Ch_22 (1)

Chapter 22: Alterations of Hormonal Regulation

Overview of Normal Hormone System

• Hypothalamus: Initiates hormonal regulation.

• Growth Hormone: Stimulates tissue growth in bones, muscles, and organs.

• Prolactin: Influences milk production in breasts.

• Hypothalamic Hormones: Control the anterior and posterior pituitary hormones.

  • Anterior Pituitary Hormones: LH, FSH, ACTH, TSH.

  • Posterior Pituitary Hormones: Oxytocin, Vasopressin (ADH).

• Target Organs:

  • Ovaries: Produce Estrogen and Progesterone.

  • Testes: Produce Testosterone.

  • Thyroid Gland: Produces Thyroid hormones.

  • Adrenal Cortex: Produces Cortical hormones.

Mechanisms of Hormonal Alterations

• Hormonal imbalances can arise from:

  • Excess or Insufficient Hormones: Too much or too little hormone can skew body processes.

  • Failure of Feedback Systems: Disruption of normal feedback mechanisms.

  • Endocrine Gland Dysfunction: Issues in hormone-producing glands.

  • Altered Hormone Release: Can include ectopic hormone sources.

  • Target Cell Dysfunction:

    • Hormone Insensitivity: Target cells fail to respond to hormones.

    • Receptor-Associated Disorders: Issues with hormone receptors.

    • Intracellular Disorders: Inside-target cell dysfunctions.

Diseases of the Posterior Pituitary

Antidiuretic Hormone (ADH) Effects

• Hyperfunction:

  • Syndrome of Inappropriate Antidiuretic Hormone (SIADH): Excess ADH leading to water retention.

• Hypofunction:

  • Diabetes Insipidus: Deficiency of ADH; results in polyuria and polydipsia.

    • Types of Diabetes Insipidus: Neurogenic, nephrogenic, dipsogenic.

Clinical Manifestations of SIADH

• Symptoms:

  • Hyponatremia (sodium <135 mEq/L).

  • Hypoosmolality (<280 mOsm/kg).

  • Urine hyperosmolality (urine osmolality higher than serum osmolality).

  • Hypervolemia: Increased blood volume leads to weight gain and dilutional hyponatremia.

  • Neurological Symptoms: Anorexia, nausea, vomiting, irritability, confusion, hallucinations, seizures.

Diseases of the Anterior Pituitary

Anterior Pituitary Functioning

• Conditions:

  • Hyperfunction (Hyperpituitarism): Overproduction of hormones, e.g., growth hormone leading to acromegaly.

  • Hypofunction (Hypopituitarism): Deficiency of pituitary hormones. Includes ACTH, TSH, FSH/LH, and GH deficiencies.

Hyperpituitarism Symptoms

• Symptoms of excessive growth hormone:

  • Acromegaly: Increased connective tissue proliferation, enlarged organs, and various systemic effects.

  • Characteristics: enlarged tongue, facial bones, hands and feet, headaches, diabetes symptoms.

Alterations of Thyroid Function

Hyperfunction (Hyperthyroidism)

• **Conditions: ** Thyrotoxicosis, Graves' disease, nodular thyroid disease.

• Symptoms: Weight loss, diarrhea, heat intolerance.

Hypofunction (Hypothyroidism)

• Conditions: Primary (e.g., Hashimoto disease), secondary, congenital, and thyroid carcinoma.

• Symptoms: Weight gain, bradycardia, cold intolerance.

Alterations in Parathyroid Function

• Conditions:

  • Hyperparathyroidism: Primary, secondary, tertiary forms.

  • Hypoparathyroidism: Caused by damage during thyroid surgery or autoimmune disorders.

Alterations of the Endocrine Pancreas

Diabetes Mellitus

• Type 1 Diabetes: Autoimmune destruction of beta cells leading to loss of insulin.

• Type 2 Diabetes: Insulin resistance and beta cell dysfunction.

Acute and Chronic Complications of Diabetes Mellitus

• Acute Complications: Hypoglycemia, diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic nonketotic syndrome (HHNKS).

• Chronic Complications: Microvascular diseases (e.g., retinopathy, nephropathy) and macrovascular diseases (e.g., coronary artery disease).

Alterations of Adrenal Function

Hyperfunction - Cushing Syndrome

• Overproduction of cortisol leads to various systemic effects such as hypertension, obesity, and glucose intolerance.

Hypofunction - Addison’s Disease

• Inadequate corticosteroid synthesis; low blood pressure, weakness, and fatigue.

Key Questions on Hormonal Disorders

1. SIADH: Expect to see hypoosmolar states and low sodium levels in urine.

2. Graves Disease: Identified by an autoimmune response leading to hyperthyroidism.

3. Hyperparathyroidism: Associated with pathologic fractures and increased calcium levels.

4. Diabetes Complications: Recognize acute effects of hypoglycemia and DKA.