Thyroid Disorders Flashcards
Thyroid: Shape and Location
a 2” butterfly-shaped gland
located in the neck
Thyroid: Secretes what? (2)
triiodothyronine (T3)
thyroxine (T4)
Thyroxine (T4): Function
regulator of body metabolism that influences almost every body system
_______ is a necessary component in the synthesis of thyroid hormone
iodine
Secretion of T4/T3
hypothalamus releases TRH–> stimulates anterior pituitary gland to release TSH–> stimulates thyroid gland to release thyroxine—> thyroxine (T4) is converted to T3, which is the active form in the body
Once we have enough to get to ideal metabolism, our body tells the hypothalamus to turn down
Thyroid 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
Goiter: Definition
An enlargement of the thyroid gland with OR without symptoms of thyroid dysfunction
Goiter: Causes (3)
excess pituitary TSH
low iodine levels
goitrogens (ex: meds)
Hypothyroidism
insufficient levels of the thyroid hormones T3 and T4
Can be:
-primary: thyroid isn’t
secreting T3 and T4
(MOST common)
-secondary: pituitary gland
is not secreting enough
TSH
Hashimoto’s thyroiditis
an autoimmune disorder
MOST common cause of hypothyroidism
Hashimoto’s: antibody
Antithyroperoxidase antibody
hallmark of the disorder
antithyroglobulin antibody as well
Hypothyroidism: Risk Factors
-female
-age > 50
-Caucasian
-pregnancy
-history of other autoimmune disorders
-family history
-medications
-treatments for hyperthyroidism
Hypothyroidism: EARLY CM (14)
cold intolerance
weight gain
lethargy
fatigue
memory deficits
poor attention span
increased cholesterol
muscle cramps
raised carotene levels
constipation
decreased fertility
puffy face
hair loss
brittle nails
Hypothyroidism: LATE CM (6)
-below normal body temperature
-bradycardia
-weight gain
-decreased LOC
-thickened skin
-cardiac complications (cardiomegaly)
Hypothyroidism: Affects?
ALL body organs
-raises cholesterol;
hyperlipidemia
-raises carotene levels
(yellows skin)
-causes anemia
-decreases filtration by
kidney (risk of
medication toxicity)
-can cause hoarse voice
Myxedema
severe hypothyroidism that has gone undiagnosed for a long time
can result in myxedema coma
results in loss of brain function
life-threatening
term is also used to describe dermatological changes that occur with hypothyroidism
Hypothyroidism: Diagnosis (Labs)
High TSH level
Low free T3
Low free T4
Antithyroglobulin (anti-Tg)
Antithyroperoxidase (anti-TPO) antibodies
Hypothyroidism: Diagnosis
In primary hypothyroidism, there is low hormone secretion by the thyroid gland, which constantly signals the pituitary to secrete TSH
In secondary hypothyroidism, both TSH and T4 will be low
Hypothyroidism: Treatment
Replacement hormone therapy with levothyroxine (T4-synthetic thyroid hormone)
-MOA: converted to T3 in
the body
-drug half life= 7 days
-levothyroxine and
warfarin taken together:
be cautious, increased
risk of bleeding
Surgical intervention if necessary
Hyperthyroidism (Thyrotoxicosis)
Excessive secretion of T3 and T4
-primary (thyroid)
-secondary (pituitary)
-tertiary (hypothalamus)
Hyperthyroidism: Causes
-Graves’ disease: MOST common
-Thyroid adenoma
-Subacute thyroiditis
-Toxic multinodular goiter
-Excessive iodine ingestion (Jod-Basedow Syndrome)
-Excessive thyroid hormone replacement
Graves’ Disease
autoimmune stimulation of the thyroid gland
excess levels of T3 and T4
thyroid-stimulating antibodies
Hyperthyroidism: Risk Factors
family history of Graves
age > 40
women
Caucasian
Medications
Excessive iodine intake
Pregnancy
Graves Disease (Hyperthyroidism): CM (9)
-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
