lifespan week 3 content

parathyroid glands produce?

parathyroid hormone

• regulates calcium and phosphate levels

which hormones secrete serum calcium? (8.6 mg/dL-10.2 mg/dL)

• calcitonin (thyroid)

• PTH (parathyroid)

calcium sources

dietary: milk, yogurt, cheese, leafy greens

active form of vitamin d needed for absorption

readily available through bone resorption

calcium losses

• excreted in the urine and GI tract

• excess deposited into the bone

what is bone resorption?

process by which osteoclasts break down bone releasing calcium into the blood

skeletal functions of calcium

binds with phosphorus to build and maintain bones and teeth

nervous system functions of calcium

required for the transmission of nerve impulses

muscular functions of calcium

required for skeletal muscle contraction

cardiac functions of calcium

required for myocardial contraction, vascular contraction, and blood clotting

hypocalcemia clinical presentation

increased neuromuscular excitability

neuro: numbness and tingling of extremities and mouth, tetany, hyperactive deep tendon reflexes, muscle cramps, CHVOSTEK AND TROSSEAU’S SIGN, laryngeal spasms, seizures

cardiac: dysrhythmias

skeletal: osteoporosis with prolonged hypocalcemia

severe hypocalcemia clinical manifestations

• severe hypotension

• ecg changes, prolonged ST interval

• prolonged QT interval

hypercalcemia clinical presentation

neuro: fatigue, muscle weakness, depressed deep tendon reflexes, confusion, memory loss, psychosis

GI: anorexia, n/v, abdominal pain

genital-urinal: polyuria, nephrolithiasis

cardiac: dysrhythmias

skeletal: bone pain and fractures (depleting bone of calcium)

total serum calcium

8.6 - 10.2 mg/dL

• combination of protein bound, complexed, and ionized

ionized serum calcium

4.6 - 5.2 mg/dL

• free calcium - the form that participates in physiologic processes

(approximately 50% calcium is bound to proteins (albumin) and other substances and is unavailable for use)

phosphorus and calcium relationship

inverse/reciprocal

• PTH release increases serum calcium and decreases reabsorption of phosphorus

• when one goes up, the other goes down

hypoparathyroidism

an underproduction of parathyroid hormone

• decreased PTH

• decreased calcium

• increased phosphorus

hyperparathyroidism

an overproduction of parathyroid hormone

• increased PTH

• increased calcium

• decreased phosphorus

primary hyperparathyroidism

condition involving the increased secretion of parathyroid hormone

• rare, most common in women in their 40s-50s

• most commonly caused by parathyroid ADENOMA

clinical manifestations of primary hyperparathyroidism?

too much calcium (s/s of hypercalcemia)

“bones, stones, abdominal groans, and psychic moans”

surgical interventions for primary hyperparathyroidism

surgical excision of the abnormal parathyroid glands

nonsurgical interventions for primary hyperparathyroidism

• lower calcium in diet, maintain adequate hydration

• high impact weight bearing exercise

• monitor calcium levels every 6 months

• medication management to treat high serum calcium

medical treatment for significantly high serum calcium

• iv fluids to promote diuresis and excretion of calcium

• loop diuretics (ex: furosemide) monitor potassium!*

• IV biphosphonates (ex: pamidronate aredia)

• calcitonin-salmon (miacalcin, synthetic form of calcitonin) nasal spray

hypoparathyroidism prevalence

primary hypoparathyroidism is very rare

most common after neck surgery

• marked by serum hypocalcemia

• most commonly seen after thyroid, parathyroid, radial neck surgery, or radiation of neck

medical treatment for significantly low serum calcium

• acute hypocalcemia

• patient on cardiac monitor

• administer IV calcium

• rebreathing (paper bag, rebreath CO2, increase acidosis, frees up serum calcium, partially corrects it)

goals of treatment for significantly low serum calcium? (hypoparathyroidism)

• treat complications (tetany)

• maintain normal serum calcium levels

• prevent long-term complications (ex: osteoporosis)

how do changes in plasma PH impact ionized calcium levels?

acidosis = frees up more ionized calcium

alkalosis = less ionized calcium

ex: rebreathing causes an increase in CO2 which results in respiratory acidosis. a decreased plasma pH level increases ionized calcium (usable form of calcium)

medical treatment for significantly low serum calcium

• chronic/long term hypocalcemia

• oral calcium supplementation

• magnesium supplements

• vitamin d supplements (necessary for calcium to be absorbed!)

