What is the management approach for a hemodialysis patient with an arteriovenous (AV) fistula, presenting with massive bilateral lower limb swelling, tenderness, fever, and elevated temperature, but no deep vein thrombosis (DVT) on ultrasound?

Management of Bilateral Lower Limb Swelling in Hemodialysis Patient with AV Fistula

This patient requires urgent fistulography to evaluate for central venous stenosis or occlusion, which is the most likely cause of bilateral lower limb swelling in a hemodialysis patient with an AV fistula, particularly given the fever and systemic signs suggesting possible superimposed infection. 1, 2

Immediate Diagnostic Approach

Obtain fistulography with dilute iodinated contrast as the reference standard imaging study to evaluate central vein patency, specifically the inferior vena cava and iliac veins, as standard ultrasound has already been performed and may miss major central venous outflow obstruction. 1, 2

• The absence of DVT on ultrasound does not exclude central venous stenosis, which is the leading cause of persistent limb swelling in dialysis patients with vascular access 1, 2
• Central venous stenosis occurs in 5-50% of hemodialysis patients and can present with bilateral lower extremity edema, tenderness, warmth, and venous collaterals 3
• Patients with prior femoral venous catheters are at particularly high risk for iliac arteriovenous fistula formation, which can present with bilateral leg swelling years after catheter removal 4

Critical Differential Diagnoses to Consider

Central Venous Stenosis/Occlusion (Most Likely)

• Downstream venous stenosis forces blood flow through venous collaterals, producing venous hypertension that manifests as limb edema and can progress to chronic venostasis 1
• The bilateral nature of swelling suggests inferior vena cava or bilateral iliac vein involvement 3
• Fever may indicate superimposed cellulitis from chronic venous stasis 5

Iatrogenic Iliac Arteriovenous Fistula

• Consider iliac AVF if patient has history of femoral venous catheter placement for hemodialysis 4
• This rare complication can present with bilateral leg swelling, warmth, and tenderness years after catheter removal 4
• Requires CT angiography or conventional angiography for definitive diagnosis 4

Superimposed Infection

• The presence of fever, raised temperature, and tenderness suggests cellulitis or soft tissue infection complicating chronic venous stasis 5
• Blood cultures and inflammatory markers (WBC, CRP) should be obtained immediately 3

Immediate Management Steps

While awaiting fistulography, initiate the following:

• Elevate both lower extremities to reduce venous hypertension and swelling 1, 2
• Obtain blood cultures before starting antibiotics given the fever and systemic signs 3
• Start empiric broad-spectrum antibiotics covering skin flora (Staphylococcus aureus and Streptococcus species) given the clinical signs of infection with fever and tenderness 3
• Temporarily avoid dialysis through the AV fistula until the underlying cause is determined, as the fistula may be contributing to venous hypertension 1, 2

Definitive Treatment Based on Fistulography Findings

If Central Venous Stenosis Confirmed (>50% stenosis)

• Perform percutaneous transluminal angioplasty (PTA) immediately during the same procedure 1, 2
• Resistant stenoses may require high-pressure balloons with prolonged inflation periods 1, 2
• Consider stent placement for acute elastic recoil after angioplasty 1, 2

If Iliac AVF Identified

• Endovascular approach is safe and effective for treatment of iliac AVF 4
• Surgical consultation with vascular surgery for definitive repair 4

Critical Pitfalls to Avoid

• Do not delay fistulography beyond 48-72 hours, as delay in treatment can lead to permanent complications including irreversible skin ulceration, access loss, or progression to sepsis 1, 2
• Do not assume the ultrasound has ruled out all vascular pathology - standard duplex ultrasound may not detect central vein stenoses, particularly in the thoracic cavity and pelvis 3, 1
• Do not attribute all symptoms to infection alone - the bilateral nature and chronicity (6 days) strongly suggest an underlying structural vascular problem with superimposed infection 1, 5
• Do not continue dialysis through the AV fistula until the cause of swelling is identified, as this may worsen venous hypertension 1, 2

Follow-Up After Intervention

• Reassess within 48-72 hours after intervention to evaluate response and ensure no progression 2
• Continue regular monitoring after intervention to detect recurrence, as stenosis can redevelop 1, 2
• Early intervention increases the likelihood of preserving the AVF for future dialysis and preventing permanent limb dysfunction 2