Blood coagulation in pathological thrombus formation and the detection in blood of a thrombotic tendency

Case report: cerebral venous thrombosis as a manifestation of acute ulcerative colitis

Ulcerative colitis is associated with a number of extraintestinal complications, including the infrequent occurrence of thromboembolic disease. Cerebral venous thrombosis is extremely rare, with only 15 cases reported in the literature. The outcome in this group of patients is poor; the result in more than 80% of the cases is permanent neurologic sequelae or death. The precise mechanisms involved in thrombogenesis remain unclear. A hypercoagulable state may occur in ulcerative colitis because of well-documented associations of thrombocytosis, elevated factors V and VIII and fibrinogen, and decreased antithrombin III. Treatment regimens for cerebral venous thrombosis remain controversial and include anticoagulation with heparin, surgical thrombectomy, and systemic and local infusion of fibrinolytic regimens. A conservative approach with antiedemic agents, anticonvulsants, antiplatelet therapy, and acetazolamide also may be beneficial and offers a substantially reduced hemorrhagic potential. A case of primary superior sagittal sinus thrombosis associated with active ulcerative colitis treated by the latter method is reported. The patient's neurologic recovery was complete, with recanalization of the thrombosed venous sinus being demonstrated by magnetic resonance imaging studies.

Prophylaxis of venous thrombosis after major thoracic surgery

The high incidence (50-60%) of deep venous thrombosis of the legs (DVT) after major thoracic surgery is reduced only by about half with routine low-dose heparin prophylaxis. The present study compared the efficacy of a higher dose of heparin (7500 U twice daily) with the commonly used dose of 5000 U twice daily in preventing scan-detected DVT in 100 consecutive patients having thoracotomy for carcinoma of the lung or oesophagus. After the higher dose of heparin, postoperative DVT was not significantly less frequent (22% compared with 33% for total DVT) but was significantly less extensive (8% and 14%, respectively, for bilateral calf DVT, and 0% and 4% for popliteal DVT). Despite prophylaxis, DVT was especially common after oesophagogastrectomy (41% total DVT, 30% extensive DVT). No excessive postoperative bleeding was noted in either group. It is concluded that an increased dose of heparin safely offers increased prophylaxis against DVT in patients undergoing major thoracic surgery for cancer.

Stroke in two young siblings with congenital dysfibrinogenemia

Two young siblings (a male of 21 and his sister of 26 years) suffered from arterial thrombosis episodes of the carotid and abdominal aorta documented by angiographic studies. In the absence of any known predisposing factor in the family and personal history, the laboratory investigation of both patients revealed coagulation abnormalities compatible with a dysfibrinogenemia. The occurrence of a similar defect also in plasma of one of the propositi's asymptomatic relatives is suggestive of an inherited fibrinogen disorder.

Detection of hypercoagulability by the measurement of the dynamic loss modulus of clotting blood

The dynamic loss modulus of clotting whole blood was measured in thrombotic patients to characterize the physical properties of coagulation in the hypercoagulable state. The dynamic loss modulus was measured by a Sonoclot. Thrombotic patients consisted of 30 with deep vein thrombosis and 25 with arterial thrombosis. An accelerated increment rate of the dynamic loss modulus at the beginning of gelling was the characteristic of hypercoagulability. This characteristic occurred more frequently than other abnormalities in other tests for hypercoagulability (beta-thromboglobulin, antithrombin III and TEG). Only in deep vein thrombosis, a moderately positive correlation was noted between the increment rate of the dynamic loss modulus and the plasma fibrinogen level.

Circulating antithrombins in pregnancy

In a cross-sectional study circulating levels of antithrombins, antithrombin III, alpha 1-antitrypsin and alpha 2-macroglobulin were measured in groups of 20 women before pregnancy, during each trimester and post partum. Blood levels of antithrombin III were significantly lower, alpha 1-antitrypsin higher and alpha 2-macroglobulin no different when compared with those of the non-pregnant and puerperal states. These findings suggest that there may be not only an increase in total antithrombin production, but also a qualitative change in antithrombin 'activity', the principal protein during pregnancy being alpha 1-antitrypsin.

Haemostatic changes in diabetic coma

Diabetic coma is frequently associated with thromboembolic complications. A prospective study was undertaken of the haemostatic changes occurring in 15 patients (12 with ketoacidosis, three with the hyperosmolar syndrome) during diabetic coma. When compared with the results after stabilization of the diabetes, ketoacidosis was associated with significantly higher levels of factor VIII coagulant activity, factor VIII-related antigen and fibrin degradation products, a shorter partial thromboplastin time and reduced concentrations of antithrombin III. These results suggest that in uncomplicated ketoacidosis, haematological changes occur which may reflect vascular endothelial damage and intravascular fibrin deposition. Out of three deaths, two patients (both with the hyperosmolar syndrome) had evidence of disseminated intravascular coagulation. To reduce further the mortality and morbidity from diabetic coma, controlled clinical trials of anticoagulant and antiplatelet drugs may be indicated.

Antithrombin III in patients on long-term oral anticoagulants

The antithrombin III (AT III) concentration in plasma was measured in 63 patients on oral anticoagulant treatment (mean age 57.7 years), 26 healthy laboratory controls (mean age 28 years), and 21 patients attending the hypertensive clinic who had never been on oral anticoagulants (mean age 50 years). Three methods were used to measure AT III: a coagulation assay, a chromogenic substrate assay, and an immunological assay. In patients on oral anticoagulants, the mean values for AT III in the three assays were: 124%, 107%, and 96% respectively. The mean AT III concentration in laboratory staff was 103.4%, 94%, and 104.1% for the three assays; patients attending the hypertensive clinic had AT III concentrations indistinguishable from those in patients on oral anticoagulants: 117.9%, 110.5%, and 93.9%. The difference between both patient groups and laboratory staff was statistically highly significant, but no difference was demonstrated between patients on anticoagulant treatment and those not receiving it. Our results show that the increase in the functional AT III concentration (measured by coagulation and chromogenic assays) observed in patients on oral anticoagulants is probably due to the effects of age and underlying disease rather than to the anticoagulant treatment itself.