A 35-year-old man comes to the clinic complaining of yellow discoloration of his skin and eyes for the past week. He also complains about loss of appetite, nausea, malaise, and severe tiredness. He has no known past medical history and takes over-the-counter acetaminophen for headache. He has smoked a half pack of cigarettes every day for the last 15 years and drinks alcohol occasionally. He has been sexually active with a new partner for a month and uses condoms inconsistently. His father and mother live in China, and he visited them last year. Temperature is 37°C (98.7°F), blood pressure is 130/90 mm Hg, pulse is 90/min, respirations are 12/min, and BMI is 25 kg/m2. On physical examination, his sclera and skin are icteric. Cardiopulmonary examination is negative, no lymphadenopathy is noted, and his abdomen is tender in the right upper quadrant (RUQ). His liver is palpated 3 cm below the costal margin. On laboratory investigations:
Laboratory test
Complete blood count
Hemoglobin 15 g/dL
Leucocytes 13,000/mm3
Platelets 170,000/mm3
Basic metabolic panel
Serum Na+ 133 mEq/L
Serum K+ 3.6 mEq/L
Serum Cl- 107 mEq/L
Serum HCO3- 26 mEq/L
BUN 12 mg/dL
Liver function test
Serum bilirubin 3.4 mg/dL
Direct bilirubin 2.5 mg/dL
AST 2,100 U/L
ALT 2,435 U/L
ALP 130 U/L
What is the next best step to do in this patient?
Q22
A 27-year-old man presents to the clinic for his annual health check-up. He currently complains of fatigue for the past few months. He has no significant past medical history. He admits to being sexually active with men and also is an intravenous drug user. He has never received a hepatitis B vaccine. His blood pressure is 122/98 mm Hg, the respiratory rate is 16/min, the pulse is 68/min, and the temperature is 37.0°C (98.6°F). On physical examination, he appears fatigued and unkempt. His tongue and buccal mucosa appear moist and without ulcerations or lesions. There are no murmurs or gallops on cardiac auscultation. His lungs are clear bilaterally. No lesions are present on the surface of the skin nor skin discoloration. The physician proceeds to order a hepatitis B panel to assess the patient’s serologic status:
HBV DNA positive
HBsAg negative
HBeAg negative
HBsAb negative
HBcAb positive
HBeAb negative
Which of the following disease states is the patient exhibiting?
Q23
A 43-year-old male presents to a clinic for routine follow-up. He was diagnosed with hepatitis B several months ago. He does not have any complaints about his health, except for poor appetite. The general physical examination is normal. The laboratory investigation reveals mildly elevated aminotransferases. Which of the following findings indicate that the patient has developed a chronic form of his viral infection?
Q24
A 31-year-old man comes to the physician because of a 2-day history of nausea, abdominal discomfort, and yellow discoloration of the eyes. Six weeks ago, he had an episode of fever, joint pain, swollen lymph nodes, and an itchy rash on his trunk and extremities that persisted for 1 to 2 days. He returned from a backpacking trip to Colombia two months ago. His temperature is 39°C (101.8°F). Physical examination shows scleral icterus. Infection with which of the following agents is the most likely cause of this patient's findings?
Q25
A 52-year-old male patient with chronic alcoholism presents to an ambulatory medical clinic, where the hepatologist elects to perform comprehensive hepatitis B screening, in addition to several other screening and preventative measures. Given the following choices, which serologic marker, if positive, would indicate the patient’s immunity to the hepatitis B virus?
Q26
A 52-year-old female presents to her primary care physician for medical evaluation prior to an elective hip replacement surgery. She has hypertension and diabetes, both of which are well controlled on oral medications. She also admits to occasional use of recreational injection drugs so a panel of serologies are obtained. Based on the results, the patient is found to have had a previous infection with hepatitis B from which she has fully recovered. Which of the following is a characteristic of the immunoglobulin subtype that most likely binds to hepatitis B core antigen in this patient?
