What is the best course of action for a patient with a history of recent femoral catheter placement and catheter-related bloodstream infection, now presenting with an edematous left leg, to rule out complications such as deep vein thrombosis (DVT) or infection?

Immediate Diagnostic Workup for Edematous Left Leg After Femoral Catheter

Obtain urgent lower extremity duplex ultrasound to rule out deep venous thrombosis (DVT), as femoral catheterization increases the risk of iliofemoral DVT 6-fold compared to uncannulated legs, and this complication can occur from 1 day after insertion up to 1 week after catheter removal. 1

Critical Initial Assessment

Physical Examination Priorities

• Examine the previous catheter insertion site for purulence, erythema, or induration 2
• Assess for signs of septic thrombophlebitis: warmth, tenderness along the venous tract, palpable cord, or systemic signs of sepsis 2
• Look for embolic phenomena: septic pulmonary emboli, metastatic seeding, or signs of endocarditis 2

Immediate Laboratory Workup

• Obtain at least two sets of blood cultures immediately - one from peripheral venipuncture and one from any remaining vascular access 2
• If purulent drainage is present at the old insertion site, obtain Gram stain and culture 2
• Do not delay imaging while awaiting culture results 1

DVT Risk Assessment

Femoral Catheter-Specific Thrombosis Risk

• Femoral venous catheters carry a significantly higher DVT risk than other central line sites 1
• DVT can develop as early as 12 hours after insertion and up to 1 week after removal 1
• Most catheter-related DVTs are asymptomatic, making clinical examination unreliable 1
• The presence of leg edema in this context mandates ultrasound evaluation regardless of other findings 1

Important Caveat

Recent data suggests that with appropriate thromboprophylaxis, short-term femoral catheterization may have lower DVT rates than historically reported 3, but this does not eliminate the need for diagnostic evaluation when symptoms develop 1

Infection Risk Assessment

High-Risk Features Requiring Catheter Site Evaluation

Given the history of catheter-related bloodstream infection (CRBSI), assess for:

• Tunnel infection or port abscess: requires 7-10 days of antibiotics even without bacteremia 2
• Suppurative thrombophlebitis: requires 4-6 weeks of antibiotics and possible surgical intervention 2
• Septic thrombosis: mandates prolonged antibiotic therapy and anticoagulation consideration 2

Empirical Antibiotic Coverage Considerations

If the patient appears septic or has positive blood cultures, initiate empirical antibiotics covering gram-positive, gram-negative, and Candida species, as femoral catheters in critically ill patients have higher rates of polymicrobial and fungal infections 2

Specifically:

• Vancomycin for MRSA coverage 2
• Broad-spectrum gram-negative coverage (e.g., fourth-generation cephalosporin or carbapenem) 2
• Echinocandin for empirical Candida coverage if risk factors present (prior broad-spectrum antibiotics, femoral catheterization, TPN) 2, 4

Diagnostic Algorithm

Step 1: Ultrasound Imaging

• Perform compression and duplex Doppler ultrasound of bilateral lower extremities 1
• Compare the catheterized leg to the contralateral leg 1

Step 2: Blood Culture Interpretation

• If blood cultures grow Staphylococcus aureus, Candida, or gram-negative bacilli, consider transesophageal echocardiography to rule out endocarditis 2, 4
• Obtain repeat blood cultures every 48-72 hours until clearance is documented 4

Step 3: Risk Stratification for Complications

Perform aggressive evaluation for metastatic complications if:

• Blood cultures remain positive >72 hours after appropriate therapy 2, 4
• Clinical deterioration despite antibiotics 2
• Persistent fever or bacteremia 2

This includes:

• Transesophageal echocardiography for endocarditis 2, 4
• Imaging for septic pulmonary emboli 2
• Evaluation for osteomyelitis or septic arthritis 2

Common Pitfalls to Avoid

• Do not assume leg edema is simply post-catheter inflammation without imaging - DVT is frequently asymptomatic and can occur days after removal 1
• Do not underestimate infection risk from femoral catheters - they require broader empirical coverage including Candida 2
• Do not delay ultrasound for clinical "observation" - catheter-related DVT has a 6-fold increased risk and requires prompt diagnosis 1
• If Candida grows from blood cultures, catheter removal is mandatory - biofilms are refractory to systemic therapy alone 4