Calf Pain
Calf pain is discomfort in the posterior lower leg that may arise from musculoskeletal strain, deep vein thrombosis, peripheral arterial disease, or neurogenic causes, requiring careful evaluation to exclude vascular emergencies.
Murtagh Diagnostic Strategy
| Category | Diagnosis | Key Discriminator | Cantonese Question / Finding | Probability |
|---|---|---|---|---|
| Probability Diagnosis | Musculoskeletal strain / muscle cramp | Acute onset after exercise; localised tenderness; no swelling/redness | 「最近有冇做運動或者行好多路？」 | ~35% |
| Chronic venous insufficiency | Aching worse at end of day, varicose veins, ankle oedema, skin pigmentation | 「企成日隻腳會唔會特別攰同脹？」 | ~20% | |
| Serious Not To Miss | Peripheral arterial disease (PAD) / Critical limb ischaemia | Intermittent claudication with fixed walking distance; absent pulses; ABI ≤0.9 [1] | 「行路行到幾遠先要停低？隻腳有冇凍或者變白？」 | ~5% |
| Deep vein thrombosis (DVT) | Unilateral calf swelling + pain + warmth; VTE risk factors; +ve Wells score [2] | 「隻腳有冇一邊腫過另一邊？最近有冇坐長途機或者做手術？」 | ~3% | |
| Compartment syndrome | Severe pain out of proportion; pain on passive stretch; tense compartment; post-trauma | 「痛係咪好嚴重、脹到好實？最近有冇撞親？」 | < 1% | |
| Necrotising fasciitis | Rapidly spreading pain, erythema, crepitus, systemic toxicity, fever | 「痛係咪越嚟越嚴重好快咁擴散？有冇發高燒？」 | < 1% | |
| Pitfalls | Cellulitis | Unilateral redness, warmth, fever; portal of entry (wound/tinea pedis) | 「腳趾之間有冇甩皮或者香港腳？」 | ~5% |
| Superficial thrombophlebitis | Tender, palpable cord along a superficial vein; redness along vein course | 「隻腳有冇一條紅色嘅線喺皮膚上面？」 | ~3% | |
| Ruptured Baker's cyst | Sudden posterior calf pain + swelling mimicking DVT; hx of knee OA/RA | 「你個膝頭有冇問題？之前有冇關節炎？」 | ~2% | |
| Masquerades | Lumbar radiculopathy (L5/S1) | Pain radiating from back; numbness in dermatomal distribution; +ve SLR | 「有冇腰痛？痛係咪由腰傳落嚟？」 | ~5% |
| Diabetic peripheral neuropathy | Bilateral burning/tingling in stocking distribution; DM hx | 「有冇糖尿？兩隻腳有冇痺或者針拮咁嘅感覺？」 | ~4% | |
| Spinal stenosis (neurogenic claudication) | Bilateral calf pain on walking, relieved by sitting/leaning forward (vs. PAD relieved by standing still) | 「行路痛嘅時候坐低會唔會好啲？」 | ~3% | |
| Medications (statins) | Myalgia after statin initiation | 「有冇食降膽固醇藥？食咗之後先開始痛？」 | ~2% | |
| Trying to Tell Me Something? | Work/functional stress | Pain limiting occupation; fear of disability/job loss | 「呢個痛有冇影響你返工？你擔唔擔心做唔到嘢？」 | ~10% |
