HEPATITIS- for medical undergraduates

 HEPATITIS

1. Introduction

Hepatitis means inflammation of the liver. The term is derived from:

• Hepat- = liver
• -itis = inflammation

Hepatitis is not a single disease. It is a clinicopathological syndrome that may result from infectious, toxic, metabolic, autoimmune, drug-related or other causes. The major causes include:

• Viral infections
• Alcohol
• Drugs and toxins
• Autoimmune disease
• Metabolic disorders
• Ischaemic injury
• Certain hereditary diseases

Among infectious causes, hepatitis viruses A, B, C, D and E are the major human viral hepatitis pathogens. WHO emphasizes that these viruses differ substantially in their modes of transmission, likelihood of chronicity, complications and prevention. (World Health Organization) Viral hepatitis is particularly important in medicine because some forms are self-limiting whereas others can progress to:

Chronic hepatitis → fibrosis → cirrhosis → hepatic failure and/or hepatocellular carcinoma (HCC).

In particular, chronic hepatitis B and C are major causes of cirrhosis and liver cancer worldwide. (World Health Organization)

2. Classification of Hepatitis

A. According to duration

1. Acute hepatitis

Usually lasts less than 6 months. It may be:

• Asymptomatic
• Symptomatic
• Anicteric
• Icteric
• Cholestatic
• Fulminant

2. Chronic hepatitis

Persistent hepatic inflammation for more than 6 months. Important causes include:

• Chronic HBV infection
• Chronic HCV infection
• Chronic HDV infection
• Autoimmune hepatitis
• Metabolic disorders
• Certain drugs and toxins

3. Classification According to Cause

A. Infectious hepatitis

Viral

• Hepatitis A virus — HAV
• Hepatitis B virus — HBV
• Hepatitis C virus — HCV
• Hepatitis D virus — HDV
• Hepatitis E virus — HEV

Other viruses can also produce hepatitis, including:

• Epstein–Barr virus
• Cytomegalovirus
• Yellow fever virus
• Herpes simplex virus

B. Non-infectious Hepatitis

1. Alcoholic hepatitis

Associated with chronic excessive alcohol consumption.

2. Drug-induced hepatitis

Examples include hepatic injury caused by:

• Isoniazid
• Rifampicin
• Pyrazinamide
• Paracetamol overdose
• Amoxicillin-clavulanate
• Certain antiepileptic drugs
• Methotrexate
• Amiodarone

3. Autoimmune hepatitis

An immune-mediated inflammatory disease of the liver.

4. Metabolic hepatitis

May occur in disorders such as:

• Metabolic dysfunction-associated steatotic liver disease (MASLD)
• Wilson disease
• Haemochromatosis
• Alpha-1 antitrypsin deficiency

4. VIRAL HEPATITIS: THE FIVE MAJOR VIRUSES

Feature	HAV	HBV	HCV	HDV	HEV
Virus type	RNA	DNA	RNA	RNA	RNA
Main transmission	Faeco-oral	Blood/body fluids	Blood	Blood/body fluids with HBV	Mainly faeco-oral
Acute hepatitis	Yes	Yes	Yes	Yes	Yes
Chronic infection	No	Yes	Yes	Yes	Usually no
Vaccine	Yes	Yes	No	Prevented by HBV vaccination	Limited availability; vaccine licensed in some countries
Important complication	Fulminant hepatitis, rare	Cirrhosis, HCC	Cirrhosis, HCC	Severe hepatitis, chronic liver disease	Fulminant hepatitis, particularly important in pregnancy
Association with HBV	No	—	No	Obligate	No

The major distinction for examinations is:

HAV and HEV → usually acute, non-chronic hepatitis.
HBV, HCV and HDV → may produce chronic hepatitis. (NIDDK)

5. Acute Viral Hepatitis

Acute viral hepatitis is an inflammatory injury to hepatocytes caused by viral infection. The clinical manifestations vary from:

Asymptomatic infection → mild illness → classical icteric hepatitis → severe hepatitis → fulminant hepatic failure.

6. Pathogenesis of Acute Viral Hepatitis

An important concept is that liver injury is not always caused simply by direct destruction of hepatocytes by the virus. In several viral hepatitis infections, particularly HBV, host immune responses against infected hepatocytes play a major role in hepatic injury.

The sequence can be summarized as:

Viral entry into hepatocytes
↓
Viral replication
↓
Expression of viral antigens
↓
Innate and adaptive immune responses
↓
Hepatocyte injury and inflammation
↓
Elevation of aminotransferases
↓
Possible jaundice

If viral infection is eliminated:

Resolution → recovery → immunity in some infections

If the virus persists:

Persistent infection → chronic inflammation → fibrosis → cirrhosis ± HCC

7. Clinical Stages of Acute Viral Hepatitis

Classically, acute hepatitis may be divided into:

1. Incubation period
2. Prodromal/pre-icteric phase
3. Icteric phase
4. Convalescent phase

7.1 Incubation period

The patient is infected but usually has no symptoms. The duration varies according to the virus.

Virus	Approximate incubation period
HAV	15–50 days
HBV	6 weeks–6 months
HCV	2 weeks–6 months
HEV	2–10 weeks

For HAV, WHO reports a usual incubation period of approximately 14–28 days. (World Health Organization)

8. Prodromal / Pre-Icteric Phase

Symptoms may include:

• Malaise
• Fatigue
• Fever
• Anorexia
• Nausea
• Vomiting
• Headache
• Myalgia
• Arthralgia
• Right upper abdominal discomfort

Some patients develop:

• Altered taste
• Aversion to cigarettes
• Mild diarrhoea
• Flu-like symptoms

These symptoms are non-specific. Therefore, acute viral hepatitis may initially be mistaken for:

• Viral fever
• Gastroenteritis
• Influenza-like illness
• Food poisoning

9. Icteric Phase

The classical features are:

• Jaundice
• Dark urine
• Pale or clay-coloured stools
• Hepatomegaly
• Right upper quadrant discomfort
• Fatigue
• Anorexia
• Nausea

Jaundice occurs because of disturbed bilirubin handling and excretion by the injured liver. The urine becomes dark because conjugated bilirubin is water-soluble and is excreted in urine.

