Viral Hepatitis

Slide 1 · Viral Hepatitis

Hepatotropic viruses, liver injury, and clinicopathologic patterns

A pathology-centered overview

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning goals

Differentiate hepatotropic from systemic viral causes of hepatitis.

Compare the five classical hepatotropic viruses by transmission and persistence.

Explain the host-response basis of hepatocyte injury.

Recognize acute and chronic morphologic patterns and their diagnostic limitations.

Emphasis: Mechanisms, morphology, and clinical interpretation.

Slide 3 · What “viral hepatitis” denotes

Narrow clinical usage

Inflammation and hepatocellular injury associated with infection by hepatotropic viruses.

Classical agents: Hepatitis A, B, C, D, and E.

Broader biologic usage

Liver involvement during systemic viral infections.

Examples include EBV, CMV, HSV, adenovirus, yellow fever virus, and SARS-CoV-2.

Slide 4 · Two routes to a viral hepatitis syndrome

Hepatotropic virus

→

Predominant liver infection

→

Hepatitic injury

Systemic viruses can also affect the liver, frequently as part of multisystem disease.

A hepatitic phenotype does not, by itself, identify the infectious agent.

Slide 5 · The five classical hepatotropic viruses

Virus

Genome or dependency

Core distinguishing feature

HAV

Positive-strand RNA

Acute, self-limited; No chronic carrier state

HBV

Partially double-stranded DNA

Acute or chronic; Can persist

HCV

Single-stranded RNA

Strong propensity for chronic infection

HDV

Circular single-stranded RNA

Requires HBV for infection

HEV

Positive-strand RNA

Usually acute; Chronicity with immunosuppression

Slide 6 · Nonhepatotropic viruses are not rare exceptions

Epstein–Barr virus and cytomegalovirus can be associated with hepatitis.

Herpes simplex virus, adenovirus, and yellow fever virus may produce liver injury.

SARS-CoV-2 infection can involve the liver, generally mildly or subclinically.

Assess whether hepatitis is the primary syndrome or a manifestation of systemic infection.

Clinical context narrows the etiologic differential.

Slide 7 · Enteric versus parenteral viral hepatitis

Pattern

Classical agents

Exposure clue

Enteric / fecal–oral

HAV, HEV

Contaminated food, water, sanitation

Blood and body-fluid exposure

HBV, HCV, HDV

Needles, blood exposure; Sexual/perinatal exposure for HBV

HBV-dependent transmission

HDV

Exposure in the setting of HBV infection

Slide 8 · Why agent identification matters

Similar liver injury can arise from viruses with very different natural histories.

HAV usually resolves without chronic infection.

HBV and HCV can produce persistent disease and fibrosis.

HDV can markedly worsen the course of HBV infection.

HEV can be particularly severe during pregnancy.

Slide 9 · From exposure to hepatocellular injury

Exposure

→

Hepatocyte infection

→

Host response

→

Cell injury

Clinical hepatitis reflects both viral infection and host-mediated tissue responses.

The balance between control and persistence shapes the outcome.

Slide 10 · Hepatocyte injury is often immune mediated

HAV is not considered directly cytopathic account.

Cytotoxic T cells and natural killer cells damage infected hepatocytes in HAV.

HBV injury is predominantly associated with cytotoxic CD8⁺ T-cell activity.

HEV-associated damage is also attributed largely to the host response.

Inflammation is not simply a measure of direct viral cell destruction.

Slide 11 · A host-response model of liver injury

Viral antigen in hepatocyte

→

T-cell / innate recognition

→

Apoptosis or necrosis

→

Aminotransferase release

The liver inflammatory infiltrate in viral hepatitis is predominantly lymphocytic.

Microscopic injury and biochemical hepatitis represent linked phenomena.

Slide 12 · Successful clearance versus persistence

Effective antiviral response

Virus-specific cellular immunity suppresses and removes infected cells.

Resolution may be followed by durable antiviral antibody responses.

Incomplete viral control

Persistent infection sustains hepatocyte injury and inflammation.

Ongoing activity can lead to fibrogenesis and eventual cirrhosis.

Slide 13 · Why hepatitis B can become chronic

HBV establishes nuclear cccDNA

→

Virus–host immune interaction

→

Clearance or persistence

HBV replication uses reverse transcription of an RNA intermediate.

Strong virus-specific CD4⁺ and CD8⁺ responses favor resolution.

Persistence is influenced by the age at infection and immune status.

Slide 14 · HCV persistence is facilitated by viral diversity

HCV RNA polymerase has low replication fidelity.

Genetically diverse quasispecies emerge during infection.

Envelope-epitope variation permits escape from some neutralizing responses.

