L7: Endocrine disorders

Question 1

most common cause for acromegaly :

Answer 1

benign pituitary GH-secreting adenoma —> elevated growth hormone —> would cause gigantism in adults

Question 2

acromegaly is associated with which conditions ?

Answer 2

increased risk of :
-carpel tunnel syndrome

-obstructive sleep apnea

-type 2 DM or glucose intolerance

-heart disease and hypertension

-arthritis

-bitemporral hemianopsia __>resulting from compression of optic chiasm by pituitary adenoma

Question 3

lab diagnosis for acromegaly :

Answer 3

measure IGF-1 (insulin like growth factor 1), usually increased in acromegaly

confirm diagnosis with oral glucose suppression test
(GH levels will remain elevated despite glucose administration so GH is NOT reliable test )

Question 4

MRI on a patient suffering from acromegaly shows :

Answer 4

sellar lesion

Question 5

treatment for acromegaly:

Answer 5

transphenoidal surgical resection or external beam radiation of the tumor

octreotide (somatostatin analog) is used to supress GH secretion

pegvisomant (GH receptor antagonist ) can be used to block peripheral actions og GH

Question 6

What is the best test for screening of thyroid disease and for assessment of thyroid function?

Answer 6

TSH measurement

Question 7

what is high TSH associated with ?

Answer 7

primary hypothyroidism

Question 8

what is low TSH associated with ?

Answer 8

primary hyperthyroidism

Question 9

why is total T4 measurement not an accurate screening for thyroid function and free T4 measurement is preferred ?

Answer 9

becasue 99% of circulating T4 is bound to thyroxine-binding protein and total T4 levels can be altered by changes in levels of binding proteins

Question 10

most common cause of hyperthyroidism :

Answer 10

graves disease : autoimmune form of hyperthyroidism

Question 11

clinical presentations of hyperthyroidism :

Answer 11

patient presents with :
-weight loss
- heat intolerance
-anxiety
-palpitations
-increased bowel frequency
-insomnia
-menstrul abnormalities

Question 12

examination of patent with hyperthyroidism reveals :

Answer 12

moist skin
-goiter
-sinustachycardia
-atrial fibrillation
-fine tremor
-lid lag
-hyperactive reflexes

Question 13

characteristic features of hyperthyroidisim of graves disease only ( not present in other type of hyperthyroidism)

Answer 13

exophthalmos

pretibial myxedema

thyroid bruits

Question 14

treatment for hyperthyroidism :

Answer 14

symptomatic treatment :
- propranolol to manage androgenic symptoms

-anti-thyroid drugs :
-methimazole or propylthiouracil

-thyroidectomy (levothyroxine T4 replacement administered if this is the case )

Question 15

how does thyroiditis affect thyroid hormone secretion ?

Answer 15

inflammation of thyroid gland causing release of previously synthesized thyroid hormone resulting in temporary hyperthyroidism phase followed by hypothyroidism

Question 16

what is thyroid storm ?

Answer 16

acute life threatening form of thyrotoxicosis

-urgent treatment with IV propranolol ,PTU , and corticosteroid

high dose of potassium iodide (SSKI) is also effective

Question 17

most common cause for hypothyroidism :

Answer 17

Hashimoto’s thyroiditis (autoimmune hypothyroidism )—> associated with antithyroglobulin and ant microsomal (anti-TPO) antibodies that precipitate thyroid destruction

Question 18

clinical features of hypothyroidisim :

Answer 18

patient presenting with :
-weakness
-fatigue
-cold intolerance
-constipation
-weight gain
-depression
hair loss
-menstural irregularities

examination reveals:
-cold, puffy skin
-edema,
- bradycardia
-delayed relaxation of deep tendon reflexes such as ankle jerk

Question 19

what is a myxedema coma ?

Answer 19

severe hypothyroidism with decreased mental status , hypothermia , and other parasympathetic symptoms—-> treat with IV levothyroxine and IV hydrocortisone if adrenal insufficiency has not been excluded

Question 20

hyperactivity disorders of adrenal gland :

Answer 20

-Cushing’s syndrome
-hyperaldosteronism
-adrenogenital syndrome

Question 21

hypoactivity disorders of adrenal gland :

Answer 21

-chronic adrenal insufficiency (Addison’s disease )
-acute adrenal insufficiency
-congenital adrenal hyperplasia

Question 22

Cushing’s syndrome results from :

Answer 22

elevated serum cortisol levels
-most frequently from iatrogenic prolonged treatment with exogenous corticosteroids

Question 23

what is the most common endogenous cause of Cushing’s syndrome ?

Answer 23

hypersecretion of ACTH from pituitary adenoma

Question 24

presenting features of cushings syndrome :

Answer 24

patient pressents with :
-HTN
-T2DM
-depression
‘-weight gain
-muscle weakness
-easy bruisability
-increased susceptibility to infection
-psychological disturbances
-hirsutism
-central obesity
-moon face
-baffalo hump
-purple striae

Question 25

diagnosis of cushings syndrome :

Answer 25

1,) elevated 24 hour free urine cortisol

2.) elevated midnight salivary cortisol level on 2 separate night

3.) 1mg dexamthasone suppression test + is AM cortisol is persistently elevated the morning after administration of dexamethasone

Question 26

if lab tests suggest Cushing’s disease what should be ordered?

Answer 26

pituitary MRI

Question 27

How can you differentiae between ACTH dependent (pituitary/ectopic) and ACTH independent causes?

Answer 27

Measure morning (8:00am) cortisol and ACTH levels. If ACTH is elevated, Cushing’s disease or ectopic ACTH is likely.

Question 28

adrenal imaging should be ordered when :

Answer 28

only if the work up suggests ACTH-independent etiology (high risk of adrenal incdentalomas)

Question 29

treatment for cushings syndrome :

Answer 29

surgical resection of source

inhibitors of adrenal steroigogenesis in case of bilateral adrenal hyperplasia

permenant hormone replacment therapy

Question 30

destruction of adrenal cortex leading to glucocorticoid (cortisol)
and mineralocorticoid (aldosterone) deficiency :

Answer 30

addisons disease(usually autoimmune)

-other causes:
TB
adrenal metastases
lymphoma
HIV
adrenal hemorrhage

Question 31

adrenal disease cauing hyperpigmentation:

Answer 31

addisons disease

Question 32

diagnosis of addisons diseas:

Answer 32

-hyponatremia
-esionophillia
-hyperkalemia
-hypercalcemia
-confirmed by 8 am plasma cortisol level test and synthetic ACTH stimulation test

failure of cortisol to rise >18ug/dl following ACTH administration confirms diagnosis

Question 33

primary treatment of Addison’s disease:

Answer 33

glucocorticoid and mineralocorticoid replacement therapy

Question 34

secondary / tertiary treatment of Addison’s disease:

Answer 34

only glucocorticoid replacement is necessary (mineralocorticoid production is not ACTH dependent )

Question 35

treatment of adrenal crisis :

Answer 35

IV steroids to correct electrolyte abnormalities

50% dextrose to correct hypoglycemia and initiate aggressive volume resuscitation

Question 36

how should chronic steroid therapy be stopped ?

Answer 36

tapered slowly to avoid secondary / tertiary Addison’s disease

Question 37

subacute forms of thyroditis present with :

Answer 37

tender thyroid , malaise , URI symptoms

all others are associated with painless goiter

Question 38

treatment for thyroditis :

Answer 38

beta blockers for hyperthyroidism

levothyroxine for hypothyroidism

for severe cases : NSAID or oral corticosteroid