1. A 64-year-old man with chronic hepatitis B (e antigen negative, HBV DNA 40,000 IU/mL) is to begin oral antiviral therapy. His estimated glomerular filtration rate is 26 mL/min/1.73m2 and a recent scan shows osteopenia. He takes no interacting medications. Which agent is the most appropriate first-line choice?
A) Tenofovir disoproxil fumarate, because it is the safest tenofovir prodrug for the kidney
B) Pegylated interferon-alpha, because his renal and bone status make finite injectable therapy preferable
C) Tenofovir alafenamide, because its lower systemic tenofovir exposure gives a better renal and bone safety profile, making it preferred in renal impairment and low bone density
D) Lamivudine, because its low resistance barrier is offset by its renal safety in this setting
E) Entecavir at a standard 0.5 mg dose with no adjustment, because entecavir is unaffected by renal function
ANSWER: C
Rationale:
This patient has both renal impairment and low bone density, the two settings in which tenofovir alafenamide is specifically preferred over tenofovir disoproxil fumarate. Tenofovir alafenamide delivers tenofovir efficiently to hepatocytes at roughly one-tenth the dose with substantially lower systemic exposure, reducing the exposure-dependent renal tubular and bone toxicities.
Option A: Option A is incorrect because tenofovir disoproxil fumarate is the prodrug with the greater renal and bone toxicity, not the safest for the kidney.
Option B: Option B is incorrect because pegylated interferon has a heavy adverse-effect burden and is not selected on the basis of renal or bone status; it is also poorly suited to an older patient with comorbidity.
Option D: Option D is incorrect because lamivudine has a low resistance barrier that makes it a poor first-line choice, and its selection is not justified by renal safety.
Option E: Option E is incorrect because entecavir does require dose reduction in renal impairment, so a standard unadjusted dose is inappropriate at this estimated glomerular filtration rate.
2. A 51-year-old woman with chronic hepatitis B was treated with lamivudine for several years in the past. She was switched to entecavir 1 mg daily, but over the past six months her HBV DNA has risen from undetectable to 8,000 IU/mL with confirmed adherence. Genotypic testing shows M204V/M204I mutations. What is the most appropriate next step?
A) Switch to tenofovir (tenofovir disoproxil fumarate or tenofovir alafenamide), because lamivudine-associated M204V/M204I mutations cause cross-resistance that undermines entecavir, whereas tenofovir retains activity
B) Increase entecavir to 2 mg daily, because higher exposure overcomes the M204 mutations
C) Add lamivudine back to entecavir, because the combination restores susceptibility
D) Switch to pegylated interferon, because all oral agents are now ineffective
E) Continue entecavir unchanged, because the rise in HBV DNA reflects laboratory variation rather than resistance
ANSWER: A
Rationale:
The lamivudine resistance mutations M204V/M204I produce cross-resistance that markedly reduces entecavir efficacy in lamivudine-experienced patients, which explains the virologic breakthrough on entecavir despite adherence. Tenofovir retains full activity against lamivudine-resistant virus and is the correct switch.
Option B: Option B is incorrect because dose escalation does not overcome M204-mediated resistance.
Option C: Option C is incorrect because re-adding lamivudine cannot restore susceptibility to a virus already carrying lamivudine resistance mutations.
Option D: Option D is incorrect because oral agents are not uniformly ineffective; tenofovir remains effective, so interferon is unnecessary.
Option E: Option E is incorrect because a confirmed rise to 8,000 IU/mL with documented resistance mutations is virologic breakthrough, not laboratory variation.
3. A 58-year-old man is diagnosed with diffuse large B-cell lymphoma and is scheduled to begin R-CHOP chemotherapy (which includes rituximab, an anti-CD20 antibody). Screening shows hepatitis B surface antigen positive with HBV DNA 1,200 IU/mL. He has no symptoms of liver disease. What is the most appropriate hepatitis B management before starting chemotherapy?
A) Withhold antiviral therapy and recheck HBV DNA only if alanine aminotransferase rises during chemotherapy
B) Administer hepatitis B immune globulin as a single dose at the start of chemotherapy
C) Begin pegylated interferon-alpha for the duration of chemotherapy
D) Defer treatment because the modest HBV DNA level indicates no reactivation risk
E) Start prophylactic nucleos(t)ide analogue therapy (tenofovir alafenamide or entecavir preferred) before chemotherapy and continue it after completion, because a surface antigen positive patient receiving anti-CD20 therapy is at high risk of reactivation that can cause acute liver failure
ANSWER: E
Rationale:
A hepatitis B surface antigen positive patient about to receive a high-risk regimen such as rituximab-containing chemotherapy requires prophylactic nucleos(t)ide analogue therapy (tenofovir alafenamide or entecavir preferred) started before and continued after treatment, because reactivation in this setting can progress to acute liver failure and death.
