Browse categories and answer follow-up questions to refine your symptom profile.
History
Presenting features
Calf pain and swelling history framework
Symptom laterality
Unilateral
Bilateral
Time course
Sudden onset
Gradual onset
Precipitating context
Trauma
Recent immobilization
Recent surgery
Long travel
OPQRST
OPQRST
Onset
Sudden
Progressive
Provocation and palliation
Worse with walking
Worse with ankle dorsiflexion
Quality
Cramping
Tightness
Region and radiation
Posterior calf
Into foot
Severity
Mild
Severe
Timing
Constant
Intermittent
Associated symptoms
Associated symptoms
Venous thromboembolism features
Pleuritic chest pain
Dyspnea
Infection features
Fever
Rigors
Ischemia and neurologic features
Numbness
Weakness
Prior episodes and baseline
Prior episodes and baseline status
Prior DVT or PE history
Provoked episode
Unprovoked episode
Baseline mobility
Independent ambulation
Baseline limited mobility
Alarm Features
Immediate limb threat triggers
Limb threat red flags
Acute limb ischemia features
Pain out of proportion
Pallor
Pulselessness
Paresthesia
Paralysis
Poikilothermia
Compartment syndrome features
Pain with passive stretch
Tense compartment
Progressive sensory change
High risk infection triggers
Necrotizing soft tissue infection concern
Severe pain out of proportion to exam
Rapid progression over hours
Skin anesthesia
Systemic toxicity
Hypotension
Altered mental status
Vital sign danger thresholds
Vital sign danger thresholds
Shock physiology
SBP under 90 mmHg
MAP under 65 mmHg
Respiratory distress
SpO2 under 90 percent on room air
RR 30 or more
Pulmonary embolism red flags
PE high risk features
Syncope
Persistent tachycardia
Hypotension
Right heart strain concern
New hypoxia
Persistent tachycardia over 120
Medications
Medication exposures relevant to thrombosis and bleeding
Medication risk review
Anticoagulants
Warfarin
DOAC therapy
Hormonal therapy
Estrogen containing contraception
Hormone replacement therapy
Antiplatelets
Aspirin
Clopidogrel
Recent changes and adherence
Recent medication changes and adherence
Missed anticoagulant doses
Missed within last 48 hours
Last dose timing
New medications
Recent antibiotics
Recent statin dose increase
Contraindications to likely therapies
Anticoagulation contraindication screen
Active bleeding
GI bleeding symptoms
Intracranial bleeding history
High risk intracranial lesion
Recent stroke
Known intracranial mass
Diet
Intake and hydration
Recent intake and hydration pattern
Reduced oral intake
Poor fluid intake
Vomiting
Dehydration contributors
Diarrhea
Diuretic use
Alcohol and stimulant exposure
Exposures that can worsen cramps or volume status
Alcohol
Recent binge
Daily use
Caffeine and energy drinks
High intake
Recent increase
Review of Systems
Cardiopulmonary
Cardiopulmonary
Dyspnea
At rest
With exertion
Chest pain
Pleuritic
Pressure like
Infectious and inflammatory
Infectious and inflammatory
Fever
Measured
Subjective
Skin changes
Rapidly spreading redness
New blisters
Musculoskeletal and neurologic
Musculoskeletal and neurologic
Weakness
New foot drop
Inability to plantarflex
Sensory symptoms
Numbness
Tingling
Collateral History and Family History
Collateral source and reliability
Collateral history
Source
Family member
Caregiver
Reliability modifiers
Cognitive impairment
Communication barrier
Family history
Family history relevant to thrombosis
VTE in first degree relative
Before age 50
Recurrent events
Known thrombophilia
Factor V Leiden
Prothrombin gene mutation
Risk Factors
Thrombosis and embolism risk
VTE risk factors
Recent immobilization
Bedrest 3 or more days
Lower limb cast
Recent surgery or trauma
Major surgery within 12 weeks
Fracture
Active malignancy
On treatment
Metastatic disease
Bleeding risk and anticoagulation complexity
Bleeding risk considerations
Recent major bleeding
Within 30 days
Uncontrolled source
High risk comorbidities
Cirrhosis
Severe thrombocytopenia
Infection and skin breakdown risk
Cellulitis risk factors
Skin barrier disruption
Tinea pedis
Ulcers
Comorbid risks
Diabetes mellitus (E11.9)
Chronic edema or lymphedema
Differential Diagnosis
Life threatening
Life threatening causes
Deep vein thrombosis (I82.4)
