Snapshot A 45-year-old woman presents to the emergency room for pain in her left calf. She reports flying back to the United States from Australia 2 days ago. Her flight was nonstop, making it a > 12-hour flight. She states having not worn any compression stockings and notes some swelling in the lower extremities bilaterally after the flight. She has a past medical history of hypertension and diabetes and currently takes oral contraceptive pills. Her vital signs are normal. On physical exam, her left calf is 2 cm larger in circumference than her right calf. It is also erythematous and warm with pitting edema. Her D-dimer levels are elevated. Introduction Clinical definition blood clot in the deep veins, typically of the lower extremities Associated conditions pulmonary embolism Epidemiology Incidence increases with age Location lower extremities Risk factors immobility hospitalization surgery thrombophilia malignancy trauma state of elevated estrogen patients on estrogen for hot flashes when patients develop a DVT, the hormone replacement therapy should be discontinued and alternative treatment should be started e.g., SSRI and SNRI Pathogenesis Virchow triad puts patients at risk for DVTs venous stasis e.g., from long trips or bed rest hypercoagulability e.g., from malignancy or oral contraceptives endothelial damage exposed collagen will trigger the clotting cascade usually secondary to lower limb trauma Presentation Symptoms lower extremity pain and swelling Physical exam examination of the affected extremity redness warmth Homan sign calf tenderness with passive dorsiflexion of the foot however, this is not a very useful sign shortness of breath may indicate pulmonary embolism Imaging Compression ultrasound with Doppler indications all patients diagnostic gold standard findings clot formation in deep venous system Studies Labs D-dimer high sensitivity low specificity often used to rule out DVT Differential Cellulitis distinguishing factors no clot found on ultrasound patients may have systemic signs, such as a fever D-dimer is negative Diagnosis Making the diagnosis based on clinical presentation and imaging Treatment Management approach most patients undergo anticoagulation for 3-6 months however, if the DVT is unprovoked with no identifiable cause, or if risk factors are persistent, patients may require longer periods of anticoagulation for prophylaxis of future DVTs Conservative appropriate prophylaxis indication all patients at risk for DVTs modalities compression stockings for long flights frequent ambulation Medical direct oral anticoagulants drugs rivaroxaban apixaban indication for outpatient management useful given once/day dosing and no monitoring low-molecular-weight heparin (LMWH) indications initial therapy patients with normal renal function unfractionated heparin indication initial therapy patients with contraindications to LMWH end stage renal disease can be used as "bridge" to therapeutic warfarin dose appropriate if > 72 hours after recent surgery warfarin indications long-term anticoagulation Operative inferior vena cava (IVC) filter placement indication patients with contraindications to anticoagulation Complications Pulmonary embolism Phlegmasia alba dolens considered a progression from a simple DVT pain, swelling, and pallor from calf all the way up the thigh