HEPATITIS B (HBV)OPTOM FASLU MUHAMMED

EPIDEMIOLOGY Approximately 5% of the world population is

infected with HBV and the prevalence ranging from 0.1% to 15%.

African Americans, Asian Americans are more likely to develop chronic HBV infection

TRANSMISSIONThe major modes of transmission of HBV are,

Injection drug use

Sexual intercourse with an infected partner

Perinatal transmission from mother to child

Tattooing with shared contaminated needles.

Use of contaminated household items such as tooth brush

At risk persons or groups

Health care providers or workers

People with multiple heterosexual or especially homosexual parteners

Residents of nursing home

Haemodialysis patients

Travelers to underdeveloped countries

PATHOGENESISHBV is not directly cytopathic instead liver injury is

immune mediated especially T lymphocytes.

The cytotoxic T-lymphocytes mediated lysis of infected hepatic cell occurs resulting in liver injury

ACUTE HEPATITIS B INFECTION Acute infection occurs approximately in 30 to 50

% of infected adults and it may be mild, severe and fulminant. The usual incubation period is varies from one to six month.

Many patients with acute hepatitis have no symptoms or often mistaken for flu

The symptoms mainly include fever, jaundice, nausea, abdominal pain and malaise

Presence of arthritis, serum sickness and a non-specific rash helpful in diagnosing the HBV infection.

DIAGNOSIS Acute HBV infection is confirmed by the serological test

of IgM anti-HBc Ag and HBs Ag

Treatment No specific or effective therapies are available for acute

hepatitis B infection, therefore treatment efforts are not largely supportive.

CHRONIC HEPATITIS B INFECTION Clinical features Only few people who cannot fight well against acute infection

progresses to develop chronic infection.

These patients will have ongoing liver damage and few may have risk of developing cancer of the liver.

Signs and symptoms mainly includes, Easy fatigability, anxiety, anorexia malaise, ascitis, jaundice,

variceal bleeding and hepatic encephalopathy can manifest.

Vomiting, seizures, icteric sclera, decreased bowel sounds, increased abdominal girth etc are also seen.

TREATMENT Goal of the treatment

To eradicate or permanently suppress the HBV

To limit hepatic inflammation and reduce the risk of fibrosis

To prevent development of long term complications like cirrhosis, liver failure and HCC

PHARMACOLOGICAL THERAPY Indications Chronic HBV infecton documented at least 6-12 months.

Evidence of active replication

Chronic lever inflammation, indicationg levels of ALT is >2 times the upper limit of normal.

Evidence of necroinflmmation on liver biopsy

LAMIVUDINE It completely inhibits the reverse

transcriptase and terminates proviral DNA chain extension

Lamivudine has shown short term benefits as it has got histological, virological and biochemical response.

The discontinuation of therapy has got chances of high rebound of HBV

Resistance mainly develops because of mutation in the region of reverse transcriptase, usually occurs after 6 months of therapy

Lamivudine should not be combined with other antiviral agents for hepatisis B since there are no proven benefits.

Lamivudine has got less ADRs when compared to Interferon alpha2b, the common side effects are fatigue, nausea, vomiting, cough, headache and diarrhoea.

Dose: 100 mg daily given orally

ADEFOVIR DIPIVOXIL It is given 10m once daily and has limited toxicities and

less likely to promote resistance

The major disadvantages of this agents is that the optimal treatmet duration is very difficult to determine and cessation of therapy resulted in viral relapse or severe hepatitis.

Adefovir is not recommende in patient with HIV and HBV with the same dose (HIV require high dose of adefovir

HBV+HCV Interferon therapy is effective against

both B and C infection But efficacy, optimal regimen and

indications for treating hepatitis with underlying infection are unkown.

In this type of co-infection lack of recommended treatment strategy and uncertain effects on underlying disease, antiviral therapy needs a expert physician

HBV+HIV Treat the patient on the basis of evidence basis of

available evidence based data

Interferon therapy is less effective

Treatment with tenofovir disoprovil fumerate, amtricitabine, tenofovir and emtricitabine and lamivudine all are active against both HIV and HBV but these patients should ordinarily not be treated for HB since these drugs will promote HIV resistance

Adefovir dipivoxil is not an optimal choice s it may cause ssross resistane for tenofovir

Entecavir does not have activity against HIV and hence it may be used as a treatment option but data are lacking for this agent

RENAL DISEASE+HBV Interferon therapy is preferred (needs dosage

adjustments)

Adefovir and lamivudine should not be used

HEPATITIS B PREVENTION General approach

There are two types of agents are available for the prevention of Hepatitis B

Hepatitis B vaccination (active immunization) Hepatitis B immunoglobulin (HBIg – passive

immunization)

HBIg is used in prophylaxis and recommended in, Perinatal exposure

Sexual exposure to HBsAg positive

Percutaneous or mucosal exposure to HBsAg positive BLOOD

Exposure of an infants to a caregiver and

Immunocompromised patients

Dose: 0.06mL/kg via IM