thyroid disorders

Question 1

what is the primary mechanism of hyperlipidemia in hypothyroidism ?

Answer 1

decrease in LDL receptor density

Question 2

what is myxedema ?

Answer 2

also called thyroid dermopathy
non pitting edema in hypothyroidism
usually in the face and around the eyes
pretibial myxedema is v common in graves

Question 3

what is a myxedema coma ?

Answer 3

coma associated with hypothyroidism

Question 4

what finding is associated with hypothyroid myopathy ?

Answer 4

increase in creatine kinase

Question 5

what is the cause of hyponatraemia in hypothyroidism ?

Answer 5

high levels of ADH ( causes SIADH)

Question 6

what are the thyroid replacement drugs ?

Answer 6

levothyroxine

Question 7

what is thyroid storm ?

Answer 7

life threatning hyperthyroidism ( thyrotoxicosis)

Question 8

what is the trigger for the occurence of thyrotoxicosis ?

Answer 8

usually an acute stressful event
usually happens in a patient with a pre existing hyperthyroid disease
after surgery, traum or infection

Question 9

what is the pathophysiology associated with thyrotoxicosis, and what is the usual cause of death ?

Answer 9

surge of catecholamines
tachycardia - with death from arrythmias

Question 10

what is a goiter ?

Answer 10

enlarged thyroid

Question 11

what is the best initial test for thyroid disease ?

Answer 11

TSH

Question 12

what is central thyroid disease ?

Answer 12

moshkela fel pituitary gland
low tsh

Question 13

what is pituitary resistance to thyroid hormone ?

Answer 13

high levels of T3 and T should suppress the production of TSH
in this case TSh stays high
T3 and T4 are also high

Question 14

what is reverse T3 ?

Answer 14

an isomer of T3

Question 15

what is the special use of reverse T3 ?

Answer 15

increased levels of it in euthyroid sick syndrome

Question 16

when should you suspect euthyroid sick syndrome ?

Answer 16

patient that has gone through some form of stress - surgery, infection
weaned off a ventialtor
normal TSH levels
normal T4
elevated levels of rT3

Question 17

what is the most common cause of hyperthyroidism ?

Answer 17

graves disease

Question 18

what is the pathophysiology of graves disease ?

Answer 18

activating autoantibodies against the TSH receptors (TSI)

Question 19

what is the clinical presentation associated with graves disease ?

Answer 19

exopthalmous
pretibial myexedma

hyperthyroid plus exopthalmous

Question 20

what is the pathology that causes the specific presentation of exopthalmous and pretibial myexedema in graves disease ?

Answer 20

t cell lymphocyte activation of fibroblasts
these fibroblasts contain TSH receptors
their stimulation leads to the secretion of glycosaminoglycans - draws in water

Question 21

what is the treatment of graves disease ?

Answer 21

beta blockers , thionamides
thionamides : PTU or methimazole

Question 22

what are the different mechanisms for the thionamides ?

Answer 22

methimazole : inhibits TPO
PTU : inhibits both TPO and 5 deiodenase

Question 23

what are the side effects associated with thionamides ?

Answer 23

rash
agranulocytosis
hepatotoxicity
methimazole is teratogenic

Question 25

which of the drugs is safe for pregnant women who are hyperthyroid ?

Answer 25

PTU

Question 26

what is the treatment for thyroid storm ?

Answer 26

propanolol thionamides SSKI - to shut off T4 production steroids

Question 27

why are steroids given in thyroid storm ?

Answer 27

to treat any possible side effects of adrenal insufficiency

Question 28

how is graves ophthalmology treated ?

Answer 28

with steroids

Question 29

what are toxic adenomas and what is the pattern of iodine uptake ?

Answer 29

1- nodules in the thyroid that function independently 2- usually contain mutated TSH receptor 3- they do not respond to TSh hot uptake on one side on radioactive iodine

Question 30

what are the findings associated with toxic adenoma ?

Answer 30

el heya toxic multi nodular goiter bardo palpable nodule hyperthyroidism symptoms

Question 31

what is the treatment for toxic adenoma ?

