Endocrine Disorders

• The endocrine system plays a vital role in growth and development, metabolism of energy, muscle and adipose tissue distribution, sexual development, fluid and electrolyte balance, and inflammation and immune responses
• The endocrine system is linked with the nervous and immune systems
• Neurotransmitters


  Chemicals released by the nervous system that can also function as hormones as needed
• Cytokines


  Hormonelike proteins produced by white blood cells in response to foreign agents that are also subject to regulation by adrenal corticosteroid hormones
• Hormones


  Chemical substances that regulate and integrate body functions, generally produced by endocrine glands
• Glands of the Endocrine System

  • Pituitary Gland
  • Thyroid Gland
  • Parathyroid Glands
  • Adrenal Glands
  • Pancreatic Islets
  • Ovaries and Testes
• Pituitary Gland (Hypophysis)


  • The master gland - influences secretion of hormones by other endocrine glands
  • Located at the inferior aspect of the brain
  • Has two parts: Anterior pituitary gland (adenohypophysis) and Posterior pituitary gland (neurohypophysis)
  • Controlled by the hypothalamus
• Anterior Pituitary Gland hormones and their function

  • Growth Hormone (GH)
  • Adrenocorticotropic Hormone (ACTH)
  • Thyroid-stimulating Hormone (TSH)
  • Gonadotropic Hormones (Follicle-stimulating Hormone (FSH), Luteinizing Hormone (LH))
  • Prolactin
  • Melanocyte-stimulating Hormone (MSH)
• Posterior Pituitary Gland hormones and their function

  • Antidiuretic Hormone (vasopressin)
  • Oxytocin
• Thyroid Gland


  • Located in the lower neck, anterior to the trachea
  • Has two lateral lobes connected by an isthmus
  • Has high metabolic activity with high blood flow
  • Produces three hormones: Thyroxine (T4), Triiodothyronine (T3), and Calcitonin
• Thyroid Hormone (T4 and T3)

  • Amino acids that contain iodine molecules bound to the amino acid (tyrosine) structure
  • Iodine (ingested as iodide) is essential for its synthesis
  • Bound to: thyroid-binding globulin (TBG), prealbumin and albumin
  • Thyroglobulin is the precursor of T3 and T4
  • Thyroid stimulating hormone (TSH or thyrotropin) from the anterior pituitary gland controls secretion of thyroid glands
  • Thyrotropin-releasing hormone (TRH) secreted by hypothalamus stimulates release of TSH from pituitary
  • Euthyroid: thyroid hormone production within normal limits
  • Primary function: control cellular metabolic activity, influence cell replication, brain development, and normal growth
• Calcitonin (Thyrocalcitonin)


  Secreted in response to high plasma levels of calcium, reduces calcium levels by increasing bone deposition
• Thyroid Gland Disorders


  • Goiter (Toxic goiter, Nontoxic goiter, Simple/colloid goiter, Nodular goiter)
  • Hypothyroidism (Myxedema, Myxedema coma, Cretinism)
  • Hyperthyroidism (Thyroid storm/Thyrotoxic crisis)
• Hypothyroidism


  • Deficiency of the thyroid hormones, can affect all body functions
  • Causes: Autoimmune thyroiditis (Hashimoto's disease), Radioiodine (I131) or antithyroid drug therapy, Thyroidectomy, Central hypothyroidism (failure of hypothalamus or pituitary gland)
  • Clinical manifestations: Decreased metabolic rate, Decreased body heat production, Hypercalcemia (due to hyposecretion of thyrocalcitonin) leading to decreased neuromuscular irritability
• Myxedema


  • Weight gain, subnormal temperature & heart rate, cold intolerance
  • Thickened skin, hair thins and falls out, dulled mental processes, apathy
  • Slow speech, husky hoarse voice, enlarged tongue, hands and feet; deafness may occur
  • Constipation, personality and cognitive changes
• Myxedema Coma


  • Rare, life-threatening condition
  • Characterized by hypothermia, depressed respiratory drive, and unconsciousness
  • Precipitated by infection/systemic disease, use of sedatives/opioid analgesics, cold
  • Complications: pleural effusion, pericardial effusion, respiratory muscle weakness, increased serum cholesterol level, coronary artery disease, poor left ventricular function
• Hyperthyroidism


