Endocrine Weight Loss Endocrine Disorders 5 — Questions and Answers
Question 1: Which surgical weight-loss procedure most dramatically alters gut hormone profiles (GLP-1, PYY) to reduce appetite beyond mechanical restriction?
- Laparoscopic adjustable gastric banding
- Roux-en-Y gastric bypass (Correct answer)
- Gastric sleeve (sleeve gastrectomy)
- Intragastric balloon
Correct answer: Roux-en-Y gastric bypass
Roux-en-Y gastric bypass produces the most pronounced post-meal GLP-1 and PYY surges, substantially reducing appetite through neuroendocrine mechanisms.
Question 2: A woman with PCOS, obesity, and insulin resistance is started on metformin. What is metformin's primary mechanism benefiting PCOS?
- Stimulates ovarian estrogen production
- Reduces insulin levels by improving insulin sensitivity, lowering androgen excess (Correct answer)
- Directly inhibits LH secretion from the pituitary
- Increases sex hormone-binding globulin (SHBG) directly
Correct answer: Reduces insulin levels by improving insulin sensitivity, lowering androgen excess
Metformin improves hepatic and peripheral insulin sensitivity, reducing hyperinsulinemia, which in turn lowers ovarian androgen production in PCOS.
Question 3: Which condition is associated with acanthosis nigricans (dark velvety skin in body folds) and strongly signals underlying insulin resistance?
- Addison's disease
- Hypothyroidism
- Insulin resistance / hyperinsulinemia (Correct answer)
- Hyperthyroidism
Correct answer: Insulin resistance / hyperinsulinemia
Acanthosis nigricans is caused by insulin stimulating keratinocyte proliferation via IGF-1 receptors, making it a cutaneous marker of insulin resistance.
Question 4: In which clinical scenario would measuring serum IGF-1 be most diagnostically relevant for evaluating weight and body composition changes?
- Suspected hypothyroidism
- Suspected acromegaly or growth hormone deficiency (Correct answer)
- Evaluation of cortisol excess
- Assessment of PCOS
Correct answer: Suspected acromegaly or growth hormone deficiency
IGF-1 (insulin-like growth factor-1) is the primary screening test for both acromegaly (excess GH) and adult GH deficiency, which affect body composition.
Question 5: Which mechanism explains why patients with hypothyroidism often retain fluid and gain weight even before significant fat accumulation occurs?
- Increased aldosterone secretion
- Accumulation of glycosaminoglycans causing myxedematous fluid retention (Correct answer)
- Excess ADH causing water retention
- Increased cortisol causing sodium retention
Correct answer: Accumulation of glycosaminoglycans causing myxedematous fluid retention
Hypothyroidism leads to accumulation of hydrophilic glycosaminoglycans in interstitial tissues, causing the characteristic non-pitting myxedema and water weight gain.
Question 6: A patient with type 2 diabetes taking a sodium-glucose cotransporter-2 (SGLT2) inhibitor loses 5 lbs. What is the primary mechanism of weight loss?
- Reduced appetite via central GLP-1 receptors
- Urinary glucose excretion causing caloric loss (Correct answer)
- Increased thyroid hormone production
- Suppression of glucagon secretion
Correct answer: Urinary glucose excretion causing caloric loss
SGLT2 inhibitors block glucose reabsorption in the proximal tubule, causing glycosuria (urinary glucose loss) that represents a real caloric deficit leading to modest weight loss.
Question 7: Which endocrine disorder presents with weight gain, hypertension, hypokalemia, and low renin due to excess aldosterone?
- Cushing's syndrome
- Primary hyperaldosteronism (Conn's syndrome) (Correct answer)
- Pheochromocytoma
- Hypothyroidism
Correct answer: Primary hyperaldosteronism (Conn's syndrome)
Primary hyperaldosteronism (Conn's syndrome) is characterized by autonomous aldosterone excess causing sodium retention, hypertension, hypokalemia, and suppressed renin.
Endocrine Weight Loss Endocrine Disorders 5
Which surgical weight-loss procedure most dramatically alters gut hormone profiles (GLP-1, PYY) to reduce appetite beyond mechanical restriction?