Endocrine System Quiz Part I

Endocrine System Overview

• Thyroid gland is not palpable.
• Thyroid hormone is produced by the thyroid gland.
• Two primary hormones: Triiodothyronine (T3) and Thyroxine (T4).
• Main functions of thyroid hormone: regulates metabolism, heart rate, cardiac output, promotes growth and development, supports brain maturation in fetal and early postnatal life.
• Signs and symptoms of thyroid disease primarily affect metabolism and cardiac function.
• Iodine is a necessary compound for thyroid hormone synthesis.

Hyperthyroidism

• Most common cause: Graves' disease, an autoimmune disorder.
• Pathophysiology: Immunoglobulins stimulate thyroid-stimulating hormone receptors, leading to increased hormone synthesis.
• Exophthalmos: Condition characterized by protruding eyeballs due to fluid accumulation and tissue buildup.
• Common signs/symptoms: Weight loss, diarrhea, heat intolerance, nervousness, sweating, hyperexcitability, tachycardia, palpitations, and exophthalmos.
• Treatment options: Thyroidectomy or radioactive iodine therapy.
• Prototype medication: Methimazole (Tapazole), suffix -mazole.
• Mechanism of action for Methimazole: Inhibits thyroid hormone synthesis.
• Effectiveness of Methimazole is indicated by the reduction of hyperthyroid symptoms (e.g., bradycardia from tachycardia).
• Risks of overtreatment: Extreme hypothyroidism signs, fever, rash, and leukopenia due to agranulocytosis.
• Agranulocytosis is life-threatening with low granulocytes, increasing infection risk, and potentially low RBCs and platelets.
• Regular checks while on Methimazole: CBC and hepatic function, as Methimazole can be hepatotoxic.

Jaundice

• Jaundice is a sign of hepatic failure or injury associated with elevated bilirubin levels, leading to yellow discoloration of skin, mucous membranes, and sclera.
• Assessing jaundice should always focus on the sclera.

Hypothyroidism

• Most common cause: Autoimmune condition known as Hashimoto’s thyroiditis.
• Pathophysiology: Antibodies attack the thyroid gland, leading to fibrotic and non-functional tissue, resulting in decreased hormone production.
• Treatment medication: Levothyroxine (Synthroid).
• Mechanism of action: Synthetic T4 is converted to active T3 in peripheral tissues, correcting hypothyroidism.
• Administration route: Oral (PO) or intravenous (IV).
• Signs of effective treatment: Increased metabolic rate.
• Possible side effects: Tachycardia, palpitations, dysrhythmias, severe angina, nervousness, tremors, anxiety, insomnia.
• Important side effect to report: Any signs indicative of adverse reactions to levothyroxine.