10. Convalescent Phase

The patient gradually recovers. There is:

• Improvement in appetite
• Reduction of jaundice
• Normalization of aminotransferases
• Regression of hepatomegaly
• Restoration of general health

Fatigue may persist for weeks or months even after biochemical recovery.

11. Clinical Features of Acute Hepatitis

Constitutional symptoms

• Fever
• Malaise
• Weakness
• Fatigue
• Anorexia

Gastrointestinal symptoms

• Nausea
• Vomiting
• Abdominal discomfort
• Right upper quadrant pain
• Occasionally diarrhoea

Hepatic manifestations

• Hepatomegaly
• Jaundice
• Dark urine
• Pale stools

Extrahepatic manifestations

Some viral hepatitis infections, particularly HBV and HCV, can produce extrahepatic manifestations. Examples include:

• Arthralgia
• Skin manifestations
• Glomerulonephritis
• Vasculitis
• Cryoglobulinaemia, particularly with HCV
• Polyarteritis nodosa, associated with HBV

12. JAUNDICE IN HEPATITIS

Jaundice is caused primarily by impaired hepatic handling and excretion of bilirubin. In hepatocellular injury:

Hepatocyte injury
↓
Impaired uptake/conjugation/excretion of bilirubin
↓
Increased serum bilirubin
↓
Jaundice

Both conjugated and unconjugated bilirubin may be increased, although conjugated hyperbilirubinaemia is prominent in established hepatocellular/cholestatic jaundice.

13. Laboratory Findings in Acute Hepatitis

13.1 Serum aminotransferases

The characteristic biochemical finding is a marked elevation of:

• ALT — alanine aminotransferase
• AST — aspartate aminotransferase

Typically: ALT > AST in uncomplicated acute viral hepatitis. ALT is more liver-specific than AST.

14. Bilirubin

Serum bilirubin may be markedly elevated, particularly in icteric disease. Usually:

• Total bilirubin ↑
• Direct/conjugated bilirubin ↑

15. Alkaline Phosphatase

ALP may be mildly to moderately increased. However: A very high ALP out of proportion to aminotransferases suggests a predominantly cholestatic process rather than uncomplicated hepatocellular hepatitis.

16. Prothrombin Time / INR

This is a very important prognostic parameter. The liver synthesizes most coagulation factors. Severe hepatocellular dysfunction results in:

↓ synthesis of clotting factors → prolonged PT / increased INR

A prolonged PT that does not correct appropriately with vitamin K suggests significant hepatic synthetic dysfunction. Therefore:

PT/INR is more useful than aminotransferases for assessing severity of acute liver failure.

17. Serum Albumin

Albumin has a long half-life. Therefore, it is not a sensitive marker of acute hepatic injury. Low albumin is more suggestive of:

• Chronic liver disease
• Malnutrition
• Protein-losing conditions
• Advanced hepatic dysfunction

18. Urine Findings

In conjugated hyperbilirubinaemia:

• Urine bilirubin may be positive.
• Urine becomes dark.

Urinary urobilinogen may vary depending on the stage and type of disease.

19. Diagnosis of Acute Viral Hepatitis

Diagnosis involves three broad steps:

Step 1 — Establish liver injury

• ALT
• AST
• Bilirubin
• ALP
• GGT

Step 2 — Assess liver function

• PT/INR
• Albumin
• Glucose
• Clinical assessment for encephalopathy

Step 3 — Identify the cause

Use specific viral serology and/or nucleic acid testing.

20. Hepatitis A

Definition

Hepatitis A is an acute infectious disease of the liver caused by hepatitis A virus (HAV). HAV is mainly transmitted by the faeco-oral route, particularly through contaminated food and water or close contact with an infected person. (World Health Organization)

Causative organism

Hepatitis A virus

Family: Picornaviridae, HAV is a small, non-enveloped RNA virus.

Transmission

Major routes:

• Contaminated food
• Contaminated water
• Poor sanitation
• Poor hand hygiene
• Close household contact
• Oral-anal sexual contact

Incubation period

Approximately: 15–50 days, Average: ~28 days, CDC reports an average incubation period of 28 days, with a range of 15–50 days. (CDC)

21. Clinical Features of Hepatitis A

HAV infection is frequently asymptomatic in young children. When symptomatic, features include:

• Fever
• Malaise
• Anorexia
• Nausea
• Vomiting
• Abdominal discomfort
• Dark urine
• Jaundice
• Hepatomegaly

Adults are more likely to develop clinically apparent illness than young children. (World Health Organization)

22. Important Feature of HAV

Hepatitis A does not cause chronic hepatitis. Most patients recover completely and develop long-lasting immunity. However, rare patients can develop:

Fulminant hepatitis → acute liver failure → death

WHO notes that a very small proportion of patients develop fulminant hepatitis. (World Health Organization)

23. Diagnosis of HAV

The principal serological marker is: Anti-HAV IgM

Indicates: Recent/acute HAV infection

Anti-HAV IgG Indicates:

• Previous infection
• Immunity following vaccination

WHO identifies HAV-specific IgM as the key serological diagnostic marker. (World Health Organization)

24. Treatment of HAV

There is no specific antiviral treatment for uncomplicated hepatitis A. Management is supportive:

• Adequate hydration
• Adequate nutrition
• Rest according to symptoms
• Treatment of nausea/vomiting when required
• Avoidance of unnecessary hepatotoxic medications
• Monitoring for severe hepatic dysfunction

