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DR15.1-3 | Pyoderma — Assignment
CLINICAL SCENARIO
A structured written assignment integrating clinical recognition, antimicrobial selection, and surgical referral decision-making in pyoderma. You will analyse a real-world case, justify diagnostic and therapeutic choices, and reflect on antimicrobial stewardship.
Instructions
Read the clinical scenario carefully. Answer all four sections in sequence. Support your reasoning with mechanisms where asked. Cite specific clinical features that drove your decisions. Word limit applies to the combined response.
Length: Total word limit: 700 words (all four sections combined). Aim for concise, evidence-based answers.
What to Submit
A 28-year-old male labourer presents with a 4-day history of a painful swelling on the right thigh. On examination: a 5 cm erythematous, indurated, tender mass with multiple openings discharging pus. Temperature 38.4°C. He has well-controlled type 2 diabetes (HbA1c 7.2%). Gram stain shows Gram-positive clusters. Name the pyoderma, classify it by depth of skin involvement, and explain the pathological mechanism (including the role of the host immune context).
The wound swab grows MSSA (methicillin-sensitive Staphylococcus aureus). Outline the systemic antibiotic you would prescribe (drug name, dose, route, duration), explaining why it is appropriate for this organism. Then list THREE adverse effects of this drug class that you must counsel the patient about. If the culture had instead returned MRSA, which oral antibiotic would you substitute, and what specific counselling point is critical for that agent?
Despite 48 hours of appropriate antibiotics, the swelling has enlarged and is now clearly fluctuant on palpation. The fever has not resolved. Explain why antibiotics alone have failed, what procedure is now indicated, and describe the decision-making framework you would use to determine whether urgent surgical referral (rather than office drainage) is required. Include at least two clinical red flags that should lower your threshold for surgical referral.
You see a different patient: a healthy 8-year-old child with three localised, small impetigo crusts on the face and no systemic features. A colleague suggests prescribing oral amoxicillin-clavulanate. Critically evaluate this choice from an antimicrobial stewardship perspective. What would you prescribe instead, and why? Reference the spectrum of activity needed and the risks of unnecessary broad-spectrum use.
Grading Rubric — Pyoderma Assignment Marking Rubric
| Criterion | Points | Full-marks descriptor |
|---|---|---|
| Section 1: Diagnosis, Classification, and Pathogenesis (correct identification of carbuncle, depth classification, Staph aureus mechanism, diabetic immune context) | 25 pts | Correctly identifies carbuncle; accurately classifies as multiple coalesced furuncles extending through subcutaneous tissue; explains Staph aureus pathogenesis (coagulase, exotoxins, pus formation) and links diabetes to impaired neutrophil function. |
| Section 2: Antimicrobial Therapy and ADRs (correct MSSA drug choice, dose, counselling; correct MRSA alternative with counselling point) | 30 pts | Correctly prescribes cloxacillin (or cephalexin) with dose/route/duration for MSSA; lists 3 relevant ADRs (allergy, GI, hepatitis); correctly identifies co-trimoxazole or doxycycline for MRSA with a specific counselling point (photosensitivity/water-upright/avoid milk). |
| Section 3: Surgical Referral Decision (explains antibiotic failure in abscess; indicates I&D; identifies red flags for surgical referral e.g., NSTI features, diabetic host, failure of office drainage, fascia involvement) | 25 pts | Accurately explains that antibiotics cannot penetrate pus-filled cavity; clearly indicates I&D as definitive treatment; identifies ≥2 specific red flags for escalation to surgical referral (e.g., signs of NSTI, diabetic host, rapid spread, pain disproportionate to findings, gas on imaging). |
| Section 4: Antimicrobial Stewardship (correctly advocates topical mupirocin over oral amoxicillin-clavulanate; explains spectrum mismatch and stewardship rationale) | 20 pts | Correctly identifies mupirocin 2% as appropriate (localised, superficial impetigo); clearly explains why oral amoxicillin-clavulanate is overprescribing (wrong route, unnecessary systemic exposure, broader spectrum than required, resistance risk, cost); references need for anti-Staph coverage only. |
PEER REVIEW
Your peer reviewer will assess whether: (1) the diagnosis is correctly named and classified by depth; (2) the antibiotic choices are appropriate for the organism specified; (3) at least two red flags for surgical referral are mentioned; (4) the stewardship argument is specific and evidence-based. Provide constructive written feedback of 80-120 words.