, paraesthesiae or numbness.

Special forms of LeprosyLucio Leprosy: Rare form of lepromatous leprosy, described in Mexico. Diffuse widespread infiltration of skin, loss of body hair, loss of eyebrows & eyelashes, and widespread sensory loss.‘Lepra Bonita’ (Pretty leprosy)Elderly persons with diffuse infiltration of face smoothes out wrinkles, giving youthful appearance. Histoid leprosy:BL patients with irregular or poor treatment complianceDrug resistant cases

Eye Involvement in LeprosyLagophthalmos (partial/complete,

unilateral/bilateral) Conjunctivitis Exposure keratitis and corneal ulcersMadarosis, trichiasis leading to corneal vascularity

and opacity Dacryocystitis (acute,subacute or chronic) Nodules on sclera, episcleritis, scleritis Corneal nodules and lepromatous pearls Microlepromata, nodules on iris and ciliary body

Nerve Involvement in LeprosySensory involvement - Anaesthesia in hands & feet,

glove and stocking anaesthesia, repeated traumaMotor involvement- Wasting and paralysis of

musclesAutonomic involvement -Icthyosis, loss of hair and

sweating.

Other featuresNasal stuffiness / crustingEpistaxisHoarseness of voiceGynaecomastiaSaddle noseBone resorptionLymphadenopathy

Differential diagnosis of leprosy

Macular lesionsVitiligo Occupational leucoderma Tinea versicolor Pityriasis alba Post kala azar dermal leishmaniasis Naevus depigmentosus Scars

Differential diagnosis of leprosy

Infiltrated lesionsLupus vulgarisLupus erythematosusGranuloma annulareAnnular syphilidesPost kala azar dermal leismaniasis (infiltrated

lesions)SarcoidosisPsoriasis

Differential diagnosis of leprosy

Nodular lesionsPost kala azar dermal leismaniasis Cutaneous leismaniasisSyphilisOnchocerciasisSarcoidosisLeukaemia cutisMycosis FungoidesNodules of neruofibromatosis

Differential diagnosis of neurological conditionsSensory impairment with or without muscle wastingPeripheral neuropathy Diabetic neuropathyPrimary amyloidosis of peripheral nerves Congential sensory neuropathy Syringomyelia Tabes dorsalis Thoracic outlet syndromeAlcoholic neuropathy

Diagnosis

Cardinal signs of leprosySensory impairment in affected areasEnlargement of peripheral nerves associated with

signs of peripheral nerve damageFinding acid-fast bacilli in the lesions

Clinical examinationType and number of skin lesionsSensory impairment Motor examinationNerve examination SweatingLoss of hair

Clinical examination: SensoryTouch Tested with wisp of cotton,nylon thread or feather.

Temperature Tested with two test tubes – one containing hot water and other cold

Pain Tested by pin prick

Clinical examination : Motor Testing of motor power- Done clinically

Electro-diagnosis - Employed in very early cases. Electrical stimulator using faradic and galvanic current used to test muscle power.

Nerves Supra/ infraorbital Greater auricularClavicularRadialSup. Radial cut

Ulnar Median Lateral popliteal Posterior tibial Anterior tibial

Sural