Do you know about Hepatitis

HBV can survive outside the body at least 7 days and still be capable of causing infection. A very large number of people around the world are infected but a few of them get to the chronic stage of that disease. Persons originating from China, Africa, Asia, South America, the Pacific islands, or the Middle East are in fact more exposed and more likely to get the HBV (Hepatitis B Virus) at least once in their lives. Statistically, an estimated one third of the global population has been infected with the hepatitis B virus (HBV). Approximately 350 million people are lifelong carriers, and only 2% spontaneously seroconvert annually.

Characteristics of HBV

Hepatitis B virus (HBV) is a hepadnavirus.It is an extremely resistant strain capable of withstanding extreme temperatures and humidity. Hepatitis B virus (HBV) can survive when stored for 15 years at –20°C, for 24 months at –80°C, for 6 months at room temperatures, and for 7 days at 44°C. The viral genome consists of a partially double-stranded circular DNA of 3.2 kilobase (kb) pairs that encodes as follows:

• The precore/core region of a nucleocapsid core protein (hepatitis B core antigen [HB _c Ag]) and a precore protein (hepatitis B e antigen [HB _e Ag]: HB _c Ag is retained in the infected hepatocyte; HB _e Ag is secreted into blood and is essential for the establishment of persistent infection.

• Envelope glycoprotein (ie, HB _s Ag), which may be produced and secreted into the blood in massive amounts: Blood HBsAg is immunogenic and can be visualized as spheres or tubules.

• A DNA polymerase with reverse transcriptase activity: Genomic replication takes place through an intermediate RNA known as pregenomic RNA. In this process, mutant viral genomes are frequently generated.

• HBV-X protein: This acts as a transcriptional transactivator for many viral and host genes through interaction with various transcription factors. HBV-X is required for viral infectivity and may have a role in the causation of hepatocellular carcinoma by regulating p53 degradation and expression.

Transmission

HBV is transmitted through activities that involve percutaneous (i.e., puncture through the skin) or mucosal contact with infectious blood or body fluids (e.g., semen, saliva), including

• Sex with an infected partner

• Injection drug use that involves sharing needles, syringes, or drug-preparation equipment

• Birth to an infected mother

• Contact with blood or open sores of an infected person

• Needle sticks or sharp instrument exposures

• Sharing items such as razors or toothbrushes with an infected person

HBV is not spread through food or water, sharing eating utensils, breastfeeding, hugging, kissing, hand holding, coughing, or sneezing.

Clinical Picture

The presence of signs and symptoms varies by age. Most children under age 5 years and newly infected immunosuppressed adults are asymptomatic, whereas 30%–50% of persons aged ≥5 years have initial signs and symptoms. Symptoms begin an average of 90 days (range: 60–150 days) after exposure to HBV. Symptoms typically last for several weeks but can persist for up to 6 months.

When present, signs and symptoms can include

• Fever

• Fatigue

• Loss of appetite

• Nausea

• Vomiting

• Abdominal pain

• Dark urine

• Clay-colored bowel movements

• Joint pain

• Jaundice

Persons with chronic HBV infection might be asymptomatic, have no evidence of liver disease, or have a spectrum of disease ranging from chronic hepatitis to cirrhosis or hepatocellular carcinoma (a type of liver cancer).

Diagnosis

All patients with chronic HBV infection should have laboratory tests to assess liver diseases (complete blood counts with platelets, hepatic panel, and prothrombin time), markers of HBV replication (HBeAg/anti-HBe, HBV DNA), and tests for coinfection with HCV (anti HCV), HDV (anti HDV) in persons from countries where HDV infection is common and in those with history of injection drug use, or HIV (anti HIV) in those at risk.

Ø Lab readings

HBeAg - indicates that the virus is replicating and the infected person has high levels of HBV (high infectivity)

HBsAg- Persistence for >6 months defines carrier status

Anti HBc- imply past infection. The presence of anti-HBc indicates previous or ongoing infection with HBV in an undefined time frame.

Anti HBs- is generally interpreted as indicating recovery and immunity from HBV infection. (implies vaccination also)

Treatment

The aims of treatment of chronic hepatitis B are to achieve sustained suppression of HBV replication and remission of liver disease. The ultimate goal is to prevent cirrhosis, hepatic failure and HCC

For acute infection, no medication is available; treatment is supportive.

For chronic infection, several antiviral drugs (adefovir dipivoxil, interferon alfa-2b, pegylated interferon alfa-2a, lamivudine, entecavir, and telbivudine) are available. Persons with chronic HBV infection require medical evaluation and regular monitoring to determine whether disease is progressing and to identify liver damage or hepatocellular carcinoma.

Surgical care includes the following:

• Liver transplantation for decompensated liver disease

• Surgical resection of hepatocellular carcinoma

A high-energy diet is desirable, and because many patients may have nausea late in the day, they best tolerate their major caloric intake in the morning. Intravenous feeding is necessary in the acute stage if the patient has persistent vomiting and cannot eat.

Complications

Fulminant hepatic failure

Relapse

Prolonged cholestasis

Chronic hepatitis

Cirrhosis

Hepatocellular carcinoma

Glomerulonephritis

cryoglobulinaemia

Prophylaxis

Any blood spills — including dried blood, which can still be infectious — should be cleaned using 1:10 dilution of one part household bleach to 10 parts of water for disinfecting the area. Gloves should be used when cleaning up any blood spills.

Vaccination- the vaccination schedule most often used for children and adults is 3 intramuscular injections, the second and third doses administered 1 and 6 months, respectively, after the first dose. Alternate schedules have been approved for certain vaccines and/or populations.

Single-antigen Hepatitis B vaccines

• ENGERIX-B®

• RECOMBIVAX HB®

Combination vaccines

• COMVAX®: Combined Hepatitis B-Haemophilus influenzae type b (Hib) conjugate vaccine. Cannot be administered before age 6 weeks or after age 71 months.

• PEDIARIX®: Combined Hepatitis B, diphtheria, tetanus, acellular pertussis (DTaP), and inactivated poliovirus (IPV) vaccine. Cannot be administered before age 6 weeks or after age 7 years.

• TWINRIX®: Combined Hepatitis A and Hepatitis B vaccine. recommended for persons aged ≥18 years who are at increased risk for both Hepatitis A virus and HBV infections.