Pathophysiology
1) caused by an infection with hepatitis D virus 2) three forms – fulminant (5%-20%), acute, and chronic 3) exists largely as coinfection or superinfection with hepatitis B virus.
Signs and Symptoms
increases severityh of hepatitis B if it occurs as a coninfection and increases likelihood of chonicity if it occurs as a superinfection
Characteristic Test Findings
Laboratory – antibodies to liver-kidney microsomes type 3 (anti-LKM3)
Histology/Gross Pathology
1) enveloped, circular, single=stranded RNA virus 2) resembles hepatitis B virions, except slightly smaller
Biochemistry
1) uses rolling circle replication model 2) characteristic delta antigen
Inheritance/Epidemiology
1) incubation period is 60-90 days 2) occurs worldwide: in Mediterranean, disease is transmited through close personal contact; in USA, via blood exposure
Treatment
1) prevention occurs if hepatitis B vaccine is given with resultant therapeutic antibody levels 2) treatment is difficult after infection, with combination antiviral medication causing a temporary decrease in viral load
Tips for USMLE
1) hepatitis D infection does not last longer than hepatitis B infection 2) if question mentions delta antigen, think hepatitis D 3) superinfection of hepatitis B with hepatitis D increases likelihood of chronicity of hepatitis B to 70-80%
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