1.
A 17-year-old male presents complaining of tea-colored urine. Pertinent patient history includes a recent backpacking trip in Asia with his girlfriend, but is otherwise unremarkable. Hepatitis serology gives the following results:
HAV IgM positive
HBsAg negative
HBcAg IgM negative
HDV IgM negative
HCV IgM negative
What is the status of this patient?
Correct Answer
A. Acute hepatitis A
Explanation
Based on the given information, the patient has a positive HAV IgM result, which indicates acute hepatitis A infection. The negative results for HBsAg, HBcAg IgM, HDV IgM, and HCV IgM suggest that the patient does not have acute hepatitis B, acute hepatitis D, acute hepatitis C, or acute hepatitis E. Therefore, the correct answer is acute hepatitis A.
2.
What is the most likely source of his infection?
Correct Answer
A. Contaminated shellfish
Explanation
The most likely source of his infection is contaminated shellfish. This is because shellfish can be a common source of foodborne illnesses, such as bacterial or viral infections. Shellfish can become contaminated if they are harvested from polluted waters or if they are not handled and cooked properly. Ingesting contaminated shellfish can lead to various infections, including gastrointestinal illnesses. Therefore, it is reasonable to assume that the individual's infection was caused by consuming contaminated shellfish.
3.
A 26-year-old woman presents complaining that her urine is dark and her stools pale. Patient history reveals that the patient has been to the Caribbean to see her long distance boyfriend. A serology panel reflects the following results:
HAV IgG positive
HBsAg positive
HBcAg IgM positive
HDV IgM negative
HCV IgM negative
What is the status of this patient?
Correct Answer
B. Acute hepatitis B
Explanation
The patient's serology panel shows positive results for HAV IgG, HBsAg, and HBcAg IgM, indicating an acute infection. The negative results for HDV IgM and HCV IgM rule out acute hepatitis D and C. The patient's history of traveling to the Caribbean suggests exposure to hepatitis E, but the absence of positive serology for HEV IgM makes acute hepatitis E less likely. Therefore, the most likely explanation is acute hepatitis B, as indicated by the positive HBsAg result.
4.
Which of these is not a potential risk for HBV transmission?
Correct Answer
D. Kissing
Explanation
Kissing is not a potential risk for HBV transmission because the hepatitis B virus is primarily transmitted through contact with infected blood or other body fluids such as semen and vaginal fluids. Kissing does not involve direct contact with these fluids, therefore the risk of HBV transmission through kissing is very low.
5.
During hepatitis A infections, what is responsible for most of the liver damage?
Correct Answer
E. CD8+ T lympHocyte-mediated cytotoxicity
Explanation
During hepatitis A infections, CD8+ T lymphocyte-mediated cytotoxicity is responsible for most of the liver damage. CD8+ T lymphocytes are a type of immune cell that can recognize and kill virus-infected cells. In the case of hepatitis A, these T lymphocytes recognize and attack liver cells that have been infected with the virus. This immune response leads to inflammation and destruction of liver tissue, causing liver damage.
6.
During acute hepatitis B infections, most liver cells are virally infected. Why do not most hepatitis B infected individuals die from acute liver failure?
Correct Answer
E. CD8+ T lympHocytes clear the virus by purging viruses from infected cells in a non-cytolytic fashion.
Explanation
During acute hepatitis B infections, most liver cells are virally infected. However, most hepatitis B infected individuals do not die from acute liver failure because CD8+ T lymphocytes are able to clear the virus by purging viruses from infected cells in a non-cytolytic fashion. This means that instead of destroying the infected cells, the CD8+ T lymphocytes remove the viruses from within the cells, allowing the cells to survive. This immune response helps to prevent widespread liver damage and ultimately prevents acute liver failure in most individuals.
7.
A 35-year-old intravenous drug abuser presents to a free clinic complaining of fatigue and loss of weight. Physical examination reveals slightly yellow-tinged sclerae. A hepatitis serology panel reflects the following:
HAV IgG positive
HBsAg negative
HBcAg IgM negative
HCV IgG positive
HDV IgM negative
Further testing reveals the following:
HIV-1 positive
HIV-1 viral load 103 RNA IU/mL
Which statement best applies to this patient?
Correct Answer
E. Patient will likely develop liver fibrosis more rapidly because of HIV-1 co-infection
Explanation
HIV-1 co-infection is known to accelerate the progression of liver fibrosis in patients with viral hepatitis. This is because HIV-1 causes chronic immune activation and inflammation, which can lead to increased liver damage. Additionally, HIV-1 may directly affect the liver and impair its ability to regenerate. Therefore, this patient's HIV-1 co-infection is likely to have a negative impact on the clinical outcome and accelerate the development of liver fibrosis.
8.
A 35-year-old intravenous drug abuser presents to a free clinic complaining that his urine is black. Following a physical examination, patient most likely suffers from hepatitis. A hepatitis serology panel shows the following results:
HAV IgG positive
HBsAg negative
HBcAg IgM negative
HBcAg IgG negative
HCV IgG positive
HDV IgM negative
HDV IgG negative
What would be the most prudent course of action in this case?
Correct Answer
E. Initiate treatment for hepatitis C, and have a PCR run for the possible presence of HBV
Explanation
Nota: HIV testing should also be done.
9.
