Hepatitis D
The content of the article:
- Causes and risk factors
- Forms of the disease
- Disease stages
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
- Prevention
Hepatitis D is an acute or chronic infection of the liver with a parenteral mechanism of infection caused by the hepatitis D virus (HDV, HDV).
A specific feature of the disease is its secondary nature. HDV infection is possible only against the background of prior infection with hepatitis B virus (HBV). About 5% (according to other sources - up to 10%) of HBV carriers are simultaneously infected with HDV. Chronic viral hepatitis caused by exposure to HBV and HDV, according to information provided by the World Health Organization, is currently confirmed in approximately 15-30 million people.
Liver damage in hepatitis D
For the first time HDV was obtained in 1977 by a group of Italian scientists from biopsies of liver cells of patients suffering from viral hepatitis B. An erroneous assumption was made that a fundamentally new HBV marker had been isolated, but further studies showed that the detected particles are independent pathogens, defective viruses (viroids). Later, a fundamentally new type of hepatitis caused by these viruses was classified, called viral hepatitis D.
The prevalence of the disease in different regions varies significantly: from isolated cases to the defeat of 20-25% of those infected with the hepatitis B virus.
According to the spread of viral hepatitis D, all regions are conditionally divided as follows:
- highly endemic - the incidence of HDV infection exceeds 60%;
- regions of average endemicity - incidence rate of 30-60%;
- low endemic - HDV is recorded in 10–30% of cases;
- regions of very low endemicity - the detection rate of antibodies to HDV is not higher than 10%.
The Russian Federation belongs to areas of low endemicity, although some researchers associate such positive statistics with the lack of mandatory diagnosis of antibodies to HDV in patients with HBV.
Synonyms: hepatitis delta, viral hepatitis D, HDV infection, HDV infection.
Causes and risk factors
Viral hepatitis D is caused by a small RNA-containing defective virus (viroid), for the functioning of which the hepatitis B virus is required. HDV belongs to the genus Deltavirus and is a satellite virus (hyperparasite): the reproduction of new viroids is impossible in the absence of the host virus due to the inability of HDV on its own build a virus envelope. Penetrating into cells colonized by the precursor virus, HDV disrupts its replication and uses HBV envelope proteins to build its own particles.
Life cycle of hepatitis D virus
Currently, 8 genotypes of HDV have been identified, which have a specific distribution and differ in clinical and laboratory manifestations (for example, the 1st genotype is common in Europe, the 2nd in East Asia, the 3rd is found mainly in Africa, tropical Asia, in the Amazon, etc.).
The main route of infection is blood contact (transmission through blood):
- during medical and diagnostic procedures (including dental);
- for cosmetic and aesthetic procedures (tattoo, manicure, piercing);
- with blood transfusions;
- when using injecting drugs.
Less common are the vertical transmission of the virus (from mother to child during pregnancy) and the sexual route. It is possible to become infected within the same family with close household contact (the formation of family foci of chronic hepatitis D is often noted in highly endemic regions).
Forms of the disease
In combination with viral hepatitis B, there are:
- co-infection (parallel infection);
- superinfection (joins against the background of existing chronic hepatitis B).
Depending on the severity of the process:
- acute hepatitis D;
- chronic hepatitis D.
Both acute and chronic disease can occur in a manifest form with a detailed clinical and laboratory picture or in the form of a latent (latent) HDV infection, when the only sign of hepatitis is a change in laboratory parameters (active symptoms are absent in this case).
According to the severity, the following forms of hepatitis D are distinguished:
- light;
- moderate;
- heavy;
- fulminant (malignant, rapid).
Disease stages
There are the following stages of hepatitis D:
- incubation (from 3 to 10 weeks);
- preicteric (on average - about 5 days);
- icteric (several weeks);
- convalescence.
Symptoms
During the incubation period, there are no symptoms of the disease; despite this, the patient is a virus-releasing agent.
The preicteric period makes its debut acutely:
- intoxication symptoms - headache, fatigue, decreased tolerance to habitual physical activity, drowsiness, muscle and joint pain;
- dyspeptic symptoms - decreased appetite up to anorexia, nausea, vomiting, bitterness in the mouth, bloating, pain and a feeling of fullness in the right hypochondrium;
- an increase in body temperature up to 38 ºС and above (observed in approximately 30% of patients).
Soreness in the right hypochondrium may indicate hepatitis D
The symptoms of the icteric period:
- characteristic staining of the skin and mucous membranes, icterus of the sclera;
- enlargement and soreness of the liver;
- subfebrile body temperature;
- weakness, decreased appetite;
- urticarial rashes like urticaria on the skin;
- discoloration of stool, dark-colored urine.
More than half of the patients have a two-wave course: after 2-4 weeks from the onset of the icteric stage of the disease, against the background of the subsiding of the symptoms of the disease, the general state of health and laboratory parameters deteriorate sharply.
Acute hepatitis-delta is stopped, as a rule, within 1.5–3 months, and chronicity of the disease occurs no more than in 5% of cases.
Acute superinfection is more severe than co-infection, it is characterized by a violation of the protein-synthetic function of the liver, the outcomes of the disease are usually unfavorable:
- death (with fulminant form, which develops in 5–25% of patients, or with severe form with the formation of subacute liver dystrophy);
- the formation of chronic viral hepatitis B + D (about 80%) with a high process activity and rapid transformation into cirrhosis of the liver.
Diagnostics
The main laboratory diagnostic method for confirming the presence of HDV infection is testing of HBsAg-positive patients (individuals who have identified hepatitis B virus antigens) for the presence of antibodies to HDV in the blood serum.
Persons with hepatitis B should donate blood for antibodies to HDV
Methods for diagnosing viral hepatitis D:
- analysis of data on previous contact with possibly infected blood, medical and other manipulations;
- characteristic clinical manifestations in the icteric form of the disease;
- determination of IgM and IgG to HDV in HBsAg-positive patients;
- detection of HDV RNA (HDV-RNA) by polymerase chain reaction;
- specific changes in the biochemical blood test (increased levels of liver enzymes AST and ALT, positive thymol test, hyperbilirubinemia, possible decrease in sublimate test and prothrombin index).
Treatment
Joint therapy for hepatitis D + B is carried out, during which the following are prescribed:
- interferons (including PEG-interferon);
- antiviral drugs (there are no specific drugs that target the hepatitis D virus);
- immunomodulators;
- hepatoprotectors;
- detoxification therapy;
- desensitizing agents;
- vitamin therapy;
- enzyme preparations.
The duration of antiviral therapy has not been determined; the question of its termination is decided depending on the patient's condition. (It may take a year or more.)
With a confirmed diagnosis, complex therapy of hepatitis B and D is carried out
For patients with fulminant hepatitis and liver cirrhosis in the latter stages, the possibility of liver transplantation is considered.
Possible complications and consequences
Complications of hepatitis D can include:
- cirrhosis of the liver;
- hepatocellular carcinoma;
- acute liver failure;
- hepatic encephalopathy;
- bleeding from varicose veins of the esophagus;
- hepatic coma, death.
Forecast
The prognosis for the acute course of HDV co-infection is favorable: most patients are cured, the disease acquires a chronic form in 1–5% of cases.
Superinfection is prognostically unfavorable: chronic hepatitis occurs in 75–80% of patients, cirrhosis develops rapidly, often with subsequent malignancy.
Prevention
Basic preventive measures:
- compliance with safety measures when working with blood;
- avoiding casual, unprotected sexual intercourse;
- refusal to take narcotic drugs;
- obtaining medical, cosmetic services in officially licensed institutions;
- the implementation of systematic professional examinations during professional contact with blood.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
