Viral hepatitis A

Viral hepatitis A (infectious hepatitis, epidemic hepatitis, Botkin's disease) is an acute viral disease of humans with a fecal-oral mechanism of transmission of the pathogen.

Characterized by inflammation of the liver, a cyclical benign course, and may be accompanied by jaundice.

[ 1 ], [ 2 ], [ 3 ], [ 4 ]

Epidemiology

The main role in the development and activation of the epidemiological process is played by a person infected with the HAV virus. The subclinical, anicteric variant of the disease is especially dangerous, when the infection goes through the incubation stage and releases the virus, which is excreted with feces. The process of releasing the hepatitis A pathogen into the external environment continues until the initial clinical manifestations of the disease and lasts up to four weeks. The first two weeks from the onset of the disease are considered the most dangerous in terms of contagiousness. During this period, the virus can be detected not only in feces, but also in urine, sperm, vaginal discharge and menstrual blood.

The epidemiology of hepatitis A is characterized by a unified mechanism of infection transmission - fecal-oral, which is carried out through food, water, household or contact. Epidemiological outbreaks of mass infections are also typical for hepatitis A, most often in institutions where a group of people simultaneously consume contaminated food or contaminated water (kindergartens, school cafeterias, etc.). Some experts claim that there is also a vertical, parenteral route of transmission of hepatitis A. Indeed, in practice, there are isolated cases of infection of a child during childbirth by a mother who is a carrier of the virus, as well as infection with HAV during injection manipulations, but these phenomena cannot be considered typical.

Hepatitis A is classified as a childhood disease by age parameters, since about 80% of those infected are children under 14 years of age; the adult population accounts for only 15-20% of all registered cases of HAV.

According to geographical parameters, the epidemiology of hepatitis A looks like this (WHO statistics):

• High epidemiological level of HAV prevalence is observed in all countries classified as developing. Poor sanitary and hygienic conditions, insufficient epidemiological control leads to the fact that more than 90% of children become infected with hepatitis A at an early age, before 10 years. Mass outbreaks of the disease are recorded quite rarely, this is explained by the fact that the majority of the adult population has already had HAV and has strong immunity to the virus.
• The average epidemiological level of HAV infection is recorded in countries classified as developing in transitional economies. Significant improvements in sanitary and hygienic standards and epidemiological control lead to the fact that young children rarely get sick with hepatitis A. However, this is also a paradoxical reason for HAV disease in adults who do not have immunity and are highly sensitive to the virus. In such countries, periodic outbreaks of mass infection with hepatitis A are observed.
• A low level of epidemiological situation associated with HAV is noted in all developed countries with a stable socio-economic situation. Cases of infection are recorded mainly among people in risk groups - people without a fixed abode, leading an asocial lifestyle. Those who make tourist trips to countries with a high epidemiological level are also at risk of contracting hepatitis A.

According to the latest WHO statistics, more than 1.4 million people worldwide become infected with hepatitis A every year.

The disease has long been aptly named the disease of dirty hands, so the higher the general sanitary and hygienic culture of the country's population, the fewer cases of infection with the HAV virus are recorded in it.

[ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ]

Causes hepatitis A

The cause of hepatitis A is the penetration of the virus into liver cells, in most cases through contaminated food. The second route of infection is water contaminated with wastewater (water). Thus, food and untreated water, even that which is used to wash raw vegetables or fruits, are the main reservoir of hepatitis A infection. The virus can also spread through contact, for example, in the environment of people infected with HAV. The following situations can provoke infection:

• Eating food prepared by a person infected with hepatitis A (especially if the person does not wash his hands after using the toilet).
• Consumption of food products (vegetables, fruits) washed with untreated water contaminated with the virus.
• Eating food prepared by a person who has not washed their hands after changing diapers, or diapering a child infected with hepatitis A.
• Eating raw seafood (oysters, mussels, other mollusks) that live in virus-infected waters, including wastewater.
• Homosexual (anal) sexual contact with a person infected with the virus.

The hepatitis virus HAV feels great in an aqueous, liquid environment and is not afraid of acidity. After eating contaminated food or water, the HAV pathogen enters the gastrointestinal tract, which it safely passes and is absorbed into the blood. Thus, hepatitis A enters the liver and begins its pathological effect on hepatocytes. Virions quickly reproduce in the cells of the organ, leave them and are excreted through the bile ducts into the intestine. Inflammation of the liver and its damage are caused by an active immune response, when T-lymphocytes enter the fight against identified damaged, and therefore subject to destruction, hepatocytes. The level of bilirubin found in the liver cells increases, it penetrates the bloodstream, coloring the skin in a jaundice shade characteristic of hepatitis. Infected cells die, provoking an inflammatory process, liver dysfunction and hepatitis itself.

