Leg Pain
Leg pain is a symptom arising from musculoskeletal, vascular, neurological, or other causes, ranging from benign muscle cramps to limb-threatening conditions such as peripheral arterial disease or deep vein thrombosis.
Murtagh Diagnostic Strategy
| Category | Diagnosis | Key Discriminator | Cantonese Question / Finding |
|---|---|---|---|
| Probability Diagnosis | Musculoskeletal strain / soft tissue injury | Acute onset after exertion, localised tenderness, no vascular/neuro deficit | 「最近有冇做運動或者扭親？」 |
| Osteoarthritis (hip/knee) | Pain on first step, worse with activity, age > 50, bony crepitus | 「行第一步會唔會痛？上落樓梯點？」 | |
| Chronic venous insufficiency / varicose veins [5] | Aching/heaviness worse with standing, relieved by elevation; visible varicosities, skin pigmentation | 「企得耐會唔會隻腳脹住痛？抬高隻腳好啲？」 | |
| Serious Not To Miss | Deep vein thrombosis (DVT) [4] | Unilateral swelling, warmth, risk factors (immobility, OCP, malignancy); Wells score | 「隻腳有冇腫咗？最近有冇坐長途機/做手術？」 |
| Acute limb ischaemia [1] | Sudden 6Ps (pain, pallor, pulseless, perishing cold, paraesthesia, paralysis); < 2 weeks | 「隻腳突然變白變凍、冇脈搏、痺或者郁唔到？」 | |
| Cauda equina syndrome [3] | Bilateral leg pain/weakness, saddle anaesthesia, urinary retention | 「會陰位有冇痺？大小便有冇失禁？」 | |
| Bone metastasis / primary bone tumour | Night pain, weight loss, constant progressive pain, hx of cancer | 「夜晚瞓覺會唔會痛醒？體重有冇輕咗？」 | |
| Pitfalls | Peripheral arterial disease (intermittent claudication) [2] | Reproducible calf pain after fixed walking distance, relieved by standing still; absent pedal pulses | 「行幾遠會開始痛？企定定幾耐會好？」 |
| Lumbar disc herniation / sciatica [3][6] | Pain radiating from back to leg (dermatomal), positive SLR, worsened by coughing/Valsalva | 「有冇痛由腰伸落去腳趾？咳嗽會唔會痛啲？」 | |
| Spinal stenosis (neurogenic claudication) [2] | Variable claudication distance, relieved by bending forward ("shopping trolley sign"), paraesthesia | 「推住架手推車行會唔會舒服啲？」 | |
| Cellulitis | Localised erythema, warmth, tenderness, fever; skin break/wound as portal of entry | 「隻腳有冇紅腫熱痛？有冇損傷或者傷口？」 | |
| Baker's cyst rupture | Sudden calf pain/swelling in patient with known knee arthritis | 「膝頭之前有冇關節炎？係咪突然間小腿腫晒？」 | |
| Masquerades | Diabetic peripheral neuropathy [7] | Glove-and-stocking burning/numbness, known DM, reduced monofilament/vibration sense | 「你有冇糖尿？隻腳底有冇痺或者好似踩住棉花咁？」 |
| Drug-induced myopathy (statins) | Diffuse muscle ache after starting statin, raised CK | 「有冇食降膽固醇藥？開始食之後隻腳有冇痠痛？」 | |
| Depression (somatisation) [8] | Multiple somatic symptoms, low mood, sleep/appetite disturbance, disproportionate worry | 「心情點？瞓得好唔好？食嘢點？」 | |
| Trying to Tell Me Something? | Psychosocial stress / fear of serious disease / work-related | Worried about amputation (family member had it), job loss, inability to care for family | 「有冇嘢令你特別擔心？屋企或者工作有冇壓力？」 |
| Time | Task | Cantonese Key Phrases | Why It Scores Marks |
|---|---|---|---|
| 0:00–0:30 | Greeting, rapport, open question | 「你好，我係今日嘅醫生，點稱呼你？」「今日有咩唔舒服想同我講？」 | Friendly opening; patient-centred start scores interpersonal marks |