| Anxiety / health anxiety | Excessive worry disproportionate to findings; checking behaviours | 「你係咪好擔心呢個痛？有冇影響到你瞓覺或者情緒？」 | ~5% |
GC Lecture High Yield [1]: Claudication = reproducible pain in a defined muscle group induced by exercise and relieved with rest. Calf claudication (most common) → SFA or popliteal artery disease. ABI 0.4-0.9 = claudication; ABI < 0.4 = critical limb ischaemia. [1]
GC Lecture High Yield [2]: DVT presents with unilateral leg swelling, pain, warmth. Asymmetrical calf circumference is the key measurement. Homans' sign is unreliable. Differentials: cellulitis, ruptured Baker's cyst, lymphoedema, haematoma. [2]
Calf Pain – Family Medicine Clinical Test Page
| Time | Task | Cantonese Key Phrases | Why It Scores Marks |
|---|---|---|---|
| 0:00–0:30 | Friendly opening, rapport, set agenda | 「你好呀！我係今日嘅醫生，點樣稱呼你呀？」「今日想了解吓你嚟睇醫生嘅原因，之後我會問幾個問題，最後睇吓我哋可以點幫你，好唔好？」 | Permission + signposting scores interpersonal marks; sets a structured frame |
| 0:30–2:00 | Chief complaint & HPI (SOCRATES) | 「你隻腳小腿邊度痛呀？幾時開始㗎？」「痛嘅感覺係點樣㗎？扯住痛定抽住痛？」「行路會唔會痛啲？休息之後好唔好返？」「隻腳有冇腫、紅、或者摸落去熱？」 | Captures onset, character, aggravating/relieving, associated Sx – builds HPI |
| 2:00–3:00 | Red flags & targeted systems review | 「有冇突然間隻腳又腫又痛？有冇氣喘或者胸口痛？」「有冇試過長時間坐飛機或者臥床？」「有冇發燒、傷口、或者皮膚有紅一撻？」 | Screens DVT/PE, cellulitis, compartment syndrome |
| 3:00–4:00 | PMHx, DHx, FHx, Social Hx | 「你有冇其他病底㗎，例如糖尿、高血壓、血管問題？」「有冇食緊血丸或者荷爾蒙藥？」「屋企人有冇血管栓塞嘅病史？」「你做咩工㗎？平時做唔做運動？有冇食煙？」 | Identifies VTE risk factors (OCP, smoking, immobility), PAD risk factors (DM, HTN, smoking), occupation |
| 4:00–5:00 | ICE – uncover hidden agenda | 「你自己覺得會唔會係咩問題呀？」(Ideas) 「你最擔心嘅係咩嘢呀？」(Concerns) 「你今日嚟最希望醫生幫你做啲咩呢？」(Expectations) | ICE directly examined on Case Report Form; hidden agenda often = fear of blood clot / cancer / disability |
| 5:00–5:30 | Summarise back | 「等我總結返：你小腿痛咗 __ 日，行路嗰陣痛啲，休息好返，冇腫冇胸痛，你擔心係唔係血管塞，想做檢查，係唔係咁？」 | Demonstrates active listening; checks understanding |
| 5:30–6:00 | Safety-net & close | 「如果之後突然隻腳好腫、又痛又紅，或者有胸痛、氣喘，要即刻去急症室㗎！」「今日多謝你，有冇嘢想問？」 | Safety-net for DVT/PE = must-have; courteous close |
Uncovering the hidden agenda: Always ask 「你今日點解決定嚟睇醫生呀？」 — the patient may have had the pain for weeks but came today because a relative had a DVT, or they read about blood clots online, or the pain is stopping them from working.