[ 13 ], [ 14 ], [ 15 ], [ 16 ], [ 17 ], [ 18 ]

Pathogenesis

Hepatitis A is considered one of the most common infectious diseases in the world. Until the end of the 19th century, the disease was called catarrhal jaundice and associated with an inflammatory process in the bile ducts. The infectious etiology of hepatitis A was identified by the great clinician S.P. Botkin, since then this concept has been leading in the practice of diagnosing and treating hepatitis, and it was only in 1973 that the pathogen was specified and identified. The HAV (hepatitis A) virus belongs to a group of small picornaviruses lacking a lipoprotein layer, with a single-stranded RNA structure. The pathogen is very resistant to the effects of various factors and can persist in the environment for several months at a comfortable room temperature. Even when frozen, the virus does not lose viability for 1.5-2 years, and its acid-resistant shell helps to overcome the protective secretions of the stomach and penetrate the liver. A person who has had hepatitis A maintains stable immunity to the virus for life.

The infection can be inactivated by boiling or steaming, and the use of disinfectants - chloramine, formalin, and ultraviolet radiation makes it possible to neutralize the hepatitis A virus.

[ 19 ], [ 20 ], [ 21 ], [ 22 ], [ 23 ], [ 24 ]

Symptoms hepatitis A

Symptoms of hepatitis A are related to the course of the disease. HAV can have different types and occur in three forms, among which are the following:

Types:

1. Typical hepatitis A, which develops classically with all the characteristic symptoms, including jaundice.
2. Hepatitis A is atypical, which is characterized by an icteric stage and a chronic course.

Forms:

1. The most common is the mild form.
2. A third of patients (28-30%) are diagnosed with a moderate form.
3. The most rare form of hepatitis A is severe (no more than 3% of cases).

Symptoms of hepatitis A can also vary and depend on the course of the disease:

1. Cyclic, acute.
2. Recurrent, long-lasting, protracted.
3. Chronic, persistent.
4. Aggressive, accompanied by cholestatic symptoms (syndrome).

In the clinical and biochemical sense, the manifestations of HAV are divided into the following syndromes:

1. Cytolysis, characterized by a sharp increase in direct bilirubin and a sharp jump in the level of ALT (alanine aminotransferase) in the patient's blood.
2. Cholestasis, which is also characterized by an increase in the level of bilirubin in the blood, as well as an increase in the amount of alkaline phosphatase and cholesterol.
3. Mesenchymal inflammatory syndrome, which is accompanied by high ESR, gamma globulin levels and a decrease in the level of sublimate in the blood.
4. Severe hepatoprotective syndrome, when the blood level of albumin and fibrinogen decreases sharply and liver failure (encephalopathy) develops.

It can take 2-4 weeks from the onset of infection to the first clinical symptoms; symptoms of hepatitis A can be as follows:

Mild hepatitis A:

• Pre-icteric period (3-7 days):
  • A slight increase in body temperature, from 37.2 to 37.7 degrees in the first 2-3 days of illness.
  • Periodic feeling of nausea, vomiting is possible.
  • Shallow, restless sleep.
  • A feeling of aching pain in the liver area, in the right hypochondrium.
  • Dyspepsia, flatulence.
  • Urine and feces become an atypical color - urine darkens, feces become depigmented.
• Jaundice period (from 7 to 10 days):
  • Gradual coloring of the skin, sclera of the eyes yellowish tint. Jaundice usually begins with the whites of the eyes and spreads over the body from top to bottom.
  • Improvement of condition, subsidence of pain in the right hypochondrium.
• Recovery stage:
  • Normalization of liver function, restoration of its normal size.
  • Residual effects of mild fatigue after physical exertion.

Symptoms of moderate hepatitis A:

• Poor appetite.
• Subfebrile body temperature.
• Decreased amount of urine.
• Enlargement of the liver.
• Severe pain in the liver area.
• Darkening of urine and discoloration of stool.
• Marked jaundice lasting up to 21 days.
• The recovery period is longer than in the mild form - up to 2 months.

