Graves' disease associated with cerebrovascular disease and antiphospholipid antibody syndrome

The incidence of venous thromboembolism in patients with overt hyperthyroidism

Hyperthyroidism is associated with several changes in the haemostatic system resulting in a hypercoagulable state. It is uncertain at this stage whether this leads to an increased risk of venous thromboembolism (VTE). The aim of this retrospective cohort study was to determine the risk of VTE in all patients with overt hyperthyroidism and to compare this to the risk of VTE in the general population. In three hospitals in the Netherlands, patients with biochemically confirmed hyperthyroidism caused by Graves’ disease, multinodular goiter or toxic adenoma were included. All available electronic and handwritten records were examined. Primary outcome was the occurrence of VTE within six months before and until six months after the diagnosis of hyperthyroidism. We included a total of 587 patients. Five patients experienced a VTE during the study period, resulting in an incidence rate of 8.7 (95% CI 2.8 – 20.2) per 1,000 person-years. Three of these five patients had a first VTE (incidence rate for first VTE was 5.3 [95% CI 1.1 – 15.6] per 1,000 person-years). Incidence rates of VTE in the general population are between 0.6 and 1.6 per 1,000 person-years for first VTE and 0.7 and 1.8 per 1,000 person-years for all VTE. In conclusion, the incidence rate of VTE in patients with hyperthyroidism appears to be high. Future prospective studies are needed to further explore this possible association and to address its clinical implications.

Thyroid Autoimmunity and Antiphospholipid Syndrome: Not Such a Trivial Association

Antiphospholipid syndrome (APS) is an autoimmune disease that manifests as recurrent venous or arterial thrombosis and/or pregnancy-related complications in the presence of persistent antiphospholipid (aPL) antibodies measured at least 3 months apart. APS occurs either as a primary condition or as a part of an underlying disorder, usually systemic lupus erythematosus (SLE). Otherwise, APS may be frequently associated with autoimmune disorders. Little is known about the association of APS and aPL antibodies with thyroid autoimmune diseases or thyroid autoantibodies. This is even more interesting that thyroid autoantibodies and aPL are both recognized causes of repeated miscarriages. Therefore, their combination is of particular importance in women of childbearing age. Several studies have pointed out an association between APS and thyroid autoimmunity, some of them suggesting common pathophysiologic processes and genetic background. A literature review was conducted on existing data on aPL/APS and thyroid autoimmune disorders, paying particular attention to the possible role of this association in obstetrical complications.

Cerebral venous thrombosis associated with thyrotoxicosis, the use of desmopressin and elevated factor VIII/von Willebrand factor

Cerebral venous thrombosis (CVT) is an uncommon disorder associated with diverse processes. We report a patient who, while receiving desmopressin and contraceptive pills (OCP), developed straight sinus thrombosis. Clinical assessment and laboratory investigations revealed untreated hyperthyroidism and a hypercoagulable state, characterised by high levels of von Willebrand factor, factor VIII coagulant activity and IgM cardiolipin antibody. The clinical picture improved with anticoagulation, treatment of hyperthyroidism and discontinuation of OCP and desmopressin. To the best of our knowledge, the association between the use of oral desmopressin and CVT has not been described. The multiple risk factors present in our case were probably additive in increasing the risk of CVT. Although this case represents a rare occurrence, practitioners should be alerted to the possible associations of desmopressin, oral contraceptives and Graves' disease with venous thrombosis.

Antiphospholipid Antibody Syndrome Associated with Graves' Disease Presenting as Inferior Vena Cava Thrombosis with Bilateral Lower Limb DVT

We report a case of a 60-year-old lady who presented with bilateral lower limb swelling and a thyroid swelling with clinical features consistent with thyrotoxicosis. Investigations revealed the presence of a thrombus in bilateral external, internal iliac veins, and inferior vena cava extending up to its infrahepatic part. Hormone profile and radioiodine uptake scan confirmed the diagnosis of Graves' disease. Further workup revealed the presence of antiphospholipid antibodies (confirmed after a repeat test at 12 weeks). The patient was treated with antithyroid drugs and anticoagulants. The patient improved with normalization of thyroid function and partial recanalization of the infrahepatic part of inferior vena cava. Hyperthyroidism has been implicated as a potential hypercoagulable state; however, the association of Graves' disease with antiphospholipid antibody syndrome is limited to isolated case reports. This case highlights a new mechanism underlying hypercoagulability associated with Graves' disease.