[Differential diagnosis of deep vein thrombosis]

The incidence of deep venous thrombosis (DVT) is high in numerous surgical and medical diseases [1]. There are increasing data on higher incidence of DVT in patients with malignant and other diseases [2]. The diagnosis of DVT is not always simple since there are subclinical and asymptomatic forms of the disease [3]. Besides, there are numerous pathological conditions that imitate deep venous thrombosis [4].

We present the results of a retrospective study over the period of January 1, 1996--June 30, 1998 at the Department of Vascular Surgery. Over that period we treated 113 patients (64 females, 49 males, average aged 60.3 +/- 7.5 years) with clinical picture of deep venous thrombosis. All patients underwent duplex scanning examinations (Toschiba SSA-100 A, 3.5 MHz and 8 MHz probes) [5, 6]. Special examinations such as angiography (8 patients), computerised tomography or nuclear magnetic resonance (27 patients) were performed in cases with unclear findings.

True DVT was established in 91 (80.3%) patients (Fig. 1). Seven of these patients had asymptomatic phlebothrombosis. Of 12 (10.6%) patients in 9 other pathologic conditions were found (Fig. 2). This symptomatic DVT was caused by malignant diseases (5 sarcomas, 2 metastatic carcinomas, 1 lymphoma); aneurysms of common femoral artery (2) and popliteal artery (2 patients). Ten patients (8.9%) with clinical picture of DVT established by special examinations had no evidence of the presence of intravenous thrombs (Fig. 3). This pseudo DVT was caused by calf haemathoma (3), Baker's cyst (2), popliteal artery aneurysm (1), lipoma of thigh (1), psoas abscess (1), gluteal abscess (1) and acute arthritis of the knee (1). The treatment of these groups of patients was different: surgical thrombectomy, use of streptokinase or heparine (true deep vein thrombosis), tumour extraction (Fig. 4) or another surgical treatment (symptomatic phlebothrombosis) and special decompression measures (Fig. 5) (pseudophlebothrombosis).

Aetiopathogenesis of true DVT is determined by Virchov's triad [3, 4, 7, 8]. The incidence of DVT in medical and surgical patients is high (30-75%). Initially true DVT may be asymptomatic in 35-70% of patients [1, 3, 8] and depended on detection methods [1, 6, 7, 9, 10]. DVT may be only a symptom of other pathological conditions [2, 3, 7]. This symptomatic DVT is mostly caused by malignant diseases [2]. Pseudo DVT or primary deep vein obstruction may be caused by external abnormalities (right common iliac artery; compression of the left common iliac vein, malignant disease, retroperitoneal fibrosis, internal iliac compression of the external iliac vein, latent femoral hernia compression of the femoral vein, masses in the thigh (large tumours, true or false aneurysms, popliteal masses/aneurysms, large Baker's cysts), changes in the wall or within the lumen of a vein as aplasia, primary tumours, intraluminal spurs [7].