Hospitalization may be required for:

• Severe dehydration
• Persistent vomiting
• Severe cholestasis
• Acute liver failure

WHO recommends supportive management because HAV infection is usually self-limiting. (World Health Organization)

25. Prevention of Hepatitis A

General measures

• Safe drinking water
• Proper sewage disposal
• Hand washing
• Food hygiene
• Safe preparation of food
• Appropriate sanitation

Specific prevention

Hepatitis A vaccination

The vaccine is highly effective in preventing HAV infection. (World Health Organization)

26. Hepatitis B

Hepatitis B is caused by hepatitis B virus (HBV). It is one of the most clinically important forms of viral hepatitis because it can produce:

Acute hepatitis → chronic hepatitis → cirrhosis → hepatocellular carcinoma

WHO estimates that approximately 240 million people were living with chronic HBV infection in 2024, emphasizing its continuing global importance. (World Health Organization)

27. Hepatitis B Virus

HBV belongs to the family: Hepadnaviridae. It is:

• Enveloped
• DNA virus
• Partially double-stranded DNA virus

The viral genome is associated with several important viral proteins/antigens.

28. Important HBV Antigens

The major antigens are:

1. HBsAg

Hepatitis B surface antigen- Indicates: Current HBV infection when persistently detected.

2. HBcAg

Hepatitis B core antigen- It is not normally detectable in serum as a free circulating antigen.

3. HBeAg

Associated with:

• Active viral replication
• Higher levels of infectivity, although not invariably

29. HBV Transmission

HBV is transmitted through infected:

• Blood
• Semen
• Vaginal secretions
• Certain other body fluids

Important routes include:

1. Perinatal transmission

Mother → infant around birth.

2. Sexual transmission

Unprotected sexual exposure.

3. Percutaneous transmission

Examples:

• Contaminated needles
• Injection drug use
• Unsafe injections
• Needle-stick injuries
• Unsterile tattooing
• Unsterile medical procedures

WHO identifies mother-to-child transmission at birth, early childhood transmission and blood/body-fluid exposure as important routes. (World Health Organization)

30. Incubation Period of HBV

Approximately: 6 weeks to 6 months, It is considerably longer than HAV.

31. Acute Hepatitis B

Clinical presentation ranges from:

• Asymptomatic infection
• Mild hepatitis
• Icteric hepatitis
• Severe hepatitis
• Fulminant hepatic failure

Some patients develop a characteristic serum-sickness-like prodrome. Features may include:

• Fever
• Malaise
• Rash
• Arthralgia
• Arthritis

These may precede jaundice.

32. Outcome of HBV Infection

The outcome depends strongly on the age at infection and immune status. In general:

Infection during infancy- High probability of chronic infection.

Infection during early childhood- Intermediate risk of chronicity.

Infection during adulthood- Most immunocompetent adults’ clear acute infection, while a smaller proportion develop chronic infection. NIDDK summarizes chronic infection rates at approximately 90% for infection acquired during infancy, 25–50% in children aged 1–5 years, and around 5% in adults. (NIDDK)

33. Chronic Hepatitis B

Chronic HBV infection is defined by persistent infection, classically reflected by: HBsAg positivity for ≥6 months, Chronic infection may be:

• Asymptomatic
• Associated with chronic hepatitis
• Associated with fibrosis
• Associated with cirrhosis
• Associated with HCC

34. Phases of Chronic HBV Infection

The clinical course of chronic HBV is dynamic. Traditionally, phases have been described as:

1. Immune-tolerant phase
2. Immune-active phase
3. Inactive phase
4. Reactivation phase

Modern guidelines emphasize that HBV disease activity is dynamic and that patients may move between phases. The 2025 AASLD/IDSA guidance specifically emphasizes individualized assessment based on HBV DNA, ALT, fibrosis, age and other risk factors. (AASLD)

35. HBV Serology

The major markers are:

• HBsAg
• Anti-HBs
• Total anti-HBc
• IgM anti-HBc
• HBeAg
• Anti-HBe
• HBV DNA

36. Meaning of HBsAg

HBsAg positive Indicates: Current HBV infection.  It may occur in:

• Acute HBV infection
• Chronic HBV infection

If HBsAg persists for ≥6 months: Chronic HBV infection

37. Meaning of Anti-HBs

Anti-HBs indicates: Immunity against HBV

It develops after:

• Recovery from natural infection, or
• Successful vaccination.

38. Meaning Of Anti-HBc

Anti-HBc indicates: Exposure to natural HBV infection. It is not produced by vaccination alone. This is a frequently tested distinction.

39. IgM ANTI-HBc

IgM anti-HBc is particularly important because it indicates: Recent/acute HBV infection, It can also reappear during some episodes of HBV reactivation.

40. HBeAg

HBeAg generally correlates with: Active HBV replication and increased infectivity. However: HBeAg negativity does not necessarily mean absence of viral replication. HBeAg-negative chronic hepatitis can occur due to HBV variants.

41. HBV DNA

HBV DNA is a direct marker of: Viral replication / viral load. It is important for:

• Assessment of disease activity
• Prognosis
• Treatment decisions
• Monitoring response to antiviral therapy

42. Important HBV Serology Table

HBsAg	Anti-HBs	IgM anti-HBc	Total anti-HBc	Interpretation
−	−	−	−	Susceptible
+	−	+	+	Acute infection
+	−	−	+	Chronic infection
−	+	−	+	Recovered from natural infection
−	+	−	−	Immunity due to vaccination
−	−	+	+	Window period

43. The Window Period

During the window period:

• HBsAg has disappeared
• Anti-HBs has not yet become detectable

The important marker is: IgM anti-HBc. Therefore:

Window period of HBV → IgM anti-HBc is the key marker.

