What are the possible causes of arm and forearm swelling in a patient with a history of arteriovenous (AV) fistula?

Arm and Forearm Swelling with Previous AV Fistula

Direct Answer

Central venous stenosis is the most common cause of persistent arm swelling in patients with an AV fistula and requires immediate evaluation with fistulography if swelling extends beyond 2 weeks. 1

Primary Causes to Consider

Central Venous Stenosis (Most Common)

• Central venous stenosis is the leading cause of persistent arm swelling and forces blood flow through venous collaterals, producing venous hypertension that manifests as arm edema. 1
• This downstream venous stenosis can progress to chronic venostasis with skin ulceration if left untreated. 1
• Standard ultrasound may miss central vein stenoses, making fistulography with dilute iodinated contrast the reference standard for definitive diagnosis. 1

Physiological Post-Operative Swelling

• Normal physiological swelling occurs within the first week after AVF placement and resolves spontaneously with arm elevation and rest. 1
• If swelling persists beyond 2 weeks, pathological causes must be investigated immediately. 1

Hematoma Formation

• Presents with discoloration, swelling, high-frequency bruit on auscultation, and altered intravascular pressure on palpation. 1
• Requires surgical treatment if it compromises the arterialized vein lumen. 1

AVF Thrombosis

• Typically occurs as a final complication after a period of dysfunction, usually due to underlying stenosis. 1
• Presents with swelling, loss of thrill, and absence of bruit on examination. 1
• Venous stenosis is the primary precipitator of access failure, causing increased pressure within the access and decreased blood flow. 2

Access Site Infection

• Can cause localized swelling with inflammatory signs, though AVF infections are rare compared to grafts. 1
• Untreated access infection may lead to bacteremia, sepsis, and death, requiring surgical exploration and removal of infected segments. 2

Steal Syndrome (Limb Ischemia)

• Characterized by distal coldness, pain during dialysis, decreased sensation, weakness, and skin changes. 2
• Usually results from arterial disease proximal or distal to the fistula and/or poor collateral supply to the hand. 3
• Critical pitfall: Failing to differentiate between venous hypertension edema and ischemic steal syndrome, as treatments differ fundamentally. 1

Lymphedema (Rare)

• Very rare complication that presents as non-pitting swelling and may require fistula takedown if the fistula is no longer in use. 4

Diagnostic Algorithm

Initial Evaluation

• Duplex ultrasound (DDU) is the preferred initial diagnostic method as it avoids iatrogenic damage from cannulation of the newly created AVF. 1
• Examine for presence or absence of thrill and bruit to assess patency. 1, 2
• Assess for signs of infection (erythema, warmth, purulent drainage) or ischemia (coldness, pallor, pain, sensory changes). 2

Advanced Imaging

• Fistulography with dilute iodinated contrast is the reference standard when persistent swelling extends beyond 2 weeks, specifically to evaluate central vein patency. 1
• The American College of Radiology recommends fistulography as the reference standard for imaging a dysfunctional dialysis access. 1

Management Approach

For Venous Stenosis/Hypertension

• Percutaneous transluminal angioplasty (PTA) for stenosis greater than 50% is indicated. 1, 2
• Resistant stenoses may require high-pressure balloons with prolonged inflation periods. 1
• Stent placement should be considered for acute elastic recoil after angioplasty. 1

Immediate Measures

• Temporarily avoid dialysis in the affected arm until the cause is determined. 1
• Elevate the arm to reduce swelling. 1

When to Consider Fistula Dismantling

• Immediate AVF ligation is required when limb-threatening ischemia develops, including fingertip necrosis, gangrene, or monomelic ischemic neuropathy. 5
• Severe steal syndrome with tissue necrosis requires immediate ligation of the fistula outflow to prevent limb loss. 5
• Uncontrolled infection at the AV anastomosis may require immediate surgery with resection of infected tissue and possible complete dismantling. 5

Critical Pitfalls to Avoid

• Delay in evaluation of persistent swelling can lead to permanent access loss or progression to irreversible complications. 1
• Missing central venous stenosis is common because standard ultrasound may not detect all central vein stenoses; fistulography is required for definitive diagnosis. 1
• Delaying evaluation of access dysfunction can lead to thrombosis and access failure. 2
• Failing to recognize early signs of infection or ischemia can lead to delayed intervention and worse outcomes. 2