NS3/4A also interferes with host antiviral signaling.

These mechanisms help explain why chronic infection is frequent.

Slide 15 · HDV depends on an existing HBV system

HBV supplies HBsAg

→

HDV packages its RNA

→

HDV infection becomes possible

HDV is a defective RNA virus requiring HBV-derived envelope proteins.

Consequently, HDV should be considered in persons with HBV infection.

Slide 16 · Transmission biology has clinical consequences

HAV and HEV are often linked to fecal contamination of food or water.

HBV can spread by blood exposure, sexual contact, and during childbirth.

HCV and HDV are predominantly associated with parenteral exposure.

Transmission route directs prevention and exposure assessment.

A common histologic injury pattern can conceal different epidemiologic mechanisms.

Slide 17 · Risk patterns that redirect investigation

Clinical history

Agent group to consider

Reasoning

Food or water outbreak

HAV / HEV

Enteric transmission

Blood / needle exposure

HBV / HCV / HDV

Parenteral transmission

Known chronic HBV with sudden worsening

HDV among other causes

Superinfection can exacerbate disease

Systemic febrile illness

Nonhepatotropic viruses

Liver involvement may be secondary

Slide 18 · Pathogenesis cannot be inferred from ALT alone

An elevated aminotransferase concentration describes hepatocyte injury—not its cause.

Different hepatotropic viruses can produce comparable hepatitic inflammation.

Autoimmune disease and drug injury can reproduce this phenotype.

Etiologic diagnosis requires virus-specific testing.

Slide 19 · The clinicopathologic spectrum

Asymptomatic infection

→

Acute symptomatic hepatitis

→

Recovery or persistence

→

Fibrosis / failure in some

Not every patient follows every step.

Acute liver failure is an uncommon but severe alternative pathway.

Slide 20 · Asymptomatic hepatitis may still be detectable

Many acute infections are clinically silent.

Mild aminotransferase elevations may be the only clue during infection.

After recovery, virus-specific antibodies may indicate previous exposure.

Symptom-based case finding alone misses a substantial fraction of infections.

Examples include subclinical HAV and HBV infection.

Slide 21 · Four phases of symptomatic acute hepatitis

1

Incubation

→

2

Preicteric symptoms

→

3

Icteric phase

→

4

Convalescence

Constitutional symptoms can precede recognizable jaundice.

Incubation length varies across the viral agents.

Slide 22 · Preicteric symptoms are nonspecific

Fatigue, malaise, anorexia, and nausea can dominate presentation.

The early syndrome may resemble other systemic infections.

The absence of jaundice does not exclude acute viral hepatitis.

Exposure history and appropriate viral testing improve etiologic assessment.

The preicteric phase is not unique to one hepatitis virus.

Slide 23 · Jaundice reflects impaired bilirubin handling

Hepatocellular dysfunction may impair bilirubin uptake, processing, or excretion.

Jaundice emerges in only a subset of acute viral infections.

Prominent jaundice does not alone establish the specific virus.

Clinical correlation includes bilirubin and tests of hepatic synthetic function.

Mechanistic linkage is hepatocellular dysfunction, not a virus-specific visual sign.

Slide 24 · Convalescence after acute infection

Antiviral response

→

Declining viral activity

→

Resolution of inflammation

→

Clinical recovery

HAV infection usually resolves without chronic persistence.

Most immunocompetent people clear acute HEV infection.

Slide 25 · Acute hepatitis versus acute liver failure

Acute hepatitis

Hepatocyte injury and inflammation of variable clinical severity.

May resolve without permanent loss of liver architecture.

Acute liver failure

Severe hepatic dysfunction following extensive hepatocyte loss.

Massive necrosis can accompany a shrunken liver.

Requires urgent specialist assessment.

Slide 26 · Acute liver failure: Viral etiologies

Hepatotropic viral infection accounts for a subset of acute liver failure.

HAV and HEV contribute importantly to cases worldwide.

Severe HEV hepatitis is particularly concerning during pregnancy.

Extensive hepatic necrosis can overwhelm regenerative capacity.

Outcome depends on the balance between residual parenchyma and injury severity.

Slide 27 · Persistence versus recovery

Outcome

Biologic feature

Long-term significance

Recovery

Virus controlled; Liver injury subsides

No ongoing virus-driven inflammation

Chronic infection

Persistent / relapsing hepatitis

Fibrosis, cirrhosis and complications

Asymptomatic carriage (HBV context)

Virus detectable without symptoms

Transmission still possible

Slide 28 · Chronic hepatitis: Interpret chronicity correctly

The Robbins description includes continuing or relapsing disease beyond 6 months.

