Endo exam 3 diagnoses/labs Flashcards
Addisons disease
labs only
low cortisol, low aldosterone
CBC- eosinophillia, lymphocytosis
CMP- for hyponatremia and hyperkalemia
BUN /Cr
Plasma cortisol at 8 am (less than 3) and incresed ACTH to dx**
Plasma ACTH greater than 200
Rapid ACTH stim test - adm cosyntropin and measure cortisol 45 m later
Plasma Renin (should be elevated if +)
Addisons disease imaging only
CXR if TB or pneumo is expected
CT abdomen: small w/o calcification is autoimmune
Enlarged: TB, fungal, hemorrhage, metastatic
Calcifications: TB, fungal, hemorrhage, pheo, melanoma
Black calcification
Interfering factors of cortisol levels for cushings
Na+ intake, age, sex, race, pregnancy, meds, renal impairment, and menstrual phase
Menstrual. Then Salty racy, age appropriate sex
Then pregnant, whoops
+ renal
Cushings syndrome lab workup
step 1
CBC- leukocytosis w/ neutrophillia, lymphocytopenia, low eosinphils
CMP- increased glucose +/- hypernatremia, hypokalemia
Cortisol causes early release of neutrophils and less apoptosis of neutrophils
Cushing syndrome Source workup
step 2
Need 2 + tests of the following:
Dexamethasone suppression, 24 h urine free cortisol, late night salivary cortisol
What is low dose dexamethasone suppression test for cushings
1 mg PO at 11 pm and then take cortisol serum at 8 AM.
greater than 5 is +
high false positives
only do low dose dexamethasone ONCE
24 h urine free cortisol cushings
begin collection after 1st morning void, all the voids after that, + first void of next morning
test cortisol in urine
+ test is 3X more than UL of normal. do test twice
cushings - What is salivary cortisol
and interfering factors
Collected by patient at 11 PM. + if above 100.
Interfering factors- steroids, brushed teeth, oral intake, inadquate collection
Elevated levels are seen with erratic sleep schedule, preg, anticonvulsants, mental illness, alcoholism, stress
MUST HAVE 2! + abn to be included as ONE of the tests
SPAAM E
Determining the DIAGNOSIS for cushings disease after the 2 tests
step 3
2 negative means refer to endocrin d/t high index of suspicion
1/2 positive - repeat test & consider cyclic cushings
2 positive - refer to endocrinologist
Next determine cause for hypercortisolism
if not 2 positive tests then you are suspicious. everything after step 3 is just determining the cause.
How to determine cause for hypercortisolism
step 4
Serum ACTH –> determines if acth dependant vs other etiology
If ACTH low, its d/t adrenal gland and a CT of adrenal gland should be ordered
If ACTH high, its dependant on ACTH, therefore its a pitutiary tumor and you should order a MRI of the brain
What should the CT or MRI show
step 5
- CT should show adrenal gland greater than 4 cm for malignancy, in addition to growth of nodules, 10 HU density
- MRI w/ contrast should show pitutiary lesion. if greater than 5 mm, begin treatment.
If no lesion or lesion is less than 5 mm, proceed with inferior petrosal sinus sampling. They go into the brain to see whats in there.
After the inferior petrosal sinus sampling, If normal ACTH, look for ectopic sources of ACTH via CT chest/abd or a PET
yellow ottoman
Inferior petrosal sinus sampling
step 6
causes increased ACTH, and confirmes the pituitary cushings disease
Congenital Adrenal Hyperplasia workup
Newborn screening CYP21A2
Ambiguous genitalia: hormonal, genetic, chromosomal testing
BMP
Hormonal workup- CYP17 and serDHEA are increased in 21 hydroxy deficiency
imaging is NOT necessary
ABD CT done to rule out adrenal hemorrhage and pelvic US
Primary aldosteronism workup initial
BMP - hypernatremia +/- hypokalemia
metabolic acidosis
Plasma renin activity (PRA) and PAC (ald concentration)
obtain in AM in seated position. PAC/PRA ratio should be greater than 20 to 25 for dx
Do the PRA/PAC lab after 2 hrs out of bed and seated for 15-60m.
Interfering meds!
Interfering meds for primary aldosteronism dx
Bad: spironolactone, ACEi, ARB, any direct renin inhib
Good: slow release verapamil, hydralazine, terazosin, doxazosin
Confirmatory Testing for primary aldosteronism
Sodium loading PO or IV
PO is 3 d of salt, and K should be assessed each day. If low K, switch to NaCl.
24 h urine collection for ald, Na, Cr at the end
Urine Na should be greater than 250.
Urine ald greater than 12 for dx
IV- 2L over 4 h, greater than 10 is dx
Determine cause of Primary aldosteronism
CT scan - abdomen for mass
(positive results)
1.unilateral - less than 4 cm is Conn. greater than 4 is carcinoma.
2.bilateral hyperplasia- gland thickening or micronodular changes.
If Negative CT – consider adrenal vein sampling if surgery is considered, ONLY if severe uncontrolled HTN AND adrenalectomy is being considered
Pheochromocytoma workup
first step - Plasma free metanephrines is most sensitive.
second step - urine fractioned metaenphrine and creatinine; clonidine suppression test
clonidine is plasma. adm clonidine, wait 3 hr and assess plasma for metanephrines. less than 40% drop is positive.
urine - 24h collection.
