endo

Endocrine Problems Study Notes

Overview of the Endocrine System

  • The endocrine system is responsible for secreting hormones that regulate various physiological functions.
  • Key components include:
    • Pituitary Gland
    • Adrenal Glands
    • Pancreas (located behind the stomach)
    • Ovaries (testes in individuals assigned male at birth)
    • Hypothalamus
    • Pineal Gland
    • Thyroid Gland

Anterior Pituitary Gland

  • Known as the "master gland" because it regulates several bodily functions.
  • Hormones secreted:
    • Growth Hormone (GH)
    • Prolactin
    • Adrenocorticotropic Hormone (ACTH)
    • Thyroid Stimulating Hormone (TSH)
    • Follicle Stimulating Hormone (FSH)
    • Luteinizing Hormone (LH)

Acromegaly

  • Definition: Overproduction of growth hormone, most often due to a GH-secreting pituitary adenoma.
  • Clinical Manifestations:
    • Develops slowly over years, may go unnoticed
    • Symptoms include:
    • Thickening and enlargement of bony and soft tissues in the feet, face, and head
    • Joint pain
    • Muscle weakness
    • Carpal tunnel syndrome or peripheral neuropathy
    • Tongue enlargement
    • Dental and speech problems
    • Deepening of voice
    • Sleep apnea
    • Changes in vision
Diagnosis
  • Methods:
    • Growth Hormone (GH) response tests
    • MRI or CT scans for detecting pituitary adenomas
  • Treatment Goals:
    • Return GH levels to normal
    • Surgical Options: Hypophysectomy (removal of the pituitary gland)
    • Other treatments include radiation therapy and drug therapy.
Drug Therapy
  • Octreotide (Sandostatin):
    • Reduces GH levels to normal; administered subcutaneously (SQ) three times a week or intramuscularly (IM) in long-acting form
  • Dopamine Agonists:
    • Bromocriptine and Cabergoline, work to reduce GH secretion from the tumor
  • GH Antagonists:
    • Pegvisomant (Somavert) blocks liver production of IGF-1, which reduces GH impact in the body.

Hypopituitarism

  • Definition: Rare condition involving a decrease in one or more pituitary hormones; commonly affects GH, LH, or FSH levels.
  • Causes:
    • Pituitary tumors
    • Autoimmune disorders
    • Infections
    • Destruction of the pituitary gland due to trauma, surgery, or radiation
Clinical Manifestations
  • Symptoms vary depending on which hormone is deficient and may include:
    • Symptoms indicative of a tumor such as headache or vision changes
    • Hormone deficiency symptoms based on specific hormones lacking (see table 54.1 for details).
Diagnosis
  • Methods:
    • MRI or CT for detecting tumors
    • Direct measurement of pituitary hormones or target organ hormones, including:
    • Thyroid-Stimulating Hormone (TSH)
    • T3 and T4 levels
Treatment
  • Approach:
    • Surgery or radiation therapy followed by lifelong hormone replacement therapy, including:
    • Somatropin for GH replacement
    • Corticosteroids for adrenal support
    • Levothyroxine for thyroid support

Comparison of Acromegaly and Hypopituitarism

  • Acromegaly:
    • Pathology: Excess growth hormone typically caused by a tumor
    • Signs and Symptoms:
    • Hypertension
    • Enlarged organs
    • Joint pain and arthritis
    • Potential for deepened voice, sleep apnea
  • Hypopituitarism:
    • Pathology: Decreased secretion of pituitary hormones
    • Signs and Symptoms:
    • Low energy
    • Decreased sex drive and infertility
    • Headaches and symptoms related to the deficient hormone

Pituitary Surgery

  • Hypophysectomy: Surgical removal of the pituitary gland, typically via a transsphenoidal approach.
  • Post-Operative Considerations:
    • Monitor for vision changes, potential CSF leaks, and neurological status
    • Keep the head of the bed (HOB) elevated to 30 degrees
    • Monitor fluid and electrolytes due to potential Diabetes Insipidus (DI) or Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH)
    • Patients will require lifelong hormone replacements:
    • ADH
    • Cortisol
    • Thyroid hormones

Posterior Pituitary Gland Problems

  • The posterior pituitary gland secretes ADH (vasopressin) and oxytocin.
  • ADH Functions:
    • Regulates water balance and serum osmolarity, mainly affecting sodium concentrations in the body.
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
  • Definition: Excessive levels of ADH leading to concentrated urine.
  • Causes:
    • Cancers such as Small Cell Lung Cancer
    • Head trauma
    • Certain drugs
    • Tumors affecting the posterior pituitary
Clinical Manifestations
  • Symptoms can include:
    • Increased thirst
    • Fatigue
    • Muscle cramps
    • Headaches
    • Severe hyponatremia (sodium < 120) can lead to confusion, seizures, or coma
Treatment of SIADH
  • Management:
    • Address the underlying cause of SIADH
    • For mild symptoms with Na > 125: Fluid restriction
    • For severe hyponatremia (Na < 120): Administer hypertonic saline intravenously.
    • Medications include:
    • Furosemide (Lasix)
    • Demeclocycline (blocks ADH at renal tubules)
    • Conivaptan (Vaprisol)
    • Tolvaptan (Samsca)

