chapter 24: Endocrine Disorders Part 2

What hormones does the thyroid produce?

Triiodothyronine (T3) and thyroxine (T4)

what is required to make thyroid hormones?

iodine

what does thyroxine do?

regulate body metabolism

thyroid disorders are more common in who?

women

what is the most common thyroid disorders?

primary thyroid disorders

what does an enlarged thyroid indicate?

hypo or hyperfunction

what does the thyroid affect?

temperature, weight, skin, metabolism

what is goiter?

enlargement of the thyroid

does goiter always cause symptoms

no

causes of goiter

excess TSH, low iodine, goitrogens

what are goitrogens?

susbtances/foods that enlarge thyroid when iodine is low

why does low iodine cause goiter?

decreased thyroid hormone synthesis

can goiter cause hypo or hyperthyroidism?

both!

most common cause of hypothyroidism?

Hashimoto's thyroiditis

what is Hashimoto's?

autoimmune destruction of the thyroid

antibodies in Hashimoto's?

anti-thyroglobulin (anti-Tg) , anti-thyroperoxidase (anti-TPO)

other causes of hypothyroidism?

drugs, genetics, thyroiditis, congenital (cretinism)

signs and symptoms of hypothyroidism?

hypercholesterolemia

cold intolerance

weight gain

fatigue, lethargy

memory loss, poor attention

constipation

cramps (LEG)

puffy face

hair loss

brittle nails

decreased fertility

hypothyroidism is associated with what lipid condition?

hyperlipidemia

what are some systemic effects of hypothyroidism?

yellow/orange skin from increased carotene

anemia

decreased kidney filtration

what is a severe hypothyroidism complication?

myxedema

what is myxedema?

severe hypothyroidism leading to swelling and coma

what is subclinical hypothyroidism?

mild form often seen in elderly patients

in order to diagnose hypothyroidism what labs need to be checked?

TSH, T3, T4

what lab values are indicative of primary hypothyroidism?

high TSH

low T3/T4

what lab values are indicative of secondary hypothyroidism?

low TSH

low T3/T4

Hashimoto's antibodies?

anti-TG

anti-TPO

what imaging is responsible for diagnosing hypothyroidism?

ultrasound

how often should women get screened for hypothyroidism?

women at 35, every year

treatment of hypothyroidism?

Levothyroxine

levothyroxine: action

synthetic T4 is converted to T3

increased metabolism and oxygen use

levothyroxine: indications

hypothyroidism, myxedema coma, post-thyroidectomy hormone replacement

levothyroxine: contraindications

untreated adrenal insuffiecny, acute MI, thyroid toxicosis

levothyroxine: caution

certain CV disease

older adults

osteoporosis

diabetes mellitus

levothyroxine: adverse effects

nausea

tachycardia

angina

nervousness

heat intolerance

diarrhea

weight loss

levothyroxine: medication interactions (DECREASED ABSORPTION)

calcium, iron, antacids

levothyroxine: medication interactions (INCREASES ABSORPTION)

anticoagulants

levothyroxine: what does this have a major medication interaction with?

insulin

levothyroxine: what should the nurse monitor for labs?

TSH

T3

T4

vitals

weight

levothyroxine: patient teachings

1) take in the morning on an empty stomach

2) report symptoms if they include: chest pain, tachycardia, severe nausea

if a patient is using calcium/antacids with levothyroxine when's should they administer the dose of levothyroxine?

2 hours apart

if a patient is taking levothyroxine, can they switch brands of the medication?

no

how long should a patient stay on levothyroxine?

lifelong

hyperthyroidism causes

Grave's disease

women under the age of 40

what is Grave's disease?

autoimmune overstimulation of the thyroid

Grave's disease clinical presentation

gland enlargement

fairly skinny

bad goiter

oligomenorrhea

hyperthyroidism: signs/symptoms

anxiety

tremor

tachycardia

nervousness

insomnia

weight loss

heat intolerance

sweating

diarrhea

exophthalmos (bulging eyes)