Q27
A 35-year-old male anesthesiologist presents to the occupational health clinic after a needlestick exposure while obtaining an arterial line in a patient with cirrhosis. In addition to a standard bloodborne pathogen laboratory panel sent for all needlestick exposures at his hospital, additional hepatitis panels are ordered upon the patient's request. The patient's results are shown below:
HIV 4th generation Ag/Ab: Negative/Negative
Hepatitis B surface antigen (HBsAg): Negative
Hepatitis C antibody: Negative
Anti-hepatitis B surface antibody (HBsAb): Positive
Anti-hepatitis B core IgM antibody (HBc IgM): Negative
Anti-hepatitis B core IgG antibody (HBc IgG): Positive
What is the most likely explanation of the results above?
Q28
In a previous experiment infecting hepatocytes, it was shown that viable HDV virions were only produced in the presence of a co-infection with HBV. To better understand which HBV particle was necessary for the production of viable HDV virions, the scientist encoded in separate plasmids the various antigens/proteins of HBV and co-infected the hepatocytes with HDV. In which of the experiments would viable HDV virions be produced in conjunction with the appropriate HBV antigen/protein?
Q29
A 28-year-old woman with a history of intravenous drug use is brought to the emergency department because of a 1-day history of fatigue, yellow eyes, confusion, and blood in her stools. She appears ill. Her temperature is 38.1°C (100.6°F). Physical examination shows pain in the right upper quadrant, diffuse jaundice with scleral icterus, and bright red blood in the rectal vault. Further evaluation demonstrates virions in her blood, some of which have a partially double-stranded DNA genome while others have a single-stranded RNA genome. They are found to share an identical lipoprotein envelope. This patient is most likely infected with which of the following pathogens?
Hepatitis B/C US Medical PG Practice Questions and MCQs
Question 21: A 35-year-old man comes to the clinic complaining of yellow discoloration of his skin and eyes for the past week. He also complains about loss of appetite, nausea, malaise, and severe tiredness. He has no known past medical history and takes over-the-counter acetaminophen for headache. He has smoked a half pack of cigarettes every day for the last 15 years and drinks alcohol occasionally. He has been sexually active with a new partner for a month and uses condoms inconsistently. His father and mother live in China, and he visited them last year. Temperature is 37°C (98.7°F), blood pressure is 130/90 mm Hg, pulse is 90/min, respirations are 12/min, and BMI is 25 kg/m2. On physical examination, his sclera and skin are icteric. Cardiopulmonary examination is negative, no lymphadenopathy is noted, and his abdomen is tender in the right upper quadrant (RUQ). His liver is palpated 3 cm below the costal margin. On laboratory investigations:
Laboratory test
Complete blood count
Hemoglobin 15 g/dL
Leucocytes 13,000/mm3
Platelets 170,000/mm3
Basic metabolic panel
Serum Na+ 133 mEq/L
Serum K+ 3.6 mEq/L
Serum Cl- 107 mEq/L
Serum HCO3- 26 mEq/L
BUN 12 mg/dL
Liver function test
Serum bilirubin 3.4 mg/dL
Direct bilirubin 2.5 mg/dL
AST 2,100 U/L
ALT 2,435 U/L
ALP 130 U/L
What is the next best step to do in this patient?
A. Reassurance and counselling
B. USG of the abdomen
C. CT scan of the abdomen
D. HBsAg and Anti-HBc IgM (Correct Answer)
E. ERCP
Explanation: **HBsAg and Anti-HBc IgM**
- The described symptoms (jaundice, fatigue, nausea, RUQ tenderness, elevated AST/ALT in the thousands) are highly suggestive of **acute viral hepatitis**, particularly given the patient's inconsistent condom use and recent travel to China.
- **Hepatitis B surface antigen (HBsAg)** indicates active infection, and **Hepatitis B core IgM antibody (Anti-HBc IgM)** signifies acute or recent infection, making these the most appropriate initial diagnostic tests.
*Reassurance and counselling*
- This patient presents with significant symptoms and abnormal liver function tests indicating acute liver injury, which requires immediate investigation and management, not just reassurance.
- Delaying diagnosis and treatment for acute hepatitis can lead to severe complications.
