NBME 25 TEST WITH COMPLETE SOLUTION 2023-2024
Patient had anaphylaxis following the transfusion of fresh frozen plasma. What is the
genetic deficiency? - ✔IgA deficiency. Patient with this disease may have preformed
antibodies against IgA
How does sitagliptin work? - ✔It is a competitive inhibitor of dipeptidyl peptidase-4
(DPP4). It prevents breakdown of GI incretins (ex: glucagon-like peptide, GLP-1) and
promote endogenous release of insulin.
** DPP4 inhibitor increases endogenous insulin
What are acoustic neuromas? - ✔Vestibular schwannoma
Benign tumors of Schwann cells that arise from the vestibulocochlear nerve (CN VIII).
How does acoustic neuromas cause symptoms? - ✔Lesions of CN VIII leads to
ipsilateral hearing loss and positional dizziness
Compression of the cerebellar peduncles leads to ipsilateral dysmetria
What is the classic presentation of pyloric stenosis? - ✔Male infant 3-6 weeks of age
with repeated vomiting after feeds, dehydration, and hypochloremic, hypokalemic
metabolic alkalosis
Explain the electrolyte and metabolic derangement seen with pyloric stenosis - ✔
Vomiting -> Hypochloremia
Hypovolemia + excess bicarb -> RAAS activation -> increase renal tubule bicarb
reabsorption -> Metabolic alkalosis
Metabolic alkalosis + hypovolemia + increased aldosterone -> renal potassium excretion
-> hypokalemia
How does hypokalemia worsens metabolic alkalosis? - ✔Hypokalemia further worsens
metabolic alkalosis via trans-cellular exchange or extracellular sodium and protons in for
potassium ions
IV drug user presents with tricuspid regurgitation and signs and symptoms of right-sided
heart failure. Diagnosis? - ✔Tricuspid valve endocarditis
Tricuspid valve endocarditis is associated with what organisms? - ✔Staph Aureus
Pseudomonas
Candida
, NBME 25 TEST WITH COMPLETE SOLUTION 2023-2024
Describe the sound and location of tricuspid regurgitation murmur? - ✔Holosystolic
murmur best heard at the left lower sternal border
What is the treatment for herpes simplex virus and varicella zoster virus? - ✔Guanosine
analogs such as acyclovir, famciclovir, valacyclovir
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.
How does HSV or VZV confer resistance to guanosine analogs? - ✔Mutation in the viral
thymidine kinase enzyme
Guanosine analog would not be phosphorylated and thus cannot inhibit viral DNA
polymerase.
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
What is the pathophysiology of nephrogenic diabetes insipidus? - ✔Renal collecting
duct becomes insensitive to ADH.
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.
What are lab findings associated with nephrogenic diabetes insipidus? - ✔Increased
serum osmolarity
Hypernatremia
Inappropritely dilute urine
How can nephrogenic DI be differentiated from central DI? - ✔Desmopressin (ADH
analog)
Nephorgenic DI - No response
Patient had anaphylaxis following the transfusion of fresh frozen plasma. What is the
genetic deficiency? - ✔IgA deficiency. Patient with this disease may have preformed
antibodies against IgA
How does sitagliptin work? - ✔It is a competitive inhibitor of dipeptidyl peptidase-4
(DPP4). It prevents breakdown of GI incretins (ex: glucagon-like peptide, GLP-1) and
promote endogenous release of insulin.
** DPP4 inhibitor increases endogenous insulin
What are acoustic neuromas? - ✔Vestibular schwannoma
Benign tumors of Schwann cells that arise from the vestibulocochlear nerve (CN VIII).
How does acoustic neuromas cause symptoms? - ✔Lesions of CN VIII leads to
ipsilateral hearing loss and positional dizziness
Compression of the cerebellar peduncles leads to ipsilateral dysmetria
What is the classic presentation of pyloric stenosis? - ✔Male infant 3-6 weeks of age
with repeated vomiting after feeds, dehydration, and hypochloremic, hypokalemic
metabolic alkalosis
Explain the electrolyte and metabolic derangement seen with pyloric stenosis - ✔
Vomiting -> Hypochloremia
Hypovolemia + excess bicarb -> RAAS activation -> increase renal tubule bicarb
reabsorption -> Metabolic alkalosis
Metabolic alkalosis + hypovolemia + increased aldosterone -> renal potassium excretion
-> hypokalemia
How does hypokalemia worsens metabolic alkalosis? - ✔Hypokalemia further worsens
metabolic alkalosis via trans-cellular exchange or extracellular sodium and protons in for
potassium ions
IV drug user presents with tricuspid regurgitation and signs and symptoms of right-sided
heart failure. Diagnosis? - ✔Tricuspid valve endocarditis
Tricuspid valve endocarditis is associated with what organisms? - ✔Staph Aureus
Pseudomonas
Candida
, NBME 25 TEST WITH COMPLETE SOLUTION 2023-2024
Describe the sound and location of tricuspid regurgitation murmur? - ✔Holosystolic
murmur best heard at the left lower sternal border
What is the treatment for herpes simplex virus and varicella zoster virus? - ✔Guanosine
analogs such as acyclovir, famciclovir, valacyclovir
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.
How does HSV or VZV confer resistance to guanosine analogs? - ✔Mutation in the viral
thymidine kinase enzyme
Guanosine analog would not be phosphorylated and thus cannot inhibit viral DNA
polymerase.
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
What is the pathophysiology of nephrogenic diabetes insipidus? - ✔Renal collecting
duct becomes insensitive to ADH.
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.
What are lab findings associated with nephrogenic diabetes insipidus? - ✔Increased
serum osmolarity
Hypernatremia
Inappropritely dilute urine
How can nephrogenic DI be differentiated from central DI? - ✔Desmopressin (ADH
analog)
Nephorgenic DI - No response