44. Difference Between Natural Immunity and Vaccine Immunity

Natural recovery

HBsAg −
Anti-HBs +
Anti-HBc +

Vaccination

HBsAg −
Anti-HBs +
Anti-HBc −

Why? Because the vaccine contains HBsAg, not the core antigen.

45. Complications of Chronic HBV

Major complications include:

1. Chronic hepatitis

2. Fibrosis

3. Cirrhosis

4. Hepatic failure

5. Hepatocellular carcinoma

6. Extrahepatic manifestations

Examples:

• Polyarteritis nodosa
• Glomerulonephritis
• Mixed cryoglobulinaemia-like syndromes

Chronic HBV is an important cause of cirrhosis and HCC. (World Health Organization)

46. Hepatitis B and Hepatocellular Carcinoma

HBV is particularly important because HCC can occur in patients with HBV-associated liver disease, sometimes even without established cirrhosis.

Mechanisms include:

• Chronic inflammation
• Repeated hepatocyte injury and regeneration
• Fibrosis/cirrhosis
• Viral DNA integration into the host genome
• Viral regulatory effects

Therefore: HBV is an important oncogenic virus.

47. Treatment Of Hepatitis B

Acute hepatitis B

Most uncomplicated acute HBV infections are managed with:

• Supportive care
• Adequate hydration
• Nutrition
• Monitoring for acute liver failure

Specific antiviral treatment is reserved for selected severe/protracted cases under specialist guidance.

Chronic hepatitis B

The aims of treatment are:

• Suppress HBV replication
• Reduce hepatic inflammation
• Prevent progression to cirrhosis
• Reduce risk of HCC
• Prevent liver-related mortality
• Achieve durable suppression and, ideally, functional cure through HBsAg loss

Important oral nucleos(t)ide analogues include:

• Tenofovir disoproxil fumarate (TDF)
• Tenofovir alafenamide (TAF)
• Entecavir

The 2025 AASLD/IDSA guideline identifies entecavir, TDF and TAF as recommended high-efficacy nucleos(t)ide analogue options. (AASLD) Pegylated interferon remains an option in selected patients but has a more limited role because of tolerability, contraindications and patient-selection considerations.

48. Prevention of Hepatitis B

1. Vaccination

The most important preventive measure.

2. Screening of blood

All donated blood should be appropriately screened.

3. Safe injection practices

Use:

• Sterile needles
• Sterile syringes
• Proper sharps disposal

4. Safe sex

Use barrier protection when appropriate.

5. Avoid sharing personal items

Examples:

• Razors
• Toothbrushes
• Needles

6. Prevention of mother-to-child transmission

Pregnant women should be appropriately screened. Infants born to mothers with HBV infection require timely prophylaxis according to national guidelines.

49. Hepatitis C

Hepatitis C is caused by: Hepatitis C virus (HCV)

HCV is an:

• Enveloped
• Positive-sense single-stranded RNA virus

It belongs to the family: Flaviviridae

50. Transmission of HCV

HCV is predominantly blood-borne. Important routes include:

• Sharing needles/syringes
• Unsafe injections
• Contaminated medical equipment
• Unsafely performed tattooing/piercing
• Transfusion of unscreened blood
• Occupational exposure
• Less commonly, sexual exposure where blood exposure occurs
• Perinatal transmission

WHO identifies blood exposure through unsafe health-care procedures, unscreened transfusion and shared injecting equipment as major routes. (World Health Organization)

51. IMPORTANT FEATURE OF HCV

Hepatitis C is frequently asymptomatic. Many patients do not know that they are infected. Consequently, chronic infection may remain undiagnosed for years.

52. NATURAL HISTORY OF HCV

After acute infection: Spontaneous clearance in a minority while: Persistent infection → chronic hepatitis

WHO estimates that approximately 30% of infected individuals spontaneously clear HCV within 6 months, while approximately 70% develop chronic infection. (World Health Organization)

53. Complications of Chronic HCV

Chronic HCV may result in:

• Chronic hepatitis
• Fibrosis
• Cirrhosis
• Hepatic failure
• Hepatocellular carcinoma

Extrahepatic manifestations include:

• Mixed cryoglobulinaemia
• Certain lymphoproliferative disorders
• Glomerular disease
• Porphyria cutanea tarda
• Lichen planus

54. Diagnosis Of HCV

The initial test is: Anti-HCV antibody, If reactive: HCV RNA by nucleic acid testing is used to determine whether there is current infection. Thus: Anti-HCV positive ≠ necessarily active infection, because antibody may remain after spontaneous or treatment-induced clearance.

CDC recommends HCV antibody testing with reflex nucleic acid testing for HCV RNA when the antibody is reactive. (CDC)

55. HCV Treatment

The treatment of HCV has undergone a major transformation. Modern therapy uses: Direct-acting antivirals (DAAs). They target specific viral proteins. Modern DAA regimens can cure more than 95% of treated patients in appropriate settings. (World Health Organization) AASLD/IDSA guidance recommends treatment for essentially all persons with acute or chronic HCV infection, except selected patients with very limited life expectancy that cannot be improved by HCV therapy or other-directed treatment. (IDSA)

 56. HCV Vaccine

There is currently no effective vaccine against hepatitis C. (World Health Organization) Therefore, prevention depends primarily on:

• Safe injection practices
• Blood screening
• Infection-control measures
• Harm-reduction measures
• Appropriate testing and treatment

57. Hepatitis D

Hepatitis D is caused by: Hepatitis D virus (HDV) HDV is a defective/satellite-like RNA virus that requires HBV infection for its replication and propagation. Therefore: HDV cannot establish infection in the absence of HBV. This is one of the most important facts about hepatitis D.