*USG of the abdomen*
- While an abdominal ultrasound can evaluate the liver and biliary system for structural abnormalities, it is less likely to be the *initial* best step in a patient with a strong clinical picture for acute viral hepatitis and markedly elevated transaminases.
- An ultrasound would be more pertinent if **biliary obstruction** or **fatty liver disease** were higher on the differential, which is not strongly supported by these lab values.
*CT scan of the abdomen*
- A CT scan offers detailed imaging but is generally not the first-line investigation for suspected acute viral hepatitis.
- It would be considered if there was concern for **abscess**, **tumor**, or complex intra-abdominal pathology, which is not indicated by the current presentation.
*ERCP*
- **Endoscopic retrograde cholangiopancreatography (ERCP)** is an invasive procedure primarily used for therapeutic intervention in cases of **biliary obstruction**, such as removing gallstones or placing stents.
- It is not indicated as a diagnostic step for acute viral hepatitis, especially before less invasive and more specific tests have been performed.
Question 22: A 27-year-old man presents to the clinic for his annual health check-up. He currently complains of fatigue for the past few months. He has no significant past medical history. He admits to being sexually active with men and also is an intravenous drug user. He has never received a hepatitis B vaccine. His blood pressure is 122/98 mm Hg, the respiratory rate is 16/min, the pulse is 68/min, and the temperature is 37.0°C (98.6°F). On physical examination, he appears fatigued and unkempt. His tongue and buccal mucosa appear moist and without ulcerations or lesions. There are no murmurs or gallops on cardiac auscultation. His lungs are clear bilaterally. No lesions are present on the surface of the skin nor skin discoloration. The physician proceeds to order a hepatitis B panel to assess the patient’s serologic status:
HBV DNA positive
HBsAg negative
HBeAg negative
HBsAb negative
HBcAb positive
HBeAb negative
Which of the following disease states is the patient exhibiting?
A. Immune from vaccine
B. Acute infection
C. Convalescent (window) period
D. Chronic infection (Correct Answer)
E. Immune from natural infection
Explanation: ***Chronic infection***
- This patient demonstrates **occult or HBsAg-negative chronic hepatitis B**, a rare variant of chronic infection characterized by **positive HBV DNA with negative HBsAg**.
- The presence of **detectable HBV DNA** confirms active viral replication despite the absence of HBsAg, which can occur due to mutations in the S gene or immune pressure suppressing HBsAg production.
- The **positive HBcAb** (IgG anti-HBc) indicates prior exposure, and combined with detectable viral DNA, confirms chronic infection rather than resolved infection.
- The patient's **high-risk behaviors** (MSM, IV drug use) and **lack of vaccination** are consistent risk factors for acquiring hepatitis B.
- **HBeAg-negative** status indicates this is likely HBeAg-negative chronic hepatitis B, which can still have significant viral replication.
*Immune from vaccine*
- Vaccine-induced immunity shows **positive HBsAb** with **negative HBcAb** (no natural exposure).
- This patient has **negative HBsAb** and **positive HBcAb**, incompatible with vaccine immunity.
- The patient explicitly states he has **never received the hepatitis B vaccine**.
*Acute infection*
- Acute infection typically presents with **positive HBsAg** and **positive IgM anti-HBc** (not just total HBcAb).
- The **negative HBsAg** and absence of IgM markers make acute infection unlikely.
- The chronic fatigue over months (not acute illness) also suggests chronic rather than acute disease.
*Convalescent (window) period*
- The window period occurs between disappearance of HBsAg and appearance of HBsAb, characterized by **positive IgM anti-HBc** as the only marker initially.
- This patient has **positive HBV DNA**, indicating active replication, which rules out the window period where the virus is being cleared.
- **Negative HBsAb** without eventual seroconversion after months of symptoms makes window period unlikely.
*Immune from natural infection*
- Immunity from resolved natural infection shows **positive HBsAb** and **positive HBcAb** with **negative HBV DNA**.
- This patient has **positive HBV DNA** (active replication) and **negative HBsAb** (no immunity), confirming ongoing infection rather than resolved disease.