| Domain | English Question | Cantonese Question | Why It Matters | If Positive, Think Of |
|---|---|---|---|---|
| Site | Where exactly is the pain? One leg or both? | 「痛喺邊隻腳呀？係小腿後面定前面？」 | Unilateral → DVT/muscle injury; bilateral → spinal/vascular | Unilateral = DVT, muscle strain; Bilateral = spinal stenosis, PAD |
| Onset | When did it start? Sudden or gradual? | 「幾時開始痛㗎？係突然間定慢慢痛起嚟？」 | Acute = DVT, muscle tear; Chronic = PAD, chronic venous insufficiency | Sudden onset + swelling = DVT or muscle tear |
| Character | What does the pain feel like? Cramping? Aching? | 「痛嘅感覺係點㗎？抽筋咁定係脹住痛？」 | Cramping on walking → intermittent claudication; constant ache → DVT | Cramping on exertion = PAD |
| Radiation | Does the pain go anywhere else? | 「痛有冇去到其他地方？」 | Radiating from back = sciatica/spinal stenosis | Back→calf = lumbar radiculopathy |
| Aggravating | Does walking make it worse? How far can you walk before pain? | 「行路會唔會痛啲？行到幾遠先開始痛？」 | Claudication distance is key for PAD severity [1] | Fixed claudication distance = PAD |
| Relieving | Does rest relieve it? How quickly? | 「停低休息幾耐先好返？」 | PAD relieved in 2-5 min standing; spinal stenosis relieved by sitting/leaning forward | Rest pain = critical limb ischaemia |
| Swelling | Is the calf swollen? One side or both? | 「小腿有冇腫？係一邊定兩邊？」 | Unilateral swelling + pain + warmth = DVT [2] | DVT, Baker's cyst rupture, cellulitis |
| Colour change | Any redness, bluish colour, or pallor of the leg? | 「隻腳有冇紅、紫、定變白？」 | Red/warm = DVT/cellulitis; Pale/cool = arterial ischaemia | Redness = DVT/cellulitis; Pallor = PAD/ALI |
| PE symptoms | Any chest pain or shortness of breath? | 「有冇胸口痛或者氣喘？」 | Must-not-miss: PE complicating DVT [2] | PE |
| Immobility/travel | Recent long flight, surgery, or bed rest? | 「最近有冇坐長途機、做手術、或者長時間臥床？」 | VTE risk factors [2] | DVT |
| Medications | Are you on the pill/HRT? Blood thinners? | 「有冇食避孕藥、荷爾蒙藥、或者薄血丸？」 | OCP/HRT ↑VTE risk | DVT |
| Smoking | Do you smoke? | 「你有冇食煙呀？」 | Major RF for PAD [1] | PAD, Buerger's disease |
| DM/HTN/lipids | Diabetes, high BP, high cholesterol? | 「有冇糖尿、高血壓、或者高膽固醇？」 | CV risk factors for PAD [1] | PAD |
| Trauma/exercise | Any recent injury, sports, or unusual exercise? | 「最近有冇拗柴、做運動、或者做咗啲平時唔做嘅嘢？」 | Muscle strain/tear, compartment syndrome | Musculoskeletal injury |
| Fever/wound | Any fever, skin break, or insect bite? | 「有冇發燒？小腿有冇傷口或者俾蟲咬？」 | Cellulitis, abscess, necrotising fasciitis | Cellulitis |
| Back pain/neuro | Any low back pain, numbness, or weakness in the leg? | 「有冇腰痛、腳痺、或者腳冇力？」 | Lumbar disc/spinal stenosis causing referred calf pain | L5/S1 radiculopathy, spinal stenosis |
| Varicose veins | Do you have varicose veins? | 「你有冇靜脈曲張？」 | CVI, superficial thrombophlebitis | Chronic venous insufficiency |
| Cancer history | Any history of cancer? | 「有冇試過有腫瘤或者癌症？」 | Malignancy = major VTE risk | DVT (paraneoplastic) |
| Functional impact | How does this affect your daily life/work? | 「呢個痛對你返工同日常生活有冇影響？」 | Scores biopsychosocial; assesses severity | Social/functional problem |
| Worry | What are you most worried about? | 「你最擔心啲咩呀？」 | Uncovers hidden concern (cancer? amputation? blood clot?) | Hidden agenda |
Case Report Form Answer Builder
Write: "Calf pain for [duration]" — then capture:
- SOCRATES: Site (unilateral/bilateral, posterior/lateral), Onset (acute/gradual), Character (cramping/aching/sharp), Radiation, Associations (swelling, redness, warmth, numbness), Timing (exercise-related/constant/nocturnal), Exacerbating (walking, standing), Severity
- Red flag screen: PE symptoms (chest pain, SOB), fever, recent immobilisation, trauma
- Risk factors: smoking, DM, HTN, OCP/HRT, cancer, recent surgery/travel
- Functional impact
Examples:
- "Worried about blood clot after reading about DVT online"
- "Pain affecting ability to walk to work"
- "Referred by GP for persistent calf pain not responding to painkillers"
- Phrasing tip: State the patient's main driver, not just the symptom. E.g., "Patient presents with right calf pain for 2 weeks; main reason for consultation is concern about deep vein thrombosis as his father had a DVT."
