The influence of thyroid function on the coagulation system and its clinical consequences

Area of Science:

• Endocrinology
• Hematology
• Thrombosis Research

Background:

• Thyroid hormone levels influence hemostatic balance.
• Hypothyroidism is linked to hypocoagulability and hyperfibrinolysis.
• Hyperthyroidism is associated with increased coagulation and reduced fibrinolysis.

Purpose of the Study:

• To review the literature on thyroid hormone's effect on the hemostatic system.
• To examine the associated risks of bleeding and venous thromboembolism (VTE).
• To highlight clinical implications for hypothyroidism and hyperthyroidism patients.

Main Methods:

• Literature review of studies investigating thyroid hormone and hemostasis.
• Analysis of the relationship between thyroid status and coagulation/fibrinolysis markers.
• Synthesis of evidence regarding bleeding and VTE risks in thyroid dysfunction.

Main Results:

• Low thyroid hormone levels (hypothyroidism) increase bleeding risk, potentially due to acquired von Willebrand's syndrome.
• High thyroid hormone levels (hyperthyroidism) elevate coagulation factors (fibrinogen, factor VIII, von Willebrand factor), increasing VTE risk.
• Hyperthyroidism is also linked to embolism secondary to atrial fibrillation.

Conclusions:

• Hypothyroidism poses a bleeding risk, especially before invasive procedures.
• Hyperthyroidism is a potential risk factor for VTE, particularly in unexplained cases.
• Further clinical studies are needed to confirm the general practice significance of these findings.