Morphologic fibrosis also indicates a chronic pathologic process.

Persistent serum aminotransferase elevations may be the sole clinical clue.

Chronic viral hepatitis requires etiologic and activity assessment.

Histologic chronicity and virologic persistence are related, but not identical constructs.

Slide 29 · The route from chronic injury to cirrhosis

Persistent hepatitis

→

Portal / periportal fibrosis

→

Bridging fibrosis

→

Cirrhosis

Fibrosis reflects repeated injury and repair rather than a single acute episode.

Portal–portal bridges distort hepatic architecture as disease advances.

Slide 30 · Carrier status requires careful language

A carrier may be asymptomatic

The person harbors and can transmit the infectious agent.

Absence of symptoms does not necessarily mean absence of tissue injury.

Virologic activity varies

Some HBV carriers have low or undetectable HBV DNA and little inflammation.

A comparable “healthy carrier” category is not recognized for HCV.

Slide 31 · Clinical appearance underestimates chronic disease

Minimal symptoms do not exclude persistent hepatitis or fibrosis.

Fatigue may be the dominant symptom of chronic hepatitis.

Laboratory tests, viral assays, and fibrosis assessment provide complementary information.

Cirrhosis and hepatocellular carcinoma are major long-term concerns in HBV/HCV.

Slide 32 · Hepatitis A: The archetype of self-limited infection

Nonenveloped positive-strand RNA virus transmitted primarily fecal–orally.

Immune-mediated hepatocyte injury follows infection.

IgM anti-HAV appears with acute symptomatic disease.

Chronic hepatitis and a persistent carrier state do not occur.

The HAV-specific lecture examines its epidemiology and diagnosis in depth.

Slide 33 · Hepatitis A serology: What the antibody class means

Marker

Interpretation

Temporal pattern

IgM anti-HAV

Recent or acute HAV infection

Appears near symptom onset

IgG anti-HAV

Previous exposure or immunity

Appears during recovery; Persists

Total anti-HAV

Prior or current exposure

Must be interpreted with IgM

Slide 34 · Hepatitis B: Multiple clinical trajectories

HBV is a partially double-stranded DNA hepadnavirus.

Outcomes include recovery, acute liver failure, chronic hepatitis, or asymptomatic carriage.

An age-dependent host response influences chronicity.

Sustained infection increases risk of cirrhosis and hepatocellular carcinoma.

HBV is an important example of host–virus outcome heterogeneity.

Slide 35 · Hepatitis B marker categories

Marker

What it primarily indicates

Important nuance

HBsAg

Current HBV infection

Can occur in acute or chronic infection

IgM anti-HBc

Recent infection

Helpful during serologic window

Anti-HBs

Protective antibody response

Seen after recovery or vaccination

HBV DNA

Viral replication / viremia

Needed when HBeAg is misleading

Slide 36 · HBV persistence is not equivalent to severe symptoms

HBsAg persistence

→

Variable HBV DNA

→

Variable liver inflammation

→

Variable fibrosis

Some chronic infections are clinically silent.

Serology, viral DNA, aminotransferases, and liver assessment answer different questions.

Slide 37 · Hepatitis C: Persistence is a central problem

Enveloped RNA virus of the Flaviviridae family.

Acute infection is often minimally symptomatic or clinically silent.

Rapid viral variation enables immune escape.

Untreated persistent infection may progress to fibrosis and cirrhosis.

HCV-related chronic disease is not reliably excluded by normal symptoms.

Slide 38 · Hepatitis C tests answer distinct questions

Test

Main inference

Limitation

Anti-HCV antibody

Exposure to HCV

Does not alone prove current viremia

HCV RNA

Current viral RNA detected

Interpreted with clinical context

Hepatic fibrosis assessment

Chronic injury burden

Cannot identify HCV without etiologic testing

Slide 39 · Hepatitis D: Two biologically different settings

Coinfection: HBV and HDV acquired together.

Superinfection: HDV acquired by someone already infected with HBV.

Superinfection is more likely to persist and exacerbate existing hepatitis.

Diagnosis incorporates HDV-specific antibodies and HDV RNA.

Every HDV diagnosis requires an HBV context.

Slide 40 · HBV–HDV coinfection versus HDV superinfection

Coinfection

Simultaneous acquisition of HBV and HDV.

May resemble acute HBV hepatitis.

Clearance of both agents often follows.

Superinfection

HDV acquired in pre-existing chronic HBV infection.

Can trigger severe flare of liver injury.

Persistent HDV infection is much more common.

Slide 41 · Hepatitis E: Usually acute, with important exceptions

Enterically transmitted positive-strand RNA virus; Zoonotic reservoirs are described.

