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ENDOCRINE SYSTEM
Endocrine system involves the release of hormones
Hormones aren’t only produced by endocrine glands but also specialized tissues e.g. GI mucosa
produces hormones like gastrin, secretin; kidneys produce erythropoietin. Neurotransmitters can
also act like hormones.
The rapid action of nervous system is balanced by slower hormonal action
Diagnostic tests
Stimulation tests – to confirm hypo function of an organ
Suppression tests – to detect hyper function of an organ
Glands of the endocrine system
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Pituitary gland
Thyroid gland
Parathyroid gland
Adrenal gland
Pancreatic islets
Ovaries
Testes
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PITUITARY GLANDS
Also known as hypophysis
Is a master gland because it affects secretion of hormones by other glands
Two lobes: anterior & posterior
Hypophysectomy
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Removal of pituitary gland through an endoscopic transnasal approach
Don’t brush teeth, blow nose or bend at the waist postop (can lead to IICP)
Monitor drainage (glucose or clear white means CSF)
Encourage deep breathing but no coughing
ANTERIOR PITUITARY
Hypothalamus releases releasing factors  pituitary portal blood system  hormones secreted
by anterior pituitary
Major hormones: FSH, LH, Prolactin, ACTH, TSH & GH
Main function of FSH, LH, ACTH & TSH is to release hormones from other glands
Oversecretion of anterior pituitary commonly involves ACTH or GH and results in Cushing
syndrome or acromegaly
Under secretion usually involves all hormones & is called panhypopituitarism
POSTERIOR PITUITARY
Hormones include vasopressin (ADH) and oxytocin
These hormones are produced in the hypothalamus & travel to the posterior pit for storage
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Diabetes insipidus
Caused by deficiency of ADH
Types:
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Primary neurogenic: defects in hypothalamus or pituitary gland
Secondary neurogenic: infections, tumors or trauma near hypothalamus or pituitary
gland
Nephrogenic: renal tubules don’t react to ADH (kidney damage, meds like lithium or
demeclocycline)
Symptoms: polydipsia (2-20 L/day), polyuria (urine output 4-30 L), tachycardia, hypotension,
dry membranes
Lab findings:
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DILUTE urine
CONCENTRATED blood
Diagnostic tests
Fluid deprivation test
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Withhold fluids for 8-12 hours till 3-5% body weight is lost.
SQ vasopressin  produces urine with increased specific gravity
If urine does become more concentrated  neurogenic
If urine doesn’t become concentrated  nephrogenic DI or psychogenic polydipsia
Plasma and urine studies should be done at the beginning & end of test
Inability to increase specific gravity & osmolarity are signs of DI
Stop if more than 2 kgs lost
Treatment
1. Ensure adequate fluid replacement
2. Replace ADH – Desmopressin, a synthetic ADH administered intranasally, orally or
parenterally w/o vascular effects & longer duration.
3. Diuretics like thiazide to facilitate vasopressin action (for neurogenic DI)
4. Correct the underlying pathology
5. May need laxatives
6. Avoid trauma to oral mucosa
Give vasopressin with caution  can cause vasoconstriction in people with CAD + monitor for
water intoxication
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SIADH
Excessive ADH
Causes
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Often endocrine, lung disease, CNS disease
Opioids, chemotherapy drugs, TCA, fluoroquinolone abx
Excess ADH  water intoxication + edema + dilutional hyponatremia
Symptoms
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Anorexia, headache, weakness
Cramps
Weight gain w/o edema bc water is retained not sodium
Hyponatremia symptoms: NV, slow DTR, lethargy
Cheyne-Stokes
Tachycardia
Lab tests:
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CONCENTRATED urine
DILUTE blood
Treatment
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Restrict fluid intake to 500-1000 ml/day (priority)
Provide ice chips, lozenges etc.