- The presence of viral DNA definitively rules out immune clearance.
Question 23: A 43-year-old male presents to a clinic for routine follow-up. He was diagnosed with hepatitis B several months ago. He does not have any complaints about his health, except for poor appetite. The general physical examination is normal. The laboratory investigation reveals mildly elevated aminotransferases. Which of the following findings indicate that the patient has developed a chronic form of his viral infection?
Explanation: ***HBsAg +, Anti-HBsAg -, Anti-HBcAg IgM -, Anti-HBcAg IgG +, HBeAg +, Anti-HBeAg -***
- The presence of **HBsAg for more than six months** is the hallmark of chronic hepatitis B infection. The absence of **Anti-HBs** indicates a lack of resolved infection or vaccination.
- The presence of **IgG anti-HBc** and absence of **IgM anti-HBc** further confirms chronic infection, as IgM anti-HBc is indicative of acute infection. **HBeAg positivity** suggests active viral replication and higher infectivity.
*HBsAg -, Anti-HBsAg +, Anti-HBcAg IgM -, Anti-HBcAg IgG +, HBeAg -, Anti-HBeAg +*
- This profile indicates **resolved HBV infection** or successful vaccination. The presence of **Anti-HBs** signifies immunity.
- The absence of **HBsAg** means the virus is no longer actively replicating in the liver.
*HBsAg +, Anti-HBsAg -, Anti-HBcAg IgM +, Anti-HBcAg IgG -, HBeAg +, Anti-HBeAg -*
- This panel is classic for an **acute HBV infection**. The presence of **HBsAg** and **IgM anti-HBc** indicates a recent and active infection.
- **HBeAg positivity** in this context points to active viral replication during the acute phase.
*HBsAg -, Anti-HBsAg -, Anti-HBcAg IgM +, Anti-HBcAg IgG -, HBeAg -, Anti-HBeAg +*
- This rare profile, sometimes referred to as the "**window period**," indicates acute infection where **HBsAg** has cleared but **Anti-HBs** has not yet appeared. The presence of **IgM anti-HBc** confirms recent infection.
- The absence of **HBsAg** and presence of **Anti-HBe** during this phase can be misleading if not interpreted with other markers.
*HBsAg -, Anti-HBsAg +, Anti-HBcAg IgM -, Anti-HBcAg IgG -, HBeAg -, Anti-HBeAg -*
- This profile is most consistent with **immunity due to vaccination**. The presence of **Anti-HBs** is from the vaccine, and there is no evidence of previous or current infection (no anti-HBc).
- The absence of all other markers excludes natural infection history.
Question 24: A 31-year-old man comes to the physician because of a 2-day history of nausea, abdominal discomfort, and yellow discoloration of the eyes. Six weeks ago, he had an episode of fever, joint pain, swollen lymph nodes, and an itchy rash on his trunk and extremities that persisted for 1 to 2 days. He returned from a backpacking trip to Colombia two months ago. His temperature is 39°C (101.8°F). Physical examination shows scleral icterus. Infection with which of the following agents is the most likely cause of this patient's findings?
A. Enterotoxigenic E. coli
B. Hepatitis B (Correct Answer)
C. Borrelia burgdorferi
D. Campylobacter jejuni
E. Hepatitis A
Explanation: ***Hepatitis B***
- This patient's presentation is **classic for acute hepatitis B infection**. The key diagnostic feature is the **serum sickness-like prodrome** that occurred 6 weeks ago, characterized by **fever, arthralgia, lymphadenopathy, and urticarial rash**.
- This prodromal syndrome results from **circulating immune complexes** (HBsAg-antibody complexes) and is a **hallmark of Hepatitis B**, occurring in 10-20% of acute HBV cases during the pre-icteric phase.
- The timeline fits perfectly: **exposure 2 months ago** (travel to Colombia) → **prodrome at 6 weeks** (4-10 weeks post-exposure is typical) → **icteric phase now** (jaundice with scleral icterus).
