1
NBME 25
NBME 25 EXAM (NEW 2025/ 2026
UPDATE) QUESTIONS & ANSWERS| GRADE A|
100% CORRECT (VERIFIED SOLUTION)
1. Describe the sound and location of tricuspid regurgitation
murmur?: Holosystolic murmur best heard at the left lower sternal
border
2. What is the treatment for herpes simplex virus and varicella
zoster virus?-
: Guanosine analogs such as acyclovir, famciclovir, valacyclovir
3. How does acyclovir, famciclovir, and valacyclovir work?:
Inhibits viral DNA polymerase
First, they are phosphorylated by the viral thymidine kinase. Then,
they are able to inhibit viral DNA polymerase by terminating the
nascent DNA chain during replication.
4. How does HSV or VZV confer resistance to guanosine
analogs?: Mutation in the viral thymidine kinase enzyme
NBME 25
,Guanosine analog would not be phosphorylated and thus cannot inhibit
viral DNA polymerase.
5. How does lithium carbonate cause nephrogenic diabetes
insipidus?: Lithium concentrates in the renal collecting duct, which
then interferes with the signaling pathway of ADH
Inhibits c-AMP-mediated pathway in the renal collecting duct
6. What is the pathophysiology of nephrogenic diabetes
insipidus?: Renal collecting duct becomes insensitive to ADH.
7. How does antidiuretic hormone work?: ADH is released by the
posterior pituitary in response to hypovolemia.
It increases aquaporin channels in the cortical collecting duct via a c-
AMP mediated pathway. This then reclaims free water -> increase
volume and decrease serum osmolality.
8. What are lab findings associated with nephrogenic diabetes
insipidus?: Increased serum osmolarity
Hypernatremia
Inappropritely dilute urine
, 3
NBME 25
9. How can nephrogenic DI be differentiated from central DI?:
Desmopressin (ADH analog)
Nephorgenic DI - No response
Central DI - decrease urine output and serum osmolarity
10. What is the pathophysiology of central diabetes insipidous?:
Absence of
ADH caused by head trauma, hypothalamic damage, pituitary tumor
11. What is the pathophysiology of volume depletion in
hyperglycemia?: Osmotic diuresis due to increased amounts of
glucose in the renal tubules.
Nephron can recover filtered glucose up to 180 mg/dL but beyond a
threshold of 300 md/dL of glucose, glucosuria and osmotic diuresis.
12. What is the treatment for nephrogenic DI?: Volume repletion
and thiazide diuretics
13. How does anorexia nervosa lead to amenorrhea and pubertal
delay/arrest?: Insufficient nutrition and weight loss leads to
NBME 25
NBME 25
NBME 25 EXAM (NEW 2025/ 2026
UPDATE) QUESTIONS & ANSWERS| GRADE A|
100% CORRECT (VERIFIED SOLUTION)
1. Describe the sound and location of tricuspid regurgitation
murmur?: Holosystolic murmur best heard at the left lower sternal
border
2. What is the treatment for herpes simplex virus and varicella
zoster virus?-
: Guanosine analogs such as acyclovir, famciclovir, valacyclovir
3. How does acyclovir, famciclovir, and valacyclovir work?:
Inhibits viral DNA polymerase
First, they are phosphorylated by the viral thymidine kinase. Then,
they are able to inhibit viral DNA polymerase by terminating the
nascent DNA chain during replication.
4. How does HSV or VZV confer resistance to guanosine
analogs?: Mutation in the viral thymidine kinase enzyme
NBME 25
,Guanosine analog would not be phosphorylated and thus cannot inhibit
viral DNA polymerase.
5. How does lithium carbonate cause nephrogenic diabetes
insipidus?: Lithium concentrates in the renal collecting duct, which
then interferes with the signaling pathway of ADH
Inhibits c-AMP-mediated pathway in the renal collecting duct
6. What is the pathophysiology of nephrogenic diabetes
insipidus?: Renal collecting duct becomes insensitive to ADH.
7. How does antidiuretic hormone work?: ADH is released by the
posterior pituitary in response to hypovolemia.
It increases aquaporin channels in the cortical collecting duct via a c-
AMP mediated pathway. This then reclaims free water -> increase
volume and decrease serum osmolality.
8. What are lab findings associated with nephrogenic diabetes
insipidus?: Increased serum osmolarity
Hypernatremia
Inappropritely dilute urine
, 3
NBME 25
9. How can nephrogenic DI be differentiated from central DI?:
Desmopressin (ADH analog)
Nephorgenic DI - No response
Central DI - decrease urine output and serum osmolarity
10. What is the pathophysiology of central diabetes insipidous?:
Absence of
ADH caused by head trauma, hypothalamic damage, pituitary tumor
11. What is the pathophysiology of volume depletion in
hyperglycemia?: Osmotic diuresis due to increased amounts of
glucose in the renal tubules.
Nephron can recover filtered glucose up to 180 mg/dL but beyond a
threshold of 300 md/dL of glucose, glucosuria and osmotic diuresis.
12. What is the treatment for nephrogenic DI?: Volume repletion
and thiazide diuretics
13. How does anorexia nervosa lead to amenorrhea and pubertal
delay/arrest?: Insufficient nutrition and weight loss leads to
NBME 25
