What Are the Different Methods of Hepatitis C Transmission?

Hepatitis C virus, referred to as Hepatitis C and Hepatitis C, is a type of viral hepatitis caused by hepatitis C virus (HCV) infection. It is mainly transmitted through blood transfusion, acupuncture, and drug use. According to World Health Organization statistics, The infection rate of HCV is about 3%. It is estimated that about 180 million people are infected with HCV, and about 35,000 new cases of hepatitis C occur each year. Hepatitis C is a global epidemic, which can lead to chronic inflammatory necrosis and fibrosis of the liver, and some patients can develop cirrhosis and even hepatocellular carcinoma (HCC). Mortality related to HCV infection (death caused by liver failure and hepatocellular carcinoma) will continue to increase in the next 20 years, which will be extremely harmful to the health and life of patients, and has become a serious social and public health problem.

Basic Information

nickname

Hepatitis C, Hepatitis C

English name

hepatitis C

Visiting department

Department of Infectious Diseases, Gastroenterology

Common locations

liver

Common causes

Hepatitis C virus infection

Common symptoms

Generally manifested as nausea, decreased appetite, and general weakness

Contagious

Have

way for spreading

Blood, sexual, mother-to-child transmission

Causes of hepatitis C virus

Hepatitis C virus infection is the root cause of the disease. Under the influence of external factors, such as drinking, exertion, and long-term use of drugs with liver toxicity, it can promote the development of the disease. The pathological changes of hepatitis C are very similar to those of hepatitis B, with hepatocyte necrosis and lymphocyte infiltration mainly. Chronic hepatitis can cause fibrous tissue proliferation in the mesial area, and in severe cases, pseudolobules can form cirrhosis.

The pathogenesis of HCV infection mainly includes immune-mediated and HCV direct damage. Viral factors include virus genotype, replication ability, and immunogenicity of viral peptides; host factors include human innate immune response, humoral immunity, and cells Immune response, etc. Factors such as alcohol consumption and the use of immunosuppressants also affect the course of HCV infection.

Routes of HCV transmission: Kissing, hugging, sneezing, coughing, food, drinking water, sharing tableware and drinking glasses, no skin damage, and other exposure without blood exposure generally do not spread HCV. HCV is transmitted mainly through:

Blood spread

(1) Transmission through blood transfusion and blood products Due to the window period of anti-HCV, the quality of anti-HCV detection reagents is unstable, and a small number of infected persons do not produce anti-HCV, therefore, HCV-positive persons cannot be completely screened, and a large amount of blood transfusion and blood Dialysis may still be infected with HCV.

(2) Transmission through damaged skin and mucous membranes This is currently the main mode of transmission. In some areas, HCV transmission due to intravenous drugs accounts for 60% to 90%. The use of non-disposable syringes and needles, dental instruments that are not strictly sterilized, endoscopes, invasive procedures, and acupuncture are also important routes for percutaneous transmission. Some traditional medical methods that may cause skin damage and blood exposure are also related to HCV transmission; sharing razors, toothbrushes, tattoos, and piercing holes are also potential HCV transmission methods.

2. Sexual transmission.

3. Mother-to-child transmission

The risk of transmission of HCV to newborns by anti-HCV-positive mothers is 2%. If the mother is HCVRNA positive during childbirth, the risk of transmission can be as high as 4% to 7%; when combined with HIV infection, the risk of transmission increases to 20%. High HCV viral load may increase the risk of transmission.

4. Other ways

Found in 15% to 30% of sporadic hepatitis C, the transmission route is unknown.

Clinical manifestations of hepatitis C virus

Acute viral hepatitis C

Acute hepatitis C in adults is relatively mild. Most are acute non-jaundice hepatitis, with elevated ALT, and a few are acute jaundice, with mild or moderate elevation of jaundice. Nausea, decreased appetite, general weakness, yellow urine and yellow eyes may appear. Hepatitis C virus infection rarely causes liver failure. In the natural state, only 15% of patients can clear HCV spontaneously to achieve recovery, and 85% of patients develop chronic hepatitis C without antiviral treatment intervention; children with acute infection with hepatitis C virus , 50% can clear HCV spontaneously.