IV hypertonic NaCl
Maintain seizure precautions
1. Diuretics (Lasix) – caution as they can worsen hyponatremia
2. Demeclocycline (not for pt with kidney damage, avoid with supplements with
calcium, iron, magnesium & antacids with aluminum & milk products)
3. Vasopressin antagonist (Ptan) – acute settings, can cause hypernatremia
If patient has enteral or gastric tube – flush with NS instead of water
Treatment of SIADH can cause  central pontine myelinolysis (destruction of myelin sheath of
pons neurons)
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Caused by rapid rise of sodium due to tx
Monitor sodium levels 2-4 hrs
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Acromegaly
Excessive growth hormone which causes increase in size of body parts but not height
If untreated, can lead to hypertension, DM, heart problems
Symptoms:
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Severe headaches
Thick lips
Dicraesed libido
Hyperglycemia
Joint pain
Growth hormone suppression test
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NPO except water for 6-8 hours
Measure growth hormone at baseline
Administer glucose (supposed to supress GH but patients with acromehaly will show a
slight decrease or none at all)
Obtain GH levels at 10, 60 and 120 min after glucose
Meds:
1. Dopamine agonists (bro, caber)
o Notify immediately if nasal discharge, dizziness, chest pain
2. Somatostatin analogs (tide)
o Inhibit GH release
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THYROID GLAND
Produces: T3, T4 and calcitonin
Iodine is essential for synthesis of these hormones
Euthyroid – normal thyroid hormone production
Hypothalamus secretes TRH  pituitary releases TSH  thyroid releases T3 & T4 (decrease in
temp  increased TRH)
T4 – weak hormone that maintains body metabolism in a steady state
T3 – 5x potent as T4. Has a more rapid metabolic action
Calcitonin – reduces plasma level of calcium by increasing its deposition in bone
Dietary intake of protein & iodine is necessary for production of thyroid hormones
Thyroid tests
i.
Serum TSH
- Helps distinguish subclinical disease from euthyroid state
- Distinguish b/w disorders of thyroid gland from disorders of pituitary or
hypothalamus dz
ii.
Serum free T4
- Most T4 is bonded to protein, but some is free, to bond with protein
- This tests unbound T4 to detect problems
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HYPOTHYROIDISM
Types & causes
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Most common type is autoimmune: Hashimoto’s
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Primary (thyroidal) dysfunction of the thyroid gland itself
Secondary (pituitary) – entirely a pituitary disorder
Tertiary (Hypothalamus) – disorder of the hypothalamus
Central – failure of pituitary gland, hypothalamus or both that causes thyroid dysfunction
Neonatal
Meds that can cause hypothyroidism: amiodarone, interferon, interleukin, lithium
Previous hyperthyroidism can lead to hypothyroidism bc of treatments or thyroidectomy
Lab tests:
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Low T3 T4
Increased TSH with primary, decreased or normal with secondary
Increased cholesterol
Symptoms
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Hair loss, brittle nails, dry skin
Husky, hoarse voice due to myxedema affecting the larynx
Weight gain
Feeling cold
Irritable behavior
Slow behavior
Constipation
Sleep apnea
Advanced dz can cause personality + cognitive changes
Later on: atherosclerosis
Diagnostic tests:
 Thyroid scan: low uptake of radioactive iodine
 ECG
! Patient with unrecognized hypothyroidism undergoing surgery can get intraoperative
hypotension, postoperative heart failure
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Medications:
1. Thyroid replacement
Levothyroxine (Synthroid) – synthetic hormone replacement
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Increases effects of warfarin
May need extra insulin & digoxin
Low doses for ppl with heart dz
Fiber, calcium, iron, antacids interfere with absorption
Take on empty stomach
Myxedema – extreme symptoms of severe hypothyroidism
Myxedema coma is a decompensated stage
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Hypothermic & unconscious
May be precipitated by an infection or systemic dz, use of opioids or sedatives, forgetting
to take thyroid replacing hormone, extreme cold
Initially S&S include depression, diminished cognitive status, lethargy, hypoventilation,
hypothermia, bradycardia
Monitor ABGs to detect hypoxia, hypercapnia, respiratory acidosis
Findings: hyponatremia, hypoglycemia
Treatment
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IV administration T3 may be needed
IV levothyroxine bolus
High dose corticosteroids every 8-12 hours for 24 hours then low dose therapy
Serum levels of thyroid hormones should be checked before and after administration
Cardiac dysfunction & hypothyroidism
Any patient who has had hypothyroidism for a long period usually has associated elevated serum
cholesterol, atherosclerosis, and coronary artery disease.
As long as metabolism is subnormal and the tissues (including the myocardium) require
relatively little oxygen, a reduction in blood supply is tolerated without overt symptoms of
coronary artery disease.
Angina or dysrhythmias can occur when thyroid replacement is initiated because thyroid
hormones enhance the cardiovascular effects of catecholamines + the oxygen demand increases,
but oxygen delivery cannot be increased unless, or until, the atherosclerosis improves.
