Unilateral Lower Extremity Edema in a Young Female Smoker

Case at a Glance

A 30-year-old female smoker presents with progressive unilateral left lower extremity swelling over a 3-week period, with elevated D-dimer but negative ultrasound for deep vein thrombosis.

Patient's Story

The patient is a 30-year-old female, height 160cm, weight 56kg, with a smoking history. She reports no recent injuries or regular medications except occasional ibuprofen for headaches. Three weeks prior to presentation, she noticed swelling in her left ankle while at work. The swelling was painless but associated with a sensation of heaviness in the affected leg. The edema has been intermittent over the subsequent weeks, with recent progression to involve the entire left lower extremity.

Initial Assessment

Physical examination revealed unilateral left lower extremity edema extending from the ankle to the thigh. The patient appeared comfortable with no acute distress. Vital signs were stable. The affected limb showed visible asymmetry compared to the contralateral leg, with pitting edema noted. No erythema, warmth, or palpable cords were observed.

The Diagnostic Journey

Initial workup included laboratory studies and imaging. D-dimer was mildly elevated on first assessment. Duplex ultrasound of the left lower extremity was performed to evaluate for deep vein thrombosis, which returned negative for acute clot formation. Due to persistent symptoms and patient concern, repeat laboratory studies were obtained two days later, showing D-dimer level of 370 ng/mL (elevated). Despite the elevated biomarker, imaging studies continued to show no evidence of thrombotic disease.

Final Diagnosis

Unilateral lower extremity edema of uncertain etiology with elevated D-dimer but negative imaging for venous thromboembolism.

Treatment Plan

Conservative management initiated including leg elevation, compression therapy, and smoking cessation counseling. Patient advised to monitor symptoms and return for follow-up if edema worsens or new symptoms develop. Further evaluation for alternative causes of unilateral edema to be considered if symptoms persist, including assessment for venous insufficiency, lymphatic disorders, or occult malignancy.

Outcome and Follow-up

Patient scheduled for close follow-up in one week to reassess symptoms and response to conservative measures. Additional imaging modalities and specialist consultation to be considered based on clinical progression.