Possible mechanisms:
(1) intimal tear or endothelial damage
(2) thromboplastin release
(3) venous compression
Reported in:
(1) jogging
(2) kick boxing
(3) football
(4) skiing
(5) soccer
Risk factors:
(1) popliteal vein entrapment or other anatomic abnormality
(2) chronic venous insufficiency
(3) strenuous exercise
Clinical features:
(1) sudden onset of unilateral leg pain not due to trauma
(2) sudden swelling of the leg and foot
(3) tenderness on compression of the lower leg
(4) pain is relieved by elevation and aggravated by a dependent position
(5) positive Homan's sign (pain in calf on dorsiflexion of foot)
(6) sudden chest pain or dyspnea if pulmonary embolism occurs
Imaging studies:
(1) Doppler ultrasonography
(2) venogram (performed when the Doppler is negative and there is a high level of clinical suspicion based on findings)
Differential diagnosis:
(1) gastrocnemius muscle tear
(2) venous thrombosis secondary to hypercoagulable state
(3) venous thrombosis secondary to blunt trauma
