Skin Injury
Skin injury is damage to the integumentary tissue caused by mechanical, thermal, chemical, or radiation forces, ranging from superficial abrasions to full-thickness wounds involving the epidermis, dermis, and underlying structures.
Murtagh Diagnostic Strategy
| Category | Diagnosis | Key Discriminator | Cantonese Question / Finding | Probability |
|---|---|---|---|---|
| Probability Diagnosis | Simple laceration / abrasion | Clean-cut or superficial wound, no deep structure involvement | 「個傷口係俾利嘢割到定係撞到？」(Sharp vs blunt?) | ~60% |
| Contusion (bruise) | Blunt mechanism, intact skin, discolouration | Tenderness, swelling, ecchymosis on inspection | ~30% | |
| Serious Not To Miss | Wound infection / necrotising fasciitis | Disproportionate pain, systemic toxicity, dishwater pus [10] | 「個傷口有冇越嚟越紅腫痛？有冇發燒？」 | ~5% |
| Tendon / nerve / vascular injury | Loss of motor/sensory function distal to wound; pulsatile bleeding | 「手指郁唔郁到？有冇痺？」 [2][5] | ~3% | |
| Open fracture | Bone visible in wound; high-energy mechanism; deformity | 「見唔見到骨？隻手/腳有冇變形？」 [9] | ~1% | |
| Non-accidental injury (child abuse) | Inconsistent history, multiple injuries at different healing stages, delay | 「佢點樣整親嘅？」— check story consistency [1] | < 1% | |
| Pitfalls | Retained foreign body | Penetrating mechanism (glass, metal); persistent pain/infection | 「有冇嘢入咗去傷口入面？」— XR if suspicious | ~5% |
| Joint penetration | Wound near joint; pain on passive ROM; synovial fluid leak | Express joint fluid or saline load test | ~1% | |
| Compartment syndrome | Pain on passive stretch, tense compartment, 6Ps | 「隻手/腳有冇越嚟越脹痛？」 | < 1% | |
| Masquerades | Bleeding disorder / anticoagulant use | Excessive/prolonged bleeding from minor wound | 「你平時容易瘀？食緊薄血丸？」 | ~5% |
| Diabetes / peripheral neuropathy | Unaware of injury; chronic non-healing wound | 「你有冇糖尿病？腳有冇痺？」 [6] | ~3% | |
| Drugs (immunosuppressants/steroids) | Poor wound healing, recurrent infection | 「有冇食緊抑制免疫力嘅藥？」 | ~2% | |
| Trying to Tell Me Something? | Cosmetic anxiety | Repeated questions about scarring; facial wound | 「你最擔心嘅係咩？」 | ~20% |
| Workplace injury / compensation | Injury at work; asking about medical certificate | 「係咪返工嗰陣整親？需唔需要病假紙？」 | ~15% | |
| Domestic violence / self-harm | Hesitant history; injuries in unusual locations (inner arms, hidden areas); parallel cuts | 「你安唔安全㗎？屋企有冇人傷害你？」 | ~5% |
6-Minute Consultation Structure
| Time | Task | Cantonese Key Phrases | Why It Scores Marks |
|---|---|---|---|
| 0:00–0:30 | Friendly opening, rapport, set agenda | 「你好呀，我係X醫生，今日由我幫你睇。你點稱呼呀？」「今日嚟有咩嘢我可以幫到你？」 | Patient-centred opening; establishes trust; interpersonal marks |
| 0:30–1:30 | Chief complaint & HPI — mechanism, timing, location, depth, bleeding, contamination, pain | 「可唔可以話我知發生咩事？」「幾時受傷嘅？」「點樣整親嘅？」「傷口有幾大幾深？」「有冇流好多血？」「有冇俾啲污糟嘢掂到個傷口？」 | Captures wound mechanism, severity, contamination — key for diagnosis and management |
| 1:30–2:30 | Red flags & associated injuries — neurovascular status, tendon function, bony injury, tetanus status, foreign body | 「隻手/腳郁唔郁到？有冇痺嘅感覺？」「有冇打過破傷風針？」「覺唔覺得入面有嘢卡住？」 | Screens for tendon/nerve/vascular injury; tetanus risk — marks for completeness |
| 2:30–3:30 | PMH, DHx, allergy, social Hx — DM, bleeding tendency, anticoagulants, smoking, occupation, immunosuppression | 「你有冇其他長期病？食緊咩藥？」「有冇藥物敏感？」「你做咩工作嘅？」「有冇食薄血丸？」 | Affects wound healing, infection risk, and management plan |
| 3:30–4:30 | ICE — uncover hidden agenda | 「你自己覺得個傷口點嚟嘅？」（Ideas）「你最擔心啲咩嘢？」（Concerns）「你今日嚟最想我幫你做啲咩？」（Expectations）「點解今日先嚟睇？」 | Critical for marks — "Why today?" often reveals hidden agenda (e.g., fear of scarring, infection, domestic violence, work injury compensation, child abuse concern) |
| 4:30–5:15 | Signpost examination & summarise | 「我想睇下你個傷口，可以嗎？」「等我總結一下你啱啱講嘅嘢…」 | Signposting and summarising score interpersonal marks |
| 5:15–6:00 | Closing: explain plan, safety-net, check understanding | 「我哋依家要幫你清洗傷口同處理。」「如果之後傷口越嚟越紅、腫、痛、有膿、或者發燒，要即刻返嚟睇。」「你有冇嘢想問？」 | Safety-net advice is a must; checking understanding shows patient-centredness |
Hidden agenda tips for Skin Injury:
- Ask 「點解今日先嚟睇？」— delayed presentation may indicate domestic violence, child abuse, self-harm, workplace injury claim, or fear of scarring/disfigurement.