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Medication interactions
Oral thyroid hormones interact with magnesium containing antacids
They decrease the effects of digitalis glycosides
Anticoagulants need to be reduced because of increased risk of bleeding
Hypnotics and sedatives with thyroid drugs cause respiratory depression that can be fatal
Nursing interventions & rationales
1) Avoid external sources of heat – reduces risk of peripheral vasodilation & vascular
collapse
2) Administer hypnotics & sedatives with caution – susceptible to respiratory depression
3) Administer drugs like thyroxine with caution – slow metabolism & atherosclerosis of
myxedema may result in angina with thyroxine
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HYPERTHYROIDISM
Causes
a. Graves disease – most common. Autoimmune disorder that results from an excessive
output of thyroid hormones caused by abnormal stimulation of thyroid gland by
immunoglobulins
b. Toxic multinodular goiter
c. Toxic adenoma
d. Thyroiditis
e. Excessive ingestion of thyroid hormone
Symptoms
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Nervousness, hyperexcitability, irritability
Palpitations, Tachycardia
Warm, soft, moist skin
Weight loss, weakness
Sinus tachycardia, dysrhythmias
Menstrual irregularities
Increase then decrease in libido
Insomnia
Exophthalmos (in Grave’s only): due to edema in extraocular muscles which can cause
blurry or double vision
Pretibial myxedema (Grave’s only): dry waxy swelling of front of legs
Diagnostic findings
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Enlarged thyroid gland (pulsating, thrill)
Low TSH in Grave’s, high in secondary or tertiary
Increased T4
Increased iodine uptake
Bruit over thyroid gland
Lab tests:
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Ultrasound
ECG
Thyroid scan to see size & function of the gland by measuring iodine uptake (aministered
orally 24 hours prior) elevated uptake = hyperthyroidism
Must be NOT pregnant
History of iodine intake can affect results
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Treatment
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Tape to close lid, patches & lubricant to prevent dryness in exophthalmos
Report temperature increase of 1-degree F: indicates thyroid crisis
1. Antithyroid medications
Thionamides – Methimazole & Propylthiouracil
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Inhibit production of thyroid hormone
Used as an adjunct to radioactive iodine to decrease hormone levels before surgery & to
treat thyrotoxicosis
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Monitor for hypothyroidism
Monitor CBC for leukopenia or thrombocytopenia
Report fever, sore throat, jaundice, bruising
Methimazole is contraindicated in pregnancy
2. Beta blockers
Treat SNS effects
o Monitor for hypoglycemia in diabetics
3. Iodine solutions
Lugol’s solution – inhibits release of thyroid hormone
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Short term only
Take 1 hour after an antithyroid med
Not to be used during pregnancy
Mix with juice to mask taste & use straw to avoid staining teeth
Eat with food
Iodinism – iodine toxicity
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Swelling of buccal mucosa
Excessive salivation
Cold symptoms
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4. Radioactive iodine therapy
Radioactive iodine is taken up by the thyroid and destroys some cells
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One dose is sufficient, nay need 2nd or 3rd
Contraindicated in pregnancy bc it crosses the placenta
Pregnancy test before administration + don’t conceive for 6 months following treatment
People at risk for complications (old people, CV dz) need pre-treatment with antithyroid
meds like Methimazole 4-6 weeks prior iodine therapy.
