Academe Learn
CBME Curriculum Preview

Page 23 of 23

DR9.1-6 | Leprosy — PBL Case

CLINICAL SETTING

You are the medical officer at a Primary Health Centre in a coastal district of Tamil Nadu. Your district is flagged by the NLEP as having a leprosy prevalence of 2.3 per 10,000 — above the national elimination threshold. Today, a 52-year-old fisherman, Murugan, is brought in by his wife, Meenakshi. She says: 'Doctor, for the past one year he has been having these skin patches, but he ignored them. Now he cannot hold the fishing net properly and keeps burning his hands on the stove without realising it.'

Trigger 1: First Encounter — History and Cardinal Signs

Murugan tells you that the skin patches started as a single pale area on his left cheek about 14 months ago. Over time, more patches appeared on his chest, arms, and legs. He noticed the patches 'don't feel things properly.' His wife adds that he has had several burns on his right palm over the past 3 months that he didn't notice until she pointed them out. On examination: - 8 hypopigmented patches across the trunk and limbs, asymmetrically distributed; partial anaesthesia on most patches - Left cheek patch: erythematous plaque with well-defined edge, complete anaesthesia - Right palm: 2-cm healing burn scar - Palpation: bilateral great auricular nerves thickened; right common peroneal nerve thickened and mildly tender at the fibular neck - No fever; no new skin nodules

DISCUSSION POINTS

  • Using the WHO cardinal signs, how many cardinal signs are present in Murugan's presentation? Which single finding alone is sufficient for a diagnosis of leprosy?
  • Apply the WHO operational classification to Murugan: is he Paucibacillary or Multibacillary based on what you know so far? What additional investigation would you order, and how would its result affect the classification?
  • Murugan's wife asks why there is a burn scar on his hand if he has a 'skin disease.' Explain the mechanism of sensory loss and nerve damage in leprosy in terms a non-medical person would understand.
  • Which nerves are enlarged in this patient? For each nerve, describe the anatomical landmark where you would palpate it and what disability to expect if it is severely damaged.
Click to reveal Trigger 2: Investigation Results and Classification Decision (discuss previous trigger first!)

Trigger 2: Investigation Results and Classification Decision

You perform a slit-skin smear from the left earlobe, right earlobe, and the left cheek lesion. Results: - Left earlobe: BI = 3+, MI = 5% - Right earlobe: BI = 1+ - Left cheek lesion: BI = 0 You refer Murugan to the district skin camp for confirmation. The visiting dermatologist notes the following Ridley-Jopling features: multiple asymmetric plaques with partial anaesthesia, satellite lesions around the cheek plaque, and the smear results. She suspects BL leprosy. You now need to initiate MDT. The NLEP blister pack for the appropriate regimen is available at the PHC free of charge.

DISCUSSION POINTS

  • The left cheek lesion shows BI = 0. Does this make any part of the patient paucibacillary? Justify your answer, explicitly referencing the rule that governs how a single positive site affects overall classification.
  • Write the complete MB-MDT prescription for Murugan: name each drug, the supervised monthly dose, the daily self-administered dose, and the total duration. What is the first rifampicin dose predicted to do to the bacterial viability (MI)?
  • Why does the dermatologist classify this as BL rather than LL or BB? Describe the key features that distinguish BL from these adjacent Ridley-Jopling categories.
  • Murugan asks why he needs three different medicines and cannot just take one. Explain the rationale for multi-drug therapy in leprosy, including what happened historically when dapsone was used alone.
Click to reveal Trigger 3: A Crisis During Treatment — Lepra Reaction (discuss previous trigger first!)

Trigger 3: A Crisis During Treatment — Lepra Reaction

Six months into MB-MDT, Murugan arrives at the PHC at 8 AM, clearly in pain. His wife says he woke up with severe pain in both legs. On examination: - Multiple new, tender, shiny erythematous nodules over both legs, forearms, and earlobes - Temperature: 38.8°C - Bilateral ankle oedema - ESR = 72 mm/h; CRP elevated - Existing skin patches are NOT more inflamed - His nerve examination is unchanged from baseline Meenakshi is upset: 'The medicines are making him worse! Should we stop?'

DISCUSSION POINTS

  • Identify the type of lepra reaction Murugan is experiencing. List three features from this presentation that support your diagnosis, and explain why this is NOT a Type 1 (reversal) reaction.
  • Explain the immunological mechanism of this reaction to the group. Which hypersensitivity type is involved? Where do the new nodules come from?
  • Write a management plan for Murugan: (a) Should MDT be continued or stopped? Justify. (b) What is the first-line drug for this reaction, and at what dose? (c) Are there any additional drugs for severe or recurrent disease? State the absolute contraindication you must check before prescribing thalidomide.
  • Meenakshi asks if this reaction means the medicines are failing and the disease is getting worse. How do you counsel her accurately, addressing both her concern and the expected duration of the reaction?
Click to reveal Trigger 4: Completing Treatment — Disability, Stigma, and Community Reintegration (discuss previous trigger first!)

Trigger 4: Completing Treatment — Disability, Stigma, and Community Reintegration

Murugan completes 12 months of MB-MDT. On release from treatment: - Skin patches have faded considerably - Slit-skin smear: BI = 1+ (from a baseline of 3+) — expected post-treatment decline - Right common peroneal nerve: permanent damage confirmed; he has foot drop on the right side and an anaesthetic right sole - Left hand: mild claw deformity of the little finger (Grade 2 WHO disability) - A plantar ulcer (2 cm, superficial) on the right forefoot He tells you: 'I want to go back to fishing, but the village headman says I should not because I might infect others with my tools. My son has stopped eating with me. I feel like a leper.' The NLEP district coordinator asks you to present this case at the monthly review meeting.

DISCUSSION POINTS

  • Assign WHO disability grades for Murugan's right foot and left hand. What specific clinical findings determine each grade?
  • Design a comprehensive disability management plan covering: (a) plantar ulcer care — immediate steps and long-term footwear; (b) foot drop management — functional options; (c) one daily self-care practice Murugan must continue for the rest of his life to prevent further ulceration.
  • Murugan is released from MDT. Is he still infectious? Cite the evidence (including what the first dose of rifampicin does to infectivity). How would you counsel the village headman who has asked Murugan to stay away from shared tools?
  • At the NLEP district meeting, what epidemiological data on leprosy in India would you present to justify continued surveillance, despite the 2005 national elimination declaration? What do 'elimination' and 'eradication' mean in this context, and why is the distinction important for ongoing NLEP strategy?