AFIB

Graves ophthalmopathy

periorbital edema and bulging of the eyes

hyperthyroidism: primary lab diagnosis

LOW TSH

HIGH T3/T4

hyperthyroidism: secondary lab diagnosis

HIGH TSH

HIGH T3/T4

hyperthyroidism: antibodies diagnosis

ANTI-TPO

hyperthyroidism: imaging

ultrasound

radioactive iodine scan

hyperthyroidism: treatment

PTU (med)

Methimazole (med)

surgery

radioactive iodine

Methimazole: action

blocks the use of iodine and decreases the thyroid hormone

Methimazole: contraindications

pregnancy, lactation

Methimazole: major adverse effects

rash

agranulocytosis

fever

GI upset

Methimazole: monitor what labs

CBC

liver function

TSH/T3/T4

Methimazole: what foods should be avoided?

foods containing iodine (salt, shellfish like shrimp)

Methimazole: patient teachings

1) report if experiencing fever, sore throat, malaise

2) do not stop med abruptly (rebound thyroid storm)

what is a thyroid storm?

Rare, life-threatening condition where there is overactivity of the thyroid and consequently extreme hyperthyroidism

what symptoms typically present with a thyroid storm?

HR over 200 bpm

fever of 105+

agitation

psychosis

thyroid storm treatment?

IV beta blockers

antithyroid meds

when there is a singular thyroid nodule, what does this indicate?

high cancer risk

when there is multiple thyroid nodules, what does this indicate?

typically benign

what are the three types of nodules?

hot nodule, warm nodule, cold nodule

hot nodule is indicative of...

hyper functioning

warm nodule is indicative of.....

normal functioning

cold nodule is indicative of...

hypo functional, possible cancer

risk factors of thyroid nodules

age under 20, over 70, male, radiation history

physical signs of thyroid nodules

hard

immobile nodule and lymphadenopathy

How many parathyroid glands are there and where are they located?

4 small, pea-sized glands located on the posterior surface of the thyroid gland

What hormone do the parathyroid glands secrete?

Parathyroid hormone (PTH)

what is the primary function of PTH?

to regulate and increase blood calcium levels

what triggers the release of PTH?

low serum calcium

what lab value regulates PTH secretion directly?

serum calcium level

what are the 3 main actions of PTH?

1) bone absorption

2) increased calcium reabsorption in kidneys

3) increased calcium absorption in intestines (via vitamin D activation)

what does PTH do to the bone?

stimulates osteoclast activity and releases calcium from bones into bloodstream

what is the long term effect of PTH on bones?

bone weakening leads to osteopenia and then fractures

what does PTH do in the kidneys?

Increases calcium reabsorption (keeps Ca in blood)

Decreases phosphate reabsorption (phosphate is excreted)

why is phosphate excreted?

to prevent calcium from binding to phosphate and lowering free calcium levels

how does PTH affect the intestines?

indirectly increases calcium absorption by activating vitamin D

hypoparathyroidism: what happens when PTH is low?

calcium decreases and hypocalcemia develops

hypoparathyroidism: causes

accidental damage/removal during thyroid surgery

genetic disorders

autoimmune destruction

why do symptoms occur in hypocalcemia?

low calcium increases neuromuscular excitability

hypoparathyroidism: Trousseeau's sign

carpal spasm when BP cuff is inflated

hypoparathyroidism: Chvostek's sign

facial twitch when tapping facial nerve

hypoparathyroidism: signs and symptoms

muscle cramps

tetany

seizures

convulsions

tingling in fingers, toes, lips

fatigue

mood changes

hypoparathyroidism: treatment

calcium replacement

vitamin D

PTH replacement

primary hyperparathyroidism cause?

parathyroid adenoma (benign tumor)

primary hyperparathyroidism labs

high PTH and high calcium

what causes secondary hyperparathyroidism?

chronic hypocalcemia

secondary hyperparathyroidism labs

high PTH and low/normal calcium

what does high calcium do in the body?

decreases neuromuscular excitability

poor concentration

confusion

fatigue

weakness

kidney stones

osteopenia

hyperparathyroidism treatment

surgery (remove adenoma)

lower calcium levels