Teaching Case

A 22-year-old man without any former history of similar symptoms or severe illnesses, developed swelling and tenseness in his left upper arm during a skiing vacation. Examinations, including upper extremity ultrasound and D-dimer analysis at a local hospital were inconclusive. However, but because of ongoing symptoms the patient consulted the emergency department when back in his homeland.

The clinical examination showed visible veins on the left side of thorax, the left upper extremity showed redness, swelling and pain upon palpation of the left upper extremity. Wells score (Fig. 1) was calculated to 3 from the positive findings in the objective examination of the body, and therefore a high clinical suspicion for deep vein thrombosis (DVT) was concluded. Blood tests showed Leucocytes = 9, 6 billions/L, CRP = 0, 7 mg/ L, and D-dimer 0, 40 FEU/ L. Because of high clinical suspicion of DVT, ultrasound of left upper extremity was performed and concluded thrombosis in left axillary vein (Fig. 2). Afterwards computed tomography (CT) examination of thorax and abdomen with intravenous contrast was performed to investigate for any possible malignancies (Fig. 3). The CT examination demonstrated thrombosis in left subclavian vein and left axillary vein, and no further pathology was found.

BACKGROUND
In 1859, Rudolph Virchow described the pathogenesis of DVT and pulmonary embolism (PE). He concluded that 1) blood stasis, 2) changes in the vessel walls, 3) hypercoagulation were the main important factors for development of venous thromboembolism [1].
CLINICAL PERSPECTIVE
DVT is in around 5 % of cases localised to upper extremities [2]. Upper extremity DVT is related to thrombosis in axillary vein or to subclavian vein and is divided into a primary upper extremity DVT, also called Paget-Schroetter syndrome (PSS) and a secondary upper extremity DVT among patients with an underlying cause [2]. PSS represents 10-20% of upper extremity DVT which is also known as "effort-thrombosis", since the majority of patients have anamneses with energetic physical activity involving the upper extremity [3]. Upper extremity DVT can potentially result in significant complications, including PE, vena cava superior syndrome and post-thrombotic venous insufficiency [4].
IMAGING PERSPECTIVE
Detection of DVT requires reliable and noninvasive diagnostic methods in addition to D-dimer analysis that has high sensitivity but low specificity [5,6]. This will be necessary both for the exact location of the DVT and for control during and after treatment. Although contrast venography was the first method for detection of DVT in history and is still the gold standard, today less invasive methods are preferred such as ultrasound that can visualise non-compressibility of the vein, echogenic thrombus within the lumen, venous distention etc. [6].
OUTCOME
Among patients with upper extremity DVT about 1/3 develop pulmonary embolism. The beneficial effects of using ultrasound in investigation for upper extremity DVT can be listed as inexpensive, noninvasive and reproducible, but unfortunately has a disadvantage in failing to detect central thrombus that is directly below the clavicle. The beneficial effect of using CT examination to diagnose upper extremity DVT is that it can detect central thrombus and may detect presence of extrinsic vessel compression [6,7].
TEACHING POINTS
DVT in upper extremity can occur among young and healthy individuals after physical effort involving the upper extremities. DVT appears despite low level of D-dimer, however high clinical suspicion including Wells score should result in additional imaging elucidation to confirm or disconfirm the suspicion of DVT.
D-dimer has a high sensitivity and negative predictive value. The clinical examination and assessment including Wells score should be involved when examining for suspicion of DVT, though D-dimer is low.
DVT in upper extremity can result in serious complications, and therefore demands treatment.
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