| 0:30–2:00 | HPI: SOCRATES for leg pain, onset, site, character, radiation, severity, aggravating/relieving, timeline | 「隻腳邊度痛？」「痛咗幾耐？」「係點樣痛法？（痺、攣、刺、脹）」「行路會唔會痛啲？休息有冇好啲？」「有冇條件會令到痛啲或者好啲？」 | Symptom analysis is the bulk of HPI marks |
| 2:00–2:45 | Red flags: acute ischaemia (6Ps), DVT, cauda equina | 「隻腳有冇變白/變藍/凍咗？」「有冇腫咗？」「有冇覺得隻腳冇力、痺或者郁唔到？」「大小便有冇問題？」 | "Must not miss" serious disorders |
| 2:45–3:30 | Targeted Hx: vascular RFs, joint/MSK, neuro, back pain | 「你有冇糖尿/高血壓/膽固醇高/食煙？」「有冇腰痛或者痛落去腳？」「關節有冇腫脹或者晨僵？」 | Differentiates MSK vs vascular vs neurogenic |
| 3:30–4:15 | PMHx, DHx, allergy, FHx, social Hx | 「之前有冇乜嘢大病或者做過手術？」「而家食緊咩藥？有冇藥物敏感？」「屋企人有冇類似嘅問題？」「你做咩工作？平時有冇做運動？有冇飲酒食煙？」 | Completeness of history |
| 4:15–5:00 | ICE + hidden agenda | 「你自己覺得咩原因引起呢？」(Ideas)「你最擔心啲咩？」(Concerns)「你嚟睇醫生最希望醫生幫你做啲咩？」(Expectations)「點解揀今日嚟睇？」(Hidden agenda: "Why today?") | ICE is a dedicated mark; hidden agenda uncovers the real RFC |
| 5:00–5:30 | Summarise back to patient | 「等我總結一下你講嘅嘢，睇下有冇遺漏…」 | Shows active listening, scores interpersonal marks |
| 5:30–6:00 | Brief plan, safety net, close | 「我會幫你安排檢查…如果隻腳突然變白、冇知覺或者郁唔到，要即刻去急症室。」「你有冇嘢想問？」 | Safe closure; safety-netting scores marks |
Hidden agenda tip: A patient with "leg pain" may actually be worried about cancer (bone mets), blood clot after travel, or peripheral artery disease because a relative had an amputation. Always ask 「點解揀今日嚟睇？有冇特別嘢令你擔心？」
| Domain | English Question | Cantonese Question | Why It Matters | If Positive Think Of |
|---|---|---|---|---|
| Site | Which part of the leg? Unilateral/bilateral? | 「邊隻腳？邊個位置痛？兩隻腳都有定係一隻？」 | Localises pathology; unilateral swelling → DVT | DVT, MSK injury, radiculopathy |
| Character | Cramping? Aching? Burning? Numbness? | 「係點樣痛法？攣住痛？脹住痛？痺痺哋？」 | Cramping on exertion → claudication; burning/numbness → neuropathy | PAD, neuropathy, spinal stenosis |
| Onset & duration | Sudden or gradual? How long? | 「係突然痛定慢慢開始？痛咗幾耐？」 | Sudden < 2wk → acute ischaemia/DVT; chronic → PAD/OA/neuropathy [1] | Acute limb ischaemia, DVT |
| Exacerbating | Walking? Standing? Rest? Going uphill/downhill? | 「行路會痛啲定係休息先痛？行幾遠先開始痛？」 | Claudication distance; vascular vs neurogenic claudication [2] | PAD (constant distance), spinal stenosis (variable distance, relieved by bending) |
| Relieving | Standing still? Sitting/bending? Elevation? | 「企定定會好啲定係要坐低彎腰先舒服啲？抬高隻腳有冇好啲？」 | Stand-still relief → vascular; bend-forward relief → neurogenic [2] | Spinal stenosis vs PAD |
| Radiation | Does pain go from back to leg? | 「有冇痛由腰背伸落去腳？」 | L4/5, L5/S1 radiculopathy → sciatica [3] | Disc prolapse, spinal stenosis |
| Swelling | One leg swollen? Both? | 「隻腳有冇腫？一隻定兩隻？」 | Unilateral oedema → DVT; bilateral → CCF, CVI [4] | DVT, CVI, lymphoedema |
| Colour/temp change | Leg turning white/blue/red? Cold? | 「隻腳有冇變色——變白、變藍或者變紅？凍唔凍？」 | White/cold → acute ischaemia (6Ps); red/warm → cellulitis/DVT [1] | Acute limb ischaemia, DVT, cellulitis |
| Neuro deficit | Weakness? Numbness? Bladder/bowel? | 「隻腳有冇冇力、痺？大小便有冇問題？」 | Cauda equina = emergency; foot drop → peroneal palsy/L5 | Cauda equina, disc prolapse, DM neuropathy |
| Vascular RFs | DM, HTN, smoking, HLD, AF, family | 「你有冇糖尿、高血壓、膽固醇高？食唔食煙？有冇心房顫動？」 | PAD risk stratification; AF → embolic source [1] | PAD, acute embolic ischaemia |