Severe hepatitis A (rarely diagnosed):

• A sudden onset of the disease and a rapid increase in symptoms.
• High body temperature – up to 39 degrees.
• Lack of appetite, food causes vomiting.
• When jaundice appears, the symptoms do not subside, but on the contrary, become more pronounced.
• All signs of general intoxication of the body appear - headaches, dizziness.
• Pain in muscles and joints.
• Hemorrhages under the skin (hemorrhagic), nosebleeds.
• Rash.
• Lack of urge to urinate.
• Hepatomegaly, splenomegaly.

Diagnostics hepatitis A

Diagnostic measures are divided into two types:

• Specific – detection of the virus, its virions and immune antibodies.
• Non-specific – determination of the liver condition and the level of hepatocyte damage.

Diagnosis of hepatitis A includes anamnesis, visual examination of the patient, palpation of the right hypochondrium. The patient's appearance is assessed - the color of the tongue, whites of the eyes, skin, the level of body temperature is noted.

Enzyme immunoassay and biochemical blood analysis are widely used as laboratory diagnostic methods. Determination of protein metabolism parameters, enzyme activity and albumin and bilirubin levels are used as a non-specific method.

List of laboratory tests that reveal hepatitis A and inflammation in the liver:

• Immunofermentogram to determine antibodies to the virus (HAV-IgM, IgA), which can only be determined during the acute period of the disease.
• Biochemical studies to determine the level of liver cytolysis enzymes - AST (aspartate transferase), ALT (alaminotransferase), Gamma GT or gamma-glutamyl transferase, alkaline phosphatase, LDH (lactic dehydrogenase).
• Determination of the level of direct and indirect bilirubin.
• A test that determines the prothrombin index, which shows the rate of blood clotting.
• Complete blood count.
• Coagulogram.
• General urine analysis.

Diagnosis of hepatitis A can be difficult in the case of asymptomatic course of the disease (anicteric form). Markers that help to identify the virus are antibodies of the immune system - IgM, which can most often be detected only in the acute course of the disease, more often IgG antibodies are determined, which is an indicator of reconvalescence, that is, restoration of liver function after infection. Also, in the initial period of the disease (prodromal), it is important to differentiate hepatitis and enterovirus infection, ARVI, since these nosological forms also manifest themselves with elevated temperature and signs of dyspepsia. However, the influenza virus is characterized by neurotoxic and catarrhal symptoms, and hepatitis tends to manifest itself with hepatomegaly and changes in liver function.

[ 25 ], [ 26 ], [ 27 ], [ 28 ], [ 29 ]

Treatment hepatitis A

The therapeutic strategy for hepatitis A is most often limited to a special gentle diet, which involves limiting fats and adding carbohydrates. As a rule, this is the appointment of diet No. 5 according to Pevzner. Bed rest, reduced physical activity and stress, and plenty of fluids are also useful. To relieve symptoms, treatment for hepatitis A involves the use of choleretic drugs, infusions, hepatoprotectors, and antispasmodics. The strategy and tactical actions of HAV therapy can be systematized and presented as follows:

Basic activities	Bed rest regime
	Diet, specific therapeutic nutrition (table No. 5). In the acute period of the disease and in moderate hepatitis, diet No. 5a is indicated
Detoxification measures for cleansing the gastrointestinal tract and liver	Purpose of enterosorbents - polyphepan, enterosgel, lignosorb
Detoxification measures to cleanse the blood through the urinary system, kidneys	Abundant alkaline drinks (mineral water, freshly squeezed vegetable and non-acidic fruit juices) It is possible to use drugs - diuretics, as well as glucocorticosteroids
Detoxification measures to remove toxins through the skin	Heat, regular baths, showers, skin care to activate sweating and blood microcirculation
Neutralization of organ tissue hypoxia, lipid peroxidation	The purpose of antioxidants is vitamins E, A, C, PP, Essentiale, Riboxin
In severe cases of the disease, extracorporeal detox methods are indicated.	Plasmapheresis, plasmasorption, hemosorption, hemoxygenation
Measures that help correct the protein functions of the liver and its regeneration	Amino acids, albumin, plasma intravenously Vitamin and mineral therapy (orally, by injection) Potassium-containing preparations
Neutralization of necrosis and fibrosis of liver tissue	Prescribing proteinase inhibitors - Gordox, Contrikal, hormonal drugs
Relief of choleostasis	Prescription of ursodeoxycholic acid and other types of acids of this group, preparations containing it - ursofalk, chenofalk, taurofalk Use of enterosorbents Tubage or prescription of choleretic agents
Treatment of hepatitis A for the purpose of correcting hemostasis	Prescriptions according to coagulogram information
Correction of functions of the gastrointestinal tract, biliary system	Prescription of probiotics, prebiotics, enzymes

Prevention

Preventive measures against many viral diseases include personal hygiene. If the nose and mouth are vulnerable to infection for the flu virus, through which the pathogen can enter the body, then prevention of hepatitis A is cleanly washed hands, because it is not by chance that HAV was called "disease of dirty hands". As in the case of other intestinal diseases, preventive measures include processing food products, purifying or boiling water and following the simplest rules of sanitary and hygienic standards. In this sense, not only personal preventive efforts are effective, but also systematic testing, treatment of drinking water, assessment of the purity and safety of food products by sanitary and epidemiological services at the level of state programs.