- Hepatitis B can be transmitted through **sexual contact, needlestick injuries, or exposure to contaminated instruments** during travel, making it highly relevant in this travel context.
*Hepatitis A*
- While hepatitis A is common in travelers to endemic areas and causes acute hepatitis, it **does NOT typically present with the serum sickness-like prodrome** described here.
- HAV prodrome is usually **nonspecific** (malaise, anorexia, nausea) and does **not include arthralgia, lymphadenopathy, or urticarial rash**.
- The described prodromal syndrome with rash and joint pain is **pathognomonic for HBV**, not HAV.
*Borrelia burgdorferi*
- This bacterium causes **Lyme disease**, characterized by **erythema migrans** (expanding target lesion), not an urticarial rash.
- Lyme disease does not cause **acute hepatitis with jaundice** or the icteric presentation seen here.
- Not consistent with the clinical timeline or hepatic involvement.
*Enterotoxigenic E. coli*
- ETEC causes **traveler's diarrhea** with watery stools, cramping, and nausea, typically within days of exposure.
- Does **not cause hepatitis**, jaundice, or a prodromal syndrome with rash and arthralgia.
- Symptoms resolve within 3-5 days without hepatic involvement.
*Campylobacter jejuni*
- Causes **bacterial gastroenteritis** with bloody diarrhea, fever, and abdominal pain.
- Does **not cause acute hepatitis** with jaundice or the serum sickness-like prodrome described.
- While travel-associated, it does not explain the hepatic and systemic findings.
Question 25: A 52-year-old male patient with chronic alcoholism presents to an ambulatory medical clinic, where the hepatologist elects to perform comprehensive hepatitis B screening, in addition to several other screening and preventative measures. Given the following choices, which serologic marker, if positive, would indicate the patient’s immunity to the hepatitis B virus?
A. HBeAb
B. HBeAg
C. HBsAb (Correct Answer)
D. HBsAg
E. HBcAb
Explanation: ***HBsAb***
- A positive **HBsAb** (Hepatitis B surface antibody) indicates immunity to hepatitis B virus, either from successful **vaccination** or **recovery from past infection**.
- This antibody provides **protective immunity** against future HBV infection and is the definitive marker of immunity.
*HBeAb*
- **HBeAb** (Hepatitis B e antibody) indicates **seroconversion** from HBeAg during chronic HBV infection, suggesting lower viral replication.
- It does **not confer immunity** against the virus itself and only reflects a phase of chronic infection.
*HBeAg*
- **HBeAg** (Hepatitis B e antigen) indicates **active viral replication** with high infectivity during ongoing hepatitis B infection.
- Its presence signifies a **replicative phase** of infection and increased risk of transmission to others.
*HBsAg*
- **HBsAg** (Hepatitis B surface antigen) indicates **active hepatitis B infection**, whether acute or chronic.
- This antigen is the **first serologic marker** to appear following exposure and confirms presence of the virus.
*HBcAb*
- **HBcAb** (Hepatitis B core antibody) indicates **previous or current exposure** to hepatitis B virus.
- It does **not differentiate** between acute, chronic, or resolved infection and does not confer protective immunity.
Question 26: A 52-year-old female presents to her primary care physician for medical evaluation prior to an elective hip replacement surgery. She has hypertension and diabetes, both of which are well controlled on oral medications. She also admits to occasional use of recreational injection drugs so a panel of serologies are obtained. Based on the results, the patient is found to have had a previous infection with hepatitis B from which she has fully recovered. Which of the following is a characteristic of the immunoglobulin subtype that most likely binds to hepatitis B core antigen in this patient?
A. It exists as a dimer
B. It is only activated by multivalent immunogens
C. It exists as a pentamer
D. It activates mast cells
E. It exists as a monomer (Correct Answer)
Explanation: ***It exists as a monomer***
- In a recovered hepatitis B infection, **anti-HBc IgG** antibodies are prominent, indicating past exposure and immunity.
- **IgG** is the most abundant immunoglobulin in serum and exists primarily as a **monomer**, providing long-term immunity.
