thyroid and parathyroid mod 5 Flashcards
describe the thyroid
The thyroid gland is a 2” butterfly-shaped gland located in the neck
Secretes triiodothyronine (T3) (active form) and thyroxine (T4) (free or bound form).
Thyroxine is the regulator of body metabolism that influences almost every body system.
Iodine is a necessary component in the synthesis of thyroid hormone.
negative feedback with hormones
most hormone released is thyroxine T4
thyroid dysfunctions
Dysfunctions are either hypothyroidism or hyperthyroidism
Primary thyroid disorders are the most common
Thyroid problems are more likely in women than men
An enlargement can occur with both types of disorders
what is a primary disorder?
involves the gland itself
what is goiter
A goiter is an enlargement of the thyroid gland with or without symptoms of thyroid dysfunction.
**nontoxic
Excess pituitary TSH
Low iodine levels - decrease thyroxine production
Enlargement of the thyroid gland can also occur from goitrogens
goitrogens- lithium, foods
hypothyroidism definition
Insufficient levels of the thyroid hormones T3 and T4
Primary - gland/thyroid **most common
Secondary- pituitary not releasing TSH
In Primary - Increase in release of TSH from pituitary (release of TSH indicates a hypoactive thyroid)
Hashimoto’s thyroiditis, an autoimmune disorder, is the most common cause of hypothyroidism.
what is the most common cause hypothyroidism?
Hashimoto’s thyroiditis, an autoimmune disorder, is the most common cause of hypothyroidism.
decrease T3/T4 = increase TSH
what is hashimoto’s?
Thyroid receptor antibodies - autoimmune destruction of thyroid
Antithyroglobulin antibody
Antithyroperoxidase antibody: hallmark of the disorder
risk factors hypothyroidism
Female Age > 50 Caucasian Pregnancy History of other autoimmune disorders Family history Medications Treatments for hyperthyroidism
early manifestations hypothyroidism
main ones: Cold intolerance Weight gain Lethargy Fatigue
other: Memory deficits Poor attention span Increased cholesterol Muscle cramps Raises carotene levels Constipation Decreased fertility Puffy face Hair loss Brittle nails
late manifestations hypothyroidism
Below normal temperature Bradycardia Weight gain Decreased LOC Thickened skin Cardiac complications (cardiomegaly) **suppression of immune system
hypothyroid and other organs
Raises cholesterol; hyperlipidemia Raises carotene levels (yellows skin) Causes anemia Decreases filtration by kidney (risk of medication toxicity) ***Can cause hoarse voice
myxedema - can be both hyper and hypothyroidism
**think skin and loss of hair
Severe hypothyroidism (coma) Describes the dermatological change that occurs with hypothyroidism
hyperthyroidism s/s
anxiety tremor tachycardia feeling warm loss weight exophthalmos atrial fib decreased fertility
hypothyroidism s/s
hypercholesterolemia gains weight easily decreased fertility delayed reflexes sluggishness feeling cold constipation lethargy fatigue
how to diagnose hypothyroidism
- High TSH level
- Low free T3
- Low free T4
secondary - autoimmune
- Antithyroglobulin (anti-Tg)
- Antithyroperoxidase (anti-TPO) antibodies
In primary hypothyroidism, there is low hormone secretion by the thyroid gland, which constantly signals the pituitary to secrete TSH.
Secondary hypothyroidism, both TSH and T4 will be low
tx hypothyroidism
levothyroxine
**take for life!
Replacement hormone therapy with levothyroxine (T4-synthetic thyroid hormone)
MOA: converted to T3 in the body - active form
Drug half life= 7 days
Surgical intervention if necessary
rn considerations
- takes months to see results
- take on empty stomach 30 mins prior to eating
warfarin increases bleeding with drug
hyperthyroidism (thyrotoxicosis)
Excessive secretion of T3 and T4
Primary (thyroid) - graves disease
Secondary (pituitary) - oversecrete TSH
Tertiary (hypothalamus) - overstimulate TRH
Graves’ disease: most common cause, an autoimmune stimulation of the thyroid gland
Other causes include thyroid adenoma, subacute thyroiditis, toxic multinodular goiter, excessive iodine ingestion (Jod-Basedow syndrome), and excessive thyroid hormone replacement
most common cause hyperthyroidism
grave’s disease - autoimmune stimulation of thyroid gland
risk factors hyperthyroidism (thyrotoxicosis)
Family history of Graves Age > 40 Women Caucasian Medications - amiodarone - has iodine Excessive iodine intake Pregnancy
graves disease
Autoimmune disorder
Excess levels of T3 and T4
Thyroid-stimulating antibodies
- bind to activate receptor in thyroid and enlarges gland
s/s grave’s disease
Nervousness Insomnia Sensitivity to heat Weight loss Gland is usually enlarged and palpable ***An audible bruit may be heard because of high glandular blood flow Atrial fibrillation Myxedema (dermatologic manifestations) Exophthalmos
what is exophthalmos associated with?
hyperthyroidism
what is exophthalmos
Wide-eyed stare associated with increased sympathetic tone and infiltration of the extraocular area with lymphocytes and mucopolysaccharides
Periorbital edema and bulging of the eyes termed Graves’ ophthalmopathy
Women are more often affected with Graves’ ophthalmopathy than men
how to diagnose grave’s disease?
Low TSH
High T3
High T4
Antithyroglobulin
Antithyrotropin receptor antibody
Ultrasound with color-Doppler evaluation
Radioactive iodine scanning and measurements of iodine uptake
In Graves’ disease, the radioactive iodine uptake is increased and the uptake is diffusely distributed over the entire gland.
tx hyperthyroidism
Antithyroid hormone medication propylthiouracil (PTU) (blocks thyroid hormone synthesis, suppresses conversion of T4 to T3
- Hepatotoxicity - Can be used in 1st trimester with caution
Radioactive iodine* treatment
—- *Radioactive iodine is taken up by the gland and suppresses its activity.
Surgery
- Replacement thyroid hormone (levothyroxine) is needed for life.
what is thyrotoxic crisis (thyroid storm)
Overwhelming release of thyroid hormones that exerts an intense stimulus on the metabolism.
This is a life-threatening condition most commonly precipitated by surgery, trauma, or infection.
**death within 48 hrs if untreated
what and where is the parathyroid gland?
The parathyroid glands are four pea-sized glands nestled within the thyroid tissue of the neck.
The glands produce and secrete parathyroid hormone (PTH)
- released with hypocalcemia
Controls calcium levels in the body
Promotes vitamin D production by the kidney
- releases calcium from bone
describe the rare hypoparathyroidism
**hypocalcemia s/s
The symptoms associated with hypoparathyroidism are the result of insufficient PTH secretion and the resultant hypocalcemia.
Muscle cramps
Irritability
Tetany
Convulsion
*Hypocalcemia causes a carpal spasm known as Trousseau’s sign and facial muscle twitch called Chvostek’s sign.
tx hypoparathyroidism
Replace PTH
Normalize serum Ca and Vitamin D levels
If parathyroid has been removed
**– replacement treatments are life long
hyperparathyroidism s/s
Symptoms of hyperparathyroidism are caused by excessive secretion of PTH with resulting hypercalcemia and bone breakdown.
Muscle weakness Poor concentration Neuropathies Hypertension Kidney stones Metabolic acidosis Osteopenia Pathological fractures Constipation Depression, confusion, or subtle cognitive deficits
hyperparathyroidism tx
Reduce levels of calcium Diuretics Calcitonin Bisphosphonates Vitamin D Surgical intervention