| DVT RFs | Recent travel/surgery/immobilisation? OCP? Cancer? Pregnancy? | 「最近有冇坐長途飛機/做手術/長時間唔郁？有冇食避孕藥？」 | Virchow's triad assessment [4] | DVT → PE |
| Joint symptoms | Morning stiffness? Locking? Giving way? | 「朝早起身有冇僵硬？行路有冇鎖住或者軟腳？」 | Morning stiffness > 30 min → inflammatory; mechanical → OA, meniscal | RA, OA, gout, knee sport injury |
| Back pain | Any low back pain? | 「有冇腰痛？」 | Referred/radicular leg pain from spine [3] | Disc herniation, spinal stenosis, spondylolisthesis |
| PMHx | Previous DVT/PE? DM? Cancer? | 「之前有冇試過腳腫/肺栓塞？有冇糖尿/癌症？」 | Recurrent VTE; DM neuropathy; bone mets | DVT, DM neuropathy, metastatic bone disease |
| Drug Hx | Statins (myalgia)? Anticoagulants? OCP? | 「有冇食降膽固醇藥？有冇食薄血藥或者避孕藥？」 | Statin-induced myalgia is a masquerade; OCP → DVT risk | Drug-induced myalgia, DVT |
| Social/Occupation | Standing job? Exercise level? | 「你返工要企好耐定係坐多？平時做咩運動？」 | Prolonged standing → CVI; athlete → sport injury | Varicose veins, muscle/tendon injury, stress fracture |
| Functional impact | Can you walk? Sleep affected? Work affected? | 「痛到有冇影響行路/瞓覺/返工？」 | Functional impact for biopsychosocial problem formulation | — |
| ICE | What do you think is causing it? What worries you most? What do you hope I can do? | 「你自己覺得咩原因？最擔心啲咩？最希望我幫到你咩？」 | Dedicated ICE marks | — |
Case Report Form Answer Builder
- CC: Leg pain × [duration], [uni/bilateral], [acute/chronic]
- HPI must include: SOCRATES, functional impact, aggravating/relieving factors (exercise vs rest), associated swelling/colour change/numbness/weakness, back pain/radiation, relevant risk factors (DM, smoking, immobilisation, OCP), relevant negatives (no bladder/bowel dysfunction, no fever)
- Common RFC examples for leg pain:
- "Worsening leg pain affecting daily walking and work"
- "Worried about blood clot after long-haul flight"
- "Concerned the leg pain may be caused by a serious condition (e.g. blood clot, poor circulation)"
- Phrasing tip: State ONE reason that explains why the patient came today. It may not be the symptom itself but the fear/functional limitation.
| Component | Example Wording |
|---|---|
| Ideas | "Patient thinks the pain may be due to poor blood circulation / slipped disc / old age" |
| Concerns | "Patient is worried about blood clot / amputation / cancer because a family member had similar problem" |
| Expectations | "Patient wants a blood test / X-ray / referral to specialist / reassurance that it is not serious" |
- Choose based on the stem's context. In a typical FM station with a middle-aged/elderly patient:
- If exercise-related calf pain with vascular RFs → Peripheral arterial disease (intermittent claudication)
- If unilateral swelling after immobilisation → DVT
- If back-to-leg radiation with neuro signs → Lumbar radiculopathy / disc herniation
- If chronic bilateral aching with varicosities → Chronic venous insufficiency
- If burning/numbness in DM patient → Diabetic peripheral neuropathy
- Minimum evidence: State 2–3 history features + 1 physical sign that support your diagnosis.
