NBSME Review topics

Question 1

Atrial natiuretic peptide (source, cause, effect)

Answer 1

Released from atrial myocytes in response to increased blood volume and atrial pressure

Acts via cGMP

Causes vasodilation and decreased Na+ reabsorption at the collecting duct

Dilates afferent arteriole and constricts efferent (increased GFR), promoting diuresis and contributing to aldosterone escape” mechanism (decreased Na+ reabsorption)

Question 2

B-type (brain) natriuretic peptide

Answer 2

Released from ventricular myocytes in response to increased tension

Similar physiologic action to ANP, with longer half-life:
Causes vasodilation and decreased Na+ reabsorption at the collecting duct;
Dilates afferent arteriole and constricts efferent, promoting diuresis and contributing to aldosterone escape” mechanism

BNP blood test used for diagnosis of heart failure

Question 3

Crigler-Najjar Syndrome

Answer 3

Absence of uridine glucuronyl transferase (UGT) - hepatic enzyme that conjugates bilirubin

Increased unconjugated bilirubin

Findings: Jaundice, kernicterus (bilirubin deposition in the brain; usually fatal

Question 4

21-hydroxylase deficiency

• Levels of aldosterone, cortisol, and sex hormones (high/low)
• Genitalia in males and females

Answer 4

Most common type of Congenital adrenal hyperplasia (CAH)

• Will be deficient in mineralocorticoids and cortisol
• Excess androgen will cause virilization in females

Labs:
-Hyponatremia (life-threatening salt-wasting) and hyperkalemia due to aldosterone deficiency

Test by measuring immediate precursor: 17-hydroxyprogesterone

Question 5

Dubin Johnson syndrome

Answer 5

Deficiency of bilirubin canalicular transport protein, MRP2 (cannot move CB from liver to bile ducts)

Findings: black liver, otherwise not clinically significant

Question 6

Annular pancreas

Answer 6

Due to abnormal migration of the ventral pancreatic bud

Question 7

What is stomatitis?

Answer 7

Oral/mucosal inflammation

Question 8

21-hydroxylase deficiency

Answer 8

Most common type of Congenital adrenal hyperplasia (CAH)

Will be deficient in mineralocorticoids and cortisol

Question 9

17-alpha-hydroxylase deficiency

• Levels of aldosterone, cortisol, and sex hormones (high/low)
• Genitalia in males and females

Answer 9

Type of CAH

• Will be deficient in Cortisol and steroids with excess Aldosterone
• Affected males are born undervirilized due to deficient testosterone
• Affected females are born with normal genitalie but fail to develope sex characteristics at puberty

Labs:
-Hypernatremia (HTN) and hypokalemia due to excess aldosterone

Question 10

11-beta-hydroxylase deficiency

• Levels of aldosterone, cortisol, and sex hormones (high/low)
• Genitalia in males and females

Answer 10

2nd most common type of CAH

• Will be deficient in Aldosterone and cortisol but will have excess 11-deoxycorticosterone (aldosterone precursor)
• Excess androgens
• Affected females will be virilized

Labs:
-11-deoxycorticosterone is still a potent mineralocorticoid so there will still be salt retention (HTN) and hypokalemia