MBBS OSCE · Dermatology / Infectious Diseases / Tropical Medicine / Neurology

OSCE — hypoaesthetic patch and thickened nerve: leprosy classification and MDT

An 8-minute OSCE station on clinical diagnosis of leprosy, Ridley–Jopling/WHO PB–MB classification, slit-skin smear concepts, WHO multidrug therapy, and reaction recognition (type 1 vs ENL).

8 min stationVerification in progress
On this page
Study tools

Exam tags

NEET-PGINICETUSMLEPLABMRCP

Brief (to candidate)

A 34-year-old man from an endemic area has a hypopigmented, anaesthetic patch on the forearm for 1 year and clawing of the ulnar fingers. Peripheral nerves feel thickened. You have 8 minutes to diagnose, classify, start MDT, and screen for reactions/disability.

Candidate instructions

  1. Recognise classic skin + nerve features of leprosy (Hansen disease).
  2. Classify using Ridley–Jopling spectrum and WHO PB vs MB.
  3. Outline diagnostic tests (clinical ± slit-skin smear/biopsy).
  4. Prescribe appropriate WHO MDT duration concept.
  5. Identify type 1 reaction vs ENL and disability prevention principles.

Examiner checklist (mark each domain / 10)

DomainKey actions expected
RecognitionHypopigmented/erythematous patches with anaesthesia, nerve thickening, trophic changes, claw hand/foot drop; history from endemic region[1][2]
ClassificationRidley–Jopling TT–BT–BB–BL–LL spectrum; WHO PB (≤5 lesions, smear-negative concept) vs MB (≥6 lesions or smear-positive/more bacillary disease) drives MDT duration[1][3]
DiagnosisOften clinical; slit-skin smear bacterial index; skin biopsy when needed; do not delay MDT if classic disease in endemic setting[2]
MDTRifampicin + dapsone ± clofazimine per WHO PB (~6 months) vs MB (~12 months) regimens (state local programme pack); counsel adherence and orange-red body fluid discolouration with clofazimine/rifampicin as relevant[1][5]
ReactionsType 1 (reversal): inflammation of existing lesions/nerves, risk of paralysis; Type 2 (ENL): crops of tender nodules, systemic upset in BL/LL — both need urgent recognition and steroids/specialist care as indicated
Disability preventionNerve function testing, eye care, footwear, physiotherapy; self-care education to prevent ulcers
CommunicationStigma-sensitive counselling; household contact screening; curable with MDT

Model key actions

  • Diagnose leprosy from anaesthetic skin lesion + thickened nerve in endemic context.[2]
  • Classify PB vs MB and start correct WHO MDT duration pathway.[1][5]
  • Screen for reactions and nerve deficit; prevent disability with self-care and follow-up.[3]

Common errors

  • Treating only the skin and ignoring nerve function.
  • Using wrong MDT duration (PB vs MB mix-up).
  • Missing type 1 reaction presenting as acute neuritis during treatment.
  • Stigmatising language or failing to counsel curability.
  • Delaying MDT waiting for complex lab confirmation when clinical diagnosis is clear.
References4Show
  1. [1]Grijsen ML, Nguyen TH, Pinheiro RO, et al. Leprosy. Nature Reviews Disease Primers, 2024.PMID 39609422
  2. [2]Maymone MBC, Laughter M, Venkatesh S, et al. Leprosy: Clinical aspects and diagnostic techniques. Journal of the American Academy of Dermatology, 2020.PMID 32229279
  3. [3]Britton WJ, Lockwood DN. Leprosy. Lancet, 2004.PMID 15081655
  4. [5]Li X, Ma Y, Li G, et al. Leprosy: treatment, prevention, immune response and gene function. Frontiers in immunology, 2024.PMID 38440733
OSCE — hypoaesthetic patch and thickened nerve: leprosy classification and MDT · MBBS OSCE · NeetVellum