Endocrine System Overview

Overview of the Endocrine System

• The endocrine system consists of endocrine glands.
• These glands include the hypothalamus, pituitary gland, adrenal glands, thyroid gland, parathyroid glands, gonads, and islet cells of the pancreas.

Endocrine Hormones

• Endocrine hormones are secreted directly into the blood system.
• Functions are directly associated with the secretion and levels of hormones in the blood.
• Endocrine dysfunctions can be primary, secondary, tertiary, or quaternary.
• A primary dysfunction occurs at the endocrine gland.
• Secondary dysfunction involves the anterior pituitary gland.
• Tertiary dysfunction relates to the hypothalamus.
• Quaternary dysfunction is the inability of target tissues to respond to hormones.

Function of the Endocrine system

• The endocrine system coordinates mental functioning.
• Blood Glucose is maintained and controlled with this system
• It regulates metabolism, growth, and development.
• Underproduction or overproduction of select hormones leads to endocrine dysfunction.

Endocrine Anatomy and Physiology

• The endocrine system's function is linked to the nervous system.
• The system is also linked to Neuroendocrine Regulation
• Hormonal secretions are regulated by a negative feedback loop.

Hypothalamus

• The hypothalamus is located beneath the thalamus.
• Hormones secreted by the hypothalamus directly affect the other endocrine glands.

Pituitary Gland - Anterior

• The anterior pituitary is regulated by the hypothalamus.
• The hypothalamus secretes hormones that target the pituitary gland tissue.
• The anterior pituitary secretes two gonadotropin hormones: Follicle-stimulating hormone (FSH), and Luteinizing hormone (LH).
• Other secreted hormones include Thyroid-stimulating hormone (TSH) and Adrenocorticotropic Hormone (ACTH).
• Prolactin, Growth Hormone (GH) and Melanocyte.stimulating are also secreted.

Pituitary Gland - Posterior

• The posterior pituitary is composed of nerve fibers.
• This gland is responsible for neuroendocrine reflexes.
• These reflexes result in hormone secretion when signals are received from the nervous system.
• The posterior pituitary secretes antidiuretic hormone (ADH) and oxytocin..

Adrenal Glands

• The adrenal cortex makes up 90% of the adrenal gland, secreting mineralocorticoids like aldosterone.
• Glucocorticoids like cortisol and androgens (male sex hormones) are secreted from the adrenal cortex.
• The adrenal medulla is controlled by the sympathetic nervous system (SNS).
• The adrenal medulla secretes epinephrine and norepinephrine, although these are also made by SNS.
• The adrenal medulla is non-essential.

Thyroid Gland

• The thyroid is in the anterior neck underneath the cricoid cartilage.
• The gland makes triiodothyronine (T3) and thyroxine (T4).
• Thyrocalcitonin (calcitonin) is also produced.
• T3 and T4 regulate the heart's rate and contractility, and respiration rate and depth.
• The thyroid also controls oxygen use and the uptake of glucose, glycolysis, and gluconeogenesis in cells.
• Protein synthesis and catabolism is also controlled as is the metabolization of fatty acids.
• Oxidation of free fatty lipids as well as cholesterol and phospholipids are regulated.

Parathyroid Gland

• The parathyroid can be partially embedded in to the thyroid gland.
• PTH, or parathyroid hormone, is secreted which increases serum calcium by stimulating bone reabsorption.
• PTH stimulates activation of Vit. D and reabsorption of renal calcium.
• Serum phosphate is diminished by PTH.
• PTH causes reabsorption of phosphate in the kidneys, bone resorption, and small intestine absorption of phosphate.

Gonads

• The gonads' sexual development and function is based on the hormones they secrete.
• Testes are male gonads.
• Ovaries are female gonads.
• Both sex organs are controlled by tropic hormones released from the anterior pgland.
• Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) stimulate the maturation of sex organs.
• In males, FSH & LH = Testosterone.
• In females, FSH & LH = Estrogen and Progesterone.

Pancreas

• The pancreas is located in the upper left quadrant of the abdomen.
• It possesses both endocrine and exocrine functions and has islet cells which aid in blood glucose control.
• Insulin and glucagon are used to regulate blood glucose.