58. Types of HDV Infection

There are two important clinical situations:

1. Coinfection

Simultaneous infection with: HBV + HDV

2. Superinfection

HDV infection occurring in a person who already has: Chronic HBV infection

59. Coinfection Vs Superinfection

Feature	Coinfection	Superinfection
HBV status	Newly acquired	Pre-existing chronic HBV
HDV acquisition	Simultaneous with HBV	Later
Severity	May be severe	Often more severe
Chronicity	Lower	Higher
Risk of cirrhosis	Lower than superinfection	High
Fulminant hepatitis	Possible	Possible

60. Diagnosis of HDV

Tests include:

• Anti-HDV antibodies
• HDV RNA
• HBV markers

HDV should be considered particularly in patients with HBV infection who have:

• Severe hepatitis
• Unexpected ALT flares
• Rapid progression of liver disease

61. Prevention of Hepatitis D

There is no independent HDV vaccine. But because HDV requires HBV: Hepatitis B vaccination prevents hepatitis D.

62. Hepatitis E

Hepatitis E is caused by: Hepatitis E virus (HEV) HEV is an RNA virus. The major route of transmission in many endemic settings is: Faeco-oral transmission, particularly through contaminated water. WHO identifies HEV as an important cause of acute hepatitis worldwide. (World Health Organization)

63. Transmission of HEV

Faeco-oral

• Contaminated drinking water
• Poor sanitation
• Contaminated food

Zoonotic transmission

Some HEV genotypes can be transmitted through consumption of:

• Raw/undercooked pork
• Wild-animal meat
• Other infected animal products

WHO notes that genotypes 3 and 4 are particularly associated with zoonotic transmission. (World Health Organization)

64. Incubation Period of HEV

Approximately: 2–10 weeks

65. Clinical Features of HEV

Symptoms may include:

• Fever
• Malaise
• Anorexia
• Nausea
• Vomiting
• Abdominal pain
• Dark urine
• Pale stools
• Jaundice
• Hepatomegaly

The disease usually resolves spontaneously within several weeks. (World Health Organization)

66. Hepatitis E and Pregnancy

This is an extremely important examination point. HEV infection can be particularly severe during pregnancy, especially in the second and third trimesters. Possible complications include:

• Fulminant hepatic failure
• Maternal death
• Fetal loss

WHO reports substantially increased mortality risk among pregnant women with HEV, particularly during the third trimester. (World Health Organization)

67. Chronic Hepatitis E

Unlike HAV, chronic HEV infection can rarely occur. It is particularly described in:

• Immunosuppressed individuals
• Solid-organ transplant recipients

Thus: HEV is predominantly an acute infection but chronic infection is possible in immunocompromised patients. (World Health Organization)

68. Diagnosis of HEV

Diagnosis may involve:

• Anti-HEV IgM
• Anti-HEV IgG
• HEV RNA by molecular testing

Anti-HEV IgM supports recent infection.

69. Treatment of HEV

For uncomplicated acute HEV:

• Supportive management
• Hydration
• Adequate nutrition
• Symptomatic treatment
• Avoid unnecessary hepatotoxic medications

Severe cases require specialist management. Chronic HEV in immunosuppressed patients may require reduction of immunosuppression and, in selected cases, antiviral therapy such as ribavirin under specialist supervision.

70. Comparison of Hepatitis A–E

Feature	A	B	C	D	E
Genome	RNA	DNA	RNA	RNA	RNA
Envelope	No	Yes	Yes	Yes*	No
Main route	Faeco-oral	Blood/body fluids	Blood	Blood/body fluids	Faeco-oral
Acute disease	Yes	Yes	Yes	Yes	Yes
Chronic disease	No	Yes	Yes	Yes	Usually no
Vaccine	Yes	Yes	No	HBV vaccine prevents HDV	Available only in limited settings
HCC association	No	Yes	Indirectly through chronic disease	Yes through chronic HDV/HBV	Not a major typical association
Pregnancy importance	Moderate	Important	Important	Important	Very important
Requires another virus	No	No	No	HBV	No

*HDV uses HBV envelope proteins for its infectious particle.

71. Acute Hepatitis VS Chronic Hepatitis

Feature	Acute hepatitis	Chronic hepatitis
Duration	Usually <6 months	>6 months
Symptoms	Often prominent	Frequently absent or mild
ALT/AST	Often markedly elevated	Variable
Jaundice	Commoner	Often absent
Fibrosis	Usually absent early	Progressive possibility
Cirrhosis	Uncommon immediately	Important long-term complication
HCC	Usually not immediate	Major concern in HBV/HCV
Liver failure	Possible in fulminant disease	Possible in advanced disease

72. Fulminant Hepatitis / Acute Liver Failure

A small proportion of acute viral hepatitis cases can progress to: Acute liver failure

The major clinical features are:

• Severe hepatic dysfunction
• Coagulopathy
• Prolonged PT/INR
• Hepatic encephalopathy

Other findings may include:

• Hypoglycaemia
• Cerebral oedema
• Renal dysfunction
• Metabolic disturbances
• Haemodynamic instability

Common viral causes include:

• HAV
• HBV
• HEV

HDV may contribute to severe HBV-associated disease.

73. Hepatic Encephalopathy

Hepatic encephalopathy results from accumulation of neurotoxic substances due to severe hepatic dysfunction and/or portosystemic shunting. Clinical features include:

• Sleep disturbance
• Personality changes
• Confusion
• Disorientation
• Drowsiness
• Asterixis
• Coma

Asterixis is a characteristic physical sign of metabolic encephalopathy.

