Endocrinology Flashcards
(42 cards)
lymphocytic hypophysitis
most cases occur during or after pregnancy
causes hypopit and possibly symptoms of a mass lesion
Explain lab findings for Hypopit (GH, FSH/LH, TSH, ACTH, Prolactin)
GH = depressed IGF-1, diminished response to insulin tolerance test
FSH/LH = depressed FSH, LH, estradiol, testosterone
TSH = depressed free T4 and TSH
ACTH = low cortisol and depressed ACTH, positive cortisol response to ACTH, (depressed response of 11-deoxycortisol and cortisol to metyrapone)
Prolactin = may be elevated due to loss of tonic inhibition
Treatment of acute pituitary apopexy
Glucocorticoids! until acute adrenal insufficiency has been ruled out. May also need urgent neurosurgical decompression,
T4 replacement is indicated only AFTER hypoadrenalism is ruled out or treated
In what cases can pituitary gland be diffusely enlarged? (not tumor)
- untreated primary hypothyroidism
2. normal pregnancy
If suspected cushings disease, what would you order?
24-hr urine cortisol excretion + dexamethasone suppression test
or
late night salivary cortisol level (elevated)
serum ACTH level (elevated or inappropriately ‘normal’)
Name 2 lab tests you should always order after diagnosis of hyperprolactinemia?
- pregnancy test
2. TSH – bc hypothyroidism can cause hyperprolactinemia
Indications for surgery for pituitary adenomas
- Secreting GH, ACTH, or TSH
- adenomas with mass effect
- visual field defects
- hypopituitarism
- prolactinomas unresponsive to dopamine agonists
How to diagnose DI?
How to differentiate between central and nephrogenic?
- Urine Osm <200 + inability to concentrate urine during water deprivation test
- Desmopressin challenge test – if positive (urine concentrates) = central DI –> order MRI pituitary. if negative (urine does not concentrate) = nephrogenic DI –> order kidney US
Treatment of Chronic central DI? Nephrogenic DI? acute DI after neurosurgery or head trauma?
- PO or IN desmopressin
- thiazide diuretic and salt restriction
- if unable to PO –> D5/0.45NS, add desmopressin if UOP high or hypernatremia
What lab tests do you order with asymptomatic empty sella?
Cortisol, TSH, free (or total) T4. If all normal - do nothing. Frequently seen in multiparous women.
name 3 forms of destructive thyroiditis. what is MOA of possibly thyrotoxicosis?
- Subacute (de Quervain), silent (painless), postpartum thyroiditis
- thyroid damage releasing preformed thyroid hormone into circulation
What are you concerned about in a patient who has sore throat or fever and taking methimazole or PTU?
presumed agranulocytosis until proven otherwise
Most important lab to check 1 week after pituitary surgery despite lack of symptoms?
Sodium
SIADH common 3-7 days post op
Initially may have DI (polyuria high-normal Na, dilute urine) followed by SIADH then again DI
Central DI may be temporary or permanent
What is one important screen to perform for diabetic female looking to get pregnant?
Dilated eye exam – b/c diabetic retinopathy gets worse with pregnancy. Monitor every trimester, and closely for 1 yr post partum.
Rapid improvement in glycemic control in the setting of retinpathy is associated with temporary worsening of retinopathy, and in pregnancy - goals are tight glycemic control.
How to treat glucocorticoid induced osteoporosis? What makes you moderate vs severe risk?
Oral bisphosphonates are 1st line in adult men/women with moderate to high fracture risk regardless of age.
In <40yo
High risk - previous osteoporotic fracture
Moderate - hip or spine BMD Z score < -3, or rapid bone loss (>10% at hip or spine over 1 yr) and continuing steroids at >7.5mg/day for >6months
what is Denosumab?
Monoclonal antibody against the receptor activator of nuclear factor κB ligand (RANKL), reduces bone resorption by inhibiting the development of osteoclasts.
Twice yearly injections, no endpoint or drug holiday like bisphosphonates
It circulates in the blood for up to 9 months after SQ injection, but once cleared from the circulation, bone resorption transiently but dramatically increases, resulting in an abrupt decline in bone mineral density and, in some cases, vertebral fractures.
When would you order calcitonin in setting of thyroid nodules?
in patients with hypercalcemia or a family history of thyroid cancer or MEN2
Indication for FNAB
thyroid nodules >1cm with normal TSH level and suspicious sonographic features
OR
thyroid nodules <1cm with risk factors of thyroid cancer or suspicious ultrasound characteristics
Name 3 ways to diagnose hypercortisolism (cushings syndrome)
1mg overnight dexamethasone suppression (fail to suppress cortisol <3mg/dL)
24hr urine cortisol (elevated) - twice
late night salivary cortisol (elevated) - twice
How to differentiate between ACTH depending or independent cushings syndrome? How about pituitary vs. ectopic source of ACTH production?
- check ACTH level
- – if <5, independent, get abd CT.
- – if >20, dependent, get pituitary MRI/CT - 8mg dexamethasone suppression. Used when you don’t find anything on MRI pituitary but ACTH is high.
- — If pituitary ACTH source - should suppress cortisol by 50%
- — If cortisol production is NOT suppressed –> ectopic tumor get CT c/a (SCLC, bronchial carcinoid, pheo, medullary thyroid cancer). If it IS suppressed – get intrapetrosal sinus sampling for ACTH to confirm pituitary source.
Pheochromocytoma is associated with these 3 conditions
- MEN2
- von Hippel-Lindae disease
- neurofibromatosis type 1
what are the 2 main causes & what labs diagnose primary hyperaldosteronism?
- aldosterone producing adrenal adenoma (40%) or bilateral adrenal hyperplasia
- aldosterone-renin activity ratio of >20 with plasma aldosterone of >15 (normal <5)
- confirm by giving high salt load (IV or PO) and having nonsuppressible elevated plasma aldosterone
- ** testing cannot be done if pt is on spironolactone or eplerenone
Secondary ammenorrhea with low estradiol + low/inapprop normal FSH and LH
Diagnosis ?
Possible causes?
- HYPOgonadotrophic hypogonadism
- hypothyroidism, hyperprolactinemia, hypothalamic (stress, weight loss, exercise), pituitary (tumor, sheehan syndrome)
“secondary”
Secondary ammenorrhea with low estradiol + high FSH and LH.
Diagnosis?
Possible causes?
- HYPERgonadotropic hypogonadism
- premature ovarian insufficiency (autoimmune), chemotherapy, pelvic radiation
“Primary”