Assessment

• An endocrine assessment includes a detailed history and palpation of the thyroid and/or testes.
• A family history of genetic illnesses should be taken.
• A physical assessment includes inspection (a head to toe exam), specific manifestation checks, and auscultation.

Disorders of the Pituitary Glands

• Anterior pituitary disorders include Hypopituitarism and Hyperpituitarism.
• Posterior pituitary disorders include Diabetes Insipidus (DI) Syndrome of inappropriate antidiuretic hormone (SIADH)

Hypopituitarism

• Hypopituitarism is caused by the hyposecretion of hormones.
• This is a rare disorder, affecting less than 200,000 individuals in the U.S.
• Possible causes are damage, compression, or inflammation of the pituitary.
• It can also be caused by a pituitary tumor or damage to the hypothalamus.
• Pathophysiology of results from a deficiency of anterior pituitary hormones, which leads to changes.
• Decreased Adrenocorticotropic Hormone (ACTH) can decrease the release of cortisol, & aldosterone from the adrenal cortex.
• Deficiency in Thyroid stimulating hormone (TSH) decreases thyroid hormone.
• Deficiency in Luteinizing Hormone (LH) & Growth Hormone (GH) can cause changes in sexual and reproductive functioning.
• Common manifestations include weakness, fatigue, decreased appetite, weight loss, sensitivity to cold, and facial swelling.
• Diagnosis depends on suspected missing hormones and hormonal studies.
• Acth stimulation test or TSH, FSH, LH, prolactin and GH tests can be undertaken
• CAT scans and MRI's can be performed
• Diagnosis can rule out tumors in the brain/pituitary gland, as well as weakness disorders
• Medications are used/managed to restore hormone levels to normal.
• Hormone replacement, such as Corticosteroids, Thyroid hormone, Testosterone and estrogen is common
• Supportive therapies include Electrolyte replacement, Vitamin D and Calcium.
• Complications include Panhypopituitarism, Lack of ACTH and Lack of TSH.
• Panhypopituitarism can cause hyposecretion of all hormones and hypothalamus issues
• Lack of ACTH results in inability to maintain fluid volume or circulatory collapse
• A lack of TSH results in decreased metabolism
• Women with estrogen replacement therapy have higher risk for HTN
• Assessment and analysis depend on the hormone(s) that are deficient.
• Risks, deficits, and imbalances include fluid volume, impaired mobility, hypoglycemia, hyperkalemia and risk for injury
• Nursing interventions involve safety implementation and increasing vitamin D and calcium intake
• Care should be given alongside dieticians and physical therapists
• The management of acute syndromes include monitoring for electrolyte imbalance and clinical manifestations

Hyperpituitarism

• Hyperpituitarism usually stems from a hypersecreting tumor.
• Female patients have higher incidences.
• It can affect children or adults and has a genetic basis
• Pathophysiology is secondary to the hormone hypersecretion.
• Diagnosis focuses on the hormone or target cells affected by the increased hormone.
• An ACTH stimulation test and measurements of TSH, FSH, LH, Prolactin and GH may be ordered.
• Other tests and scans include CAT scans, MRIs, and serum studies
• Additionally, hands, feet and facial bones are measured
• Medications used to treat or reduce hormone secretion
• Dopamine Agonists (Bromocriptine mesylate) inhibit production
• If a tumor must be removed, medication can be used to shrunk it prior
• Surgical management includes stereotactic radiosurgery and transsphenoidal hypophysectomy
• Trassphenoidal hypophysectomy includes sub-label transeptal approach and endoscopic approach.
• Complications for the increased ACTH are hyperglycemia, hypertension, and acromegaly.
• An increased TSH can result in Severe hypothyroidism and Thyroid storm.
• An increased GH can result in Organ overgrowth and hypertrophy.
• Hypertrophy can occur in the heart, thyroid, liver, and kidneys
• Nerve entrapment, pain, and sensory fluctuations can occur
• Surgical related complications should be taken into consideration
• Nursing management requires patient assessment depending on the specific hormone involved
• Assessment should include vital signs, neurological evaluation, vision, intake and output, daily weight, and serum electrolytes
• Elevated ICP will be a consideration
• Nursing diagnoses include: Fluid volume excess, Body image disturbance, pain, acromegaly, hyperglycemia, and hypertension
• Dopamine agonists should be given, in addition to somatostatin
• Hormone supplements and teaching about adherence to medications is necessary