74. Differential Diagnosis of Jaundice

Jaundice should be classified into:

1. Prehepatic

Example:

• Haemolysis

2. Hepatic

Examples:

• Viral hepatitis
• Alcoholic hepatitis
• Drug-induced liver injury
• Autoimmune hepatitis

3. Posthepatic

Examples:

• Common bile duct stone
• Biliary stricture
• Pancreatic carcinoma

75. Hepatocellular VS Cholestatic Pattern

Hepatocellular pattern

Predominant increase: ALT/AST

Examples:

• Viral hepatitis
• Autoimmune hepatitis
• Ischaemic hepatitis

Cholestatic pattern

Predominant increase: ALP/GGT

Examples:

• Biliary obstruction
• Cholestatic liver diseases

This distinction is clinically very important.

76. Liver Function Tests in Hepatitis

The commonly ordered tests include:

Hepatocellular injury markers

• ALT
• AST

Cholestatic markers

• ALP
• GGT

Excretory function

• Total bilirubin
• Direct bilirubin

Synthetic function

• PT/INR
• Albumin

Other tests

• Total protein
• Glucose
• CBC
• Renal function
• Electrolytes

77. Liver Biopsy

Liver biopsy is not routinely required to diagnose uncomplicated acute viral hepatitis. It may be considered when:

• Diagnosis is uncertain
• Autoimmune hepatitis is suspected
• Chronic liver disease requires histological assessment
• Competing diagnoses need differentiation
• Staging of certain chronic liver diseases is required when non-invasive tests are insufficient

Non-invasive approaches such as:

• Elastography
• Serum fibrosis markers
• Imaging

are increasingly important for assessing fibrosis.

78. Histopathology of Acute Viral Hepatitis

Typical histological features include:

• Hepatocyte injury
• Lobular disarray
• Hepatocyte ballooning
• Acidophilic/Councilman bodies
• Mononuclear inflammatory infiltrate
• Focal hepatocyte necrosis
• Kupffer cell hyperplasia

Severe disease may produce: Confluent necrosis → bridging necrosis → massive/submassive necrosis

79. Chronic Hepatitis- Histopathology

Chronic hepatitis is characterized by:

• Portal inflammation
• Interface hepatitis
• Lobular inflammation
• Hepatocyte injury
• Progressive fibrosis

Persistent injury can result in: Portal fibrosis → bridging fibrosis → cirrhosis

80. Cirrhosis

Cirrhosis represents advanced chronic liver disease characterized by:

• Diffuse fibrosis
• Formation of regenerative nodules
• Architectural distortion
• Vascular reorganization

The progression can be summarized:

Chronic viral hepatitis
↓
Persistent inflammation
↓
Hepatocyte injury
↓
Fibrogenesis
↓
Bridging fibrosis
↓
Cirrhosis
↓
Portal hypertension + hepatic dysfunction
↓
Decompensation

81. Complications of Cirrhosis

Major complications include:

• Portal hypertension
• Ascites
• Oesophageal varices
• Splenomegaly
• Hepatic encephalopathy
• Coagulopathy
• Hypoalbuminaemia
• Hepatorenal syndrome
• Spontaneous bacterial peritonitis
• Hepatocellular carcinoma

82. Extrahepatic Manifestations

Extrahepatic manifestations are especially important in HBV and HCV.

HBV

Associated with:

• Polyarteritis nodosa
• Glomerulonephritis
• Serum sickness-like syndrome

HCV

Associated with:

• Mixed cryoglobulinaemia
• Glomerulonephritis
• Porphyria cutanea tarda
• Lichen planus
• Certain lymphomas

83. Screening and Testing

Modern hepatitis control depends heavily on identifying people with silent infection. For HBV, CDC recommends a triple-panel screening approach:

• HBsAg
• Anti-HBs
• Total anti-HBc

for initial screening of chronic HBV infection. (CDC) For HCV: Anti-HCV antibody → reflex HCV RNA is a standard diagnostic pathway for identifying current infection. (CDC)

84. Prevention of Viral Hepatitis

Prevention can be divided into:

A. General measures

• Safe water
• Sanitation
• Hand hygiene
• Food hygiene
• Safe sexual practices
• Safe injection practices
• Screening of blood
• Universal precautions
• Proper sterilization
• Safe disposal of sharps

B. Vaccination

Currently important vaccines include:

• HAV vaccine
• HBV vaccine

Because HDV requires HBV: HBV vaccination also prevents HDV infection.

85. Universal Precautions

Healthcare workers should assume that blood and certain body fluids may be infectious. Important measures:

• Hand hygiene
• Gloves when indicated
• Safe handling of sharps
• Proper sharps disposal
• Appropriate protective equipment
• Avoid recapping needles
• Safe sterilization of instruments

86. Needle-Stick Exposure

A healthcare worker exposed to potentially HBV-infected blood should undergo prompt assessment. Management depends upon:

• Vaccination status
• Anti-HBs status
• Source patient's HBV status

Depending on the situation, hepatitis B vaccine and/or hepatitis B immunoglobulin (HBIG) may be indicated. This is a medical emergency requiring institutional occupational-health protocols.

87. Post-Exposure Prophylaxis

For HAV

Depending on timing and risk:

• Hepatitis A vaccine
• Immune globulin in selected situations

For HBV

Depending on immune status and source:

• HBV vaccine
• HBIG
• Both

For HCV

There is no routinely recommended vaccine or effective post-exposure prophylaxis. Instead:

Early testing → detection of infection → treatment if infection develops

88. Hepatitis B Vaccination

HBV vaccination uses recombinant HBsAg. It induces: Anti-HBs antibodies. It does not induce: Anti-HBc Therefore:

Anti-HBs positive + Anti-HBc negative → immunity due to vaccination.

89. Hepatitis A Vaccine

Hepatitis A vaccines are generally inactivated vaccines. They induce protective antibodies against HAV. Vaccination is particularly important for susceptible individuals at increased risk and according to national immunization recommendations.