Unilateral swelling and pain
Risk factors for VTE
Pulmonary embolism (I26.99)
Dyspnea
Pleuritic chest pain
Acute limb ischemia (I74.3)
6 Ps
Pain out of proportion
Compartment syndrome (T79.A)
Pain with passive stretch
Tense compartments
Necrotizing soft tissue infection (M72.6)
Rapid progression
Systemic toxicity
Common
Common causes
Muscle strain or tear
Exertional trigger
Focal tenderness
Cellulitis (L03.1)
Warmth
Erythema
Superficial thrombophlebitis (I80.0)
Palpable cord
Localized tenderness
Ruptured Baker cyst (M66.0)
Posterior knee pain
Calf swelling after pop
Less common
Less common and mimics
Achilles tendon rupture (S86.0)
Sudden pop
Weak plantarflexion
Rhabdomyolysis (M62.82)
Myalgias
Dark urine
Osteomyelitis (M86.9)
Persistent focal pain
Fever
Popliteal artery aneurysm thrombosis (I72.4)
Acute ischemia
Pulsatile popliteal mass
Past Medical History
Chronic conditions relevant to presentation
Relevant comorbidities
Prior VTE history
Provoked
Unprovoked
Peripheral arterial disease (I73.9)
Prior claudication
Prior revascularization
Chronic venous insufficiency (I87.2)
Baseline edema
Venous stasis changes
Prior procedures and devices
Procedures and devices
Recent orthopedic procedures
Knee surgery
Hip surgery
Indwelling venous catheters
PICC
Port
Physical Exam
Vitals and general appearance
Global assessment
Vital signs pattern
Tachycardia
Fever
Toxic appearance
Ill appearing
Diaphoretic
Lower extremity exam
Lower extremity focused exam
Inspection
Asymmetry
Erythema
Palpation
Calf tenderness
Pitting edema
Measurements
Calf circumference difference
Thigh circumference difference
Vascular and neurologic exam
Vascular and neurologic
Pulses
Dorsalis pedis
Posterior tibial
Perfusion
Capillary refill delay
Cool limb
Sensation and motor
Sensory deficit distribution
Weakness pattern
Skin and soft tissue exam
Skin and soft tissue
Cellulitis pattern
Warmth
Lymphangitic streaking
Necrotizing infection clues
Bullae
Crepitus
Lab Studies
Core labs when systemic illness or limb threat
Core laboratory evaluation
CBC
Leukocytosis
Anemia baseline for anticoagulation safety
CMP
Creatinine for contrast and anticoagulant selection
AST and ALT for hepatic dysfunction
Coagulation studies
INR if warfarin exposure
aPTT baseline if heparin planned
Thrombosis evaluation
DVT and PE laboratory adjuncts
D dimer
Use only in low pretest probability
Not a rule out in high pretest probability
Troponin if PE concern
Risk stratification
Alternative diagnosis assessment
Muscle injury and ischemia evaluation
Muscle and ischemia labs
CK
Rhabdomyolysis support
Trend if ongoing muscle injury
Lactate
Shock or severe infection support
Limb ischemia severity support
Inflammation and infection evaluation
Inflammatory and infectious markers
CRP
Support severe infection pattern
Baseline for trend
Blood cultures
Systemic toxicity
Immunocompromised host
Imaging
Scoring Systems
Pretest probability tools
Wells score for DVT
Use in suspected lower extremity DVT
Guides D dimer versus ultrasound strategy
Wells score for PE
Use if concurrent dyspnea or chest pain
Guides imaging pathway selection
MRI
MRI indications
Deep infection concern
Pyomyositis
Osteomyelitis
Soft tissue injury clarification
Muscle tear extent
Tendon rupture when ultrasound unclear
CT
CT indications
CT angiography lower extremity
Acute limb ischemia concern
Surgical planning and level localization
CT for necrotizing infection
Gas in soft tissues
Fascial thickening
Ultrasound
Ultrasound and POCUS
Compression ultrasound for DVT
Proximal compression strategy
Whole leg study when available
POCUS soft tissue
Abscess versus cellulitis pattern
Subcutaneous gas concern
Special Tests
Bedside maneuvers
Bedside tests
Thompson test
Achilles tendon rupture support
Compare bilaterally
Passive stretch pain
Compartment syndrome concern
Repeat during reassessment loop
Compartment pressure testing
Compartment syndrome diagnostics
Compartment pressure measurement
Consider when exam equivocal
High suspicion overrides normal pressure early
Delta pressure concept
Diastolic BP minus compartment pressure
Low delta supports fasciotomy pathway local protocol dependent
ECG
Indications and high risk findings