• high calcium, low phosphorus meal plan

• regular monitoring of calcium levels

PTH therapy

available, not widely recommended

• expensive

• has to be administered parenterally

food sources high in calcium

• cheese

• margarine

• butter

• fortified milk

• healthy cereals

• fatty fish

myxedema coma

medical emergency

• exceptionally low levels of thyroid hormone (extreme hypothyroidism)

• subnormal temp

• hypotension

• hypoventilation

• lethargy

• decreased LOC

• coma

tx: supportive therapy, IV thyroid hormone replacement

thyroid storm

medical emergency

• exceptionally high levels of thyroid hormone (severe hyperthyroidism)

• severe symptoms

• tachycardia

• heart failure

• shock

• hyperthermia

• agitation, seizures

• delirium

• abd pain, v/d

• coma

tx: supportive therapy, antithyroid drugs

hypothyroidism

a condition in which the thyroid gland produces an inadequate amount of T3 and T4

• common medical condition

etiology

• primary: thyroid (causes problem)

• secondary: pituitary (not secreting enough hormone)

• tertiary: hypothalamus (not releasing TRH to release TSH to release T3 and T4 calcitonin)

primary hypothyroidism

thyroid gland origin

• 85% of hypothyroid cases

• HASHIMOTO’S THYROIDITIS (AUTOIMMUNE DISEASE)

• radioiodine therapy for hyperthyroidism

• surgical removal of thyroid

• iodine deficiency (rare in US, thyroid needs iodine to make T3 and T4)

hashimoto’s thyroiditis

thyroid cells are attacked by patients own immune system

secondary hypothyroidism

pituitary gland origin

• pituitary gland does not make enough TSH

• caused by damage to the pituitary gland due to tumor or surgery

tertiary hypothyroidism

hypothalamus origin

• hypothalamus fails to produce sufficient TRH

recommended dietary intake of iodine

150 mg

¼ teaspoon of ionized salt = 75 mcg

thyroid needs iodine to make T4 and T3!

hypothyroidism clinical manifestations

• cold intolerance

• constipation

• weight gain (low metabolism)

• fatigue

• bradycardia

• dry skin, brittle nails

• hair thinning

• poor concentration

• goiter (late)

hypothyroidism nursing diagnoses

fatigue r/t decreased metabolic rate

risk for overweight r/t decreased metabolic rate

constipation r/t decreased gastric motility

ineffective thermoregulation r/t decreased metabolic rate

impaired skin integrity r/t dry skin

disturbed body image r/t changes in appearance secondary to goiter and weight gain

readiness for enhanced health management

hypothyroidism lab findings

TSH levels high

• determines if thyroid hormone feedback system is working

• pituitary is very sensitive to changes in T3 and T4 levels (senses low T3 and T4, starts pumping out TSH)

• HIGH because its trying to jump start thyroid

T4 levels low

• portion of total T4 thyroid that is available to the tissues

hypothyroidism collaborative care

• thyroid hormone replacement (levothyroxine!)

• monitor thyroid hormone levels and adjust dosage (TSH needs to be monitored regularly)

• nutritional therapy (to promote weight loss)

• patient and caregiver teaching (managing meds, managing symptoms like cold intolerance, dry skin and hair, and constipation)

levothyroxine (synthroid)

thyroid hormone replacement (drug of choice)

• absorption is reduced by food, admin in the morning on an empty stomach 30-60 min before breakfast

• assess HR, cardiac history, thyroid labs (TSH and T4)

• works within first few weeks, 4-8 weeks to notice full effect/improvement in thyroid function

• can be administered IV, but only for myxedema coma

• lifelong medication

final dose determined at 6-8 weeks based on T4 and TSH levels

levothyroxine mechanism of action

synthetic version of thyroxine (T4)

• replaces body’s missing T4 thyroid hormone

• body converts some of the T4 to T3 (more active thyroid hormone)