90. Hepatitis E Vaccine

A recombinant hepatitis E vaccine has been licensed in China and some other countries. However, unlike hepatitis B vaccination, HEV vaccination is not universally available worldwide. (World Health Organization)

91. Important Differences Between HAV and HBV

Feature	HAV	HBV
Genome	RNA	DNA
Transmission	Faeco-oral	Blood/body fluids
Chronic infection	No	Yes
Carrier state	No	Yes
Cirrhosis	No chronic disease	Yes
HCC	No	Yes
Vaccine	Yes	Yes
Post-infectious immunity	Usually lifelong	Usually protective after recovery
Maternal transmission	Not major	Important
Acute liver failure	Rare	Rare but possible

92. Important Differences Between HBV and HCV

Feature	HBV	HCV
Genome	DNA	RNA
Vaccine	Yes	No
Chronic infection	Yes	Yes
Major transmission	Blood/body fluids	Blood
Chronicity in adults	Lower	High
HCC	Yes	Yes, particularly with advanced chronic liver disease
Treatment	Suppressive therapy for many patients	Usually curative
Main modern therapy	Nucleos(t)ide analogues ± selected therapies	Direct-acting antivirals

WHO and current specialty guidance emphasize the very different treatment paradigm: chronic HBV is generally suppressed rather than reliably eradicated, whereas modern HCV therapy can cure the infection in most treated patients. (AASLD)

93. High-Yield HBV Serology - Rapid Revision

Acute HBV

HBsAg +
IgM anti-HBc +
Anti-HBs −

Chronic HBV

HBsAg +
IgM anti-HBc −
Total anti-HBc +
Anti-HBs −

Recovered HBV infection

HBsAg −
Anti-HBs +
Anti-HBc +

Vaccinated individual

HBsAg −
Anti-HBs +
Anti-HBc −

Window period

HBsAg −
Anti-HBs −
IgM anti-HBc +

94. High-Yield Points On Hepatitis A

Remember: HAV = A = Alimentary route

• RNA virus
• Non-enveloped
• Faeco-oral transmission
• Acute infection
• No chronic carrier state
• Anti-HAV IgM = acute infection
• Anti-HAV IgG = immunity
• Vaccine available
• Usually self-limiting

95. High-Yield Points on Hepatitis B

Remember: HBV = Blood + Body fluids + Birth

• DNA virus
• Enveloped
• Can become chronic
• HBsAg = current infection
• Anti-HBs = immunity
• Anti-HBc = natural exposure
• IgM anti-HBc = acute/recent infection
• HBeAg = high replication/infectivity marker
• HBV DNA = viral replication
• Vaccine available
• Cirrhosis and HCC are important complications

96. High-Yield Points on Hepatitis C

Remember: HCV = Chronic + Curable

• RNA virus
• Blood-borne
• Frequently asymptomatic
• High risk of chronic infection
• Anti-HCV = exposure
• HCV RNA = current infection
• DAAs are highly effective
• No vaccine

WHO reports that DAAs can cure more than 95% of people with HCV infection. (World Health Organization)

97. High-Yield Points on Hepatitis D

Remember: HDV = Dependent on HBV

• RNA virus
• Requires HBV
• Coinfection = HBV + HDV acquired together
• Superinfection = HDV in chronic HBV
• Superinfection is generally more likely to cause severe chronic disease
• Prevented by HBV vaccination

98. High-Yield Points on Hepatitis E

Remember: HEV = Enteric + Especially important in pregnancy

• RNA virus
• Mainly faeco-oral
• Contaminated water is important
• Usually acute
• Usually self-limiting
• Can cause fulminant hepatitis
• Severe disease particularly important in pregnancy
• Chronic infection is rare but possible in immunosuppressed patients

WHO specifically highlights the increased risk of severe disease and maternal mortality in pregnancy. (World Health Organization)

99. Examination-Oriented One-Liners

1. Hepatitis means inflammation of the liver.
2. The five major hepatitis viruses are HAV, HBV, HCV, HDV and HEV.
3. HAV and HEV are primarily enterically transmitted.
4. HBV, HCV and HDV are primarily blood/body-fluid-associated viruses.
5. HAV does not cause chronic hepatitis.
6. HBV can cause acute and chronic hepatitis.
7. HCV commonly becomes chronic.
8. HDV requires HBV for infection.
9. HEV is particularly dangerous during pregnancy.
10. HBsAg indicates current HBV infection.
11. Anti-HBs indicates immunity.
12. Anti-HBc indicates natural exposure to HBV.
13. IgM anti-HBc indicates recent/acute HBV infection.
14. Anti-HBc is not produced by HBV vaccination alone.
15. The window period of HBV is characterized by IgM anti-HBc positivity.
16. Anti-HCV indicates exposure, not necessarily current infection.
17. HCV RNA indicates current HCV infection.
18. There is no effective HCV vaccine.
19. HBV vaccination protects against HDV indirectly.
20. Chronic HBV and HCV can lead to cirrhosis and HCC.
21. PT/INR is an important marker of hepatic synthetic function and severity in acute liver failure.
22. Albumin is a poor marker of acute hepatic injury because of its long half-life.
23. ALT is generally more liver-specific than AST.
24. Marked aminotransferase elevation suggests hepatocellular injury.
25. Marked ALP elevation relative to aminotransferases suggests cholestasis.

100. Clinical Approach to a Patient with Suspected Acute Hepatitis

A patient presenting with: Fever + malaise + anorexia + nausea + jaundice + dark urine should be evaluated systematically.

Step 1: Confirm hepatic injury

Order:

• ALT
• AST
• ALP
• GGT
• Bilirubin

Step 2: Assess severity

Assess:

• PT/INR
• Glucose
• Mental status
• Renal function
• Electrolytes

Step 3: Determine the cause

Consider:

• HAV
• HBV
• HCV
• HEV
• Drug-induced liver injury
• Alcohol
• Autoimmune hepatitis
• Ischaemic hepatitis
• Biliary obstruction

Step 4: Look for complications

Particularly:

• Coagulopathy
• Encephalopathy
• Hypoglycaemia
• Acute kidney injury

Step 5: Identify chronic disease

If viral hepatitis is suspected, perform appropriate serological and molecular testing.