*It exists as a dimer*
- This characteristic primarily describes **secretory IgA**, which is found in mucosal secretions like tears, saliva, and breast milk.
- While IgA can be involved in host defense, it's not the primary antibody subtype associated with sustained immunity after hepatitis B recovery, nor does it typically target the **core antigen** in this context.
*It is only activated by multivalent immunogens*
- This statement is more characteristic of **IgM**, which often requires multiple binding sites to activate complement efficiently due to its pentameric structure.
- **IgG** can bind to both univalent and multivalent antigens and is effective in neutralizing pathogens and activating other immune responses.
*It exists as a pentamer*
- This describes **IgM**, which is typically the first antibody produced during a primary immune response and is found on the surface of B cells.
- In a recovered infection, IgM would have largely subsided, replaced by **IgG**.
*It activates mast cells*
- This is a hallmark function of **IgE**, which binds to receptors on mast cells and basophils, triggering the release of histamine and other mediators in allergic reactions.
- **IgG** has different effector functions, such as opsonization, neutralization, and complement activation.
Question 27: A 35-year-old male anesthesiologist presents to the occupational health clinic after a needlestick exposure while obtaining an arterial line in a patient with cirrhosis. In addition to a standard bloodborne pathogen laboratory panel sent for all needlestick exposures at his hospital, additional hepatitis panels are ordered upon the patient's request. The patient's results are shown below:
HIV 4th generation Ag/Ab: Negative/Negative
Hepatitis B surface antigen (HBsAg): Negative
Hepatitis C antibody: Negative
Anti-hepatitis B surface antibody (HBsAb): Positive
Anti-hepatitis B core IgM antibody (HBc IgM): Negative
Anti-hepatitis B core IgG antibody (HBc IgG): Positive
What is the most likely explanation of the results above?
A. Window period
B. Chronic infection
C. Acute infection
D. Immune due to infection (Correct Answer)
E. Immune due to vaccination
Explanation: ***Immune due to infection***
- The presence of **anti-HBc IgG** along with **anti-HBsAb** in the absence of **HBsAg** indicates past resolution of HBV infection.
- This combination confers **natural immunity** following a prior exposure, distinguishing it from vaccine-induced immunity (which would lack anti-HBc IgG).
*Window period*
- This period is characterized by the absence of **HBsAg** and **anti-HBsAb**, with the only positive marker being **anti-HBc IgM**.
- The patient's results show positive **anti-HBsAb** and **anti-HBc IgG**, which rule out a window period.
*Chronic infection*
- Chronic infection is defined by the persistence of **HBsAg** for more than six months.
- The patient's **HBsAg is negative**, therefore excluding chronic infection.
*Acute infection*
- Acute infection would be evidenced by the presence of **HBsAg** and often **anti-HBc IgM**.
- Both **HBsAg** and **anti-HBc IgM** are negative in this patient, ruling out acute infection.
*Immune due to vaccination*
- Vaccination leads to the development of **anti-HBsAb** but does not produce **anti-HBc antibodies**.
- The presence of **anti-HBc IgG** in this patient indicates exposure to the complete virus, not just vaccination.
Question 28: In a previous experiment infecting hepatocytes, it was shown that viable HDV virions were only produced in the presence of a co-infection with HBV. To better understand which HBV particle was necessary for the production of viable HDV virions, the scientist encoded in separate plasmids the various antigens/proteins of HBV and co-infected the hepatocytes with HDV. In which of the experiments would viable HDV virions be produced in conjunction with the appropriate HBV antigen/protein?
A. HBV DNA polymerase
B. HBV RNA polymerase
C. HBsAg (Correct Answer)
D. HBcAg
E. HBeAg
Explanation: ***HBsAg***
- **Hepatitis D virus (HDV)** is a **defective virus** that requires co-infection with **hepatitis B virus (HBV)** to complete its replication cycle.
- Specifically, HDV uses the **hepatitis B surface antigen (HBsAg)**, encoded by HBV, to form its **outer envelope** and assemble viable virions.
*HBV DNA polymerase*
- HBV DNA polymerase is essential for **HBV DNA replication**, converting the viral pregenomic RNA into DNA.
