STEPTRACKERMICROBIOLOGY + GASTROENTEROLOGY | HEPATITIS VIRUSES | HIGH-YIELD REVIEW

Hepatitis Viruses

Five unrelated viruses that share one target — the hepatocyte. Separate them by route, chronicity and serology; HBV markers are the most tested table in virology.

FOCUS ON

Fecal-oral, acute only: HAV (picornavirus) and HEV (hepevirus; high mortality in pregnancy, undercooked pork/game). Blood/sex/perinatal, can be chronic: HBV (hepadnavirus, DNA with RT; chronic in ~90% of neonates, < 5% of adults), HCV (flavivirus; chronic in most; IVDU; cured by direct-acting antivirals), HDV (needs HBsAg; coinfection vs superinfection). HBV serology: HBsAg = infected, anti-HBs = immune, IgM anti-HBc = acute (only marker in the window period), IgG anti-HBc = past or chronic, HBeAg/HBV DNA = replication and infectivity.

VIRUS

STRUCTURE · ROUTE

COURSE

CLUE · MANAGEMENT

Hepatitis A

+ssRNA naked picornavirus · fecal-oral (shellfish, travel, daycare, MSM)

Acute hepatitis, jaundice (more in adults), never chronic

IgM anti-HAV · vaccine; immune globulin for exposures

Hepatitis E

+ssRNA naked hepevirus · fecal-oral water, pork, deer

Acute; fulminant in pregnancy (~20% mortality); chronic in transplant patients

Epidemics after monsoon floods

Hepatitis B

Partly dsDNA hepadnavirus with RT · blood, sex, perinatal

Acute (often subclinical) → chronic risk falls with age at infection; cirrhosis, HCC even without cirrhosis (integration)

Tenofovir, entecavir · vaccine (HBsAg) at birth

HBV extrahepatic

Immune complexes

Polyarteritis nodosa, membranous nephropathy, serum-sickness prodrome (rash, arthralgia)

—

Hepatitis C

+ssRNA flavivirus; no proofreading → quasispecies · IV drugs, transfusion before 1992, tattoos

Mostly asymptomatic acute → chronic in most → cirrhosis, HCC

Anti-HCV screen → HCV RNA confirms · sofosbuvir + NS5A inhibitor (8–12 weeks, > 95% cure)

HCV extrahepatic

B-cell stimulation

Mixed cryoglobulinemia, membranoproliferative GN, porphyria cutanea tarda, lichen planus, B-cell lymphoma

Palpable purpura + low C4

Hepatitis D — coinfection

−ssRNA circular, uses HBsAg coat · acquired together with HBV

Usually clears with HBV

IgM anti-HBc ⁺

Hepatitis D — superinfection

HDV on top of chronic HBV

Severe acute flare, rapid progression to cirrhosis

IgG anti-HBc ⁺ · HBV vaccine prevents HDV too

Acute viral hepatitis labs

Hepatocyte necrosis

ALT > AST (often > 1000), ↑ bilirubin

Ballooning degeneration, Councilman bodies

Chronic hepatitis histology

Lymphocytic portal inflammation, interface hepatitis

HBV: ground-glass hepatocytes (HBsAg in ER) · HCV: lymphoid aggregates, steatosis

—

Perinatal HBV prevention

Mother HBsAg ⁺

Infant gets HBV vaccine + HBIG within 12 h

Tenofovir in 3rd trimester if high viral load

Picture it — hepatitis B markers over time

Acute HBV that resolvesHBsAg and HBeAg appear first and fall as the patient recovers. IgM anti-HBc marks acute infection and is the only positive marker in the window, before anti-HBs appears. Total anti-HBc (IgG) stays for life; anti-HBs signals immunity. Timing is approximate.

Schematic diagrams, not to scale.

Mechanism — HBV replicates through RNA

Partly ds DNA enters nucleus

→

Repaired to cccDNAPersists → hard to cure

→

Pregenomic RNA

→

Reverse transcriptase → DNATenofovir, entecavir block

Reading HBV serology

PATTERN

HBsAg

ANTI-HBs

ANTI-HBc

Acute infection

−

IgM

Window period

−

IgM

Chronic infection

+ (> 6 months)

−

IgG

Recovered

−

IgG

Vaccinated

−

How it's tested

COMMON CONFUSIONAnti-HBc distinguishes natural infection from vaccination — vaccine contains only HBsAg, so vaccinated people have anti-HBs alone.

THE TRAPA ⁺ anti-HCV antibody may mean past cleared infection — confirm with HCV RNA before treating.

YOUR APPROACHRoute (fecal-oral vs blood) → acute vs chronic → serology pattern → special host (pregnancy, HBV carrier) → treatment or prophylaxis.

If you see… think…

Pregnant woman in South Asia with fulminant hepatitis → HEV

Acute hepatitis after raw oysters, recovers fully → HAV

Only ⁺ marker is IgM anti-HBc → window period

HBsAg ⁺ for over 6 months → chronic HBV

Anti-HBs ⁺ alone → vaccinated

HCC in a non-cirrhotic liver → HBV (integration)

Ground-glass hepatocytes → chronic HBV

Palpable purpura, arthralgia, low complement, IV drug use → HCV cryoglobulinemia

Chronic HBV carrier with sudden severe flare → HDV superinfection

Newborn of HBsAg ⁺ mother → HBV vaccine + HBIG within 12 h