102. Important Clinical Pearls

Pearl 1- A patient can have viral hepatitis without jaundice.

Pearl 2- A patient can have chronic hepatitis B or C for years without symptoms.

Pearl 3- Normal or mildly abnormal liver enzymes do not necessarily exclude significant chronic liver disease.

Pearl 4- The degree of ALT elevation does not always correspond to the amount of fibrosis.

Pearl 5- In acute liver failure, INR and encephalopathy are more important indicators of severity than the absolute ALT value.

Pearl 6- HBV can cause HCC even in the absence of established cirrhosis in some patients.

Pearl 7- HCV is now usually a curable infection, not merely a disease that can be suppressed.

Pearl 8- HDV cannot independently establish a productive infection without HBV.

Pearl 9- HEV should be considered particularly in patients with acute hepatitis who have relevant epidemiological exposure and in pregnant patients with acute hepatitis.

Pearl 10- Hepatitis is not synonymous with viral hepatitis. Alcohol, drugs, autoimmune disease and metabolic disorders can also cause hepatitis.

103. Natural History of Viral Hepatitis

Exposure to virus
↓
Incubation period
↓
Viral replication
↓
Immune response
↓
Hepatocyte injury
↓
ALT/AST elevation
↓
± jaundice
↓

Outcome

HAV/usually HEV

→ Recovery
→ Immunity
→ No chronic infection in usual circumstances

HBV

→ Recovery
OR
→ Chronic infection
→ Chronic hepatitis
→ Fibrosis
→ Cirrhosis
→ HCC

HCV

→ Spontaneous clearance in a minority
OR
→ Chronic infection
→ Fibrosis
→ Cirrhosis
→ HCC

HDV + HBV

→ Acute hepatitis
→ Possible severe disease
→ Chronic hepatitis
→ Accelerated fibrosis/cirrhosis

104. Revision Table

Topic	Must remember
Definition	Inflammation of liver
Main viral types	A, B, C, D, E
Enteric viruses	A, E
Blood/body-fluid viruses	B, C, D
Chronic infection	B, C, D
Vaccine available	A, B
No HCV vaccine	Yes
HDV dependency	Requires HBV
Dangerous pregnancy association	HEV
HAV diagnosis	IgM anti-HAV
HBV current infection	HBsAg
HBV acute infection	IgM anti-HBc
HBV immunity	Anti-HBs
Natural HBV exposure	Anti-HBc
Vaccine-induced HBV immunity	Anti-HBs only
HBV viral replication	HBV DNA
HCV screening	Anti-HCV
Current HCV infection	HCV RNA
HCV treatment	Direct-acting antivirals
Major chronic complications	Cirrhosis, HCC
Acute liver failure	Coagulopathy + encephalopathy
Important pregnancy virus	HEV

105. Summary

Hepatitis is inflammation of the liver and may be infectious or non-infectious. The five major viral hepatitis viruses are HAV, HBV, HCV, HDV and HEV. The most useful conceptual classification is:

HAV + HEV → predominantly acute, enterically transmitted hepatitis

HBV + HCV + HDV → blood/body-fluid-associated hepatitis with potential chronicity

The most important distinguishing features are:

• HAV: faeco-oral, acute, no chronic infection, vaccine available.
• HBV: DNA virus, blood/body-fluid transmission, acute and chronic infection, vaccine available, cirrhosis and HCC.
• HCV: blood-borne RNA virus, frequently asymptomatic, high chronicity, no vaccine, highly curable with DAAs.
• HDV: defective/satellite-like virus requiring HBV; HBV vaccination therefore prevents HDV.
• HEV: faeco-oral, usually acute, potentially severe in pregnancy, particularly important in endemic regions.

References and Further Reading

Standard Medical textbooks

1. Kumar, Abbas, Aster. Robbins & Cotran Pathologic Basis of Disease. Elsevier. Chapters on liver and biliary tract disease.
2. Jameson et al. Harrison's Principles of Internal Medicine. McGraw-Hill. Sections on viral hepatitis and liver disease.
3. Davidson's Principles and Practice of Medicine. Elsevier. Chapters on hepatobiliary disease and viral hepatitis.
4. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. Elsevier.
5. Williams & Wilkins. Cecil Essentials of Medicine. Sections on hepatic disorders.
6. Guyton and Hall Textbook of Medical Physiology. Elsevier. Relevant sections on hepatic physiology and bilirubin metabolism.

Authoritative online and guideline sources

• World Health Organization (WHO): Hepatitis overview and fact sheets for hepatitis A, B, C and E. WHO identifies A–E as the five major hepatitis viruses and provides current epidemiological, diagnostic, preventive and therapeutic information. (World Health Organization)
• Centers for Disease Control and Prevention (CDC): Clinical overview of viral hepatitis, diagnostic testing and prevention. (CDC)
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK/NIH): Viral hepatitis and hepatitis B clinical information. (NIDDK)
• American Association for the Study of Liver Diseases (AASLD): Current evidence-based guidance for hepatitis B and C. (AASLD)
• AASLD/IDSA HCV Guidance: Evidence-based recommendations for testing, management and treatment of HCV infection. (IDSA)
• AASLD/IDSA 2025 Chronic Hepatitis B Guideline: Current recommendations concerning prevention, surveillance and antiviral treatment of chronic HBV. (IDSA)

Note for medical students: Drug regimens, vaccination schedules, screening recommendations and public-health policies may be updated. For clinical practice, always follow the latest national guidelines and institutional protocols; the above notes are intended primarily for undergraduate medical education and examination preparation.