- If the patient is a child brought by a carer, be alert for inconsistent history (non-accidental injury). [1]
- If the patient asks about cosmetic outcome → concern about scarring → expectations for plastic surgery referral.
| Domain | English Question | Cantonese Question | Why It Matters | If Positive Think Of |
|---|---|---|---|---|
| Mechanism | How did you get injured? What caused the wound? | 「點樣整親嘅？係咩嘢整到？」 | Classification of injuries [2]: sharp/blunt/crush/bite/burn determines wound type and management | Stab → deep structure injury; bite → infection risk; burn → depth grading |
| Timing | When did the injury happen? | 「幾時整親？幾耐之前？」 | Wounds > 6–8 hours have higher infection risk; delayed closure contraindicated | Late presentation → infection; think of hidden agenda |
| Location & depth | Where is the wound? How deep is it? | 「傷口喺邊度？有幾深？見唔見到骨/筋？」 | Hand/face wounds need specialist referral; depth determines structure involvement | Tendon/nerve/vessel injury; joint penetration |
| Bleeding | How much did it bleed? Is it still bleeding? | 「流咗好多血？依家仲有冇流緊？」 | Profuse bleeding → vascular injury [2]; scalp lacerations bleed profusely [3] | Arterial injury; haemodynamic compromise |
| Contamination/FB | Was the wound contaminated? Any foreign body? | 「有冇俾泥、鐵釘、玻璃掂到？覺唔覺有嘢入咗去？」 | Contamination → infection/tetanus risk; retained FB → needs imaging | Wound infection [4]; tetanus; abscess |
| Neurovascular | Can you feel/move beyond the wound? | 「傷口以下嘅位置有冇痺？郁唔郁到手指/腳趾？」 | Nerve and vascular injury [2] — must document before any procedure | Nerve transection; compartment syndrome |
| Tendon function | Can you bend/straighten each finger? | 「每隻手指可唔可以曲直？」 | Common hand injuries [5] — tendon injury easily missed | Flexor/extensor tendon laceration |
| Tetanus | When was your last tetanus vaccination? | 「你上次打破傷風針係幾時？」 | Tetanus prophylaxis decision — high-yield management point | Need TIG + Td if not immunised |
| PMH | Any chronic diseases? Diabetes? | 「有冇長期病？糖尿病？」 | DM → impaired wound healing, infection risk [6] | Diabetic foot ulcer; poor healing |
| Medications | Taking blood thinners or steroids? | 「有冇食薄血丸？類固醇？」 | Anticoagulants → prolonged bleeding; steroids → poor healing | Warfarin/NOAC → bleeding tendency |
| Allergies | Any drug allergies? Latex allergy? | 「有冇藥物敏感？對膠手套敏感？」 | LA/antibiotic allergy affects wound management | Allergy to local anaesthetic, chlorhexidine [7] |
| Occupation | What is your job? | 「你做咩工作嘅？」 | Occupational injury → compensation; manual worker → functional impact | Workplace accident claim; needs MC |
| Domestic/NAI screen | (If history inconsistent) Can you tell me more about how this happened? | 「可唔可以再詳細啲講下點整親？」 | Non-accidental injury [1] — inconsistent history, delay in seeking help, multiple injuries | Child abuse; domestic violence; self-harm |
| Functional impact | Does the injury affect your daily life/work? | 「個傷口有冇影響你返工/日常生活？」 | Functional impact is a biopsychosocial problem | Unable to work; unable to care for self/children |
| Cosmetic concern | Are you worried about scarring? | 「你擔唔擔心留疤？」 | Links to ICE and hidden agenda | Plastic and reconstructive surgery referral [8] |
Case Report Form Answer Builder
- CC: "Skin injury to [site] for [duration]" — use patient's own words
- HPI high-yield points:
- Mechanism of injury (sharp/blunt/crush/bite/burn) [2]
- Timing (when, how long ago)
- Location, size, depth
- Bleeding amount, current haemostasis status
- Contamination, foreign body possibility
- Neurovascular status distal to wound
- Tetanus immunisation status
- Current symptoms: pain, swelling, signs of infection
- Any prior self-treatment
- Examples: "Wound management and closure," "Concern about infection," "Worried about scarring," "Pain and unable to work," "Need tetanus shot"
- How to phrase: State the single most important reason the patient came TODAY — often it is the concern/expectation, not just the wound itself.
