endocrine

Overview of Endocrine Disorders

• Two main types:

  • Parathyroid Disorders

  • Adrenal Disorders

Thyroid Disorders

Types

• Hypothyroidism (low thyroid hormone)

• Hyperthyroidism (high thyroid hormone)

Causes

• Primary Causes

  • Intrinsic dysfunction of the thyroid gland.

• Secondary Causes

  • Dysfunction of hypothalamus or pituitary gland.

Functions of the Thyroid

• Regulates metabolism.

• Important for growth and development.

• Regulates blood pressure and heart rate.

• Maintains body temperature.

• Regulates calcium and phosphorus levels.

Hypothyroidism

Key Hormones

• Triiodothyronine (T3)

• Thyroxine (T4)

Causes of Primary Hypothyroidism

• Low or absent T3/T4 production due to:

  • Congenital agenesis

  • Autoimmune diseases (Hashimoto’s thyroiditis)

  • Radiation treatment

  • Surgical removal (thyroidectomy)

  • Iodine deficiency

Hashimoto's Thyroiditis

• Autoimmune disorder causing thyroid inflammation.

• Characterized by an enlarged thyroid gland (goiter).

• Leads to decreased thyroid hormone production, elevated TSH levels.

Secondary Hypothyroidism Causes

• Head trauma, cranial neoplasms, brain infections.

Diagnostic Tests

• Measure TSH, T3, T4, and thyroid autoantibodies.

• Elevated TSH, low T3/T4 in hypothyroid.

Clinical Manifestations

• Weight gain.

• Reduced heart rate (bradycardia).

• Cold intolerance.

• Fatigue and forgetfulness.

• Constipation and decreased bowel motility.

• Hair loss and dry skin.

• Heavy menstrual periods (menorrhagia).

Complications

• Myxedema (severe, untreated hypothyroidism).

• Myxedema coma (medical emergency).

  • Generalized edema due to substance buildup (glycosaminoglycans).

Hyperthyroidism

Causes

• Excessive T3/T4 production from:

  • Autoimmune disease (ex: Graves' disease)

  • Adenomas or carcinomas.

Graves’ Disease

• Most common cause of hyperthyroidism.

• Autoantibodies stimulate the TSH receptors, causing increased hormone production.

Diagnostic Tests

• Similar to hypothyroid but with an inverse relationship:

  • Elevated T3 and T4, low TSH.

Clinical Manifestations

• Weight loss despite increased appetite.

• Increased heart rate (tachycardia).

• Heat intolerance and excessive sweating (diaphoresis).

• Increased bowel motility (diarrhea).

• Anxiety and irritability.

• Emotional changes and impaired memory.

• In women, amenorrhea (absence of periods).

• Bulging eyes (exophthalmos).

Complications

• Thyroid storm: life-threatening excess T3/T4 release.

Parathyroid Disorders

Function

• Regulates calcium by:

  • Releasing calcium from bones.

  • Absorbing calcium in intestines.

  • Reabsorbing calcium in kidneys.

Hypoparathyroidism

• Low parathyroid hormone leads to hypocalcemia.

• Clinical manifestations:

  • Numbness, tingling around the mouth (circumoral numbness).

  • Muscle cramps, spasms, and irritability.

  • QT interval prolongation on ECG.

• Diagnostic tests include serum calcium levels and EKG.

• Chvostek’s sign (twitching on cheek stroke) and Trousseau's sign (hand spasm during BP cuff inflation).

Hyperparathyroidism

• High parathyroid hormone leads to hypercalcemia.

• Clinical manifestations:

  • Bone pain, kidney stones.

  • Anorexia, nausea, and constipation.

  • Confusion, fatigue, and depression.

  • EKG changes possibly leading to dysrhythmias.

• Diagnostic tests show elevated calcium and PTH levels.

Adrenal Disorders

Overview

• Adrenal glands regulate stress response, electrolyte balance, and metabolism.

Addison's Disease (Adrenocortical Insufficiency)

• Causes:

  • Destruction of adrenal cortex (autoimmune, idiopathic).

  • Tuberculosis, trauma, hemorrhage, or certain medications (steroids).

• Symptoms include weight loss, electrolyte imbalances (hyperkalemia), low BP, and hyperpigmentation of skin.

• Diagnostic test: ACTH stimulation test.

Cushing’s Syndrome (Hypercortisolism)

• Causes:

  • Adrenal adenoma or excessive corticosteroid use.

• Symptoms:

  • Moon facies, buffalo hump, thin extremities, fluid retention, and purple striae.

  • Increased risk of osteoporosis, infections, and hypertension.

• Diagnostic tests include ACTH levels, 24-hour urine collection, glucose levels, and dexamethasone suppression test.

Key Differences

• Addison’s is characterized by low cortisol while Cushing’s is characterized by high cortisol levels.