| DDx | One Key Discriminator |
|---|---|
| Peripheral arterial disease (intermittent claudication) | Fixed claudication distance, absent pedal pulses, vascular RFs |
| Lumbar disc herniation / sciatica | Dermatomal radiation from back, positive straight leg raise |
| Deep vein thrombosis | Unilateral swelling + warmth, immobilisation risk factor, elevated Wells score |
(Adjust based on your chosen most likely diagnosis — these three should be alternatives to it.)
| Domain | Problem |
|---|---|
| Biological | Uncontrolled DM / hypertension / smoking contributing to vascular disease |
| Psychological | Anxiety about amputation or cancer; fear of serious underlying disease |
| Social | Unable to work (standing/walking job); reduced mobility affecting ADLs and social activities; caregiver burden |
| Diagnosis/DDx | Best Supporting Physical Sign | How to Elicit It | Why It Supports This Diagnosis |
|---|---|---|---|
| PAD / Intermittent claudication | Absent or weak dorsalis pedis / posterior tibial pulse [2] | Palpate dorsalis pedis (lateral to extensor hallucis longus tendon) and posterior tibial (behind medial malleolus); compare bilaterally; use handheld Doppler if needed | Absent pulses indicate arterial insufficiency distal to the occlusion |
| DVT | Unilateral calf swelling (>3 cm difference in calf circumference) [4] | Measure calf circumference 10 cm below tibial tuberosity bilaterally | Asymmetric swelling is the most reliable clinical sign; Homans' sign is unreliable |
| Lumbar disc herniation | Positive straight leg raise (SLR) test [3][6] | Patient supine, passively raise affected leg with knee extended; positive if radicular pain reproduced at < 60° | Stretches L5/S1 nerve roots; highly sensitive for lower lumbar disc herniation |
| Chronic venous insufficiency | Varicose veins with haemosiderin skin pigmentation at medial malleolus [5] | Inspect lower legs while patient standing; note tortuous dilated veins and brownish discolouration around gaiter area | Venous hypertension → RBC extravasation → haemosiderin deposition |
| Diabetic peripheral neuropathy | Reduced sensation to 10g monofilament [7] | Apply 10g monofilament to plantar surface of foot (1st, 3rd, 5th metatarsal heads, great toe); ask patient to report when felt | Loss of protective sensation confirms peripheral neuropathy in a known diabetic |
| Acute limb ischaemia | Absent pulse with pale, cold limb [1] | Palpate all LL pulses (femoral, popliteal, dorsalis pedis, posterior tibial); assess limb colour and temperature | 6Ps confirm acute ischaemia; absent pulse is the cardinal sign |
| Spinal stenosis | Reduced lumbar extension reproducing symptoms | Ask patient to extend lumbar spine; symptoms reproduced with extension, relieved with flexion | Extension narrows spinal canal, compressing neural elements |
| Cellulitis | Localised erythema with warmth and tenderness, well-demarcated border | Inspect and palpate affected area; mark the border of erythema with pen | In brief FM station, may be the only diagnosis with clear, visible sign |
Top Traps That Lose Marks
- Forgetting to ask about back pain — leg pain is commonly referred from the lumbar spine. Always ask about back pain and radiation.
- Missing DVT risk factors — immobilisation, recent surgery, OCP, malignancy, pregnancy. If you don't ask, you can't diagnose.
- Confusing vascular and neurogenic claudication — vascular: fixed distance, relieved standing still; neurogenic: variable distance, relieved by bending forward [2].
- Not checking ICE — dedicated marks. If you forget to ask "What are you worried about?", you lose easy marks.
- Diagnosing DVT without considering cellulitis and Baker's cyst — the DDx overlap is a favourite exam trap.
- Writing "musculoskeletal pain" without specifying — be specific: OA knee, muscle strain, stress fracture.
