According to new data from the World Health Organization (WHO), an estimated 325 million people worldwide are living with chronic infection caused by the hepatitis virus. Considering that in 90% of cases, viral hepatitis A occurs in an anicteric form, it is difficult to imagine how much the real figures exceed the official figures. The high incidence of hepatitis A is associated primarily with the poor condition of the water supply system and sewerage facilities.
This article on estet-portal.com will present modern approaches to the diagnosis, treatment and prevention of viral hepatitis A that meet international recommendations and the principles of evidence-based medicine.
- Mechanism of transmission and ways of spreading viral hepatitis A
- Viral hepatitis A: how urgent is this problem
- Viral hepatitis A: modern approaches to the diagnosis of the disease
- Hepatitis A Treatment: Avoiding Unreasoned Therapy
- Hepatitis A Prevention: Non-Specific interventions and vaccination
Mechanism of transmission and ways of spread of viral hepatitis A
The main mechanism of transmission of viral hepatitis A is the fecal-oral route, in particular, the waterway. The role of the food and contact routes in the spread of infection is controversial, since infection occurs only when a large number of viruses enter the human body.
And although these ways of transmitting viral hepatitis A are theoretically possible, it is difficult to imagine how this can be done in practice with food, and even more so – with dirty hands. Accordingly, the old name of the disease – "disease of dirty hands", to some extent does not reflect the true path of transmission of hepatitis A. Another thing – water. The concentration of the infectious agent in untreated water is usually high and sufficient to cause infection.
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It is obvious why viral hepatitis A is most often registered in rural areas, where the state of water used by the population without the necessary treatment, in most cases, leaves much to be desired.
Viral hepatitis A: how urgent is this problem
The urgency of the problem of viral hepatitis A is associated not only with the poor level of sanitary and hygienic conditions in the country. There is another, no less important problem. To date, there is no etiotropic treatment for viral hepatitis A. However, both among patients and some doctors, “liver-protective drugs” are widely popular, but do not have the necessary proven base.
If treatment is not indicated – it is contraindicated.
Given the violation of liver function, the unreasoned appointment of "pathogenetic" therapy in some cases is not only ineffective, but also dangerous. Any medication for acute hepatitis should be prescribed according to strict indications. Read more about modern approaches to the treatment of hepatitis A in the article.
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Clinical picture of hepatitis A: periods of the disease and their features
In most cases, hepatitis A is anicteric, and the diagnosis is often made only retrospectively. With a manifest course of infection, the disease is characterized by a certain cyclicity.
The following periods should be distinguished in the clinical picture of hepatitis A:
1. Incubation: 15 to 50 days;
2. Preicteric: characterized by anorexia, nausea, fever, body aches, headache, due to which patients are often misdiagnosed as "Flu";
3. Icteric: discoloration of the skin, sclera, mucous membranes, and in some cases – darkening of the urine and lightening of the feces, already without any doubt indicates the true nature of the disease.
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An important point should be noted: it is during the peak period, when the yellowed patient is actively demonstrated to medical students, that his state of health improves significantly, which is associated with the pathogenetic features of this infection.
4. Reconvalescence: can last up to 6 months and is characterized by the presence of hepatomegaly and astheno-vegetative syndrome.
A patient with viral hepatitis A is an epidemic threat in the preicteric and the first week of the icteric period. Subsequently, the virus in faeces is not detected.
Viral hepatitis A: modern approaches to the diagnosis of the disease
In the biochemical analysis of blood, a significant increase in the level of transaminases, due to the pronounced cytolytic properties of the RNA-containing hepatitis A virus, draws special attention. However, the levels of ALT (alanine aminotransferase) and AST (aspartate aminotransferase) do not are indicators that reflect the severity of the course of the disease.
In this regard, the indicators albumin and PTI (prothrombin index) are more specific. A decrease in their levels below 30 g / l and 40%, respectively, indicates an increase in liver failure and is a poor prognostic sign. The severity of the condition also correlates with the severity and duration of hyperbilirubinemia (an increase in the level of bilirubin occurs due to the conjugated fraction) and the general condition of the patient.
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Specific diagnosis of viral hepatitis A consists in determining the presence of specific antibodies in the patient's serum – anti-HAV-IgM – ELISA method (enzymatic immunoassay). This study is highly specific already after the first week of illness.
Treatment of viral hepatitis A: avoiding unreasoned therapy
As mentioned above, there is no etiotropic treatment for viral hepatitis A. Strict diets, popular in the last century, have also not proven to be effective, except for restriction of alcohol consumption: the latter should be strictly excluded from the patient's diet.
Also, don't force the patient to lie in bed all day – moderate physical activity does not pose a threat, unless the patient himself prefers bed rest. And here is a plentiful drink – up to 2-3 liters per day – may have a beneficial effect on his general condition.
Indication for infusion therapy in acute hepatitis is repeated vomiting. In such cases, the drug of choice is a 5% glucose solution.
Many patients with hepatitis A can develop cholestasis. In such cases, the appointment of ursodeoxycholic acid is indicated. Against the background of the cholestatic component, debilitating itching often takes place. In such cases, the appointment of antihistamines to the patient is justified.
We emphasize once again that all medications for acute hepatitis should be used only according to strict indications.
Hepatitis A Prevention: Non-Specific Interventions and Vaccination
Non-specific prevention of viral hepatitis A consists in observing the rules of hygiene, avoiding the use of water from dubious sources, as well as food products, the structure, production and storage of which is associated with water (mussels, frozen vegetables and fruits) in endemic areas.
Non-specific measures to prevent the development of hepatitis A are associated with improving the state of water supply, wastewater disposal, as well as increasing public knowledge about the nature and mechanism of the spread of viral hepatitis.
Improving sanitation and vaccinating against hepatitis A are effective methods of reducing the incidence.
Specific prevention of hepatitis A is active vaccination. In many countries, in particular the USA, Israel, China, Turkey, Argentina, it is mandatory and is included in the vaccination schedule. In the CIS countries, vaccination against hepatitis A is recommended, which to some extent, of course, is associated with economic aspects.
The inactivated vaccine can be used over one year of age. After the first dose of the vaccine, specific antibodies appear within 15-28 days.
That is why tourists who go on a trip to endemic territories, including the countries of Northern Europe, are recommended to be vaccinated at least 2 weeks before the trip. After a single dose of the vaccine, immunity persists for a year. To create a longer immune protection, it is necessary to administer a booster dose of the vaccine 6-12 months after the first vaccination. In this case, immunity to hepatitis A persists for 5-10 years.
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