Overview of Hepatitis

 Chronic hepatitis


– Persistent, often progressive inflammatory process characterized by lymphocytic inflammation of portal tracts with varying degrees of parenchymal inflammation, hepatocellular injury, and fibrosis

image Chronicity judged in several ways: Clinical, laboratory, morphologic

image Practically defined as 6 months or more of elevated transaminases



image Acute hepatitis

– Active hepatocellular damage and necrosis

image Usually of short &/or self-limited duration

image Most often due to viral infection or adverse drug reaction

image Infrequently biopsied because diagnosis usually made by clinical or laboratory data



ETIOLOGY/PATHOGENESIS


Viral Hepatitis




• Hepatotropic viruses (A, B, C, E)

• Other viruses, such as Epstein-Barr virus, CMV


Autoimmune Hepatitis




• Type 1: ANA/SMA(+), hypergammaglobulinemia, concurrent autoimmune diseases

• Type 2: Anti-LKM antibodies, more likely to develop cirrhosis

• Type 3: Less well characterized; anti-SLA/LP antibodies; may have AMA(+)


Drug-Associated Hepatitis




• Necroinflammatory
image Acetaminophen, phenytoin, Macrodantin, sulphonamides

• Cholestatic
image Many antibiotics, steroids

• Granulomatous
image Allopurinol, many antibiotics, phenytoin


Other




• Wilson disease
• α-1-antitrypsin deficiency

• Nonspecific reactive hepatitis

image Reaction to extrahepatic infection or neoplasm, severe systemic illness, or to adjacent mass lesion in liver


CLINICAL IMPLICATIONS


Clinical Presentation




• Fatigue

• Malaise

• Jaundice

• Anorexia

• Fever

• Nausea

• Abdominal pain

• Signs and symptoms of liver failure

• Many patients are asymptomatic


Laboratory Findings




• Elevated transaminases

• Alkaline phosphatase may be mildly elevated

• Viral serologies positive in viral hepatitis

• Autoimmune serologies usually positive in autoimmune hepatitis

• Other serologic tests, such as urinary copper, ceruloplasmin, serum α-1-antitrypsin, may be helpful


MICROSCOPIC


General Features




• Broad range of histologic appearances with some features in common
image Portal inflammation

– Infiltrate consists primarily of lymphocytes

image May have admixed plasma cells, histiocytes, and granulocytes

– Lymphoid follicles common in hepatitis C

– Nonspecific ductular reaction may be present at periphery of portal tract

image Lobular inflammation/necrosis

– Necrosis may be mild and spotty or confluent and bridging

– May be accompanied by ballooning degeneration, reactive hepatocellular changes

image Piecemeal necrosis (interface activity)

– Defined as extension of inflammation into adjacent parenchyma with destruction of individual hepatocytes at interface

– Results in ragged interface between portal tract and hepatic parenchyma

image Fibrosis

• Predominant pattern of inflammation in given case may be portal, periportal, lobular, or combination
image Acute hepatitis usually diffusely involves lobule and is not confined to portal area

• Inflammatory process may be sporadically distributed within liver, resulting in sampling bias

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