Post Transsphenoidal Hypophysectomy

• Post operative assessment should include monitoring vital signs, neurological status, and intake and output.
• Assessment includes checking mucous membranes, urine specific gravity, and serum sodium.
• The nurse should keep the patient administered humidified oxygen.
• IV access should be maintained
• Desmopressin and Vasopressin should be administered
• The head of the bed should be maintained at 45-60 degrees.
• Provide adequate oral fluids and mouth care.
• The nursing staff should monitor singing of meningitis, signs, Diabetes Insipidus, and drainage from nose
• The nursing staff should also use toothbrushes when cleaning patient’s mouth

Diabetes Insipidus

• Approximately 30% of DI cases are Idiopathic, 25% secondary to brain tumors.
• About 20% occurs after intercranial surgery and 20% after head trauma.
• Pathophysiology comes from a minimal ADH
• ADH created and stored in posterior pituitary glands, and working within the kidneys
• Causes water reabsorption for circulation and kidneys becomes permeable
• Clinical manifestations include weight loss, polyuria, hypovolemia, and hemoconcentration.
• Hemoconcentration commonly causes thirst, fatigue, and tenting skin turgor
• For diagnosis, urine osmolality is calculated
• Normal is typically less than 200 mOsm/kg and a Urine specific gravity with less than 1.005.
• Fluids should given orally and/or intravenously if the px is unconscious
• Medications include Desmopressin, a synthetic analog of ADH and Vasopressin which is shorter acting Nursing managements includes:
• Monitor serum electrolytes and vital signs
• Assessment should include electrolyte values - increased serum sodium and hematocrit.
• Serum Osmolality will be altered
• Lab values and blood pressure is altered, including HR Nursing Implementation includes Daily weighing, Intake and output, Neurological tests, skin integrity checks
• Nursing also includes monitoring serum sodium and osmolality and Urine specific gravity

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

• SIADH stems from increased ADH. _ This can stemmed from CNS issues
• SIADH can stem from medication(side effects such as NSAIDs. medication, or tumors
• Pathophysiology comes from ADH causing body to be overloaded with water and hemodilution.
• In clinical practice this may show as sodium dropping
• Early findings include anorexia, malaise, headache, confusion and fatigue.
• Severe cases are often associated with seizures of sodium drops below 120.
• Brain edema and neurological changes are most common
• Treatment to include fluid restrictions, diuretics, antibiotic treatment
• Fluid restriction must less than what is out ( urine,emesis, stool).
• Antibiotics increases urine production
• Diuretics - promotes dieresis and helps with serum osmolarity
• Nursing assessment includes neurological function, weight , serum and skin assessments
• Patients has excess fluids and at risk with neurological injuries
• Patients also have Knowledge deficit so education is important

Hypothyroidism

• TSH and controlled by Anterior pituitary gland and hypothalamus.
• Commonly related with autoimmune disorders.
• Hallmark sign decreases signs of metabolism.
• Causes either decrease disorders in anterior pituitary
• Most common Manifestations= lack of energy and sleep , fatigue , weight and appetite increase.
• Diagnosis includes - laboratory testing for T3&T4 and , TSh.
• Treatment includes thyroid hormonal replacement.
• Complications =Myxedema coma, Hypothermia and hypoglycemia
• Management and care should provide additional blankets if px feels cold

Hyperthyroidism

• Most Common in female ranging about 20-40 years old.
• 10x more likely to be founded from females then males
• Grave's Diseases(autoimmune disorder) , most common to find and cause.
• Primary - overactive thyroid causes excessive T3 and T4 production
• Diagnosis treatment goals, Monitor fluid&electrolyte, Promotes both rest& stress
• Beta blockers are included to slow heart rates and palpitation.´
• If surgery is preformed - maintain airways and use positioning
• thyroid Storm - Airway Management and fluids resuscitation (medical treatment)
• High fever and blood pressure, tachycardia ,monitor breathing , and be safe to prevent all injuries.