Typical infection is self-limited in immunocompetent individuals.

Severe disease may occur during pregnancy.

Chronic HEV infection can occur with immunosuppression.

HEV should not be simplistically described as always nonchronic.

Slide 42 · A–E: Rapid comparison of persistence

Virus

Usual tendency

Important caveat

HAV

Acute and self-limited

No chronic hepatitis / carrier state

HBV

Recovery or persistence

Chronicity strongly shaped by age and immunity

HCV

High chronicity tendency

Acute infection may be clinically silent

HDV

Depends on HBV

Superinfection often persists

HEV

Acute and self-limited

Chronicity in immunosuppressed hosts

Slide 43 · Viral hepatitis is a pattern, not a unique histology

Acute and chronic morphologic changes overlap with other hepatitic disorders.

Viral hepatitis, autoimmune hepatitis, and drug injury can look similar.

Wilson disease can also produce an overlapping hepatitic pattern.

Serologic and molecular results provide necessary etiologic specificity.

Slide 44 · Gross appearance in acute viral hepatitis

Liver size may be normal despite clinical hepatitis.

Inflammation can produce hepatomegaly.

Acute liver failure with massive necrosis can produce a shrunken liver.

Gross size alone is not sufficient to establish diagnosis or severity.

Schematic depictions below are not source photomicrographs.

Slide 45 · Acute hepatitis: Lobular injury schematic

ORIGINAL SCHEMATIC — NOT A HISTOLOGIC SPECIMEN

Lymphocytes

Injured hepatocyte

Characteristic components

Predominantly lymphocytic inflammatory infiltrate in portal tracts and lobules.

Hepatocyte apoptosis and necrosis occur with variable severity.

Macrophages may remove necrotic cell debris.

Slide 46 · Acute injury: Apoptosis and necrosis

Damaged hepatocytes may undergo apoptosis or necrosis.

Apoptotic hepatocytes can appear as condensed eosinophilic bodies.

Pigmented macrophages may scavenge necrotic material.

Tissue injury is accompanied by portal and lobular inflammatory cells.

The distribution and severity of injury matter more than a single cell.

Slide 47 · Severe acute injury: Anatomic extension

Individual cell death

→

Confluent necrosis

→

Bridging necrosis

→

Massive loss in severe cases

Bridging necrosis connects vascular structures.

Panlobular / panacinar necrosis affects an entire lobular unit.

Massive necrosis can produce life-threatening hepatic failure.

Slide 48 · Chronic viral hepatitis: Defining morphology

Portal lymphocytic or lymphoplasmacytic inflammation.

Inflammatory cells may cross the limiting plate into periportal parenchyma.

Portal and periportal fibrosis reflects ongoing injury.

Lobular inflammation may coexist with interface activity.

Fibrosis is the distinctive chronic consequence to recognize.

Slide 49 · Interface hepatitis: Site of inflammatory damage

ORIGINAL SCHEMATIC — NOT A HISTOLOGIC SPECIMEN

Portal tract

Hepatocyte parenchyma

Inflammation crossing interface →

Why this matters

Inflammatory cells cross the hepatocyte–portal tract interface.

Periportal hepatocyte injury accompanies the inflammatory front.

The finding is not specific for viral etiology.

Slide 50 · Fibrosis progression is architectural

ORIGINAL SCHEMATIC — NOT A HISTOLOGIC SPECIMEN

Portal fibrosis

Bridging

Cirrhotic remodeling

Cumulative injury

Early: Portal and periportal fibrosis.

Progression: Portal–portal bridging fibrosis.

Advanced: Cirrhotic remodeling of the parenchyma.

Conceptual stages — shapes do not reproduce a biopsy field

Slide 51 · Acute versus chronic biopsy patterns

Feature

Acute hepatitis

Chronic hepatitis

Inflammatory distribution

Lobular ± portal

Portal ± interface and lobular

Hepatocyte injury

Apoptosis and necrosis

Variable ongoing injury

Fibrosis

Not defining

Defining feature / disease stage

Advanced injury

Confluent or bridging necrosis

Bridging fibrosis to cirrhosis

Slide 52 · HBV: Ground-glass hepatocytes

Accumulated HBsAg expands hepatocyte endoplasmic reticulum.

This can impart a ground-glass appearance to the cytoplasm.

HBsAg and HBcAg immunostains help document HBV infection.

Other inflammatory features may overlap with chronic hepatitis of other causes.

Ground-glass morphology is a supportive finding, not a standalone serologic diagnosis.

Slide 53 · HCV: Recognizable but nonexclusive clues

Lymphoid aggregates or follicles may be prominent in portal tracts.

