L7: Endocrine disorders Flashcards
most common cause for acromegaly :
benign pituitary GH-secreting adenoma —> elevated growth hormone —> would cause gigantism in adults
acromegaly is associated with which conditions ?
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
lab diagnosis for acromegaly :
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 )
MRI on a patient suffering from acromegaly shows :
sellar lesion
treatment for acromegaly:
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
What is the best test for screening of thyroid disease and for assessment of thyroid function?
TSH measurement
what is high TSH associated with ?
primary hypothyroidism
what is low TSH associated with ?
primary hyperthyroidism
why is total T4 measurement not an accurate screening for thyroid function and free T4 measurement is preferred ?
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
most common cause of hyperthyroidism :
graves disease : autoimmune form of hyperthyroidism
clinical presentations of hyperthyroidism :
patient presents with :
-weight loss
- heat intolerance
-anxiety
-palpitations
-increased bowel frequency
-insomnia
-menstrul abnormalities
examination of patent with hyperthyroidism reveals :
moist skin
-goiter
-sinustachycardia
-atrial fibrillation
-fine tremor
-lid lag
-hyperactive reflexes
characteristic features of hyperthyroidisim of graves disease only ( not present in other type of hyperthyroidism)
exophthalmos
pretibial myxedema
thyroid bruits
treatment for hyperthyroidism :
symptomatic treatment :
- propranolol to manage androgenic symptoms
-anti-thyroid drugs :
-methimazole or propylthiouracil
-thyroidectomy (levothyroxine T4 replacement administered if this is the case )
how does thyroiditis affect thyroid hormone secretion ?
inflammation of thyroid gland causing release of previously synthesized thyroid hormone resulting in temporary hyperthyroidism phase followed by hypothyroidism
what is thyroid storm ?
acute life threatening form of thyrotoxicosis
-urgent treatment with IV propranolol ,PTU , and corticosteroid
high dose of potassium iodide (SSKI) is also effective
most common cause for hypothyroidism :
Hashimoto’s thyroiditis (autoimmune hypothyroidism )—> associated with antithyroglobulin and ant microsomal (anti-TPO) antibodies that precipitate thyroid destruction
clinical features of hypothyroidisim :
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
what is a myxedema coma ?
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
hyperactivity disorders of adrenal gland :
-Cushing’s syndrome
-hyperaldosteronism
-adrenogenital syndrome
hypoactivity disorders of adrenal gland :
-chronic adrenal insufficiency (Addison’s disease )
-acute adrenal insufficiency
-congenital adrenal hyperplasia
Cushing’s syndrome results from :
elevated serum cortisol levels
-most frequently from iatrogenic prolonged treatment with exogenous corticosteroids
what is the most common endogenous cause of Cushing’s syndrome ?
hypersecretion of ACTH from pituitary adenoma
presenting features of cushings syndrome :
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
diagnosis of cushings syndrome :
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
if lab tests suggest Cushing’s disease what should be ordered?
pituitary MRI
How can you differentiae between ACTH dependent (pituitary/ectopic) and ACTH independent causes?
Measure morning (8:00am) cortisol and ACTH levels. If ACTH is elevated, Cushing’s disease or ectopic ACTH is likely.
adrenal imaging should be ordered when :
only if the work up suggests ACTH-independent etiology (high risk of adrenal incdentalomas)
treatment for cushings syndrome :
surgical resection of source
inhibitors of adrenal steroigogenesis in case of bilateral adrenal hyperplasia
permenant hormone replacment therapy
destruction of adrenal cortex leading to glucocorticoid (cortisol)
and mineralocorticoid (aldosterone) deficiency :
addisons disease(usually autoimmune)
-other causes:
TB
adrenal metastases
lymphoma
HIV
adrenal hemorrhage
adrenal disease cauing hyperpigmentation:
addisons disease
diagnosis of addisons diseas:
-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
primary treatment of Addison’s disease:
glucocorticoid and mineralocorticoid replacement therapy
secondary / tertiary treatment of Addison’s disease:
only glucocorticoid replacement is necessary (mineralocorticoid production is not ACTH dependent )
treatment of adrenal crisis :
IV steroids to correct electrolyte abnormalities
50% dextrose to correct hypoglycemia and initiate aggressive volume resuscitation
how should chronic steroid therapy be stopped ?
tapered slowly to avoid secondary / tertiary Addison’s disease
subacute forms of thyroditis present with :
tender thyroid , malaise , URI symptoms
all others are associated with painless goiter
treatment for thyroditis :
beta blockers for hyperthyroidism
levothyroxine for hypothyroidism
for severe cases : NSAID or oral corticosteroid