Answer 31

radioactive iodine or surgery

Question 32

what are the contraindication of using radioactive iodine ?

Answer 32

breast feeding pregnancy

Question 33

what are the different rsults associoated with radioactive iodine?

Answer 33

hot nodule - non cancerous cold nodule - often more suspicious , need to be biopsied

Question 34

what is the jod basedow phenomenon ?

Answer 34

iodine induced hyperthyroidism often occurs in areas with iodine deficiency also usually happens in patients who already have toxic adenoma

Question 35

what are the triggers associated with the occurence of jod-basedow phenomenon ?

Answer 35

drugs administered with high iodine content expectorant ( potassium iodide ) Ct contrast with dye amiodarone

Question 36

what are the types of hyperthyroidism associated with amiodarone ?

Answer 36

type 1 - pre existing thyroid disease type 2 - destructive thyroiditis , excessive release of T3 and T4 , can occur in patients without pre existing thyroid disease

Question 37

most common cause of hypothyroidism ?

Answer 37

hashimotos thyroiditis

Question 38

how can excess iodine cause hypothyroidism ?

Answer 38

by the wolff chaikoff effect

Question 39

how does an iodine load cause hyperthyroidism ?

Answer 39

through thr jad- basdow effect in a patient with a pre existing thyroid condition who then takes an iodine load

Question 40

what are the goitrogens ?

Answer 40

iodine lithium cassava millet

Question 41

how does amiodarone cause hypothyroidism ?

Answer 41

1- excess iodine - through the wolff chaikoff effect byroo7 lwa7do some patients who have pre existing thyroid disease have " failure to escape" 2- mimics T4

Question 42

what are the mechanisms in which amiodarone causes hypothyroidism ?

Answer 42

iodine load thyroiditis

Question 43

what must be done before starting amiodarone ?

Answer 43

check TSH levels

Question 44

what syndrome happens with congenital hypothyroidism ?

Answer 44

cretinism

Question 45

what is the most common cause of cretinism?

Answer 45

dysfunctional TPO

Question 46

what are the physical features associated with cretinism ?

Answer 46

mental retardation coarse facial features short stature umbilical hernia enlarged tongue

Question 47

what are the causes of iatrogenic hypothyroidism ?

Answer 47

thyroid surgery radioiodine therapy neck radiation

Question 48

what is the cause of hashimotos thyroiditis ?

Answer 48

ly,phocytes infiltrate the thyroid gland autoimmune

Question 49

what is the histology associated with hashimotos ?

Answer 49

massive lymphocytic infiltrate (germinal centres) hurthle cells (enlarged eosinophilic follicular cells)

Question 50

what risk is carried with hashimotos ?

Answer 50

increased risk of non hodgkin b cell lymphoma

Question 51

what is the other name for subacute thyroiditis and what is the associated pathology ?

Answer 51

also called de queverian thyroiditis granulomatous inflammation of the thyroid

Question 52

what is riedel's thyroiditis ?

Answer 52

fibroblast activation and proliferation rock hard thyroid extends byond the thyroid

Question 53

what are the extra-thyroid manifestations of riedels disease ?

Answer 53

parathyroid gland affection - hypoparathyroidism recurrent laryngeal nerve damage - hoarsness trachea compression - difficulty breathing

Question 54

what is the immunology associated with riedel's thyroiditis ?

Answer 54

IgG4 plasma cells

Question 55

what is lymphocitic thyroiditis ?

Answer 55

painless thyroiditis a variant of hashimotos can look like graves but with no clinical findings

Question 56

what are the causes of drug induced thyroidits and what is the iodine uptake pattern ?

Answer 56

caused by lithium or amiodarone will present with decreased iodine uptake on RAIU

Question 57

what are the features of subclinical hypothyroidism ?

Answer 57

increased TSH normal T3 and T4

Question 58

what can riedel thyroiditis sometimes mimic ?

Answer 58

anaplastic thyroid carcinoma

Question 59

what is struma ovarii ?

Answer 59

ovarian tumor secreting T3 and T4