- Ignoring statin-induced myopathy — always check drug history.
- Missing cauda equina red flags — bilateral symptoms, bladder/bowel disturbance, saddle anaesthesia = immediate referral.
Must-Not-Miss Red Flags — Urgent Referral
- Acute limb ischaemia (6Ps): Pulseless, pale, perishing cold, painful, paraesthesia, paralysis → Emergency vascular referral [1]
- DVT with PE symptoms: Leg swelling + chest pain / dyspnoea / haemoptysis → Emergency A&E [4]
- Cauda equina syndrome: Bilateral leg weakness + saddle anaesthesia + urinary retention → Emergency spinal surgery referral [3]
- Suspected bone malignancy: Night pain, weight loss, constant pain, pathological fracture risk → Urgent orthopaedic / oncology referral
GC High-Yield Lecture Point: Lumbar disc herniation at L4/5 and L5/S1 are the most common levels. Physical examination includes straight leg raise test (SLR) — positive at < 60° reproduces radicular pain. Crossed SLR (raising the unaffected leg reproduces pain in the affected leg) is less sensitive but highly specific. [3][6]
GC High-Yield Lecture Point: For intermittent claudication, differentiate from neurogenic claudication: vascular claudication has a constant claudication distance and is relieved by standing still ("shop window to shop window"); neurogenic claudication has a variable claudication distance and is relieved by flexion ("park bench to park bench"). [2]
Safety-net line (for closing): 「如果隻腳突然變白、冇感覺、或者郁唔到，要即刻去急症室。如果痛咗越嚟越嚴重或者有新嘅症狀，記得返嚟覆診。」
High Yield Summary
What to ASK: SOCRATES for leg pain; back pain/radiation; swelling/colour/temperature change; walking distance and relief pattern; bladder/bowel symptoms; vascular RFs (DM, smoking, AF); DVT RFs (immobilisation, OCP, cancer); drug history (statins); ICE and "Why today?"
What to WRITE: Specific CC with laterality and duration; HPI with red-flag negatives documented; ONE main RFC reflecting the patient's real concern; ICE in their own words; most likely diagnosis with 2–3 supporting features; three DDx with discriminators; biopsychosocial problems; one physical sign with reasoning.
What NOT to MISS: Acute limb ischaemia (6Ps), DVT → PE, cauda equina syndrome, bone malignancy. Always ask about back-to-leg radiation. Always check ICE. Always palpate pedal pulses.
Active Recall - Family Medicine Clinical Test
[1] Senior notes: Maksim Surgery Notes.pdf (Acute limb ischaemia, p.168) [2] Senior notes: Ryan Ho Cardiology.pdf (Intermittent claudication and vascular vs neurogenic claudication, p.205) [3] GC Lecture slides: GC 226. Lumbar Spine Pathology_Part B.pdf (Physical Examination of back pain) [4] Senior notes: Block A - Leg swelling and chest pain_ deep vein thrombosis; pulmonary embolism; Thrombophilia.pdf (DVT clinical features, p.21); Ryan Ho Haemtology.pdf (VTE, p.131) [5] Lecture slides: Clinical Demonstration_Vascular.pdf (Venous examination, p.3); MBBS Final MB (Surgery) (Felix PY Lai).pdf (Varicose veins, p.949) [6] AOS material: AOS - Radiology.pdf (Sciatica case, p.32) [7] Senior notes: Ryan Ho Endocrine.pdf (Diabetic peripheral neuropathy, p.98); Maksim Medicine Notes.pdf (Diabetic foot, p.89) [8] Senior notes: Ryan Ho Psychiatry.pdf (Somatic symptom disorder, p.202)
Leg / Ankle Swelling
Leg or ankle swelling is the abnormal accumulation of fluid (edema) in the lower extremities, resulting from venous insufficiency, lymphatic obstruction, heart failure, hypoalbuminemia, or local inflammatory and musculoskeletal conditions.
Leg Ulcers
Leg ulcers are chronic open wounds on the lower extremities, most commonly caused by venous insufficiency, arterial disease, or neuropathy, that fail to heal within the expected timeframe.