- It plays no direct role in the **packaging or formation of the HDV envelope**.
*HBV RNA polymerase*
- HBV, like other DNA viruses, utilizes the **host cell's RNA polymerase** for transcription of its RNA templates, not its own.
- HBV itself does not encode an RNA polymerase, and even if it did, it would not be relevant for HDV virion packaging.
*HBcAg*
- **Hepatitis B core antigen (HBcAg)** forms the **capsid** of the HBV virion, encapsulating the viral genome.
- While critical for HBV replication, it is **not incorporated into the HDV virion outer envelope**.
*HBeAg*
- **Hepatitis B e-antigen (HBeAg)** is a soluble protein derived from **HBcAg** that is secreted into the blood.
- It plays a role in **immune modulation** and is a marker of HBV replication but does not contribute to HDV virion assembly.
Question 29: A 28-year-old woman with a history of intravenous drug use is brought to the emergency department because of a 1-day history of fatigue, yellow eyes, confusion, and blood in her stools. She appears ill. Her temperature is 38.1°C (100.6°F). Physical examination shows pain in the right upper quadrant, diffuse jaundice with scleral icterus, and bright red blood in the rectal vault. Further evaluation demonstrates virions in her blood, some of which have a partially double-stranded DNA genome while others have a single-stranded RNA genome. They are found to share an identical lipoprotein envelope. This patient is most likely infected with which of the following pathogens?
A. Deltavirus (Correct Answer)
B. Filovirus
C. Calicivirus
D. Hepevirus
E. Herpesvirus
Explanation: ***Deltavirus***
- The presence of both **partially double-stranded DNA virions** (Hepatitis B virus) and **single-stranded RNA virions** (Hepatitis D virus) sharing an identical lipoprotein envelope is pathognomonic for **coinfection with Hepatitis B and Deltavirus (HDV)** [1].
- **Hepatitis D (Deltavirus)** is a **defective RNA virus** that is obligately dependent on **Hepatitis B surface antigen (HBsAg)** for its replication, assembly, and transmission—explaining why both viruses share the same lipoprotein envelope [1].
- This coinfection or superinfection with HDV causes **more severe acute hepatitis** and higher rates of **fulminant hepatic failure** compared to HBV alone, consistent with the patient's presentation of jaundice, confusion (hepatic encephalopathy), and GI bleeding [1].
- The patient's **IV drug use** is a key risk factor for both HBV and HDV transmission [1].
*Filovirus*
- **Filoviruses** (e.g., Ebola, Marburg) cause **viral hemorrhagic fever** with severe bleeding manifestations and can present with bloody stools.
- However, they are **single-stranded RNA viruses** only and do not involve coinfection with a DNA virus, nor do they share envelopes with DNA viruses.
- Geographic exposure and clinical context (African hemorrhagic fever outbreaks) would be expected.
*Calicivirus*
- **Caliciviruses** (e.g., Norovirus, Sapovirus) are **non-enveloped, single-stranded RNA viruses** that cause acute **gastroenteritis** with vomiting and diarrhea.
- They do not cause hepatitis with jaundice and hepatic encephalopathy, nor do they involve DNA virus coinfection or envelope sharing.
*Hepevirus*
- **Hepatitis E virus (Hepevirus)** is a **non-enveloped, single-stranded RNA virus** that causes acute hepatitis, primarily through **fecal-oral transmission** (contaminated water).
- While it causes liver disease, it does not involve coinfection with a DNA virus or envelope sharing, and it is not typically associated with IV drug use.
- It can cause severe disease in pregnant women but does not explain the dual genome findings.
*Herpesvirus*
- **Herpesviruses** are **enveloped, double-stranded DNA viruses** that cause various infections (HSV, VZV, EBV, CMV).
- While they have DNA genomes and envelopes, they do not coinfect with RNA viruses sharing the same envelope structure, nor are they typically associated with acute severe hepatitis in IV drug users.
- Hepatitis from CMV or EBV would have different serologic and molecular findings.