| Example Wording | |
|---|---|
| Ideas | "I think I might need stitches" / "I'm worried it might be infected" |
| Concerns | "I'm afraid of permanent scarring" / "Worried about tetanus" / "Scared it won't heal because I have diabetes" |
| Expectations | "I want the wound cleaned and closed properly" / "I want a referral to a plastic surgeon" / "I need a sick leave certificate for work" |
- Traumatic laceration (or abrasion/contusion depending on mechanism)
- Minimum supporting evidence: history of sharp/blunt trauma → breach of skin integrity → wound of stated size/depth at stated location → no deep structure involvement on examination
| DDx | One Key Discriminator |
|---|---|
| 1. Wound infection / infected wound | Erythema, warmth, purulent discharge, fever — especially if delayed presentation |
| 2. Tendon / nerve injury | Loss of specific motor function or sensation distal to wound (e.g., cannot flex DIP = FDP injury) [5] |
| 3. Non-accidental injury | Inconsistent history, unusual injury pattern, multiple injuries at different stages [1] |
| Domain | Problem |
|---|---|
| Biological | Risk of wound infection / impaired healing (especially if diabetic or immunosuppressed) |
| Psychological | Anxiety about scarring / cosmetic outcome; fear of needles/procedures; PTSD if assault/accident |
| Social | Unable to work (especially manual labourer) → financial impact; childcare difficulty if dominant hand injured; if NAI → safeguarding concern |
| Diagnosis/DDx | Best Supporting Physical Sign | How to Elicit | Why It Supports This Diagnosis |
|---|---|---|---|
| Traumatic laceration (most likely) | Clean-cut wound with visible depth, bleeding edges, intact deep structures | Direct inspection of wound after cleaning; assess wound edges (sharp = laceration, irregular = tear/crush) | Confirms mechanical skin breach consistent with reported mechanism [4] |
| Wound infection | Surrounding erythema, warmth, tenderness, purulent discharge | Inspect wound margins; palpate for fluctuance; note discharge character | Signs of infection indicate secondary bacterial wound infection |
| Tendon injury | Loss of active movement at specific joint | Test each tendon individually: e.g., FDS — hold other fingers in extension, ask to flex PIP; FDP — hold PIP, ask to flex DIP [5] | Loss of isolated joint movement = tendon discontinuity |
| Nerve injury | Loss of sensation in specific nerve territory | Light touch and two-point discrimination in median/ulnar/radial nerve territories | Sensory deficit in defined territory confirms nerve transection [2] |
| Non-accidental injury | Multiple bruises/injuries at different stages of healing; patterned injuries | Full skin survey; look for injuries inconsistent with stated mechanism | Multiple-stage injuries suggest repeated trauma [1] |
| Open fracture | Bone visible in wound; bony crepitus; deformity | Inspection of wound base; gentle palpation of underlying bone | Visible bone or crepitus = open fracture requiring urgent orthopaedic referral [9] |
Exam Discriminators and Traps
Must Not Miss Red Flags — Urgent Referral
- Pulsatile / uncontrolled bleeding → vascular injury → apply direct pressure, urgent surgical referral
- Loss of distal motor/sensory function → nerve/tendon injury → urgent hand surgery / ortho referral [2][5]
- Visible bone / joint penetration → open fracture → IV antibiotics + urgent orthopaedic referral [9]
- Disproportionate pain + systemic toxicity + dishwater pus → necrotising fasciitis → emergency surgical debridement [10]
- Inconsistent history in a child → non-accidental injury → safeguarding protocol, do NOT discharge before senior review [1]
- Human/animal bite to hand → high infection risk (Pasteurella, Eikenella) → prophylactic antibiotics + close follow-up
- Forgetting to ask about tetanus immunisation — a very common exam omission.
