Hepatitis B

 Typically transmitted vertically, parenterally, or sexually






Clinical Issues




• 10% of infected patients become chronically infected
image 400 million people worldwide have chronic HBV

• Symptoms include mild flu-like syndrome, nausea, vomiting, jaundice
image > 50% are asymptomatic

• Lifelong risk of developing cirrhosis &/or HCC

• Useful laboratory tests include serology for HBV viral antigens, anti-HBV antibodies, and HBV DNA viral load


Microscopic




• Acute hepatitis B
image Hepatocytic swelling, predominantly lobular inflammation, spotty necrosis

image Severe cases may show confluent and bridging necrosis, collapse of hepatocytic cords, hepatocytic regeneration

• Chronic hepatitis B
image Portal-based inflammation with variably present ground-glass hepatocytes, “sanded nuclei” in hepatocytes, variable fibrosis 
– Stage of fibrosis indicates disease progression and is important therapeutic and prognostic indicator

• Immunohistochemistry for HBcAG and HBsAG may be useful, but not invariably positive


Top Differential Diagnoses




• Hepatitis A, hepatitis C, autoimmune hepatitis, other viral infections (CMV, EBV)
image Histologic features may be very nonspecific, so correlation with history and serology is crucial

image
Ground-Glass Hepatocytes
Ground-glass hepatocytes image have glassy eosinophilic cytoplasm representing proliferation of smooth ER in response to HBsAg.


image
Sanded Nuclei
Hepatitis B-infected hepatocytes may have pale pink, finely granular intranuclear inclusions (sanded nuclei image ) representing nuclear accumulation of HBcAg. These may be hard to detect on routine H&E staining.

image
HBV, Acute
This case of acute HBV infection shows lobular disarray with marked hepatocyte swelling and lobular inflammation.

image
HBV, Chronic
This section shows interface hepatitis in chronic hepatitis B consisting of chronic inflammatory cells that extend beyond the limiting plate image into the periportal parenchyma.


TERMINOLOGY


Abbreviations




• Hepatitis B virus (HBV)


Synonyms




• Australia antigen: Hepatitis B surface antigen (HBsAg)


Definitions




• Infection by HBV
image Member of Hepadnaviridae family

image Genome comprises partially double-stranded DNA virus


ETIOLOGY/PATHOGENESIS


Infectious Agents




• Transmitted parenterally
image Vertical transmission: Mothers to newborn infants

image Horizontal transmission: Between young children

image Sexual contact

• Liver injury appears to be immune mediated
image HBV-specific T cells play key role in pathogenesis and viral clearance


CLINICAL ISSUES


Epidemiology




• Incidence
image 400 million people worldwide are chronically infected with HBV


Presentation




• Acute hepatitis B
image Symptoms include mild flu-like symptoms, nausea, vomiting, jaundice

– > 50% are asymptomatic

image < 1% develop fulminant liver failure leading to death or liver transplantation

image Serum HBsAg and anti-HBc virus IgM Ab positive

• Chronic hepatitis B
image Serum HBsAg positive and anti-HBc virus IgM Ab negative


Laboratory Tests




• Serology for HBV viral antigens: HBsAg, HBcAg, HBeAg

• Serology for anti-HBV antibodies: Anti-HBs, anti-HBc, anti-HBe

• Serum HBV DNA and viral load

• Elevated transaminases


Natural History




• 10% of infected individuals become chronically infected
• Life-long risk of developing cirrhosis &/or HCC in chronic hepatitis B

image Cirrhosis is not prerequisite for developing HCC

– HBV viral genome can act as oncoprotein and intergrade into host genome

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Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Hepatitis B
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