Thyroid Flashcards
Thyroid produces what hormones?
T3 (triiodothyronine) & T4 (tetraiodothyronine)
Hormone for bone regulations
Calcitonin
T4:T3 ratio
13:1
Main component of thyroid hormone
Iodine
RDI of iodine
150 mcg/day
RDI of iodine for pregnant
200 mcg/day
Transporter of thyroidal hormone
Sodium iodide symporter
Enzyme that oxidizes iodide to iodine
Thyroidal peroxidase
Carry T3 to organs
Albumin & Proalbumin
Enzyme in deiodination
5-deiodinase
Via _________ T3 and T4 will be sent to the blood.
Proteolysis
Medications that could block the symporter
Thiocyanate
Perchlorate
Pertechnetate
Hypothalamus secretes
TRH
Apical pituitary gland secretes
TSH
In normal individuals, excess iodide inhibits thyroid hormone synthesis
Wolff chaikoff block
An autoimmune disease wherein there’s a destruction of thyroid cells or thyroglobulin
Hashimoto’s thyroiditis
Hashimoto’s thyroiditis is example of
Hypothyroidism
An autoimmune disorder that involves overactivity of the thyroid (hyperthyroidism)
Grave’s disease
Common caused of Grave’ disease
TSH antibodies
Hallmarks of the condition are bulging eyes, redness, and retracting eyelids
Ophthalmopathy
Spooning of fingernails
Koilonychias
DOC for pretibial dermopathy
Topical Corticosteroid
Large tongue
Macroglossa
Decreased peripheral vascular resistance; increased heart rate, stroke volume
Thyrotoxicosis
Increased peripheral vascular resistance; decreased heart rate, stroke volume
Hypothyroidism
decreased vital capacity
Thyrotoxicosis
hypercapnia
Hypothyroidism
Increased appetite; increased frequency of bowel movements
Thyrotoxicosis
Decrease the dose of warfarin
Thyrotoxicosis
Decreased appetite; Decreased frequency of bowel movements
Hypothyroidism
Ascites
Hypothyroidism
Prone to edema
Hypothyroidism
Increased erythropoiesis
Thyrotoxicosis
Decreased erythropoiesis; anemia
Hypothyroidism
Menstrual irregularities
Thyrotoxicosis
Hypermenorrhea
Hypothyroidism
Oligospermia
Hypothyroidism
decreased gonadal steroid metabolism
Hypothyroidism
Increased basal metabolic rate
Thyrotoxicosis
Decreased basal metabolic rate
Hypothyroidism
increased requirements for fat- and water-soluble vitamins
Thyrotoxicosis
decreased cholesterol and triglycerides
Thyrotoxicosis
increased cholesterol and triglycerides
Hypothyroidism
increased warfarin
Hypothyroidism
decreased hormone degradation
Hypothyroidism
These medications are bad for the treatment of obesity
Levothyroxine, Liothyronine, Liotrix
Drug of Choice for thyroid replacement therapy and suppression therapy
Levothyroxine
Not recommended for routine therapy because of greater risk for cardiotoxicity
Liothyronine
Best for short term suppression of Thyroid Stimulating Hormone (TSH)
Liothyronine
combination of T4 and T3 with a ratio of 4:1
Liotrix
Drug of choice fot thyrotoxicosis
Methimazole, Propylthiouracil (PTU)
Thioamides
Methimazole, Propylthiouracil (PTU)
Drug that is converted to methimazole
Carbimazole
DOC for adult and children
Methimazole
Methimazole adr
Cholestatic jaundice
Has black box warning: Severe hepatitis
Propylthiouracil
Reserved for 1st trimester pregnancy in case of thyroid storm
PTU
Given to px with ADR from methimazole
PTU
FATAL ADR OF THIOAMIDES
AGRANULOCYTOSIS
Block uptake of Iodide through competitive inhibition of iodide transport
Anion inhibitors
Blocks the thyroidal reuptake of iodine, especially in patients with iodine induced hyperthyroidism
K perchlorate
K perchlorate adr
Aplastic anemia
Inhibits the organification of hormone release
Iodides
preparation of surgical thyroidectomy
Iodides
Only isotope for thyrotoxicosis
I131
Penetration ranges of I131
400-2000 nm
patient (usually infant) has mental retardation and disadvantages
Cretinism
end state of untreated hypothyroidism
Myxedema coma
Levothyroxine loading dose
300 - 400 mcg
Levothyroxine regular dose
50 - 100 mcg
Elevated TSH, normal thyroid hormone
Subclinical hypothyroidism
Most common form of hyperthyroidism
Grave’s disease
Grave’s disease aka
Diffuse toxic goiter
If beta-blocker is contraindicated, give
Diltiazem
Usually seen in older women with nodular goiters already
Toxic Mononodular Goiter
spontaneously resolving hyperthyroidism
Subacute thyroiditis
Sudden onset of all the symptoms of thyrotoxicosis
Thyroid Storm
This is usually because of the passage of maternal TSH-R antibodies through the placenta
Neonatal Grave’s Disease
Propranolol dose in Neonatal Grave’s Disease
2 mg/kg/day
Suppressed TSH level but normal thyroid hormone
Subclinical Hyperthyroidism
Diuretic that inhibits T4 to T3 conversion
Amiodarone
Syndrome of enlarged thyroid without excessive thyroid hormone production
Non toxic goiter
Can be benign or malignant
Thyroid neoplasm
Type 1 for px with underlying thyroid disease
Iodine Induced Thyrotoxicosis
Due to the leakage of thyroid hormone in the circulation
Inflammatory Thyroiditis
Vaused by viral infection
Subacute Thyroiditis
Associated with large goiter
Toxic Mononodular Goiter
increased cardiac output, inotropy, and chronotropy
Hyperthyroidism
Should not be administered to pregnant or nursing mothers as it may cross the placenta and breast milk and it can also destroy the infant’s thyroid gland.
I131
Beta-blocker without ISA
Propranolol, Metoprolol, Atenolol
Examples of iodides
Lugol’s solution & KI2
Half-life of Levothyroxine
7 days
Half-life of Liothyronine
24 hrs
Usually given to patient with HYPOthyroidism
Levothyroxine, Liothyronine, Liotrix
Active form in deiodination
3-5-3
Incorporation of iodine into thyroglobulin for the production of thyroid hormone
Iodide organification
Lethargy; general slowing of mental processes; neuropathies
Hypothyroidism
Nervousness; hyperkinesia; emotional lability
Thyrotoxicosis
Other term for Hyperthyroidism
Thyrotoxicosis
Shelf-life of Levothyroxine, Liothyronine, Liotrix
2 years