treatment of thyroid diseases Flashcards
describe the process of regulation thyroid hormone
hypothalamus release TRH
TRH will stimulate pituitary to release TSH
TSH will release THYROID HORMONE
thyroid hormone will negatively inhibit TSH and TRH
what are the stuff we can inhibit in case of hyperthyroidism ?
peroxidase enzyme which is responsible coupling and iodination
inhibit the release of thyroid
inhibit the uptake of iodine
what drugs inhibit the peroxidase enzyme?
thioamides
what drugs inhibit the uptake of iodine?
potassium iodide
how do we inhibit the release of thyroid hormone?
lithium
what is the normal level of TSH?
0.4 - 4.0 mIU/L
what are some drugs that inhibit the release of TSH?
D2 receptor agonist
GHIH analogs –> octreotide
glucocorticoids
metformin
what are some dopamine agonists ?
dopamine
dobutamine
levodopa
cabergoline
bromocriptine
these inhibit prolactin and GH ( in acromegaly ) and TSH
what are some stuff that increases TSH secretion?
dopamine receptor antagonist ( D2 receptors )
what are some dopamine receptor antagonists?
metoclopramide
domperidone
what are the manifestation of hyperthyroidism ?
nervousness
emotional
disturbance
weight loss
heat intolerance
palpitations
proximal muscle weakness
increase frequency of bowel movements
irregular menses
what is grave disease?
autoimmune disease where antibodies that are similar to TSH bind to the TSH receptor and stimulate more production thyroid hormone and the release of it
what are the characteristics of graves disease?
thyroid enlargement
exophthalmos
what are the none pharmacological therapy for hyperthyroidism?
surgery
thyroidectomy
when do you consider surgery?
large thyroid gland
severe ophthalmopathy
lack of remission on antithyroid drug
what are the drugs used for preparation of thyroidectomy?
thionamides –> inhibit production of T3,T4
beta blockers/ propranolol –? relief symptoms and inhibit T3 production
supersaturated iodine–> reduces gland vascularity
lethium carbonate –> block thyroid release
dexamethasone/corticosteroid —-> reduces TSH levels and inhibit T4 to T3 conversion
what is wolff chaikoff effect?
when the body gets a large amount of iodine at once this will temporarily inhibit the thyroid synthesis due to inhibition of thyroid peroxidase
this will reduce the vascularity temporarily as well
what are the pharmacological treatments for hyperthyroidism?
antithyroid medications
iodides
adrenergic blockers
radioactive iodine
what are some antithyroid medications?
thionamides :
methimazole
propylthiouracil
what is the MOA of methimazole?
inhibit coupling of MIT AND DIT to form T3 AND T4
what is the MOA of propythiouracil ?
inhibit coupling
INHIBIT PERIPHERAL CONVERSION OF T4 to T3
more effective compared to methimazole because it works peripherally as well
which antithyroid drug is the choice for pregnant women?
propylthiouracil
what are the side effects of antithyroid medications ?
pruritic maculopapular rashes
arthralgias
fever
benign transient leukopenia
AGRANULOCYTOSIS –> LOW AMOUNT OF AGRANULOCYTES –> INFECTION –> major side effect
congenital malformation –> ONLY WITH METHIOMAZOLE
hepatoxicity
what is the MOA of iodides?
temporarily block thyroid hormone release
inhibit thyroid hormone biosynthesis
decrease size of the gland
what could happen if we give large doses of iodide ?
hyperthyroidism
or
wolff chaikoff effect
when is iodide contraindicated?
multinodular goiter
what is the clinical use of iodine ?
before thyroid surgery
what is the example of iodine we give?
potassium iodide
what is an adjuvant therapy we can use for iodide?
iodide + radioactive iodine
what are the side effects of iodide?
hypersensitivity
salivary gland swelling/enlargement
iodism –> burning of the mouth and throat , headache, metallic taste
gynecomastia –> enlargement of breast tissue in males
when is radioactive iodine given?
is the agent choice for :
grave disease
toxic autonomous nodules
toxic mngs
when is radioactive iodine contraindicated
pregnancy
what is given before Radioactive iodide in elderies?
thioamides
what type of adrenergic blockers we use in hyperthyroidism?
beta blockers
NONE SELECTIVE bcz selectives dont work
propranolol
why do we use beta blockers?
js to relief the symptoms
adjunctive therapy with antithyroid drugs, RAI, iodides
what is the meaning QID?
4 times a day
when is propranolol contraindicated?
decompensated heart failure
sinus bradycardia
what are the side effects of beta blockers?
nausea
vomitting
anxiety
insomnia
light headedness
bradycardia
hematologic disturbance
asthma
what is the first drug of choice in grave disease + pregnancy?
propylthiouracil
what is the drug choice for neonatal and pediatric hyperthyroidism ?
methimazole first line
if no effect = propythiouracil
what is the first drug of choice in thyroid storm?
propythiouracil
then antiadrenergic ( BB )
corticosteroids -> prednisone
palliative treatment
what are the drugs used in cause of hyperthyroidism associated with ophthalmophaty
or Grave ophthalmopathy ?
Teprotumumab —> antibody for IGF1 RECEPTOR IN EYE
treat protrusion not hyperthyroidism
if it is too severe surgery
what are the signs and symptoms of hypothyroidism?
lethargy
cold intolerance
weight gain
Constipation
myxedema
myxedema coma due to hypoglycemia
what is the most common cause of hypothyroidism in adults?
hashimoto disease
other causes :
radioactive iodine
surgical removal
iodine deficiency
pituitary/hypothalamic dysfunction –> Secondary hypothyroidism
what is the treatment in cause of hypothyroidism?
thyroid replacement therapy
what are examples of synthetic thyroid hormones?
levothyroxine
liothyronine
liotrix
what is the drug of choice out of the 3?
levothyroxine
why is levothyroxine the drug of choice?
chemically stable
inexpensive
uniform potency
what are the disadvantages of liothyronine?
higher incidence of cardiac adverse effects
higher cost
difficulty monitoring with labs
what is liotrix?
4 :1 mixture of T3
Advantages : stable, predictable , potency
disadvantages : high cost
what are the clinical features of myxedema coma?
hypothermia
advanced stage of hypothyroid symptoms
altered sensorium ranging from delirium to coma
what is the initial treatment of myxedema coma?
IV bolus thyroxine
then maintenance treatment also given IV
IV hydrocortisone
why is IV hydrocortisone given?
to rule out coexisting adrenal suppression
Cuz low TSH is usually has Low ACTH as well so low cortisol
what is the treatment in congenital hypothyroidism?
maintenance therapy early
levothyroxine
what is the treatment for hypothyroidism in pregnancy?
levothyroxine as well
