Endocrinology

Question 1

Most common cause of thyroid cancer

Answer 1

1) Papillary - risk factor includes radiation to the involved field as a child
2) Follicular (second most common)
3) Medullary (1-2% of cases), associated with RET, MEN2A (pheo, hyperparathyroidism), and MEN2B (marfanoid habitus and mucosal ganlioneuromas)

Question 2

What class is liraglutide a part of? Side effect profile?

Answer 2

1) GLP-1 receptor agonist
2) Associated with weight loss
3) Screen for history of thyroid cancer (associated with medullary)
4) watch out for pancreatitis

Question 3

Diagnostic criteria for primary adrenal insufficiency? Most common etiology?

Answer 3

1) Serum cortisol less than 3 ug/dL AND
2) Elevated ACTH AND
3) Clinical features

If not all are met, consider cosyntropin testing

Most common cause is autoimmune adrenalitis (positive 21-hydroxylase antibodies)

Question 4

At what prolactin level should imaging be considered?

Answer 4

> 100 ng/mL

If level is lower (~50 ng/mL), it could be attributed to medication, hypothyroidism

Question 5

Treatment of primary adrenal insufficiency

Answer 5

Glucocorticoid and mineralocorticoid 
Usually hydrocortisone (2-3x daily) and fludrocortisone (once daily)

High doses of hydrocortisone (>40 mg/d) can be used alone

Note, if secondary adrenal insufficiency is present, only glucocorticoid therapy is required. Aldosterone secretion is not under ACTH control.

Question 6

Likely cause of progressive hirsutisim and virilization over a short period of time in a woman

Answer 6

Androgen-producing adrenal or ovarian tumor

Elevated DHEAS (>700) suggests adrenal source, as the adrenal gland is the major producer of DHEAS

Question 7

Low risk osteoporotic women can discontinue anti-resorptive therapy after how many years?

Answer 7

5 years

Low risk characteristics

• <76
• femur neck T-score above 2.5
• no prior osteoporotic fractures

Question 8

First line therapy of hirsutism, acne, menstrual dysfunction in PCOS?

Answer 8

OCPs (assuming fertility not desired)

Consider metformin (off-label use) for pre-diabetes or T2DM

Question 9

What complication can be seen in women with T1 or T2 DM who are planning pregnancy?

Answer 9

Progression of retinopathy, screen with dilated eye exam every trimester and up to one year postpartum

TSH should be monitored every 4-6 weeks once pregnancy is confirmed

Question 10

What biochemical testing is indicated for incidental adrenaloma?

Answer 10

Must have

1) Cortisol - test with LDST
2) Plasma or urine metanephrines

Consider:

3) Aldosterone if HTN/hypoK
4) Androgen excess if clinical suspicion (exam c/w androgen excess)

Question 11

Medications that interfere with metanephrine testing (eval for pheo)

Answer 11

Antidepressants that inhibit NE (amitrriptyline, nortriptyline, venlafaxine, duloxetine)

False-positive (elevates plasma NE): levodopa, buspirone, prochlorperazine, amphetamines

Question 12

Difference between type 1 and type 2 - amiodarone induced thyrotoxicosis

Answer 12

Type 1: Hyperthyroidism with underlying Graves or MNG. Treat with methimazole. U/S will have increased vascularity/flow. Thyroidectomy if refractory.

Type 2: Destructive. Occurs in pts. w/o underlying thyroid disease (more common). Can continue amiodarone if needed. Self-limiting, may require glucocorticoids.

Question 13

At what TSH should you consider treating subclinical hypothyroidism?

Answer 13

TSH > 10 uU/mL

Treat all pregnant women with subclinical hypothyroidism

Question 14

Most common ACTH-secreting malignant tumors

Answer 14

1) SCLC
2) Bronchial carcinoid
3) Pheo
4) Medullary Thyroid CA

If no pituitary tumor, non-suppressed cortisol after 8 mg dexamethasone suppression test, select CT chest/abd

Question 15

Treatment for amiodarone-induced hypothyroidism

Answer 15

Treat with levothyroxine

Can continue amiodarone, especially if therapy is indicated (recurrent arrhythmia, etc)

Question 16

Antibodies associated with latent autoimmune diabetes of adulthood (LADA)

Answer 16

Anti-islet cell (ICA)
Antibodies to glutamic acid decarboxylase (GAD)

Consider dx in patients with lower BMI, early requirement of insulin after diagnosis (due to oral meds/diet ineffective)

Question 17

Diastolic hypertension, bradycardia, tongue enlargement, puffy face/hands, hypothermia

Answer 17

Myxedema coma

Also look for hypoglycemia and hyponatremia

Question 18

Diagnostic testing for Cushing Syndrome

Answer 18

1) Low dose overnight dexamethasone suppression test (avoid if on OCPs - high FP rate)
2) Late-night salivary cortisol
3) 24-hour urine free cortisol

Once confirmed, obtain ACTH to differentiate source of excess cortisol

Question 19

Anti-hypertensive class most likely to increase risk of diabetes?

Answer 19

Thiazide diuretics