Hepatitis B - Symptoms, Transmission and Vaccine

Hepatitis B is an infectious disease caused by a virus called HBV, an acronym for hepatitis B virus. Hepatitis B is a pandemic that affects about 350 million people worldwide. In some regions of Asia, about 20% of the population is carrying the virus.

Hepatitis B virus
Hepatitis B virus
 

Hepatitis is a term that means inflammation of the liver. It can be caused by viruses, by alcohol, by drugs, by the accumulation of fat in the liver, etc.

There are 5 different hepatitis caused by viruses:
  • Hepatitis A
  • Hepatitis B
  • Hepatitis C
  • Hepatitis D
  • Hepatitis E

In medical practice, almost all cases of hepatitis are caused by viruses A, B or C. Hepatitis D and E are rare.

It is important to know that the viruses that cause each of these hepatitis are completely different from each other. The hepatitis C virus, for example, is genetically much closer to dengue and yellow fever viruses than to hepatitis B virus. Therefore, among the 5 types of viral hepatitis, forms of transmission, disease progression, the treatment and the vaccines are also different. The only thing in common is the fact that these viruses have a preference for the liver.

The hepatitis D virus presents a particularity, it only attacks those already infected with hepatitis B. Therefore, every patient with hepatitis D must also have hepatitis B. Patients with hepatitis B + D present a much more aggressive picture of liver damage.

Transmission

Hepatitis B is an STD - sexually transmitted disease. About 70% of cases are sexually transmitted, about 2/3 for heterosexual relationships and 1/3 for homosexual relationships.

Other HBV transmission routes include vertical (from mother to fetus), blood transfusions and sharing or accidents with needles or other hospital materials infected.

Another way to contract hepatitis B is through the common use of toothbrushes and razor blades. This path is rare, but it becomes possible if the shared object has had contact with blood.

There are also reported cases of transmission through acupuncture, tattoos and body piercing, performed with non-disposable material.

You do not get hepatitis B in pools, through cups or cutlery, with kisses (unless there is direct blood contact), cuddling, coughing, sneezing or breastfeeding. The use of condoms (condoms) is indicated to prevent sexual transmission.

The hepatitis B virus can survive for up to 7 days out of the body.

Symptoms

Hepatitis B is divided into two phases: acute infection and chronic infection.

a) Acute hepatitis B


The incubation period, that is, from the moment of contamination to the onset of the first symptoms, is usually 1 to 4 months.

About 70% of patients infected with hepatitis B virus have mild and non-specific symptoms of infection. Often the acute phase can be confused with an influenza picture. It is not uncommon for patients to find out that they have had hepatitis years later by doing blood tests. Only 30% develop a typical clinical picture of hepatitis, called the icteric form of acute hepatitis B.

Jaundice is a yellowing of the skin and mucous membranes due to inflammation of the liver and accumulation of bilirubin in the blood. Along with jaundice also usually appear a dark urine and feces of very light color.

Other symptoms of acute hepatitis B include:
  • Tiredness
  • Nausea and vomiting
  • Joint pain
  • Abdominal pain, especially in the upper right region
  • Fever
  • Loss of appetite

Fulminant hepatic failure is rare and occurs in less than 0.5% of cases.

During the acute phase, in blood tests, markers of liver damage are usually very high. TGO (AST) and TGP (ALT) are usually above 1000 IU/L.

95% of adults who contract hepatitis recover spontaneously and are completely cured within 6 months. Only 5% progress to a chronic form of hepatitis. The younger the patient, the greater the risk of developing into a chronic form, to the point that up to 50% of children under 5 and 90% of newborns can not achieve cure.

b) Chronic hepatitis B


Chronic hepatitis occurs when our immune system can not eliminate HBV for up to 6 months. These patients remain indefinitely with the virus in the body, slowly destroying their liver, and may contaminate other people through the pathways cited at the beginning of this text.

The fact that he had acute hepatitis with few or many symptoms does not seem to influence evolution to a chronic form.

Chronic hepatitis B is usually asymptomatic for many years. Even those who have typical symptoms of acute hepatitis, spontaneously improve the picture, although they are not free of the virus B. The values of GRT and TGP fall, remaining only slightly to moderately elevated, proving a slow and progressive destruction of the liver.