• T3 increases metabolism, energy use, heat production, and supports normal heart function and growth

levothyroxine side effects

rarely causes adverse effects

acute overdose → thyrotoxicosis

• tachycardia

• angina

• tremor

• nervousness

• insomnia

• hyperthermia

• heat intolerance

• sweating

chronic overdose

• accelerated bone loss

• increased risk a-fib

levothyroxine contraindications

• untreated adrenal insufficiency - can trigger adrenal crisis

• untreated thyrotoxicosis

• not for treating obesity

• acute myocardial infarction

a patient has been taking levothyroxine (synthroid) for about a year and a half. she mentions to you that she has recently noticed some heart palpitations. should you be concerned about this?

yes, TSH levels may be too high. may need dose adjustment…

hyperthyroidism etiology

low prevalence 1.2%

thyrotoxicosis: hypermetabolic condition associated with elevated levels of T3 and T4 in the blood.

graves disease (autoimmune disease)

toxic adenoma (results in toxic nodular goiter)

hyperthyroidism clinical manifestations

• tachycardia

• warm moist skin

• heat intolerance

• tremors

• hyperactivity, nervousness, insomnia

• weight loss despite increased appetite

• diarrhea

• protruding eyes (exophthalmos) (photophobia, excess lacrimation, blurred vision)

• enlarged thyroid (goiter)

think, excessive energy use, excessive heart use, excessive growth and development…

what is thyroid storm?

life threatening condition that develops in cases of untreated thyrotoxicosis

hyperthyroidism nursing diagnoses

imbalanced nutrition, less than body requirements r/t increased metabolic rate

anxiety r/t increased metabolic rate

insomnia r/t increased metabolic rate

ineffective thermoregulation r/t increased metabolic rate

diarrhea r/t increased gastric mobility

risk for injury r/t protruding eyeballs secondary to exophthalmos

disturbed body image r/t changes in appearance secondary to exophthalmos

radioactive iodine uptake and scan

way of diagnosing hyperthyroidism

24 hour RAIU test

• 24 hr after taking an oral iodine 123 tracer, the thyroid uptake of iodine is very high in patients with Grave’s disease and toxic adenoma’s

• (thyroid works hard to convert iodine into T3 and T4)

hyperthyroidism collaborative care

meds

• antithyroid medications: methimazole and propylthiouracil (PTU)

• radioactive iodine therapy

• surgery

symptoms

• nonpharm interventions

• pharm: beta blockers, typically propanolol (controls HR)

nutrition

• high calorie high protein diet (4000-5000 calories per day)

• frequent meals

• pt has high metabolism, lots of energy!

methimazole

used to treat hyperthyroidism, suppress synthesis of thyroid hormone

• first line drug

• safer, more convenient

• 3-12 weeks to produce euthyroid state

• can be given to pt experiencing thyrotoxic crisis

• graves disease!

• adjunct radiation therapy

• tx continues 1-2 years

• monitor free T4 and T3 every 4 weeks

methimazole contraindications

• pregnant women

• breastfeeding women

methimazole mechanism of action

1. prevents oxidation of iodine, inhibit corporation of iodine into tyrosine

2. prevents iodinated tyrosines from coupling

both effects result from inhibiting peroxidase

methimazole risks

agranulocytosis

• reduction in circulating granulocytes (wbc needed to fight infection)

• sore throat, fever, mouth sores

• often develops rapidly

• can cause liver failure but risk much higher in PTU!

*monitor thyroid labs, watch for infection

propylthiouracil (PTU)

gradually inhibit thyroid hormone synthesis

• blocks enzyme thyroid peroxidase inside thyroid gland

• 4-12 weeks to see results

• monitor free T4 and T3 every 4 weeks

• RISK OF LIVER FAILURE

• agranulocytosis risk (infection, sore throat, fevers!)