Both plasma and urine should be 3X the UL of normal to be dx.
third: imaging. non-contrast of CT of adrenal gland.
if CT negative, do a CT/MRI of the chest, abd, pelvis.
MRI pref in kids and preg.
PET scan to r/o malignancy.
Adrenal Adenoma Workup
CT of adrenal gland w/o contrast, and refer to surgeon
+related labs
functional adenoma have sx
non functioning will be asymptomatic
functional adenoma greater than 1 cm that secretes steroids independantly from ACTH
Adrenal Carcinoma
Hormonal evaluation - pheo, hyperald, hypercortisolism
hyperandrogenism - FSH, LH, DHEAS, prolactin, 17 ohp, total and free testosterone
Imaging: CT abd and pelvis w/ contrast (tiger)
PET = increased uptake of radiotracer
Fine needle aspiration. only to r/o metastasis. pheo must be r/o already
fine needle not greater due to risk of tumor seeding into retroperitoneum.
Hyperprolactinemia workup
Hx of HA and vision changes means order MRI- definitive test for chiamsal syndrome
Serum PRL - more than 20 is +. get in the morning.
May be falsely incr. due to sleep, exercise, stress, breast stimulation, high protein meals
TSH and T4 levels to r/o hypothyroidism
Serum hCG pregnancy test
CMP to r/o liver and kidney dz.
Men get total and free T, LH, FSH.
Women w/ amen are ordered serum estradiol, LH, FSH for potential hypogonadism
If suspect adenoma, MRI IS DEFINITIVE.
if mass is found on sella turcica, investigate secr of other hormones should be tried.
if normal, its idiopathic hyperprolactinoma.
Growth hormone deficiency kid workup
R/o chronic systemic dz, undernutrition, inflammation, hypothyroidism, turner syndrome, skeletal disorders). if r/oed, then order a STIM test.
GH stim x2, IGF-1, IGFBP-3, Bone age Xray of distal radius
MRI if GH does NOT increase with stim (+ result), test to r/o pituitary tumor.
a CT w/ contrast is done only if MRI not available. Refer to genetic test.
GH stim test children
random serum GH not helpful!
combine GH w/ measurments of IGF-1 and IGF-1BP3. physio X2 OR pharm stim X2.
Pharm stimuli are: L dopa, clonidine, propanolol, arginine, insulin induced hypoglycemia
Green appls n dope lol + adult meds
stim performed after an overnight fast.
+ if it stays the same or changes less than 7
GH adult deficiency workup, first step
Prerequsities for diagnostic tests-
Pituitrary surgery, pituitary or hypothalamic tumor, hx cranial infection, evidence of pituitary lesion, childhood GH replacement tx, unexplained low age and sex matched IGF-1 levels
P- STL , HT
Brain infected, low IGF, replace therapy from childhood
GH adult def workup 2nd step
Pharm GH stim test - insulin +/- physiologic stimuli.unable to produce GH hormone.
under 3 is severe, 5 moderate
for diabetics, use GHRH + arginine test. its alternative to insulin. +/- physiologic stimuli
Acromegaly - adult
age and sex matched serum IGF1
Dx of acromegaly is confirmed w/ failure of GH suppression to less than 0.4 w/in 1-2 hours of PO glucose load.
Gigantism
age and sex matched serum IGF1
Dx of acromegaly is confirmed w/ failure of GH suppression to less than 0.4 w/in 1-2 hours of PO glucose load.
Hypogonadism males
Males - check testosterone in the morning (free T and serum T). low if under 240. free t low if under 35.
Verify with repeat test + serum LH/FSH and PRL.
Hypogonadism females
hCG, serum PRL, FSH/LH and TSH
stimulation w/ GnRH causing increased LH/RSH should get a normal response if intact pitutiary and hypothalmic working. If so then order MRI b/c of secondary hypogonadism
MRI of the brain. if pituitary and hypothalamic is abn
if problem at the gland, primary
if problem at the brain (secondary, then both pituitary and hypogonadism)
SIADH workup
diagnosis of exclusion
R/o first - HF, cirrhosis, CKD
Hyponatremia w/ serum hypoosmol (dilute)
Continued renal excretion of salt w/ high urine osmosles
Absence of volume depletion - normal skin turgor and normal BP
**Corrected by fluid restriction! **
+ order BMP to check renal function
Diabetes Insipidus workup
1st step- 24 h urine collection to check the total volume of urine and Cr
Urine must be 2L/24h at least to continue
2nd step- water restriction test. patients can’t drink water. urine will remain dilute if positive. (also r/o psychogenic)
3rd step- vasopressin challenge test. Desmopressin acetate is given. urine volume is measured 12 hrs before desmo is given, and 12 hrs after desmo is given.
Pts with nephrogenic DI will have NO CHANGE
Pts w/ central DI will get better from this. If we know its not genetic, or inherited from their family, then..
4th step- MRI of pituitary and hypothalamus.
MRI skull for mass lesions.