Option A: Option A is incorrect and unsafe because waiting for alanine aminotransferase to rise forfeits the purpose of prophylaxis.
Option B: Option B is incorrect because immune globulin is not used to prevent reactivation in a chronically infected patient.
Option C: Option C is incorrect because pegylated interferon is not used as reactivation prophylaxis and is poorly tolerated alongside chemotherapy.
Option D: Option D is incorrect because reactivation risk in a surface antigen positive patient on anti-CD20 therapy is high regardless of a modest baseline HBV DNA, so deferral is inappropriate.
4. A 47-year-old treatment-naive man has chronic hepatitis C, genotype 3, with compensated cirrhosis (Child-Pugh A). His renal function is normal and he takes no interacting medications. Which regimen and duration is an appropriate pan-genotypic first-line choice?
A) Pegylated interferon plus ribavirin for 24 weeks, because genotype 3 responds best to interferon-based therapy
B) Sofosbuvir/velpatasvir for 12 weeks, a pan-genotypic regimen effective in genotype 3 including compensated cirrhosis
C) An NS5A inhibitor alone for 8 weeks, because genotype 3 is highly susceptible to NS5A monotherapy
D) Sofosbuvir monotherapy for 12 weeks, because its high resistance barrier makes a single agent sufficient
E) No antiviral therapy, because genotype 3 cirrhosis cannot achieve sustained virologic response
ANSWER: B
Rationale:
Sofosbuvir/velpatasvir is a pan-genotypic regimen active against genotype 3 — historically the most treatment-resistant genotype — and is appropriate for 12 weeks in compensated cirrhosis. This patient has normal renal function and no interacting drugs, so a sofosbuvir-containing regimen is suitable.
Option A: Option A is incorrect because interferon-based therapy is now obsolete for genotype 3 given the high cure rates and tolerability of direct-acting antivirals.
Option C: Option C is incorrect because NS5A inhibitors are never used as monotherapy owing to their low resistance barrier.
Option D: Option D is incorrect because sofosbuvir is not used as monotherapy; it is combined with at least one other class.
Option E: Option E is incorrect because genotype 3 cirrhosis can achieve high sustained virologic response rates with modern pan-genotypic regimens.
5. A 69-year-old woman with chronic hepatitis C (genotype 1, no cirrhosis) has paroxysmal atrial fibrillation maintained on amiodarone, which her cardiologist does not want to change. The pharmacy proposes a sofosbuvir/velpatasvir regimen. Renal function is normal. What is the most appropriate action?
A) Proceed with sofosbuvir/velpatasvir and add a calcium channel blocker for rate control
B) Proceed with sofosbuvir/velpatasvir but check a single electrocardiogram before the first dose, then no further monitoring
C) Discontinue amiodarone the morning of the first sofosbuvir dose, since the interaction resolves once the drug is stopped
D) Select a sofosbuvir-free regimen such as glecaprevir/pibrentasvir, because a sofosbuvir-containing regimen combined with amiodarone risks serious, potentially fatal symptomatic bradycardia
E) Withhold all hepatitis C therapy indefinitely, because amiodarone makes cure impossible
ANSWER: D
Rationale:
Amiodarone combined with a sofosbuvir-containing regimen risks serious, potentially fatal symptomatic bradycardia. With amiodarone being continued, the appropriate action is to choose a sofosbuvir-free regimen such as glecaprevir/pibrentasvir, which avoids the interaction entirely and is suitable in this genotype-1 non-cirrhotic patient with normal renal function.
Option A: Option A is incorrect because adding a rate-control agent does not mitigate the bradycardia hazard and the regimen still pairs sofosbuvir with amiodarone.
Option B: Option B is incorrect because a single pre-dose electrocardiogram is inadequate; the safe course is to avoid the combination rather than to monitor lightly.
Option C: Option C is incorrect because amiodarone has an extremely long half-life (weeks), so same-day discontinuation does not promptly remove the risk.
Option E: Option E is incorrect because cure is readily achievable by selecting a sofosbuvir-free regimen; withholding therapy is unwarranted.
6. A 60-year-old man with end-stage renal disease on maintenance hemodialysis has chronic hepatitis C (genotype 2, no cirrhosis). He is treatment-naive and takes no interacting medications. Which regimen is the most appropriate choice given his renal status?
