Endocrine Flashcards
What will radioactive scan show in a toxic goiter?
“toxic”= makes T4
T4 up
TSH down
Normal thyroid will react to down TSH and not make T4 and will not take up iodine
Goiter is active despite any TSH stimulus and so will make T4 and take up iodine
SO RAIU will show increased uptake but only in nodular tissue
What will radioactive scan show in a Graves’ disease?
The entire thyroid gland will be hot with diffuse uptake because Thyroid Stimulating antibodies work throughout the thyroid equally.
Graves’ will show thyroid stimulating antibodies, proptosis, exophthalmos, pretibial myxedema, and a diffusely enlarged thyroid on exam.
What is the treatment for Follicular thyroid cancer?
Total thyroidectomy plus postoperative radioactive iodine.
What is the MEN type 1 syndrome?
MEN1 on chrom 11
Parathyroid tumors or hyperplasia
Pituitary tumors
Pancreatic endocrine tumors
What is the MEN type 2a syndrome?
RET on chrom 10
Parathyroid hyperplasia
Pheochromocytoma
Medullary thyroid carcinoma
Marfanoid habitus
What is the MEN type 2b syndrome?
RET on chrom 10
Pheochromocytoma
Medullary thyroid carcinoma
Mucosal neuromas- Intestinal/oral ganglioneuromatosis
Marfanoid habitus
What is the treatment for central diabetes insipidus?
Deficiency of ADH from the posterior pituitary
With exogenous ADH administration, the Diabetes Insipidus is reversed and the urine concentrates.
Treatment for central diabetes insipidus is DDAVP.
What is the treatment for nephrogenic diabetes insipidus?
Nephrogenic diabetes insipidus has no ADH-receptors. No matter how much ADH there is, endogenous or exogenous, the kidneys will not reabsorb water. Therefore, the urine osmolality will not change during the water deprivation test. This is treated with gentle diuresis (furosemide)
What is the best test to screen for diabetes?
A fasting blood glucose is the best test to screen for diabetes. It is cheap and effective, though it does require confirmatory testing. While a random glucose > 200 (any one time) gives you the diagnosis of diabetes, a fasting glucose measurement >125 on two occasions gives you diabetes.
When is the two-hour glucose tolerance test done?
When a patient is screened with a fasting glucose and screens positive (bg > 125). So retesting is indicated.
If the second fasting glucose is negative (bg < 125),
THEN a 2 hour glucose tolerance test is performed.
How do you screen for Cushing’s syndrome?
Low-Dose Dexamethasone Suppression test (which can be replaced by a 24-hour urinary cortisol) is the screening tool for Cushing’s syndrome.
Cushing’s presents with hypertension, diabetes, central obesity, moon facies (Acne), purple striae (stretch marks), and extremity wasting.
How is pheochromocytoma diagnosed?
1st- Biochem evidence- values of VMA, epinephrine, and norepinephrine in a 24-hour urinary collection.
With biochemical evidence of pheochromocytoma, the subsequent steps are imaging for a mass, then adrenal vein sampling to confirm, then resection.
MIBG scan is the choice when there is biochemical evidence of pheochromocytoma but the imaging is negative. It is possible to have ectopic tumors producing catecholamines. If you dont clearly have a mass on some imaging, but biochemically she is positive, get the MIBG.
What does the RAIU scan look like for Hashimoto’s, silent lymphocytic, and de Quervain’s thyroiditis?
All would show low T4, high TSH, and a cool thyroid on RAIU
How is primary hyperaldosteronism (conn’s syndrome) diagnosed?
Elevated Aldosterone WITHOUT an elevated renin, and an Aldo:Renin ratio >20.
Some form of confirmatory test (salt suppresion, captopril challenge, fludrocotisone suppression).
After biochemical confirmation, identifying an adrenal mass is the goal, and CTs are cheaper and just as good as MRIs for Conn’s syndrome.
What is the workup for acromegaly?
The first step is to check an Insulin-Like Growth Factor 1. Growth hormone unreliable as it is too variable throughout the day. ILGF-1, on the other hand, which GH stimulates the liver to make, is reliable.
Growth hormone levels are useful though. After the ILGF-1 is elevated, the next step is to get a glucose suppression test where the GH level fails to suppress, confirming the diagnosis.
After that, it is an MRI pituitary to see the lesion.
How does hyperosmolar hyperglycemic Non-ketotic coma present?
Combination of a low sodium because of a high glucose (hyperosmolar), a high sugar (hyperglycemic), and a coma
Make sure it is NOT DKA there is no acidosis or ketones
more common in Type II DM
How is primary adrenal failure diagnosed?
Failure of the cosyntropin stimulation test to produce any increase in cortisol levels.
Low sodium and high potassium, indicating that aldosterone is also not effective.
How is the treatment for primary adrenal failure?
both prednisone and fludrocortisone to support the cortisol and aldosterone deficiencies.
What is the treatment for a patient in DKA?
Diabetes (elevated sugar), Ketosis (ketones in the urine), and Acidosis (pH < 7.4)
1) vigorous hydration
2) Insulin
3) Potassium
since insulin shifts potassium into cells
if K is low Give fluids+K THEN Insulin
If K is high or normal.. its safe to give insulin then fluids
What is syndrome of inappropriate ADH (SIADH)?
- High ADH, water intoxication (too much)
- Low sodium (dilutional)
- concentrated high urine sodium
- Risk of seizures
Demeclocycline causes a nephrogenic diabetes insipidus by preventing the binding of ADH to its receptors and reverses the pathology.
What is diabetes inspidus?
- Low ADH, low water in body
- High sodium
- Polyuria, high urine output
- Treat w/ DDAVP (ADH)
What is the Dawn and Somogyi effects?
Dawn phenomena- early (3 AM) sugar reveals hyperglycemia (the Dawn Phenomena). While patients sleep, the liver produces glucose (gluconeogenesis) and an insufficient load of night time insulin may cause hyperglycemia
or Somogyi effects- there is too much insulin at night, leading to an undetected hypoglycemia with subsequent rebound in the morning. This is corrected by REDUCING the amount of qHS insulin.
These are differentiated by the early morning blood glucose.
What is psychogenic polydipsia?
“young woman with asymptomatic hyponatremia”
A low sodium (dilute blood) combined with a dilute urine indicates medullary washout, as caused by psychogenic polydipsia
Also look for the comatose or seizing young female without a seizure disorder whose sodium is critically low.