Hepatitis

Objectives

At the end of this lecture, students will be able to –

•       Identify the symptoms of hepatitis

•       Describe the structure of HBV

•       Explain different stages of hepatitis

Hepatitis

Hepatitis is a group of viral infections that primarily affect the liver. It can lead to a range of symptoms and health complications. In this article, we will explore the symptoms of hepatitis, describe the structure of the Hepatitis B virus (HBV), and explain the different stages of hepatitis.

•       Inflammation of liver

•       Results in damage to hepatocytes with subsequent cell death

Etiology of hepatitis

•       Viral infections – Hepatitis A, B, C, D, E ; Epstein barr virus, yellow fever virus, cytomegalo virus & herpes virus

•       Autoimmune chronic hepatitis

•       Toxins, Alcohol

•       Drugs used for the treatment of tuberculosis e.g. Isoniazid

Symptoms of hepatitis

Types of hepatic viruses

Structure of HBV

The Hepatitis B virus (HBV) is a member of the Hepadnaviridae family. Its structure consists of several key components:

• Outer Envelope: The virus has an outer envelope derived from the host cell’s membrane. This envelope contains proteins that are essential for the virus’s ability to infect liver cells.
• Core Capsid: Inside the envelope, HBV has a core capsid that contains the viral DNA. This core is made up of protein subunits and plays a crucial role in the virus’s replication.
• DNA: The genetic material of HBV is circular, partially double-stranded DNA. This DNA serves as the template for viral replication.

•       Only DNA containing virus

•       Belongs to group ‘hepadnaviridae’

•       Diameter- 42 nm; incubation period is 6-8 weeks

•       Comprises of core and a capsule

•       Core consists of DNA & DNA polymerase

•       Core is surrounded by markers

–      Hepatitis B core antigen (HB_c Ag)

–      Hepatitis B envelope antigen (HB_e Ag)

–      Hepatitis B  surface antigen (HB_s Ag)

Mode of transmission of Hepatitis

•       Present in all body secretion

•       A close contact with an infected person spreads the disease

•       By blood transfusion

•       Not through fecal matter

Stages of hepatitis (Assessed by different markers)

Stage 1

•       HB_s Ag is identified in asymptomatic phase

•       It appears even before the onset of a disease

•       Reaches the peak level during disease stage

•       The counts become less with in 3-6 months

Stage 2

•       HB_e Ag, HBV DNA, DNA polymerase appears

•       HB_e Ag – indicates the progression of infection

•       Continues viral replication

Stage 3

•       IgM and anti HB_c is detected

•       Ab is identified just before the onset of symptoms

•       After several months of infections IgG and anti HB_c

Phases of HBV infection

Proliferative phase

•       Shows the presence of symptoms

•       DNA of HBV has accessory replicative chromosomes and forms virions

•       HB_s antigen binds with MHC class molecule and activated CD8+ T-cells

Integrative phase

•       Viral DNA gets incorporated into the host genome

•       Damage of hepatocytes  by activation of CD8+ T- cells

Types of Hepatitis

Acute hepatitis

comprises of 4 phases

1. Incubation period –depends on type of virus

•       HAV – 12 weeks

•       HBV – 10 weeks

•       HCV – 7 weeks

•       HDV – 6 weeks

•       HEV – 2-8 weeks

Patient does not show any signs or symptoms in incubation period

2. Symptomatic pre – icteric phase

•       Non specific symptoms like fatigue, nausea, vomiting, weight loss, low fever, headache, muscle & joint aches, diarrhoea

3. Symptomatic icteric phase

•       Yellow coloration appears

•       Jaundice appears in 3^rd stage

4. Phase of recovery

•       Takes place depending upon the severity of infection

Chronic hepatitis

•       Hepatic diseases remain for more than 6  months

•       Inflammation & necrosis takes place

•       Fatigue, Malaise, Lack of apetite, mild jaundice

•       Symptoms are highly variable & not predictive in nature

Cirrhosis:

In some cases, chronic hepatitis can progress to cirrhosis, which is characterized by extensive scarring of the liver tissue. Cirrhosis can lead to severe liver dysfunction.

Liver Cancer:

Individuals with long-standing, untreated chronic hepatitis, particularly Hepatitis B and C, are at an increased risk of developing liver cancer.

Fulminant Hepatitis:

In some rare cases, acute hepatitis can progress to fulminant hepatitis, a severe and life-threatening form of the disease. This stage is characterized by rapid liver failure and requires immediate medical intervention, often with a liver transplant.

Asymptomatic Carrier State:

Some individuals, particularly those with chronic Hepatitis B or C, may become carriers of the virus without exhibiting noticeable symptoms. These carriers can still transmit the virus to others, and monitoring their condition is essential.

Resolution:

In a fortunate scenario, acute hepatitis can resolve on its own, with the body successfully clearing the virus. This typically occurs with Hepatitis A but can also happen with other forms. Individuals who recover from acute hepatitis usually develop immunity to that specific strain of the virus.

Management of Hepatitis

1. Medical Evaluation: If you suspect you have hepatitis or exhibit symptoms, it’s crucial to seek medical evaluation. Your healthcare provider will conduct blood tests to determine the type of hepatitis and its stage.
2. Antiviral Medications: In the case of chronic hepatitis, particularly Hepatitis B and C, antiviral medications may be prescribed to slow down viral replication and reduce liver inflammation.
3. Supportive Care: Proper rest, hydration, and a balanced diet can help your body recover from acute hepatitis. Avoid alcohol and any medications that can harm the liver.
4. Vaccination: For Hepatitis B, vaccination is available and highly effective for prevention. Vaccination is recommended for individuals at risk of exposure to the virus.
5. Regular Monitoring: People with chronic hepatitis, especially those with advanced liver disease, require regular monitoring to assess the progression of the condition and evaluate the need for additional treatment or liver transplantation.
6. Prevention: Prevention is key to avoiding hepatitis. Practicing safe sex, using clean needles, avoiding sharing personal items that may have blood on them, and maintaining good hygiene are essential preventive measures.
7. Liver Transplant: In severe cases of liver damage or cirrhosis, a liver transplant may be necessary to replace the damaged liver with a healthy one.

Summary

•       Hepatitis is inflammation of liver that results in damage to hepatocytes with subsequent cell death

•       It may occur due to viral , autoimmune chronic hepatitis, Toxins, Alcohol and drugs

•       HBV is main causative organism

•       Types of hepatitis include acute and chronic

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