Diabetes Insipidus (DI)

  • Definition: Low production of ADH or the body’s inability to respond to it.
  • Types:
    • Central: Lack of production of ADH
    • Nephrogenic: Kidney response issues to ADH
    • Primary: Psychological causes leading to increased thirst and urination
Clinical Manifestations of DI
  • Symptoms include:
    • Polydipsia (excessive thirst)
    • Polyuria (excessive urination)
    • Low specific gravity in urine (< 1.005)
    • Low urine osmolality
    • Elevated serum osmolality
    • Potential for hypernatremia
    • Extreme fatigue and generalized weakness, with risks of hypovolemic shock
Treatment of DI
  • Management Strategies:
    • Maintain hydration, potentially through IV hypotonic saline or D5W
    • Medications such as Carbamazepine (Tegretol) to decrease thirst associated with central DI
    • DDAVP (Desmopressin) available in oral, IV, SQ, or nasal form
    • Low sodium diet to help manage symptoms (< 3 g/day)
    • Indomethacin, a NSAID that helps improve renal responsiveness to ADH

Thyroid Gland Problems

  • The thyroid gland secretes T3 and T4 hormones that regulate energy metabolism and growth development.
Hyperthyroidism
  • Causes:
    • Graves Disease
    • Toxic nodular goiter
    • Thyroiditis
    • Excess iodine intake
    • Pituitary tumors
Graves Disease
  • Definition: An autoimmune disorder in which antibodies stimulate the TSH receptors, increasing the release of T3 and T4.
  • Clinical Manifestations:
    • Goiter
    • Bruit over the thyroid
    • Exophthalmos (bulging eyes)
    • Weight loss
    • Nervousness and anxiety
    • Palpitations
Treatment of Hyperthyroidism
  • Includes:
    • Antithyroid drugs like Propylthiouracil and Methimazole
    • Iodine
    • Beta-adrenergic blockers such as Propranolol and Atenolol
    • Potential radioactive iodine therapy or thyroidectomy
Acute Thyrotoxicosis
  • Also known as thyroid storm, occurs with excess amounts of thyroid hormones released, often triggered by stress, surgery, or infection.
  • Signs and Symptoms:
    • Tachycardia
    • Shock
    • Hyperthermia
    • Agitation and seizures
    • Gastrointestinal effects like vomiting and diarrhea
    • Coma in severe cases
Postoperative Monitoring after Thyroidectomy
  • Watch for hypocalcemia, airway compromise, and overall patient monitoring post-surgery, ensuring the availability of emergency kits and suction devices nearby.

Hypothyroidism

  • Clinical Manifestations:
    • Symptoms include tiredness, lethargy, depression, weight gain, and cold intolerance.
  • Severe form: Myxedema coma, considered a medical emergency.
  • Causes: Infection, drugs, trauma that leads to decreased thyroid levels.
Hashimoto Thyroiditis
  • Description: Autoimmune destruction of the thyroid gland, leading to hypothyroidism.
  • Risk Factors: Family history, older age, being Caucasian, and female.
  • Objective results: Increased TSH, decreased T3 and T4 levels.
Diagnosis of Hypothyroidism
  • Confirmed by measuring TSH levels and Free T4; adjustments in diet and Levothyroxine as a treatment strategy.

Calcium Regulation Disorders

Hyperparathyroidism
  • The parathyroid hormone (PTH) regulates calcium and phosphate levels through actions in bones, kidneys, and intestine.
  • Clinical Manifestations: Can be asymptomatic and diagnosed through increased calcium and PTH levels.
Treatment for Hyperparathyroidism
  • Depending on severity, treatment may include surgical intervention, IV fluids, and monitoring of overall calcium levels.
Hypoparathyroidism
  • Definition: Lower levels of PTH lead to hypocalcemia. Symptoms relate to low calcium, causing conditions like tetany and increased muscle excitability.
  • Management: Calcium replacement through IV or nutrition, with monitoring for dysrhythmias.

Adrenal Cortex Problems

  • Composed of steroid hormones like glucocorticoids (Cortisol), mineralocorticoids (Aldosterone), and androgens.
Cushing Syndrome
  • Definition: Chronic exposure to excess cortisol leading to symptoms like weight gain and “moon face.”
  • Management: Drugs to suppress cortisol production or direct treatment of underlying conditions.
Addison’s Disease
  • Overview: Characterized by adrenocortical insufficiency, often autoimmune.
  • Clinical Manifestations: Symptoms include anorexia, nausea, weakness, weight loss, and skin hyperpigmentation.
  • Addisonian Crisis: Can occur with abrupt steroid withdrawal or extreme stress, requiring urgent intervention.
Nursing Considerations for Cushing vs. Addison’s
  • Utilize mnemonics and key symptoms to differentiate:
    • Cushing syndrome typically presents as increased weight and cortisol levels while Addison’s features weight loss and a bronzed appearance.