• preferred for pregnancy 1st trimester (no risks)

• preferred for THYROID STORM

radioactive iodine (131) therapy (RAI)

• low cost

• spared risks and discomfort of thyroid surgery

• death from this is rare

• no tissue other than thyroid is injured

• oral

• effects delayed (several months to become maximized)

• treatment associated with incidence of delayed hypothyroidism

• contraindicated pregnancy and lactation

nursing considerations radioactive iodine

• contraindicated in pregnant/breastfeeding

• monitor TSH, T4, T3, after treatment

• full effect takes weeks to months

• radiation safety! (limit close prolonged contact, careful hand washing, toilet hygiene, sleeping separately)…

vitamin d

increase calcium and phosphorus absorption from the intestines

• helps with hypoparathyroidism bc calcium too low

contraindications

• hypercalcemia

• vitamin d toxicity

• caution w/kidney disease, kidney stones

major side effects

• hypercalcemia (n/v, constipation, weakness fatigue, kidney stones)

nursing admin

• monitor serum ca, phos, and vitamin d

• monitor kidney function

• assess signs of hypercalcemia

oral and parenteral calcium salts

oral: replaces calcium and increases calcium absorption in intestines

IV calcium: raises blood calcium more rapidly more rapidly for severe or symptomatic hypocalcemia

contraindications: hypercalcemia, caution w/kidney disease or kidney stones, iv calcium caution w/digoxin bc risk of dysrhythmias

nursing considerations

• oral calcium: monitor calcium and kidney function, calcium carbonate best taken w/food, calcium citrate can be taken with or without food, separate calcium and levothyroxine by at least FOUR hours

• iv calcium: monitor ecg, HR, and blood pressure during administration, admin slowly, assess IV site, never mix calcium with IV solutions w/phosphate or bicarbonate unless compatibility confirmed (precipitation risk)

hyperthyroid surgical therapy

• less risk of graves recurrence

• endoscopic thyroidectomy

• subtotal thyroidectomy (risk for laryngeal nerve damage and hypoparathyroidism, risk for postop complications)

postop care for subtotal thyroidectomy

• have O2 equipment and tracheostomy tray readily available (airway obstruction can occur if hematoma, swelling, laryngeal nerve damage…)

• monitor for laryngeal stridor and difficulty breathing (monitor airway patency, freq swallowing and choking to monitor for)

• ensure IV calcium salts (calcium gluconate) available

• position the patient properly (semifowlers to decrease swelling)

• monitor calcium levels

• assess for tetany

• control post op pain

what to assess for with subtotal thyroidectomy

• irregular breathing

• neck swelling

• frequent swallowing

• choking

• sensations of fullness at incision site (hematoma risk)

T4 and T3 function

regulate metabolism

• controls the rate at which carbs, fats, and proteins are converted to energy

thermogenesis

regulates brain and skeletal growth in children

subclinical hypothyroidism

the TSH is elevated, but T4 is WNL

often asymptomatic or associated with mild, nonspecific symptoms

most common cause of hypothyroidism in the world?

iodine deficiency

adults need 150 mcg of iodine each day

• you need ½ to ¾ tsp of iodized salt daily

most common cause of primary hypothyroidism in the united states?

hashimoto’s thyroiditis (autoimmune disorder)

• body makes autoantibodies against components of the thyroid gland

potential side effects to report levothyroxine

• heart palpitations or HR greater than 100

• increase in BP (>140 systolic)

• any chest pain

• s/s you are taking too much thyroid hormone: nervousness, tremors, insomnia, weight loss

• overtreatment can result in AFIB

increased risk bone fractures, TSH monitored at least once a year

graves disease

autoimmune condition in which antibodies bind to and activate TSH receptors on the thyroid gland, causing the thyroid to produce and release excess T3 and T4. the continuously stimulated thyroid hormone becomes enlarged, resulting in a goiter

diagnosing grave’s disease

clinical features: goiter, eye changes (graves ophthalmopathy), symptoms of hyperthyroidism (weight loss, palpitations, heat intolerance, tremors)

thyroid function test: low TSH elevated free T4

antibody testing: positive for thyrotropin receptor antibodies (TRAb)

imaging (if needed): radioactive iodine uptake (RAIU) scan

• typically shows diffuse increased uptake, which distinguishes graves from thyroiditis or nodular disease

RAI mechanism of action

thyroid gland takes up the radioactive iodine (1-131) and the local radiation destroys some of the thyroid cells that produce thyroid hormone

HYPOTHYROIDISM may develop after treatment

acute hypoparathyroidism manifestations

muscle twitching, spasms, cramps due to hypocalcemia

how do biphosphonates like alendronate (fosmax) lower serum calcium levels?

biphosphonates inhibit osteoclasts, reducing bone breakdown and the release of calcium from bone into the bloodstream