In addition, prevention of hepatitis A is a medical examination of the population and observation of persons who come into contact with patients infected with the HAV virus. Monitoring of the condition of contacts is carried out for 30-35 days with mandatory weekly recording of clinical symptoms, checking the activity of ALT (biochemical blood test), detection of antibodies to the virus (immunoenzyme test). If the contacts are pregnant women and children under 12-14 years old, the introduction of a prophylactic dose of immunoglobulin is indicated. The most effective method of prevention throughout the world is considered to be timely vaccination against hepatitis A, especially in areas with an increased epidemiological level of infection.

Other recommendations for prevention are not difficult to implement:

• Wash your hands thoroughly, preferably with soap, after each visit to a private or public toilet.
• Wash raw vegetables and fruits thoroughly, preferably with boiled water, or, in extreme cases, with running water for a long time.
• If possible, it is advisable to pour boiling water over vegetables and fruits, especially if they are intended for children.
• Use raw water only from clean sources tested by the relevant services. If the source of the water is in doubt, the water should be boiled for 3-5 minutes.
• Wash your hands every time before preparing food, as well as before eating.
• Wash your hands after visiting public places, after traveling on public transport.
• Teach children to observe the rules of personal hygiene.
• Do not try fruits and berries at spontaneous markets.
• Avoid eating foods of questionable appearance.
• Regularly check the hygiene certificates and expiration dates of products purchased in stores and supermarkets.
• Do not use cutlery or personal hygiene items of people infected with hepatitis.

Hepatitis A Vaccination

Today, vaccination against hepatitis A is considered the basis of preventive measures that help stop the infection of the population with the HAV virus. The vaccine is a neutralized virus that is characterized by high immunogenicity. Vaccination is carried out twice with an interval of six months and a year. Immune antibodies to the administered vaccine appear in the body after 1.5-2 weeks, immune protection after vaccination lasts for at least six years, maximum - ten years.

It is believed that vaccination against hepatitis A is effective from a very early age, however, it is most often carried out from the age of three. Vaccinations are also indicated for adults who have not had HAV, and for people in groups of potential infection (risk groups).

Categories of people who are at risk of contracting hepatitis A:

• Medical personnel of inpatient treatment facilities who have contact with groups of patients, as well as personnel of infectious disease hospitals.
• All employees of children's schools and preschool institutions without exception.
• Employees working in public catering establishments, as well as persons working in the water supply system of populated areas.
• People with a history of liver disease.
• People planning trips to countries with high epidemiological levels of hepatitis infection.
• Persons in contact with patients/carriers of hepatitis A (family members, relatives).
• Persons who have sexual contact with infected partners.

Vaccination against hepatitis A is also advisable for those who use injection drugs and prefer homosexual sexual contacts.

Today, the pharmaceutical industry has begun to produce vaccines that can be used for children aged one year and older.

[ 30 ]

Forecast

Among all types of hepatitis, HAV is considered relatively safe for the liver, indeed, the disease can resolve itself after 5-6 weeks from the onset of infection, this is especially typical for the acute form of hepatitis. In this sense, the prognosis for hepatitis A is favorable, and severe complications are considered an exception rather than a typical consequence. Transformation of HAV into a fulminant (rapid) form, ending in the death of the patient, is extremely rare.

Such cases are diagnosed in patients with a history of hepatitis B and C. The fatal outcome in such patients is due to general intoxication of the body, acute liver failure and extensive necrosis of liver tissue. The risk of an unfavorable outcome of the disease is low and is:

• Children under 10 years old – 0.1%.
• Children from 10 to 15 years old – 0.3%.
• Adults under 40 years of age – 0.3%.
• Persons over 40 years old – 2.1-2.2%.

In addition, the prognosis of hepatitis A depends on regional epidemiological specifics, the state of the immune system and liver function of a person at the time of infection with the virus. However, HAV in most cases ends in complete recovery.

[ 31 ], [ 32 ], [ 33 ], [ 34 ]