A 27-year-old female sex worker presents to a free clinic complaining of tea-colored urine and clay-colored stools. Patient history reveals a recent trip to Mexico and non-specific systemic symptoms such as fatigue, nausea, and low-grade fever. She admits to alcohol and intravenous drug abuse. Physical examination reveals epigastric discomfort and yellow-tinged sclerae. Blood work shows elevated aminotransferase concentrations, but normal alkaline phosphatase levels.
The following graph depicts the progression of this patient’s disease:
Based on this graph, what is the most likely virus responsible for this patient’s disease?
Correct Answer
B. Hepatitis B virus
Explanation
The most likely virus responsible for this patient's disease is Hepatitis B virus. This is indicated by the graph which shows a prolonged duration of infection, with persistent high levels of viral replication and liver inflammation. Hepatitis B virus is known to cause chronic liver disease and can be transmitted through sexual contact, intravenous drug use, and exposure to contaminated blood or body fluids. The patient's risk factors, symptoms, and abnormal liver function tests are consistent with Hepatitis B infection.
10.
Is it an acute or chronic disease?
Correct Answer
B. Chronic
Explanation
The given answer is "Chronic" because chronic diseases are characterized by long-term persistence or recurrence. Acute diseases, on the other hand, have a sudden onset and a short duration. Therefore, if a disease is classified as chronic, it means that it lasts for a prolonged period of time or is recurring in nature.
11.
What is the percentage of healthcare workers that get infected by the Hepatitis B virus following an accidental needlestick puncture containing blood from an HBeAg-positive patient?
Correct Answer
C. 25%
Explanation
The correct answer is 25%. This means that 25% of healthcare workers who experience an accidental needlestick puncture containing blood from an HBeAg-positive patient are likely to get infected by the Hepatitis B virus.
12.
Using the graph below depicting the progression of a hepatitis A infection, around which week is the IgM titer most likely to peak?
Correct Answer
B. 6
Explanation
The IgM titer is most likely to peak around week 6 of the hepatitis A infection based on the graph. This is because the graph shows a steady increase in the IgM titer from week 0 to week 6, after which it starts to decline. Therefore, week 6 is the point at which the IgM titer is expected to reach its highest level before decreasing.
13.
Using the graph below, determine the week at which anti-HAV IgGs are most likely to plateau?
Correct Answer
E. 12
Explanation
Based on the graph, the level of anti-HAV IgGs increases steadily until week 12, after which it remains constant or plateaus. Therefore, week 12 is the most likely week at which anti-HAV IgGs are expected to plateau.
14.
A 27-year-old female sex worker presents to a free clinic complaining of tea-colored urine and clay-colored stools. Patient history reveals a recent trip to Mexico and non-specific systemic symptoms such as fatigue, nausea, and low-grade fever. She admits to alcohol and intravenous drug abuse. Physical examination reveals epigastric discomfort and yellow-tinged sclerae. Blood work shows elevated aminotransferase concentrations, but normal alkaline phosphatase levels. Which graph best exemplifies the case of a resolved, acute hepatitis B infection?
Correct Answer
C. III
Explanation
Graph III best exemplifies the case of a resolved, acute hepatitis B infection because it shows a pattern of elevated aminotransferase concentrations, which is indicative of liver damage. The normal alkaline phosphatase levels suggest that there is no obstruction in the bile ducts, which is consistent with a resolved infection. The patient's symptoms, history of travel to Mexico, and risk factors such as alcohol and intravenous drug abuse are also consistent with hepatitis B infection.
15.
Using the graph below depicting the progression of a hepatitis A infection, which week is most likely to correspond to the peak CTL response?
Correct Answer
A. 4
Explanation
The peak CTL response is most likely to correspond to week 4 because the graph shows a steady increase in the CTL response from week 0 to week 4, after which it starts to decline. Therefore, week 4 is the most likely week for the peak CTL response.
16.
A 27-year-old female sex worker presents to a free clinic complaining of tea-colored urine and clay-colored stools. Patient history reveals a recent trip to Mexico and non-specific systemic symptoms such as fatigue, nausea, and low-grade fever. She admits to alcohol and injection drug abuse. Physical examination reveals epigastric discomfort and yellow-tinged sclerae. Blood work shows the following:
Three months later, a second hepatitis serology panel is performed on the same patient:
Which graph best exemplifies the progression of this case?
Correct Answer
C. III
Explanation
The patient's initial presentation with tea-colored urine, clay-colored stools, fatigue, nausea, low-grade fever, epigastric discomfort, and yellow-tinged sclerae suggests hepatocellular dysfunction and jaundice, which are consistent with hepatitis. The elevated ALT and AST levels in the initial blood work indicate liver cell injury. The second hepatitis serology panel shows the presence of hepatitis B surface antigen (HBsAg), indicating acute hepatitis B infection. The progression of the case can be best exemplified by graph III, which shows an initial rise in ALT and AST levels followed by a gradual decline as the infection resolves.
17.
Which graph best exemplifies the progression of a hepatitis C virus infection?
Correct Answer
D. IV
18.
What proportion of infected individuals will present with symptoms in the first few months following HCV infection (and although all the answers are logically correct, choose the one that is most precise)?
Correct Answer
E.
Explanation
Nota: You should never see such a question from me on an exam or from the NBME because