| Likely Content | Example Wording for CRF | |
|---|---|---|
| Ideas | "I think it might be a blood clot" / "I think it's just muscle pain" | Patient thinks the pain may be due to a blood clot / muscle strain |
| Concerns | Fear of DVT/PE, fear of amputation (if PAD), worry about cancer | Patient is worried about having a blood clot that could travel to the lungs |
| Expectations | Wants ultrasound / blood test / referral / reassurance | Patient expects an ultrasound scan to rule out DVT |
Depends on the stem. Common FM clinical test scenarios:
| Scenario | Most Likely Diagnosis | Minimum Supporting Evidence |
|---|---|---|
| Middle-aged smoker + cramping on walking + relieved by rest + fixed distance | Peripheral arterial disease (intermittent claudication) | Smoking hx, claudication distance, absent pedal pulses, ABI ≤0.9 |
| Post-travel/surgery + unilateral calf swelling + pain + warmth | Deep vein thrombosis | Unilateral swelling, risk factor (immobility), +ve Wells score |
| Young person + acute onset after sport + localised tenderness + no swelling | Muscular strain (gastrocnemius/soleus) | Clear exercise trigger, localised tenderness, no systemic features |
| DDx | Key Discriminator |
|---|---|
| DVT | Unilateral swelling + risk factors + Wells score |
| PAD (intermittent claudication) | Cramping on walking, fixed distance, absent pulses |
| Lumbar radiculopathy | Pain radiating from back, dermatomal numbness, +ve SLR |
| Cellulitis | Spreading erythema, warmth, fever, portal of entry |
| Ruptured Baker's cyst | Sudden onset posterior calf pain, pre-existing knee arthritis |
| Muscle strain | Post-exercise onset, localised tenderness, no systemic signs |
(Pick three that contrast with your most likely diagnosis.)
| Domain | Example |
|---|---|
| Biological | Uncontrolled cardiovascular risk factors (smoking, DM, HTN) contributing to PAD / VTE risk |
| Psychological | Anxiety about serious vascular disease (DVT/amputation); health anxiety affecting sleep and mood |
| Social/Functional | Reduced walking capacity affecting ability to work (e.g., security guard who needs to walk) or care for family; social isolation due to limited mobility |
| Diagnosis/DDx | Best Supporting Physical Sign | How to Elicit It | Why It Supports This Diagnosis |
|---|---|---|---|
| DVT | Asymmetric calf circumference ≥3 cm difference | Measure bilateral calf circumference at the widest point (10 cm below tibial tuberosity) with a tape | Unilateral swelling due to venous outflow obstruction is the hallmark [2] |
| PAD | Absent or diminished dorsalis pedis / posterior tibial pulse | Palpate dorsalis pedis (lateral to EHL tendon) and posterior tibial (behind medial malleolus) bilaterally | Absent pulses indicate arterial occlusion proximal to measurement site [1] |
| Cellulitis | Well-demarcated erythema with warmth and tenderness | Inspect and palpate; mark the border with a pen to track spread | Spreading erythema + warmth indicates soft tissue infection |
| Lumbar radiculopathy | Positive straight leg raise (SLR) test | Patient supine; lift extended leg — positive if radicular pain reproduced at < 60° | Stretches L5/S1 nerve roots; reproduction of calf pain confirms radicular origin |
| Ruptured Baker's cyst | Popliteal fossa fullness / fluctuant swelling behind knee | Palpate popliteal fossa with knee slightly flexed | Cystic swelling in popliteal fossa with acute calf pain mimics DVT |
| Muscle strain | Localised tenderness at gastrocnemius/soleus with pain on resisted plantarflexion | Squeeze the calf; ask patient to push foot down against resistance | Localised tenderness + pain on contraction confirms muscular origin |
| Compartment syndrome | Pain on passive dorsiflexion of the foot (passive stretch) | Passively dorsiflex the ankle — severe pain in the anterior/deep posterior compartment | Pain on passive stretch is the earliest and most reliable clinical sign |
Top Traps That Lose Marks
- Forgetting to ask about PE symptoms — DVT without asking about chest pain/SOB = missed marks. Always screen.
