Endocrine Abstracts

Hyperthyroidism is not a well-known cause of venous thromboembolism. Hyper-coagulable and hypofibrinolytic states are described in hyperthyroidism. A meta-analysis of 51 studies evaluating the consequence (exogenous and endogenous effect on coagulation, raised thyroid levels were associated with a rise in clotting factor VIII, IX, Von Willebrand factor and fibrinogen. The procoagulant effect noticed in hyperthyroidism facilitated by thyroid hormone receptor beta gene. 40-year-old HGV driver presents with hot sweats, weight loss over 10 months, tremor. Examination revealed mild tremor, Heart rate 80 per minute. No sympathetic signs of thyrotoxicosis and thyroid eye disease. Blood test showed TSH<0.01mIU/l FT4-76.3 pmo/l, normal white cell count, high TRAB antibody titres. A diagnosis of Graves’ disease was made and was commenced on carbimazole 20 mg bd and propranolol 20 mg tds. He was rendered neutropenic and carbimazole was stopped. Following this he was started on dexamethasone 1 mg BD and cholestyramine 4g TDS. Given the severe symptoms and high antibody titres he was offered surgery. Lugol’s iodine, propranolol, cholestyramine, dexamethasone was used to achieve the pre-operative objective of thyroid function of FT4<30 pmo/l and FT3-<10 pmo/l. Three days prior to surgery, he presented back to hospital with acute painful right lower limb. He has been having intermittent claudication since past 2 weeks. An MRA revealed embolus or thrombus in the right common to external iliac artery obstructing the flow into the right internal iliac artery. He then underwent right femoral tibial embolectomy, on table angiogram and thrombolysis and fasciotomies. Unfortunately, the limb could not be salvaged, and he was planned for a below knee amputation. Total thyroidectomy and Guillotine amputation were performed, at this stage the thyroid function normalised. This case emphasise the significance of hyperthyroidism in hyper coagulable states. There is a paucity of large scale prospective multi-centre studies in establishing hyperthyroidism as a risk factor for VTE.