  • Hypersecretion of thyroid hormones
  • Severe form: Thyroid storm/Thyrotoxic crisis
  • Causes: Graves' Disease, Toxic nodular goiter, Thyroiditis after irradiation, Presence of tumor, Excessive ingestion of thyroid hormone, Emotional shock, stress, or infection
  • Clinical manifestations: Increased metabolic rate, Increased body heat production, Hypocalcemia (due to hypersecretion of thyrocalcitonin) leading to increased neuromuscular irritability
• Thyroid Storm/Thyrotoxic Crisis


  • Abrupt onset, fatal if left untreated
  • Characterized by hyperpyrexia, extreme tachycardia, exaggerated signs/symptoms of hyperthyroidism with disturbances of a major system, and altered mental state
  • Precipitated by stress, injury, infection, surgery, tooth extraction, DKA, pregnancy, abrupt withdrawal of antithyroid meds
  • Complications: dysrhythmias, heart failure, osteoporosis, and fractures
• Eye manifestations are associated with hyperthyroidism
• Smoking has been shown to aggravate ocular changes
• Others


  • ↑ appetite
  • progressive weight loss
  • abnormal muscular fatigability & weakness
  • amenorrhea
  • changes in bowel function
• Enlarged thyroid gland


  • A thrill can be palpated and a bruit heard over the thyroid arteries
• Advanced cases


  • ↓ serum TSH
  • increased free T4
  • increased radioactive iodine uptake
• THYROID STORM/THYROTOXIC CRISIS


  Usually of abrupt onset, fatal if left untreated
• Symptoms of thyroid storm/thyrotoxic crisis

  • Hyperpyrexia (above 38.5°C)
  • extreme tachycardia (>130 bpm)
  • exaggerated s/s of hyperthyroidism with disturbances of a major system (e.g. GI – wt loss, diarrhea, abdl pain, CV – edema, chest pain, dyspnea, palpitations)
  • altered mental state – appears as delirium psychosis, somnolence, or coma
• Thyroid storm/thyrotoxic crisis is precipitated by stress – injury, infection, surgery, tooth extraction, DKA, pregnancy abrupt withdrawal of antithyroid meds
• Complications of hyperthyroidism


  • dysrhythmias (atrial fibrillation)
  • heart failure
  • osteoporosis
  • fractures
• "Everything is high, fast and wet."
• Eye manifestations


  • exopththalmos
  • lid lag
  • bright-eyed stare
• Medical Management Goal


  To reduce thyroid hyperactivity
• Medical Management Goals


  • Improve nutritional status
  • Improve coping ability
  • Improve self-esteem
  • Maintenance of normal body temperature
  • Absence of complications
• Radioactive Iodine Therapy


  1. Use of irradiation with the radioisotope iodine 131 (to destroy the overactive thyroid cells)

  2. Radioiodine is tasteless, colorless; given as a single dose (some pts need more)

  3. Monitor for hypothyroidism – incidence is high after treatment; small doses of thyroid hormone replacement may be needed

  4. Contraindicated during pregnancy & BF–crosses the placenta & secreted in breastmilk; pregnancy should be postponed for at least 6 mos. after treatment

  5. Place pt on isolation for a few days – body secretions are radioactive –contaminated. Use gloves when handling body secretions
• Antithyroid medications


  Block the utilization of iodine by interfering with the iodination of tyrosine and coupling of iodotyrosines in the synthesis of thyroid hormones
• Antithyroid agents


  • Propylthiouracil (PTU) – treatment of choice during pregnancy; C/I in late pregnancy to avoid goiter and cretinism in the fetus
  • Methimazole (Tapazole) – more toxic than PTU
• Toxic complications of antithyroid medications: fever, rash, urticaria, agranulocytosis, thrombocytopenia, pharyngitis, mouth ulcers
• Instruct not to use decongestants for nasal stuffiness (poorly tolerated)
• Iodine or Iodide compounds

  • Potassium iodide (KI)
  • Lugol's solution
  • Saturated solution of potassium iodide (SSKI)
• Iodine or Iodide compounds

  • Suppress release of thyroid hormone/ reduce activity of thyroid hormone and the vascularity of the thyroid gland
  • Usually given with antithyroid meds to prepare the patient for surgery
  • Give with milk or fruit juice, using straw to prevent permanent staining of the teeth
  • Avoid cough medications, expectorants, bronchodilators, and salt substitutes – may contain iodide
  • Monitor for iodine toxicity (iodism): swelling of the buccal mucosa, excessive salivation, coryza, skin eruptions
• Other medications


  • Beta-adrenergic blocking agents (propranolol)
  • Glucocorticoids (dexamethasone)
• Beta-adrenergic blocking agents


  Given to control SNS effects of hyperthyroidism