Endocrinology Flashcards
Nelson syndrome
rapid enlargement of pituitary adenoma after removal of both adrenal glands for Cushing’s disease; characterized by bitemporal hemianopsia and hyperpigmentation
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Dx. nelson’s syndrome
MRI - suprasellar extension of pituitary adenoma
labs - very high plasma ACTH levels (since youve taken away the adrenal’s products, which usually provide negative feedback)
tx. nelsons syndrome
surgery and/or pituitary radiation– makes sense since you just can’t have such a rapidly enlarging pituitary adenoma messing with your vision and pigment
lab findings in non-functioning pituitary adenoma
- hypogonadism - low levels of FSH and LH
- serum alpha subunit levels are elevated
note- the only symptoms the patient gets is from sheer mass effect, or from loss of normal pituitary function. if the adenoma compresses the pituitary too much, it won’t be able to make hormones normally
alpha subunit + beta subunit present in gonadotropins: hcg, LH, FSH, TSH
preferred therapy for nonfunctioning pituitary adenoma
trans-sphenoidal surgery
tx. prolactin-secreting adenomas
DA agonists ex. cabergoline
Note- MEN1 patients get prolactinoma
males with prolactinoma will have lower testosterone levels so they may have less libido
women lose their menstrual periods and have incrased breast milk production
what dyslipidemia is common in HIV pt
triglyceridemia assoc. with elevated LDL and TC; decreased HDL
tx. of hypertriglyceridemia in HIV pt on antiretroviral therapy
if TG> 500 -> fibrate medication (gemfibrozil)
if TG < 500, can use a statin
amiodarone effects on thyroid
INTRINSIC DRUG EFFECT:
- blocks thyroid hormone from entering cells
- inhibits 5’ deiodinase, so decreased conversion from T4 to T3 = decreased T3 and increased T4 levels
- less T3 binding the T3 receptor
- can cause a destructive thyroiditis
IODINE EFFECT:
- cant escape wolff-chaikoff effect
- iodine thyroid autoimmunity
- upregulates hormone production via jod-basedow effect
diagnoses of DM
- two FPG > 126 (<110 normal)
- one random glucose > 200 with symptoms
- abnormal OGTT > 200 2 hours post-load (<140 normal)
- HbA1c > 6.5%
pt with type 2 DM that is not adequately controlled with metformin - next step?
add sulfonylurea (ex glipizide)
S/E of metformin
lactic acidosis
contraindications of metformin
renal insufficiency (Cr > 1.4, CCl < 50)
use of contrast agents –> ARF
alcohol abuse
liver disease
CHF
what should you do in pt on metformin about to have a contrast procedure done?
- stop metformin 1 d prior
- if high risk for RF, give NaHCO3 or NS before procedure, adequately hydrate
DPP-IV inhibitors
sitagliptin, saxigliptin - increase insulin release and block glucagon
C/I to rosiglitazone/pioglitazone
CHF
insulin secretagogues
nateglinide, repaglinide - short acting - cause hypoglycemia
GLP analogs
exenatide, liraglutide - decrease gastric motility (increase feeling of fullness)
- increase satiety - promote weight loss
s/e exenatide or liraglutide
NV
dyspepsia
sensation of fullness/bloating
best test to determine severity of DKA
serum bicarb (also: ph < 7.3 or anion gap high)
effect of glucose on Na levels
high glucose artificially drops Na levels
which hyperlipidemia drug is C/I in diabetes
niacin - worsens glucose intolerance
“niacin not nice to diabetics”
Tx. diabetic neuropathy
gabapentin pregabalin
Tx. diabetic gastroparesis
erythromycin (gut motility stimulator and antibiotic) or metoclopramide (reglan- gut motility stimulator)
lab findings in TSH secreting adenoma
elevated TSH and T3/T4
increased serum alpha subunit levels
s/e of sulfonylrureas
hypoglycemia
SIADH
TH resistance syndrome
elevated TSH and T3/T4 symptoms of hypothyroidism
increased RAIU
Graves disease
goiter
tsh secreting adenoma
decreased RAIU
subacute/painless thyroiditis
iatrogenic/factitious disorder
Grave’s opthalmopathy
Tx. does not affect the ocular findings if severe, may lead to compression of the optic N. with visual field deficits
what intervention may decrease severity of graves ophthalmopathy
smoking - increases severity
Tx. Grave’s disease
PTU or MTZ acutely,
then RAI to ablate the gland
target TSH levels in treatment of thyroid cancer? if mets?
TSH between 0.1 and 0.3 uU/mL.
