What causes swelling in the legs and arms and how is it treated?

Swelling in Legs and Arms: Causes and Treatment

The most critical priority when evaluating limb swelling is to immediately rule out deep vein thrombosis (DVT), as 70% of pulmonary embolism cases originate from lower extremity DVT and can be fatal if untreated. 1

Immediate Diagnostic Approach

First: Determine Distribution Pattern

• Unilateral swelling strongly suggests DVT, venous obstruction, or localized pathology requiring urgent evaluation 2, 1
• Bilateral swelling suggests systemic causes (heart failure, kidney disease, hypoalbuminemia) or central venous obstruction 3, 4
• Upper extremity involvement accounts for 10% of all DVTs and requires the same urgency as lower extremity cases 2, 5

Second: Rule Out DVT Emergently

Duplex ultrasound with Doppler is the initial imaging modality of choice, with >80% sensitivity and specificity for DVT. 1, 4 Do not delay anticoagulation in high-risk patients while awaiting imaging, as this increases morbidity and mortality from thromboembolic complications. 1

Critical DVT risk factors to assess:

• Indwelling venous devices (catheters, pacemakers, defibrillators) - highest risk 2, 1
• Active malignancy 2, 1
• Recent surgery or trauma 1
• Advanced age 2, 1
• Heart failure 2, 1

Primary Pathophysiologic Mechanisms

Swelling occurs through four main mechanisms:

Increased capillary hydrostatic pressure:

• DVT/superficial vein thrombosis causes venous hypertension, presenting with unilateral extremity swelling (80% of cases), pain (75%), and erythema (26%) 2, 1, 4
• Central venous obstruction (superior vena cava syndrome, iliac vein compression) 2, 3
• Heart failure 2, 4

Increased capillary permeability:

• Infection, inflammation, allergic reactions 2, 4

Decreased capillary oncotic pressure:

• Cirrhosis, malnutrition, hypoalbuminemia 2

Lymphatic obstruction:

• Lymphedema causes protein-rich fluid accumulation exceeding lymphatic transport capacity 2, 1

Clinical Presentation Patterns

Upper Extremity Swelling

Patients typically present with ipsilateral arm edema, pain, paresthesia, and functional impairment. 2, 5 Catheter-associated thrombosis may be asymptomatic, manifesting only as catheter dysfunction. 2 Unilateral swelling indicates obstruction at the brachiocephalic, subclavian, or axillary vein level. 2

Lower Extremity Swelling

Post-thrombotic syndrome develops when characteristic symptoms (pain, swelling, heaviness, fatigue, itching, cramping) occur in patients with prior DVT, typically diagnosed after 3-6 months when acute DVT symptoms have resolved. 2 Symptoms worsen by day's end or with prolonged standing/walking and improve with rest or elevation. 2

Venous claudication presents as bursting leg pain during exercise, caused by persistent venous obstruction of major venous confluences (iliofemoral or popliteal veins). 2

Critical Diagnostic Pitfalls to Avoid

• Never assume bilateral presentation excludes venous pathology - central venous obstruction can cause bilateral swelling 3, 4
• Acute hypoechoic thrombi may be missed on grayscale ultrasound alone - Doppler flow assessment is essential 2, 1
• Temperature asymmetry >2°C between limbs suggests active inflammatory process (DVT, infection, Charcot arthropathy) requiring urgent evaluation 1
• In diabetic patients with unilateral red, warm, swollen foot with intact skin, always suspect active Charcot neuro-osteoarthropathy after excluding infection, gout, and DVT 1

Ultrasound Technique Specifics

Grayscale imaging identifies thrombus by visualizing echogenic material and lack of vein compression with probe pressure. 2 Doppler US detects altered blood-flow patterns, with dampening of cardiac pulsatility or respiratory variation indicating central venous obstruction. 2 Rapid inspiration ("sniffing") should normally collapse central vein walls; impairment suggests central obstruction. 2

US is most reliable for veins peripheral to the subclavian (jugular, axillary, basilic, cephalic, brachial). 2 For suspected central venous stenosis with extremity swelling, fluoroscopy fistulography allows both diagnosis and treatment via percutaneous transluminal angioplasty in a single intervention. 2

Treatment Approach

For Confirmed DVT

Immediate anticoagulation is mandatory. 1, 6 Upper extremity DVT requires the same anticoagulation approach as lower extremity DVT. 5 For catheter-related thrombosis, mandatory functioning catheters can remain with anticoagulation; all others should be immediately removed. 5

For Post-Thrombotic Syndrome

Leg elevation, compression garments, and range-of-motion exercises are beneficial. 2, 7 Treatment addresses venous hypertension from persistent obstruction or valvular incompetence. 2

For Non-Thrombotic Causes

• Sodium restriction and diuretics for volume overload states 7
• Loop diuretics alone or in combination for edema management 7
• Spironolactone reduces morbidity and mortality in NYHA class III-IV heart failure 7
• Lymphedema requires compression garments and range-of-motion exercises 7
• Dihydropyridine-induced edema responds to ACE inhibitors or angiotensin-receptor blockers 7

For Central Venous Stenosis

Percutaneous transluminal angioplasty is indicated for handicapping extremity edema from central vein occlusions in the outflow tract. 2 High suspicion is warranted in patients with multiple prior catheter placements or chronic dialysis catheter use. 2

Special Considerations

Warfarin-associated complications: Necrosis and gangrene can occur within days of starting anticoagulation, associated with local thrombosis, requiring careful monitoring. 6 Purple toes syndrome (dark, purplish toes occurring 3-10 weeks after warfarin initiation) may progress to gangrene requiring debridement or amputation. 6

Heparin-induced thrombocytopenia: Cases of venous limb ischemia, necrosis, and gangrene have occurred when transitioning from heparin to warfarin, sometimes requiring amputation. 6