Hyper2

• Tachycardia

  Thyroid hormones work on Beta2 receptors in heart to cause tachycardia
• Potentiate the β-adrenergic response

  Increasing the number of β-adrenoreceptors with an opposite action on α-adrenergic receptors
• Systolic hypertension and widened pulse pressure

  • Due to decreased systemic vascular resistance, increased heart rate, and increased cardiac output
  • T3 dilates resistance arterioles, reducing systemic vascular resistance, which stimulates renin release and sodium reabsorption, expanding blood volume and increasing venous return to the heart
  • Erythropoietin stimulation also contributes to blood volume
• Pretibial myxedema

  • Deposition of hyaluronic acid in the dermis and subcutis
  • Fibroblasts are stimulated to produce abnormally high amounts of glycosaminoglycan (GAG) under the influence of cytokines due to exposure to thyrotropin receptor antibody (TRAB) and antigen-specific T cells
• Grave's ophthalmopathy

  • Antibody reaction against the TSH receptor that results in activation of T cells against tissues in the retro-orbital space that share antigenic epitopes with thyroid follicular cells
  • Inflammation (lymphocyte infiltration of orbital tissue and release of cytokines that stimulate orbital fibroblasts to multiply and produce mucopolysaccharides (glycosaminoglycans), which absorb water)
  • Extraocular muscles thicken and adipose and connective tissue of the retro-orbit increase in volume