These meds are stopped 3 days before and restarted 3 days after iodine and tapered over
4-6 weeks
 Stay 1 m away from pregnant women
 Don’t share toilets
 Take laxatives
Thyroidectomy
Removal of some or all of the thyroid gland
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Subtotal thyroidectomy: when medications or RI fails to treat hyperthyroidism,
cancer or diffuse goiter
Total: pt will need lifelong thyroid hormone replacement + high carb, high protein
diet prior to surgery
Client receives thionamides + iodine 4-6 weeks before surgery
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May need oral & tracheal suction
Have tracheostomy supplies available
Check for hypocalcemia
Ensure IV calcium gluconate are available
Complications like hemorrhage can occur (moderate drainage is expected, monitor vor vocal
changes)
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Thyroid storm
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Life threatening
Abrupt onset
Causes
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Due to radioactive iodine therapy that causes increased thyroid hormones initially
Can be precipitated by stress, injury, nonthyroidal surgery (tooth extraction), diabetic
ketoacidosis, pregnancy, abrupt withdrawal of meds
Symptoms
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Exaggerated symptoms of hyperthyroidism – GI (weight loss, diarrhea, pain) or CV
(edema, chest pain, dyspnea), neuro (delirium, coma)
High fever
Treatment
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Hypothermia blanket, ice packs
Hydrocortisone (treat shock or adrenal insufficiency), acetaminophen
Continuous cardiac monitoring
Beta blockers to block SNS effects
Not salicylates bc they displace thyroid hormone from binding
Humidified oxygen
IV fluids with dextrose to replace liver glycogen
Propylthiouracil (PTU) or methimazole to impede formation of thyroid hormone & block
conversion of T4 to T3
If atrial fibrillation, dysrhythmias and heart failure occur, patient may be placed on
Propranolol combined with digitalis
Cold fluids and ice are tolerated better initially
Talk less to reduce edema to the vocal cords
Note for voice changes  indicates injury to recurrent laryngeal nerve
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PARATHYROID GLANDS
Normally four
Produce parathormone – regulates calcium & phosphorous metabolism
Increased parathormone  increased calcium absorption from kidneys, intestines and bones 
increased blood calcium levels & lower phosphorous levels
Vitamin D  enhances effects of parathormone
Excess calcium phosphate can lead to tissue calcification
HYPERPARATHYROIDISM
1. Primary hyperparathyroidism
o 2 to 4 times more often in women
o 50% people don’t have symptoms
2. Secondary hyperparathyroidism
o Patients with chronic kidney failure as a result of phosphorus retention and
increased stimulation of parathyroid glands
Symptoms
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May have no symptoms
Apathy, fatigue
Weakness
NV, constipation
Hypertension
Cardiac dysrhythmias
Neuro (psychosis)
Nephrolithiasis
Kidney damage
Skeletal pain
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Diagnostic findings
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Primary hyperparathyroidism is diagnosed by persistent elevation of serum calcium
levels and parathormone
Radioimmunoassay differentiate primary parathyroidism from other causes of
hypercalcemia
Bone changes via x-rays
Double antibody parathyroid hormone test: distinguish b/w malignancy & primary
parathyroidism
Treatment
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Surgical removal of abnormal tissue is recommended
Asymptomatic patients who only have mildly elevated serum calcium must be monitored
closely but surgery is delayed
If, a patient is under 50, or unable to follow up or serum calcium levels > 1 mg above
normal range, GFR < 60 or bone density is < 2.5 or previous fracture or nephrolithiasis
may need surgery
High fluid intake is recommended to avoid renal calculi
Encourage mobility bc it helps bones retain calcium
Hypercalcemic crisis
Levels > 13 can cause acute hypercalcemia
Rapid rehydration with large volumes of IV isotonic saline fluid to maintain urine output of 100150 ml/hr is combined with calcitonin (promotes renal excretion of calcium & increases bone
resorption) – If patient develops edema, stop fluids and start loop diuretic
If emergency  calcitonin + corticosteroids
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HYPOPARATHYROIDISM
Causes
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Near total removal of thyroid removal (most common reason)
Abnormal parathyroid development
Destruction of parathyroid glands (surgical removal or autoimmune response)
Vitamin D deficiency
S&S
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Tetany due to hypocalcaemia
Latent tetany: Numbness, tingling, cramps, stiffness
Over tetany may cause bronchospasm, laryngeal spasm, carpopedal spasm (flexion of
elbows and wrists and extension of pharyngeal joints and dorsiflexion of feet), dysphagia,
photophobia, cardiac dysrhythmias, seizures
Diagnostic findings
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Positive Chvostek (sharp tapping over facial nerve) or Trousseau sign (carpopedal spasm)
– latent tetany
Aches a pain (vague symptoms)
Increased phosphate levels
Decreased calcium levels
Increased bone density (calcification)
Treatment
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Goal is to increase calcium levels to 9-10 mg
Calcitriol + calcium + magnesium + vitamin D2 / D3
When hypocalcemia + tetany occurs after thyroidectomy, immediate treatment is IV calcium
gluconate – if it doesn’t help, sedatives may be given
Reduced stimuli in environment
Diet high in calcium and low in phosphorous
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Milk products, eggs are high in calcium but also high in phosphorus so eat restrictively
Avoid spinach
Aluminum hydroxide gel or aluminum carbonate promotes phosphorous excretion