Endocrine Flashcards
T3/T4 is low and TSH is up
primary hypothyroid
What causes Primary hypothyroidism
Autoimmued dz (hashimotos) Thyroid can’t release T3/T4. T3/T4 acts as a negative feedback to the pituitary so when it is low the pituitary will think there isn’t enough TSH so will pump out more Resulting in High TSH and Low T3/T4
T3/T4 is LOW and TSH is low
Secondary hypothyroid
What causes secondary hypothyroid
The pituitary isn’t producing enough TSH so the thyroid isn’t being told to produce T3/T4. This is because the problem is with the feedback response. T3/T4 although low is not getting the message through to the pituitary to produce more TSH
If you have a low TSH and FT4 what should you do next?
Test all the other hormones. Secondary hypothyroid is concerning for pituitary hypothalamic dysfunction. MRI of the brain should be done too
TSI is high, TRH is low, TSH is low and T3/T4 is markedly elevated
primary hyperthyroidism (Graves)
describe what happens in primary hyperthroidism
An excess of thyroid stimulating immunoglobulins bind to TSH receptors and stimulate them causing an increase of T3T4. The T3/T4 then tells the pituitary to dec production of TSH and the hypothalamus to dec production of TRH
TSI is nml, TRH is low, TSH is markedly elevated as well as T3/T4
2nd Hyperthyroidism
Why does 2nd hyperthyroid occur?
TSH secreting adenoma releases tons of TSH regardless of feedback loop. T3/T4 is produced en masse which tells the hypothalamus to dec. TRH
Management of Thyroid storm
Methimazole, PTU BBlockers for sx relief IV fluids
Highly suspicious nodule on RAIU
Cold (no iodine uptake)
signs of hyperarathyroidism
stones bones abdominal groans psychic moans
Hyperparathyroidism is caused by what?
Excess PTH production
MC cause of primary hyperparathyroid
Parathyroid adenoma
Hyperparathyroidism results in what imbalance in the body?
Hypercalcemia
signs of hypocalcemia
Trousseau and Chvostek’s signs
perioral paresthesias
inc DTR
Carpopedal spasm
Describe
Hypocalcemia
Prolonged QT interval
Describe
Dx
Hypercalcemia
Short QT interval, long PR interval, QRS widening
In a child w/ Delayed fontanel closure, growth retardation, delayed dentition, costal cartilage enlargement and bowing of long bones what do you think?
Rickets
Etiology of Rickets
Vid D deficiency leads to dec calcium and phosphate and soft bones
Tx for Rickets
vit D supplementation, and ca supplementation
Addisions disease
Adrenal gland desttruction causing lack of cortisol AND aldosterone
Difference between 2nd and 1ry Adrenocortical insuff.
2ry usually has intact aldosterone function
Because of this Addisons (1ry) has additional sx of - Hyperpigmentation, horthostatic hypotension, hyperkalemia, hyponatremia, and dec libido (sex hromones) in women.
Low ACTH + Low cortisol
Secondary adrenocortical insuff.
Tx ofr adrenocortical insuff.
Hormone replacement
Glucocorticoids, mineralocorticoids in addisons
When do we use fludorcortisone in adrenocortical insuff.
When it is primary (addisons
Tx for Addisonian crisis
IV fluids to correct hypotension, and hypovolemia (D5NS if hypoglyc)
Glucocorticoids (dexamethasone if undx, hydrocortisone if Add known)
Reversal of lyte abnor. (Hyponat, hyperka, hypogly, hypercal)
Fludricortisone
Cushing’s Syndrome
Sx and sg related to cortisol excess
Cushing’s Disease
Cushings syndrome cased specifically by Pituitary increase of ACTH secretion
Sx of Cushings
Central obesity
moon facies
buffalo hump
SCV fat pads
Extremity wasting
Wt gain, hypokalemia
acanthosis nigricans
psychosis
Etiologies of cushings
Iatrogenic : long-term high dosecorticosteroid tx.
benign pituitary adenoma or hyperplasia
Screening test for cushings
Low dose dexamethasone suppression (NO Suppression = Cushing)
24h urinary free cortisol levels (inc=cushi)
Differentiating tests for Cushings
High dose dexamethasone supp:
no supp = cushing dz
supp = Adrenal or ectopic ACTH producing tumor
Tx for cushings
Cushing dz - Transphenoidal surgery
Ectopic or adrenal tumors - removal, ketaconazole in non operative
Iatrogenc steroid tx - Gradual steroid withdrawal (to prevent addisonian crisis)