Steatosis is common, particularly with genotype 3 infection.

Focal bile duct injury can mimic a primary biliary process.

Morphology requires virologic correlation.

Avoid treating a suggestive pattern as etiologically pathognomonic.

Slide 54 · Activity and stage are different biopsy questions

Activity / grade

How much ongoing inflammatory hepatocyte injury is present?

Depends on inflammation and necroinflammatory activity.

Fibrosis / stage

How much scarring and architectural remodeling has accrued?

Portal fibrosis may progress to bridges and cirrhosis.

Slide 55 · Etiologic diagnostic approach to hepatitic injury

Clinical and exposure context

→

Hepatic injury pattern

→

Virus-specific assays

→

Interpret with morphology

Biopsy does not reliably distinguish all viruses.

Serologic and molecular studies distinguish current infection from prior exposure.

Slide 56 · Test choice must match the diagnostic question

Question

Typical test class

Example

Recent infection?

Virus-specific IgM

IgM anti-HAV / anti-HEV

Current HBV?

Antigen + viral nucleic acid

HBsAg; HBV DNA

Current HCV?

Viral nucleic acid

HCV RNA

Possible HDV?

Antibody + viral nucleic acid

Anti-HDV; HDV RNA

Slide 57 · Why an antibody result may not equal active infection

IgG to a virus may persist after the infection resolves.

Anti-HCV indicates exposure; HCV RNA addresses current viremia.

HBV surface antigen and anti-HBs have different meanings.

Interpret antigen, antibody, and nucleic acid markers together.

Avoid equating “antibody-positive” with transmissible current infection.

Slide 58 · Why liver biopsy remains useful

Biopsy can evaluate

Inflammatory activity and interface injury.

Distribution and severity of fibrosis.

Competing or coexisting causes of hepatic injury.

Biopsy alone cannot reliably

Determine which hepatotropic virus is present.

Establish current viremia.

Replace targeted serologic and molecular testing.

Slide 59 · Diagnostic pitfalls in viral hepatitis

Pitfall

Why it fails

More defensible approach

Diagnosing virus from morphology

Patterns overlap

Add virus-specific assays

Equating absent jaundice with no hepatitis

Many infections are subclinical

Use risk and laboratory evidence

Equating seropositivity with viremia

Antibodies may persist

Test antigen / RNA / DNA

Equating low symptoms with mild fibrosis

Chronic damage may be silent

Assess liver disease burden

Slide 60 · Chronic disease: One integrated assessment

Etiology

→

Virologic activity

→

Necroinflammation

→

Fibrosis stage

These axes are complementary, not interchangeable.

A patient may have few symptoms despite substantial structural disease.

Slide 61 · Case: Acute hepatitis after contaminated water

ILLUSTRATIVE CLINICAL SCENARIO

An adult presents with anorexia, fatigue, and jaundice several weeks after a shared water exposure.

What etiologic group and laboratory test class should be prioritized?

Discussion answer in presenter notes

Slide 62 · Case: Hepatitis with established HBV infection

ILLUSTRATIVE CLINICAL SCENARIO

A person known to have chronic HBV develops an abrupt severe flare after a new parenteral exposure.

What additional hepatotropic infection is especially relevant?

Discussion answer in presenter notes

Slide 63 · Case: Silent infection and portal fibrosis

ILLUSTRATIVE CLINICAL SCENARIO

A patient has few symptoms but persistent viral markers; Biopsy shows portal inflammation, interface activity, and bridging fibrosis.

Is this an acute-only process, and what should be reported from the biopsy?

Discussion answer in presenter notes

Slide 64 · Three diagnostic contrasts worth remembering

Comparison

The discriminating concept

Practical consequence

HAV vs HCV

Self-limited vs high persistence tendency

Different chronic follow-up implications

HBV vs HDV

HBV independent; HDV depends on HBV

Evaluate HDV in HBV context

Acute vs chronic pattern

Necroinflammation vs fibrosis

Morphology estimates duration / accumulated damage

Slide 65 · Integrative synthesis

The etiologic virus and the tissue injury pattern answer different diagnostic questions.

The five hepatotropic viruses share a hepatitic phenotype.

Transmission and molecular tests identify the agent.

Host response determines cellular injury and the course.

Biopsy establishes activity and structural damage but is rarely agent-specific.

Slide 66 · References and source boundary

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026. Chapter 18, pp. 755–762.

Primary heading: “Viral Hepatitis” (pp. 755–756).

Supporting context: individual hepatitis viruses and clinicopathologic syndromes (pp. 756–762).

Original diagrams in this lecture are editable schematics, not diagnostic specimen images.