A) Sofosbuvir/velpatasvir at full dose, because sofosbuvir is removed by dialysis and therefore safe
B) Sofosbuvir/velpatasvir with the sofosbuvir dose halved, to account for metabolite accumulation
C) Pegylated interferon plus ribavirin, because direct-acting antivirals cannot be used in dialysis
D) Sofosbuvir monotherapy, because dialysis clears the inactive metabolite between sessions
E) Glecaprevir/pibrentasvir, because it contains no sofosbuvir and requires no dose adjustment in renal impairment, making it preferred in advanced chronic kidney disease including dialysis
ANSWER: E
Rationale:
Glecaprevir/pibrentasvir contains no sofosbuvir component and requires no dose adjustment in renal impairment, making it the preferred pan-genotypic regimen for patients with advanced chronic kidney disease, including those on dialysis.
Option A: Option A is incorrect because sofosbuvir's inactive metabolite accumulates in severe renal impairment, and relying on dialysis removal is not the established approach; a sofosbuvir-free regimen is preferred.
Option B: Option B is incorrect because simple dose-halving of sofosbuvir is not the recommended strategy in this setting.
Option C: Option C is incorrect because effective oral direct-acting antivirals exist for dialysis patients, so interferon and ribavirin are unnecessary.
Option D: Option D is incorrect because sofosbuvir is not used as monotherapy and metabolite accumulation makes a sofosbuvir-containing approach less suitable than a sofosbuvir-free regimen here.
7. A 55-year-old woman with chronic hepatitis C is about to start glecaprevir/pibrentasvir. Her medication list includes rosuvastatin 20 mg daily for hyperlipidemia. What is the most appropriate action regarding her statin?
A) Continue rosuvastatin unchanged, because statins do not interact with glecaprevir/pibrentasvir
B) Double the rosuvastatin dose, because the antiviral lowers statin levels
C) Stop rosuvastatin during glecaprevir/pibrentasvir therapy, because rosuvastatin is contraindicated with this regimen owing to a marked increase in statin exposure and myopathy risk
D) Switch rosuvastatin to high-dose atorvastatin with no dose limit
E) Replace the statin with pegylated interferon to avoid the interaction
ANSWER: C
Rationale:
NS3/4A protease inhibitors raise statin exposure through inhibition of CYP3A4 and the hepatic uptake transporter OATP1B, increasing myopathy risk; with glecaprevir/pibrentasvir, rosuvastatin is contraindicated, so it should be stopped during therapy.
Option A: Option A is incorrect because a clinically important statin interaction does exist with this protease inhibitor-containing regimen.
Option B: Option B is incorrect because the regimen raises, not lowers, statin exposure, so increasing the dose would worsen toxicity.
Option D: Option D is incorrect because atorvastatin requires dose capping with this regimen, not unlimited high dosing.
Option E: Option E is incorrect because pegylated interferon is not a lipid-lowering agent and is not a substitute for a statin; the correct action is to hold the contraindicated statin.
8. A 62-year-old man with hepatitis C-related cirrhosis completes glecaprevir/pibrentasvir and achieves sustained virologic response at 12 weeks. He feels well and asks whether he can now stop his every-six-month liver ultrasound surveillance. What is the most appropriate counsel?
A) Stop surveillance now, because achieving sustained virologic response reverses cirrhosis and removes cancer risk
B) Continue hepatocellular carcinoma surveillance, because the residual cirrhosis still carries cancer risk even after the virus is cured
C) Reduce surveillance to once every five years, because cure lowers the risk to that of the general population
D) Replace ultrasound with annual alanine aminotransferase testing alone, since normal enzymes exclude cancer
E) Stop surveillance and instead monitor only HCV RNA, since detectable virus is the sole driver of cancer risk
ANSWER: B
Rationale:
Sustained virologic response reduces but does not eliminate hepatocellular carcinoma risk, and the structural cirrhosis persists after the virus is cleared, so ongoing hepatocellular carcinoma surveillance is required in patients with cirrhosis after cure.
Option A: Option A is incorrect because cure does not fully reverse cirrhosis or abolish cancer risk.
Option C: Option C is incorrect because risk in a cirrhotic liver does not fall to general-population levels after cure, so extending the interval to five years is unsafe.
Option D: Option D is incorrect because normal aminotransferases do not exclude hepatocellular carcinoma, and enzyme testing is not a substitute for imaging surveillance.
Option E: Option E is incorrect because hepatocellular carcinoma can arise in a cured but cirrhotic liver; active viral replication is not the sole driver of risk.
9. A 38-year-old man who emigrated from a region where hepatitis D is endemic has chronic hepatitis B. Despite an HBV DNA of only 900 IU/mL, he has marked transaminase elevation, advancing fibrosis on elastography, and clinical features more severe than his HBV DNA would predict. What is the most appropriate next diagnostic step?