- Confusing neurogenic claudication (spinal stenosis) with vascular claudication (PAD) — Neurogenic: bilateral, relieved by sitting/flexion, variable distance. Vascular: unilateral or bilateral, relieved by standing still, fixed distance.
- Not measuring calf circumference bilaterally — This is the ONE physical sign for DVT. Don't just eyeball.
- Relying on Homans' sign — It is unreliable and no longer recommended [2]. Don't cite it as your main sign.
- Missing Baker's cyst as a DVT mimic — Always ask about knee arthritis history.
- Not asking about statins — Statin myopathy is a classic masquerade for bilateral calf pain.
- Forgetting ICE — ICE is directly examined. If you don't ask, you cannot write it.
- Writing "calf pain" as the reason for consultation — The RFC is WHY they came TODAY, not the symptom itself.
Must-Not-Miss Red Flags — Urgent Referral
- DVT → PE: Unilateral swelling + dyspnoea/chest pain/tachycardia → A&E immediately
- Acute limb ischaemia (6 Ps): Pulseless, Painful, Pallor, Perishing cold, Paraesthesia, Paralysis → Vascular surgery emergency
- Compartment syndrome: Severe pain, tense swelling, pain on passive stretch → Surgical emergency (fasciotomy)
- Necrotising fasciitis: Rapid spread, crepitus, systemic toxicity → Surgical emergency + IV antibiotics
Shortest safe management / safety-net line:
「如果你突然間隻腳好腫好痛、又紅又熱，或者有胸口痛、突然氣喘，一定要即刻去急症室。呢啲可能係嚴重嘅血管問題，要即時處理。」
High Yield Summary
What to ASK: SOCRATES for calf pain; unilateral vs bilateral; claudication distance & relieving factors; swelling/redness/warmth; PE symptoms; VTE risk factors (immobility, OCP, surgery, cancer); PAD risk factors (smoking, DM, HTN); back pain/numbness; statin use; ICE.
What to WRITE: Chief complaint with duration; one clear RFC (patient's driver); ICE; most likely diagnosis with supporting evidence; 3 DDx with discriminators (DVT vs PAD vs radiculopathy vs muscle strain vs cellulitis); biopsychosocial problems; one physical sign (asymmetric calf circumference for DVT, absent pedal pulse for PAD).
What NOT TO MISS: PE screening in any DVT suspect; acute limb ischaemia (6 Ps); compartment syndrome; necrotising fasciitis. Homans' sign is unreliable — use calf circumference instead.
Active Recall - Family Medicine Clinical Test
[1] MBBS Final MB (Surgery) (Felix PY Lai).pdf — Lower extremity pain / Intermittent claudication / ABI interpretation (p.924, 932, 936) [2] Block A - Leg swelling and chest pain: deep vein thrombosis; pulmonary embolism; Thrombophilia.pdf — DVT clinical features, differentials, diagnostic evaluation (p.21); Ryan Ho Haemtology.pdf (p.131) [3] PPT_Clinical Demonstration_Vascular_2022.pdf — Venous examination: history and physical examination of lower limb veins (p.3) [4] Ryan Ho Respiratory.pdf — PE clinical approach, Wells score, CTPA, V/Q scan (p.134-136) [5] Ryan Ho Endocrine.pdf — Diabetic peripheral neuropathy and diabetic foot (p.97-98) [6] Block A - High blood pressure: hypertension.pdf — Renovascular hypertension and peripheral vascular disease (p.26) [7] WCS 002 - Toe gangrene and leg ulcer - by Prof SWK Cheng.pdf — Vascular surgery approach
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