Hemostatic abnormalities in endocrine and metabolic disorders

Abstract

The hemostatic balance is a complex system where the delicate equilibrium is regulated by several factors, including hormones. This review summarizes current knowledge of the effects of most frequent endocrine and metabolic diseases (such as hypothyroidism, hyperthyroidism, Cushing's syndrome, GH-related pituitary dysfunctions, pituitary prolactin-producing adenomas, polycystic ovary syndrome, primary hyperparathyroidism, and metabolic syndrome) on coagulation and fibrinolysis. Overt hypothyroidism appears to be associated with a bleeding tendency, whereas all other endocrine diseases appear to be associated with a thrombotic tendency. Globally, the disorders of coagulation and fibrinolysis usually range from mild to moderate, and, rarely, to severe laboratory abnormalities (for example, bleeding diathesis in overt hypothyroidism mainly due to an acquired von Willebrand's disease type 1). Further larger and high-quality studies are needed to provide more definitive information on the effects of endocrine disorders on coagulation and fibrinolysis.

Prothrombotic changes due to an increase in thyroid hormone levels

“…Differentiated thyroid cancer patients (nZ112), severely hypothyroid 4-5 weeks following total thyroidectomy without LT 4 replacement, were admitted for RAI thyroid remnant ablation. Before discharge, thyroid hormone suppression therapy (LT 4 , 150 mg/day) was initiated and 6-8 weeks later they were examined in the outpatient follow-up clinic.…”

“…However, reports on the influence of thyroid hormones on coagulation and fibrinolysis, while mostly suggesting a hypercoagulable state in thyrotoxicosis, have often been of low methodological quality (3,4,5). Indeed, no high-quality study was identified in a systematic review in 2007 (3).…”

“…Demir et al (6) report a significant increase in plasminogen activator inhibitor 1 (PAI1), von Willebrand factor (VWF) and fibrinogen following levothyroxine (LT 4 ) suppression treatment for thyroid nodules. In their randomised crossover study in healthy volunteers, van Zaane et al (7) describe a dosedependent effect of LT 4 exposure on several variables of coagulation and fibrinolysis, the most prominent being an increase in PAI1 (by 116%) and VWF activity and antigen (by 24 and 26% respectively).…”

Negative association between free triiodothyronine level and international normalized ratio in euthyroid subjects with acute myocardial infarction

“…Because prolonged APTT and PT results indicate a reduced coagulation response and a bleeding tendency, these findings indicate that hyperthyroidism might be associated with hypercoagulability [12] . Previous studies largely have explored patients with clinically overt hypo-or hyperthyroidism who appeared to have an increased risk of bleeding or thrombosis [13] .…”

“…Several biological mechanisms have been proposed to explain this intriguing association, including the effects of thyroid hormones on the synthesis of coagulation factors and the thyroid-related autoimmune processes [13,19] . However, the exact mechanism underlying the relationship between FT3 and INR remains unclear.…”