10 to 20% of patients with hepatitis B develop extrahepatic diseases. The two main ones are:
  • A vasculitis called polyarteritis nodosa
  • A kidney disease called membranous nephropathy

Among the hepatic complications of chronic hepatitis B are cirrhosis and liver cancer. Most patients with the chronic form do not evolve into these two frames, and when they do, this usually occurs for several years, sometimes decades, later.

Patients with acquired hepatitis B at birth usually reach the age of 30 without major complications of the disease. In adult acquired disease, about 10 to 20% develop signs of cirrhosis after 5 years of illness.

Several factors influence the chance of progression to cirrhosis, including viral load (blood virus count), rate of virus activity, consumption of alcoholic beverages, co-infection with other viral hepatitis such as hepatitis C and hepatitis D, etc.

About 10% of patients with cirrhosis due to hepatitis B develop liver cancer.

Diagnosis of acute and chronic hepatitis B

The diagnosis of hepatitis is confirmed by blood serology. The serological interpretation is complex and it is not necessary here to explain it in detail. However, some information can be passed:

HBsAg = is a protein on the surface of the virus. If HBsAg is positive, it indicates that the virus is present in the circulation. Patients with chronic hepatitis B remain with HBsAg positive forever since they never get rid of the virus. Cured patients have negative HbsAg.

Anti-HBs = It is the antibody produced against the virus. Usually it appears when the infection is cured or when the patient has been vaccinated. Patients with chronic hepatitis B never have anti-HBs positive. Patients with anti-HBs positive and HBsAg negative are those who are immune to hepatitis, either by vaccination, or by having previously had the disease.

HBeAg and Anti-HBe =HBeAg is a virus core protein and is usually present when it is in high activity. HBeAg is usually positive in the acute phase and in cases of chronic hepatitis B with high viral replication.

Anti-HBe is an antibody that arises when the patient heals himself or when his chronic infection is asleep and the virus is not multiplying.

Anti-HBc = It is another antibody against B virus. Anti-HBc IgM is positive in acute cases. Anti-HBc IgG is an antibody that is present in all who have had hepatitis or have it chronically. Those who, for example, were vaccinated presented anti-HBs positive, but did not present anti-HBc.

Vaccine

The hepatitis vaccine is very safe and has effectiveness above 95%. Hepatitis B is a potentially eradicable disease if there are effective mass vaccination campaigns. In Brazil and Portugal vaccination for hepatitis B is already part of the basic vaccination schedule for children.

The current schedule is done in 3 doses, with doses 2 and 3 administered after 1 month and after 6 months, respectively. Ex: first dose on 10.01.2010, second dose on 10.02.2010 and third dose on 10.07.2010.

If there is a failure between the first and third doses, it is not necessary to restart every regimen, but the chance of creating antibodies (anti-HBs) is greater if the regimen is respected.

Two months after the end of the vaccination schedule, serology can be performed to determine the presence of anti-HBs, which reflects the success of the vaccine. As in the general population this success rate is very high, most physicians only indicate the serology when the proof is essential, as in healthcare professionals, partners of infected people, patients on hemodialysis , etc.

As the vaccine takes several months to create protection against hepatitis, it is not to be used in cases of accidents with contaminated needles, for example. In this case, if the person who has been injured has not been vaccinated or has never had hepatitis B, the administration of immunoglobulin for hepatitis B is indicated as a cocktail of antibodies against the virus. Immunoglobulin should be given as soon as possible, preferably within 24 hours after the accident, to avoid contamination. After 7 days of contamination, the immunoglobulin is ineffective.

Treatment

Treatment for hepatitis B is indicated only in cases of chronic hepatitis B with signs of activity, either because of HBeAg positive, elevations in SGOT and TGP, and/or a high viral load.

In acute hepatitis is indicated only resting, hydration and avoid alcohol and drugs that may harm the liver. There is no special diet and there are no alternative treatments that have been proven to improve. Avoid the so-called natural remedies, since in addition to having no evidence of effectiveness, they can make the picture worse.

Once treatment is indicated, there are several drugs available such as lamivudine, adefovir, entecavir, telbivudine, interferon and tenofovir. The treatment is usually long and with success rates ranging from 20 to 70% depending on the situation. The goal of the therapy is to prevent the multiplication of the virus and prevent future complications such as cirrhosis and liver cancer.

In more severe cases, with signs of cirrhosis and liver failure, liver transplantation may be indicated.

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