Hepatitis B

Hepatitis B

    * Introduction
    * Signs and symptoms
    * Diagnosis
    * Treatment
Hepatitis B is a serious infection of the liver caused by hepatitis B. In some patients, the infection becomes permanent, leading to liver failure, cirrhosis, liver cancer or disease that causes destruction of liver cells.

 
Hepatitis B is transmitted through contact with blood or body fluids of patients, the same way as for the transmission of human immunodeficiency virus (HIV) that causes AIDS. However, hepatitis B is about 100 times more infectious than AIDS.

 
An increased risk of infection by the people who share syringes and other medical instruments (sterilized) through sexual contact with infected people or those who were born or travel in regions of the world where hepatitis B is widespread. In addition, pregnant women carrying the virus usually infects children during childbirth.

 
Most adults infected with hepatitis B recover completely, even if severe signs and symptoms. Children are at increased risk of developing a chronic infection. Although there is no treatment for hepatitis B disease can be prevented with a vaccine. Infected people should take preventive measures so as not to spread hepatitis B.
Pathogenesis
Hepatitis B virus belongs to the genus hepadnavirus. It is very resistant to high temperatures and humidity, and can survive storage at -20 degrees Celsius for 15 years and 6 months at room temperature. Dintrun viral genome consists of double-stranded circular DNA encodes four genes: -S tires, codind protein pre-S1, pre-S2 and S -C for the core, and core nucleocapsid protein codind AG's X-X protein DNA polymerase-P. S gene encodes the viral envelope. There are five main determinants Ag: a, common to all HBsAg, d, y, w, and r, which are important epidemiologically. HBc Ag Ag core, is the protein that causes viral DNA, can be expressed on the surface of hepatocytes, initiating cellular immune response. HB s Ag is a marker of active viral replication, the obocei can be detected in patients with circulating viral DNA in serum. Best viral replication indi8ce virus is present in the blood. PCR or hybridization are used for its detection. Role of gene X is to encode proteins that act as transcriptional transactivatori to help viral replication. It has been shown to be involved in carcinogenesis. On first contact with HBV, a previously healthy person develops an acute hepatitis, after a few weeks completely eliminating Ag in the serum. An infant or a person with low immunity, shows a large amount of viral DNA, HBeAg without liver injury. In the older children or adults, is immune clearance phase, diminished in serum viral DNA, HBeAg, persist on the surface of hepatocytes are different Ag, HBc Ag mainly. , Producing a rapid progression of liver inflammation. In the older patients becomes silent infection, viral DNA is low, absent HBeAg, HB Ac is present. Are normal or moderately elevated transaminases, histology is suggestive of inactive chronic hepatitis, cirrhosis or hepatocellular carcinoma. Evolution is chronic infection phase, characterized by immunological tolerance and recognition followed by immunological and initiate the process of clearance. In the stage of clearance if the immune response can eliminate the virus is powerful, if not only produces a response necroinflamator increase with worsening disease. As fibrosis occurs and istrugerea normal architecture. HBs-Ag appears in plasma at 6 weeks after infection and disappears within three months, six months after giving persistent chronic carriers status. Ac-occurring anti-HBs at 3 months of acute and records provided immunity. HBeAg-su is a sign of viral replication infectivity disappears after 10 weeks is chronic if it persists. Ac-HBe markers of low infectivity. HBc-Ag can be detected in blood. Recorded acute infection, can be found in chronic. Classic chronic infection are found in IgG anti-HBc without anti-HBs. Ac anti-HBs associated with anti-HBc IgG is a history of infection. Viral DNA detected by PCR is the most reliable test for viral replication. Fctori risk People at risk of developing hepatitis B are: Needle-stick contaminated drug, unvaccinated health care, dentists -Use of cocaine by nose by open lesions that form in the nasal mucosa Tattoo-people who practice acupuncture, or piercing -Unprotected sex with an infected partner, heterosexual or homosexual Printrun-organ transplant or blood transfusion from an infected donor A natural-born mother is infected.