- Not testing tendon function individually — especially flexor tendons in hand lacerations; FDS and FDP must be tested separately. [5]
- Missing a retained foreign body — always ask and consider X-ray (glass is radio-opaque!).
- Not screening for NAI when the history doesn't fit — especially in children or vulnerable adults. [1]
- Forgetting ICE / hidden agenda — the patient may not care about the wound itself but about scarring, compensation, or fear of an underlying condition.
- Not performing safety-netting at closing — must warn about infection signs (redness, swelling, pus, fever, red streaks) and when to return.
- Confusing wound terminology: excoriation = exogenous injury to epidermis; erosion = partial loss of epidermis; ulcer = full-thickness loss extending to dermis/subcutis [4][11].
- Clean wound < 6 hrs: irrigate, debride, primary closure ± tetanus prophylaxis
- Contaminated / > 6–8 hrs: irrigate, debride, consider delayed primary closure, tetanus +/- antibiotics
- Wound healing phases: haemostasis → inflammation → proliferation → remodelling [4]
- Safety-net: 「如果傷口越嚟越紅、腫、痛、有膿、或者發燒，要即刻返嚟。」
Key GC lecture point: Classification of injuries — clean vs contaminated; sharp (incised) vs blunt (laceration with ragged edges) vs crush vs penetrating vs bite — determines wound management approach [2][4].
Key GC lecture point: Wound infection and antiseptic technique — wound irrigation is the single most important step in reducing wound infection [4].
Key GC lecture point: Common hand injuries — always test individual tendon function; mallet finger (extensor tendon avulsion at DIP), jersey finger (FDP avulsion), and gamekeeper's thumb (UCL injury) are commonly tested [5].
Key GC lecture point: From GC 190 Burns — assess burn depth (superficial/partial/full thickness), TBSA (rule of nines), and need for fluid resuscitation [12].
High Yield Summary
What to ASK: Mechanism, timing, contamination, FB, neurovascular status, tendon function, tetanus status, PMH (DM), medications (anticoagulants), ICE, and screen for NAI/self-harm/domestic violence if history is inconsistent.
What to WRITE: CC in patient's words with mechanism and timing → HPI covering wound details and functional status → RFC (often concern-driven, e.g., "worried about scarring") → ICE → Most likely Dx = traumatic laceration → DDx: wound infection, tendon/nerve injury, NAI → Biopsychosocial: infection/healing risk, anxiety/scarring concern, work/functional impact → Physical sign: wound inspection + tendon testing.
What NOT to MISS: Tendon/nerve/vascular injury (test individually!), retained FB (XR if suspicious), tetanus status, NAI in children, necrotising fasciitis red flags, and safety-net advice at closing.
Active Recall - Family Medicine Clinical Test
[1] Senior notes: Adrian Lui Pediatrics Notes.pdf (p. 492 — Child Abuse / Non-accidental injuries) [2] GC lecture slides: GC 182. Chopped and stabbed wound in gang fight Nerves and vascular injury; Classification of injuries.pdf [3] Senior notes: Ryan Ho Neurology.pdf (p. 200 — Scalp and Skull Injury) [4] GC lecture slides: GC 178. An ugly wound Wound healing; Wound infection; Anti-septic technique.pdf [5] GC lecture slides: GC 233. Common Hand Injuries.pdf [6] Senior notes: Ryan Ho Endocrine.pdf (p. 98 — Diabetic Foot) [7] Senior notes: Block A - Dermatology PBL 1.pdf (p. 11 — Chlorhexidine contact dermatitis) [8] GC lecture slides: GC 192. I want to look better Plastic and reconstructive surgery.pdf [9] GC lecture slides: GC 231. High Energy Trauma Open Fracture_Part 2.pdf [10] GC lecture slides: GC 237. Musculoskeletal infection [Updated in 2025].pdf (p. 41 — Necrotising fasciitis clinical diagnosis) [11] Medicine lecture slides: Derm General Clerkship 2026 Part1.pdf (p. 4 — Types of secondary lesions) [12] GC lecture slides: GC 190. I have a scald Burn.pdf
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