Management of Persistent Left Leg Pain and Swelling After Cortisone Injection with Negative Initial DVT Workup
Obtain an immediate repeat complete duplex ultrasound (CDUS) from thigh to ankle, as persistent symptoms two months after onset with normal initial imaging warrant repeat evaluation to exclude propagated DVT or alternative diagnoses. 1
Immediate Diagnostic Action
Perform CDUS now rather than waiting, as your patient has persistent and potentially worsening symptoms that have lasted 2 months—far beyond the typical timeframe where repeat imaging is indicated (5-7 days after initial negative study). 2, 1
The repeat ultrasound must be comprehensive, including:
- Compression ultrasound from common femoral vein through the ankle 2, 3
- Specific evaluation of posterior tibial and peroneal veins in the calf 2, 3
- Color and spectral Doppler of common femoral and popliteal veins 2, 3
- Assessment of symptomatic areas for superficial venous thrombosis or other pathology 1
Why Repeat Imaging Is Critical
The initial ultrasound may have missed an isolated calf DVT that could have propagated proximally—approximately 15% of untreated distal DVTs extend within the first 2 weeks. 1
Two months of persistent symptoms represents a clear indication for repeat imaging regardless of the timing of the initial study. 2, 1
The temporal relationship to cortisone injection raises concern for iatrogenic vascular injury or thrombosis that may not have been fully developed at the time of initial imaging. 4
If Repeat CDUS Is Negative
Consider iliocaval DVT imaging with CT or MR venography, particularly given the extensive duration of symptoms and whole-leg presentation, as isolated iliac vein thrombosis can be missed on standard ultrasound. 2, 1, 5
Whole-leg swelling with normal compression ultrasound suggests iliocaval disease that may not be adequately visualized on standard examination. 2, 1
CT venography or MR venography should be pursued if clinical suspicion remains high despite negative CDUS. 2, 3
Alternative Diagnoses to Evaluate
If DVT is definitively excluded, the differential diagnosis includes:
Post-injection complications: Vascular injury, compartment syndrome, or inflammatory reaction from the cortisone injection itself 4
Superficial thrombophlebitis: Can present with pain and swelling and may require treatment 1
Baker's cyst: Ultrasound can identify cystic lesions causing leg swelling 1
Lymphedema: Can present as unilateral leg swelling, though typically develops more gradually 6
Chronic venous insufficiency: May be identified on duplex ultrasound but does not require vascular surgery referral unless severe 5
May-Thurner syndrome: Left-sided iliac vein compression that can cause persistent leg symptoms 7
Role of D-Dimer Testing
D-dimer may be helpful if repeat ultrasound is technically compromised or shows equivocal findings, but given the 2-month duration of symptoms, D-dimer is less likely to be useful as a standalone test. 2, 1
In patients with persistent symptoms and negative imaging, D-dimer can help determine if recurrent DVT is present. 2
If Repeat Imaging Confirms DVT
Initiate anticoagulation immediately if acute DVT is confirmed. 2, 1
For isolated distal DVT, assess severity of symptoms and risk factors for extension (positive D-dimer, extensive thrombosis, no reversible provoking factor, active cancer, history of VTE). 1
For severe symptoms or high-risk features, initiate anticoagulation with subcutaneous low-molecular-weight heparin or fondaparinux. 1
Critical Pitfalls to Avoid
Do not assume the initial negative ultrasound definitively excludes DVT when symptoms persist for 2 months—this is precisely the scenario where repeat imaging is mandated. 2, 1
Do not accept limited proximal-only ultrasound when symptoms suggest calf involvement, as this misses isolated distal DVT. 3
Do not overlook isolated iliac vein thrombosis in patients with extensive unexplained leg swelling—this requires pelvic/iliocaval imaging. 2, 1, 5
Do not miss superficial thrombophlebitis, which can present with similar symptoms and may require treatment. 1