Flashcards in Endocrinology Deck (36):
What is the most common etiology of primary hyperparathyroidism?
The most common etiology is a single adenoma.
What EKG finding will be seen in hypercalcemia?
A shortened QT interval will be seen. Conversely, hypocalcemia will demonstrate a prolonged QT interval.
What are the classic symptoms of hypercalcemia?
“Bones, Stones, abdominal moans, and psychic groans”
a. osteolitis, fibrosa cystica
b. renal stones
c. anorexia, nausea, constipation
d. lethargy, depression, psychosis
What are the two most common causes of secondary hyperparathyroidism?
1. Chronic renal failure
2. Vitamin D deficiency
What are chvostek and trousseau sign?
These are physical exam findings consistent with hypercalcemia
1. Chvostek – tapping in front of the tragus will illicit facial twitching.
2. Trousseau – Inflating blood pressure cuff over the arm will lead to tetany
What physical exam findings differentiate graves disease from other causes of hyperthyroidism?
Graves disease is the only form of hyperthyroid that will present with eye and skin manifestations.
What is the only cause of hyperthyroidism that will present with an elevated TSH and free T4?
Pituitary adenoma. The next best step is MRI of the pituitary.
What will radioactive iodine uptake show in Graves?
Graves is the only form of hyperthyroidism that will have an increased uptake scan. All others will demonstrate a decreased uptake.
36 y/o patient, 8 weeks gestation, is presenting with palpitations, anxiety, and exophthalmos. TSH is suppressed. What is the treatment of choice?
PTU should be the treatment of choice for hyperthyroidism during the first trimester. Afterwards, the medication is switched to methimazole.
What is the most common etiology of hypothyroidism?
24 year old female has a suppressed TSH and free T4. What test must be ordered prior to initiating levothyroxine therapy?
This patient’s lab findings are consistent with central hypothyroidism. An ACTH stimulation test should be ordered to evaluate adrenal gland function. Starting levothyroxine in a patient without functioning adrenal glands will result in adrenal crisis. If the patient has adrenal insufficiency, give glucocorticoids with levothyroxine.
What risk factors increase the risk of malignancy when evaluating a thyroid nodule?
1. History of head and neck radiation
2. >60 years of age
A patient is discovered to have a .8cm nodule. What is the next step in management?
The next step is to order a TSH.
What does a radionuclide iodine uptake scan show us when evaluating a thyroid nodule?
It will classify the nodule as hyperfunctioning (warm) or non-functioning (cold). Those which are non-functioning (cold) are at increased risk for malignancy and should be biopsied. Those which are non-functioning (warm) have a low risk for malignancy and should be evaluated with ultrasound.
If risk factors for malignancy are present, what is the nodule size threshold for biopsy? What if no risk factors are present?
.5cm and larger nodules with risk factors requires biopsy.
Why do patients with Cushings have hyperpigmentation?
An elevated ACTH for whatever reason will lead to hyperpigmentation.
What are the three screening tests that can be used in the workup of Cushings disease?
1. 24 hour urinary free cortisol level
2. Low dose dexamethasone test
3. Late night salivary test
40 year old patient is presenting with signs and symptom of Cushings. The patient has a low ACTH. What is the next best step in management?
A low ACTH means that the Cushings is independent of ACTH. Cortisol is being produced in the absence of ACTH stimulation. This means that the cause is from the source of corti- sol production: adrenal glands. The next step is CT of the adrenal glands.
What if the above patient had an elevated ACTH?
An elevated level means that ACTH is needed for the rise in cortisol. The cortisol is elevated because ACTH is being oversecreted. This means we have a dependent cause: lung tumor or pituitary adenoma. The next step is a high dose dexamethasone test to differentiate the two.
What electrolyte abnormalities are seen in patients with Addisons?
A patient is suspected of having Addisons diease. ACTH stimulation is done. After administration of ACTH, cortisol levels rise. What does this tell us about the patients adrenal glands?
This signifies that the adrenal glands are working adequately and adrenal insufficiency has been ruled out. A subnormal response rules in adrenal insufficiency (true for both primary and secondary causes).
46 year old male patient is complaining of swelling of the hands and feet. He states that his wedding ring no longer fits. He has also noticed he has gone up three shoe sizes as of late. Physical exam reveals the patient to be hypertensive and diabetic. What is the first test ordered in the evaluation of this patient?
This patient is showing signs and symptoms consistent with acromegaly. The first test ordered should be insulin like growth factor. This will be increased in patient with acromegaly.
What does dopamine do to prolactin?
Dopamine will inhibit prolactin.
What is the hook effect?
This is an artificially low value secondary to a prolactinoma.
Most medications will not raise a prolactin over what level?
A prolactin will usually not exceed 100 from medications.
What is the first line treatment for a prolactinoma?
First line treatment is cabergoline - a dopamine agonist.
A fasting glucose over what value is diagnostic for diabetes?
A fasting glucose >126 is consistent with diabetes.
Will patients with type 1 DM have a low or high c-peptide? Why?
C-peptide is secreted along with insulin and is used to determine if a patient is producing insulin. A person with type 1 DM cannot produce insulin, therefore, their c-peptide levels will be low.
What is the target HA1c for the management of diabetes?
The target HA1c is
What is the mechanism of action for metformin?
Metformin increases insulin sensitivity and stops gluconeogenesis. Metformin will never lead to hypoglycemia.
Why should metformin be avoided in patients with an elevated creatinine?
Metformin is renally excreted. Those with renal impairment can form a buildup of metformin and lactate, increasing the risk of lactic acidosis.
What is the blood pressure goal in patients who are diabetic?
The JNC 8 guidelines state that a diabetic have a blood pressure
What happens to potassium levels durin DKA?
Regardless of what the serum potassium levels show, these patients are hypokalemic. Potassium leaves the cell, so that hydrogen ions can enter the cell. It is for this reason that the patient might appear to be hyperkalemic, but in reality have low total body stores.
When should screening start for hyperlipidemia in patients without risk factors?
Males >35 and Females >45.
What is the only lipid lowering therapy that has proven benefit in terms of mortality?
Statins are the only medication that has proven benefit in terms of mortality.