A) Repeat the HBV DNA in three months and take no further action now, since the current level is low
B) Begin empiric pegylated interferon without further testing, since severe hepatitis B warrants immediate treatment
C) Order a liver biopsy as the only way to explain the disease severity
D) Reassure the patient that the severity is expected for hepatitis B and pursue no additional workup
E) Test for anti-hepatitis D virus antibody given the disproportionate severity and endemic-region origin, and confirm active infection with HDV RNA quantification, since anti-HDV IgG reflects exposure but does not distinguish active from resolved infection
ANSWER: E
Rationale:
Disease severity out of proportion to the HBV DNA level, combined with origin from an endemic region, is a classic clue to hepatitis D superinfection, which is frequently missed because anti-HDV testing is not part of the routine hepatitis B panel. The correct step is to test for anti-HDV antibody and, because anti-HDV IgG reflects exposure rather than active replication, to confirm active infection with HDV RNA quantification.
Option A: Option A is incorrect because simply repeating HBV DNA ignores the most likely explanation and delays diagnosis.
Option B: Option B is incorrect because empiric interferon without establishing the diagnosis is inappropriate, and hepatitis D management depends on confirming the infection first.
Option C: Option C is incorrect because the diagnosis is made serologically and by HDV RNA, not primarily by biopsy.
Option D: Option D is incorrect because the severity is not expected for low-level hepatitis B alone and warrants testing for hepatitis D.
10. A 24-year-old woman is brought to the emergency department reporting an intentional acetaminophen overdose approximately 16 hours earlier. She is nauseated with mild right upper quadrant tenderness. A serum acetaminophen level has been sent but results are not yet back. What is the most appropriate immediate action?
A) Wait for the serum acetaminophen level before deciding whether to treat, since treatment at 16 hours is futile
B) Administer activated charcoal as the definitive treatment, since it is now too late for the antidote
C) Give oral N-acetylcysteine loading despite her nausea, since the oral route is always preferred
D) Initiate intravenous N-acetylcysteine now without waiting for the acetaminophen level, because the history is consistent with a toxic ingestion and N-acetylcysteine still confers benefit at this time point
E) Discharge her with outpatient follow-up, since 16 hours without fulminant symptoms indicates no significant risk
ANSWER: D
Rationale:
When the history is consistent with a toxic acetaminophen ingestion, intravenous N-acetylcysteine should be started promptly without waiting for the serum level, because efficacy — though greatest within roughly 8 to 10 hours — is reduced but not lost at later time points, and delay forfeits benefit.
Option A: Option A is incorrect because waiting for the level delays therapy, and treatment at 16 hours is not futile.
Option B: Option B is incorrect because activated charcoal is most useful early after ingestion and is not the definitive treatment; N-acetylcysteine is the antidote.
Option C: Option C is incorrect because oral loading is specifically avoided in a nauseated or potentially encephalopathic patient owing to aspiration risk, and intravenous administration is appropriate here.
Option E: Option E is incorrect and dangerous because the absence of fulminant symptoms at 16 hours does not exclude significant toxicity; hepatotoxicity characteristically evolves over the following days.
11. A 44-year-old woman develops acute liver failure attributed to an idiosyncratic reaction to an herbal supplement (a non-acetaminophen cause). She has grade II hepatic encephalopathy and a prothrombin time of 110 seconds (international normalized ratio 6.8). She has no pre-existing liver disease. What is the most appropriate combined management?
A) Start intravenous N-acetylcysteine and urgently contact a transplant center for listing, because the prothrombin time exceeding 100 seconds meets a King's College Criterion for non-acetaminophen acute liver failure, and N-acetylcysteine improves transplant-free survival in non-acetaminophen disease with greatest benefit in early-grade (I-II) encephalopathy
B) Withhold N-acetylcysteine because it benefits only acetaminophen toxicity, and observe without transplant referral
C) Give high-dose corticosteroids as first-line therapy and reserve transplant referral for steroid failure
D) Delay transplant evaluation until grade IV encephalopathy develops, since earlier listing is premature
E) Administer lactulose titrated to aggressive catharsis as the primary intervention to reverse the liver failure
ANSWER: A
Rationale:
This patient's prothrombin time above 100 seconds independently meets a King's College Criterion for non-acetaminophen acute liver failure, prompting urgent transplant listing. Concurrently, intravenous N-acetylcysteine improves transplant-free survival in non-acetaminophen disease, with the benefit concentrated in early-grade (I-II) encephalopathy — exactly this patient's stage — so both actions should occur together.
Option B: Option B is incorrect because N-acetylcysteine is now recommended in non-acetaminophen acute liver failure, and forgoing transplant referral is unsafe.
Option C: Option C is incorrect because high-dose corticosteroids are not established first-line therapy for this presentation, and delaying transplant referral is inappropriate.
Option D: Option D is incorrect because waiting for grade IV encephalopathy forfeits both the N-acetylcysteine window of greatest benefit and timely transplant listing.
Option E: Option E is incorrect because lactulose has limited evidence in acute liver failure and aggressive catharsis is harmful; it is not the primary intervention.
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