A 23-year-old man comes to the emergency department due to 7 days of fever and malaise. He has also had nausea and a poor appetite. The patient has no significant medical history but regularly uses injection drugs and has had multiple sexual partners. Temperature is 38 C (100.4 F). On physical examination, there is scleral icterus. A tender, smooth liver edge is palpable 4 cm below the right costal margin. Appropriate therapy is initiated. The following graph illustrates this patient's hepatitis B serologic markers over time. Which of the following best explains these observed findings?

Question

A 23-year-old man comes to the emergency department due to 7 days of fever and malaise.  He has also had nausea and a poor appetite.  The patient has no significant medical history but regularly uses injection drugs and has had multiple sexual partners.  Temperature is 38 C (100.4 F).  On physical examination, there is scleral icterus.  A tender, smooth liver edge is palpable 4 cm below the right costal margin.  Appropriate therapy is initiated.  The following graph illustrates this patient's hepatitis B serologic markers over time.  Which of the following best explains these observed findings?

Quizplus · Accepted Answer

11ec160b_37d2_b64b_9249_911453ba3820_MD0001_00 Serologic evidence of hepatitis B virus (HBV) exposure is present in ~2 billion people worldwide. Perinatal transmission is most common in high-incidence areas (eg, sub-Saharan Africa). In low-prevalence countries such as the United States, Western Europe, and Canada, most cases arise due to unsafe sexual practices or injection drug use. Serological markers for HBV can be used to distinguish between acute infection, chronic infection, and a protective vaccination response. Acute HBV infection is marked by the proliferation of the virus in hepatocytes with the release of viral antigens (HBsAg, HBeAg) and HBV DNA into the bloodstream and the generation of IgM against HB core antigen. Many patients with acute infection will have subclinical, anicteric disease, but approximately 30% develop several weeks or months of jaundice, fatigue, hepatomegaly, and elevated transaminases. Most adults with HBV clear the virus and generate protective immunity against future infection. This is reflected serologically by the following progression: Anti-HBe antibodies develop 3-6 months after initial infection and are associated with the elimination of HBeAg. This correlates with reduced viral replication and infectivity. HBsAg is eliminated around the time that HBeAg becomes undetectable. Anti-HBsAg antibodies form several weeks/months later and provide protective immunity against future infection. (Choices A and B) Patients with chronic hepatitis B have elevated HBsAg >6 months after initial infection. Chronic hepatitis B with high infectivity is represented by persistent elevation of HBsAg, HBeAg, and HBV DNA with no anti-HBe. Transition from high infectivity to low infectivity usually occurs years later and is marked by anti-HBe, the elimination of HBeAg, and the continued production of HBsAg. (Choice C) Patients with an exacerbation of chronic hepatitis B have an abrupt increase in liver enzymes and increased levels of HBV DNA. Exacerbations are often asymptomatic, but some individuals develop symptoms of acute hepatitis. (Choice D) Vaccination against hepatitis B would be identified by the presence of anti-HBs with no anti-HBc, anti-HBe, or viral antigens. Educational objective: The presence of anti-HBc and anti-HBs antibodies in the serum without detectable viral antigens indicates recovery from acute hepatitis B infection. In contrast, patients vaccinated against hepatitis B will have anti-HBs antibodies without detectable levels of anti-HBc. Chronic hepatitis B is indicated by persistent levels of HBsAg and HBV DNA in the serum. __________ References: The laboratory diagnosis of hepatitis B virus. (http://www.ncbi.nlm.nih.gov/pubmed/18159530)

A 23-Year-Old Man Comes to the Emergency Department Due to 7