ECG use when cardiopulmonary symptoms present
Suspected PE
Tachycardia pattern
Right heart strain patterns
Alternative cardiopulmonary diagnoses
ACS screen in chest pain
Arrhythmia screen in syncope
Assessment
Problem representation and risk stratification
Working syndromic assessment
Suspected DVT pathway
Pretest probability category from Wells score
Bleeding risk summary
Suspected limb ischemia pathway
6 Ps presence
Doppler signal status
Suspected severe infection pathway
Systemic toxicity presence
Rapid progression over hours
Key complications to rule out
Complications to exclude early
PE in symptomatic patient
Hypoxia
Pleuritic chest pain
Compartment syndrome after injury
Increasing pain despite analgesia
Neuro deficits progression
Plan
Approach to the critical patient
First 5 minutes workflow
Monitoring and access
Continuous pulse oximetry
Cardiac monitor if PE or shock concern
IV access criteria
Two large bore IV if hypotension
Consider IO if unable and unstable
Oxygen criteria
Titrate to SpO2 92 percent or higher
Escalate to high flow oxygen if persistent hypoxia
Diagnostic sequencing
Diagnostic plan and timing
If limb threat suspected
Immediate vascular surgery consult
Immediate CT angiography if available and no delay to reperfusion
If DVT suspected without limb threat
Wells score based pathway selection
Compression ultrasound timing target within same visit when possible
Therapeutics
Treatment plan by likely diagnosis
Suspected DVT without contraindication
Anticoagulation start if imaging delayed and high probability local protocol dependent
Apixaban oral 10 mg twice daily for 7 days then 5 mg twice daily if appropriate
Suspected acute limb ischemia
Start unfractionated heparin IV bolus and infusion local protocol dependent
Keep limb at neutral position and warm
Cellulitis without abscess
Cephalexin oral 500 mg four times daily for 5 to 7 days typical adult dosing
MRSA coverage based on local resistance and risk factors
Reassessment loop
Reassessment loop
Timing
Recheck pain and neurovascular status every 30 to 60 minutes in high risk cases
Repeat vitals after analgesia and fluids
Escalation triggers
Worsening pain out of proportion
New sensory or motor deficit
Disposition
Level of care criteria
Disposition decision framework
ICU or resuscitation bay criteria
Hypotension or shock physiology
Rapidly progressive infection with systemic toxicity
Inpatient admission criteria
Acute limb ischemia
Compartment syndrome concern
Observation pathway criteria
Suspected DVT awaiting definitive imaging
Moderate cellulitis requiring IV antibiotics
Discharge criteria and follow up timing
Discharge pathway
Criteria
No limb threat features
Pain controlled with oral medications
Follow up timing
Confirmed DVT outpatient follow up within 3 to 7 days
Cellulitis recheck within 24 to 48 hours if high risk
Discharge Instructions
Copy discharge instructions
Patient instructions
Summary
You were seen for calf pain and swelling
Your evaluation did not show an emergency cause today or is being treated as discussed
Medications
Take medications exactly as prescribed
If on blood thinner avoid NSAIDs unless your clinician says it is safe
Activity
Walk as tolerated unless instructed otherwise
Elevate the leg when resting
Follow up
Follow up with your clinician within the advised timeframe
If an ultrasound was deferred return for the scheduled study
Return to the ED now for
New or worsening shortness of breath
Chest pain or fainting
Worsening leg pain with numbness or weakness
Rapidly spreading redness or fever
References
Guidelines and validated tools
Reference set
American Society of Hematology guidelines for venous thromboembolism management 2020
CHEST guideline and expert panel report on antithrombotic therapy for VTE disease 2021
NICE guideline venous thromboembolic diseases diagnosis and management most recent update local protocol dependent
AHA and ACC guideline for the management of patients with lower extremity peripheral artery disease 2016
IDSA guideline for skin and soft tissue infections 2014 update local protocol dependent
Source instructions
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.