Even lower in distant mets
s/e of treatment with suppressive doses of levothyroxine
bone loss
A.fib
silent thyroiditis
autoimmune process with a nontender gland and hypothyroidism;
RAIU normal or decreased, + TPO ab
Tx. silent thyroiditis
none - spontaneously resolves
CF: Subacute thyroiditis
likely due to viral infection; pt presents with fever, tender* thyroid gland and hyperthyroid followed by hypothyroid symptoms
Lab findings in subacute thyroiditis
TSH low, T4 high
RAIU decreased
Tx. subacute thyroiditis
Aspirin propranolol - to decrease sx Steroids - if symptoms severe and not resolving with NSAIDs
only cause of hyperthyroidism with an elevated TSH
pituitary adenoma
Tx. thyroid storm
iodine PTU or MTZ dexamethasone propranolol
MCC of Hypercalcemia
Primary hyperparathyroidism
MCC hypophosphatemia
Continuous glucose infusions
Clinical presentation of hypophosphatemia
Muscle weakness, ESP. Diaphragm giving respiratory weakness Decreased cardiac contractility
When do you treat hyperparathyroidism surgically? (4)
Symptomatic disease Renal insufficiency Markedly elevated 24 hr urine calcium Very elevated serum calcium > 12.5
Presentation of acute severe hypercalcemia
Confusion Constipation Short QT syndrome Polyuria, polydipsia from nephrogenic DI Renal insuff, ATN, kidney stones
Management of acute hypercalcemia
- Hydration: 3-4 L normal saline 2. Furosemide: only after hydration has been given - if those two don’t work, can try calcitonin 3. Bisphosphonate (pamidronate) - chronic management
Clinical findings in severe Hypocalcemia
Seizures Neural twitching Arrhythmia prolonged QT
Diagnosis of Cushing syndrome
- 1 mg dexamethasone suppression test - if this fails to suppress: 2. 24 hour urine cortisol test
You find a pt to have high cortisol, high ACTH level that suppresses to high dose dexamethasone test. You suspect pituitary adenoma but MRI does not show any lesions. What should you do next?
Inferior petrosal sinus sampling
CF of Addison Disease
Fatigue, anorexia, weakness, weight loss, hypotension Thin pt with hyperpigmented skin Concomitant autoimmune disorders
Lab findings in Addison’s disease
Hyperkalemia with metabolic acidosis Hyponatremia Hypoglycemia Neutropenia Peripheral eosinophillia
Most accurate diagnostic test
Cosyntropin (ACTH) stimulation test - give ACTH , should have increase in cortisol, if no increase then you have adrenal insufficiency
Tx. Addison’s disease
- Acute crisis (ie hypotensive) - give hydrocortisone or dexamethasone (doesn’t interfere with cortisol measurement) and IVF
- Chronic - prednisone
- If still hypotensive despite steroid replacement, give fludrocortisone
CF in hyperaldosteronism
Hypertension Hypokalemia with metabolic alkalosis Weakness Nephrogenic DI from Hypokalemia (polyuria and polydipsia)
Diagnostic findings in hyperaldosteronism
Low renin Hypertension Elevated aldosterone level despite salt loading with normal saline
Tx. Hyperaldosteronism
Solitary adenoma - surgery
Hyperplasia - spironolactone
Best initial tests for pheochromocytoma
High plasma and urinary catecholamine levels
Plasma free metanephrine and VMA levels
Most accurate test for pheochromocytoma
CT or MRI of the adrenal glands
When do you do a MIBG scan for pheochromocytoma
If >5 cm in size and suspicion of extra renal disease
Positive hormone levels but negative imaging
Tx. Hypertensive crisis in pheochromocytoma
IV nitroprusside
Phentolamine
Nocardipine
Tx. Hypotensive crisis in pheo
Normal saline bolus
Pressors if no response
Tx. Hypoglycemia in pheo
IV dextrose infusion
Cardiac tachyarrhythmias
IV lidocaine or esmolol
Medical prep prior to surgery for pheo
Phenoxybenzamine for 10-14 days
Propranolol before surgery (1-2d)
Features of all types of CAH
Low aldosterone and cortisol
High ACTH levels
Tx. Prednisone
Most accurate test for prolactinoma
MRI of the brain
Best initial therapy for prolactinoma
DA agonists - bromocriptine, cabergoline
Note- dopamine inhibits prolactin release
Best initial test for acromegaly
IGF1 level
Most accurate test for acromegaly
OGTT - normally, GH is suppressed by glucose
Suppression of GH by glucose excluded acromegaly
Tx. Acromegaly
Surgical removal - transsphenoidal resection
Octreotide, cabergoline, bromocriptine - prevent release of GH
Pegvisomant
GH receptor antagonist
Testicular feminization - features
Female, who does not menstruate
Breasts present
Exam: vagina ends in blind pouch, no cervix, uterus or ovaries Genetically, XY!
CF of Klinefelters
Tall men, small testicles
XXY karyotype
Insensitivity to FSH and LH on their testicles (high levels but no testosterone is produced)
Tx. Klinefelters
Testosterone
Kallmans syndrome
Anosmia
Hypogonadism - low LH, FSH, GnRH
Pituitary apoplexy
Sudden hemorrhage into pituitary gland causing a rapid drop in cortisol level and hypotension that fails to respond to IVF
Patient ends up obtunded
Tx. Pituitary apoplexy
Stabilized with high dose steroids and IVF.
Give fludrocortisone
In what situation should you not use Ringers lactate solution
Hyperkalemia - it contains K+
think RinKKKKers laKtate
Insulin dosing prior to surgery
Admin of 1/3 usual insulin dose