2. Chronic hepatitis C

Symptoms are mild and manifest as common symptoms of hepatitis, such as easy fatigue, poor appetite, and abdominal distension. Or without any conscious symptoms. Test ALT fluctuates repeatedly and HCVRNA continues to be positive. One-third of patients with chronic HCV infection have always had normal liver function, and anti-HCV and HCVRNA continued to be positive. Liver biopsy showed chronic hepatitis manifestations and even liver cirrhosis.

3. Cirrhosis

In HCV infection, 20% to 30% of patients can develop cirrhosis, and 1% -5% of patients will develop hepatocellular carcinoma (HCC) and cause death. Once decompensation of cirrhosis occurs, such as jaundice, peritoneal effusion, rupture of varicose veins, and hepatic encephalopathy, the survival rate decreases sharply.

Hepatitis C virus examination

Liver function

Including serum ALT, AST, total bilirubin, direct bilirubin, indirect bilirubin, albumin, globulin, cholinesterase, alkaline phosphatase, transpeptidase, etc.

2. Hepatitis C virus antibody

Anti-HCV.

3. Quantification of HCV

Serum HCVRNA to understand the activity of hepatitis C virus replication.

4. Imaging

Abdominal liver, gallbladder, and spleen ultrasound examinations were performed to determine if there was chronic liver damage. If necessary, perform abdominal enhanced CT or MRI to understand the degree of disease damage.

5. Liver transient elastic wave scan

It is a non-invasive test that can be used to evaluate the degree of liver fibrosis in patients with chronic hepatitis C. Evaluation of liver fibrosis in patients with hepatitis C is important to determine treatment options.

6. Liver tissue biopsy

It is the gold standard for evaluating liver inflammation grade and fibrosis stage in patients.

Diagnosis of hepatitis C virus

Anti-HCV

Hepatitis C antibody is currently the main indicator for the diagnosis of hepatitis C virus. However, anti-HCV appears relatively slowly after infection with HCV. Generally, it only turns to be positive 2 to 6 months after the onset of infection, so it cannot be used as an early diagnosis method. Moreover, a negative result cannot directly negate the diagnosis. When all types of viral hepatitis specific markers are negative, clinical symptoms and single ALT are elevated, suggesting acute viral hepatitis, it should be considered whether it is viral hepatitis C.

2.HCV-RNA

That is, the ribonucleic acid of hepatitis C virus is the genetic material of HCV and a direct indicator of HCV infection in vivo. Currently, PCR can be used to directly detect HCV-RNA in blood, which can be used for early diagnosis of HCV infection. Because it appears earlier than the hepatitis C antibody, it is a useful indicator for the diagnosis and judgment of infectivity of hepatitis C.

In short, for patients with typical clinical manifestations whose onset is closely related to blood transfusion and blood products, and other suspected hepatitis C patients with hepatitis have been excluded, HCV-RNA and anti-HCV can be further investigated. If HCV-RNA and anti-HCV are positive Or HCV-RNA alone can be diagnosed as viral hepatitis C.

Differential diagnosis of hepatitis C virus

The main diseases identified include: other types of viral hepatitis: hepatitis B, D, hepatitis E, EBV hepatitis, and CMV hepatitis. Differential diagnosis is based on specific serological tests.

Hepatitis C treatment

Antiviral treatment plan

Before treatment, it should be clear whether the liver disease of the patient is caused by HCV infection. Only patients with confirmed hepatitis C virus serum HCVRNA need antiviral treatment. Antiviral therapy is currently recognized as the most effective regimen: long-acting interferon PEG-IFN combined with ribavirin, which is now the EASL approved standard protocol for chronic hepatitis C treatment (SOC), followed by the general IFN or combined IFN and ribavirin therapy are better than IFN alone. Polyethylene glycol (PEG) interferon alpha (PEG-IFN) is an inactive, non-toxic PEG molecule cross-linked on IFN molecules, which delays the absorption and body clearance process after IFN injection. Its half-life is long, 1 weekly. The effective blood concentration can be maintained in one administration.

Direct-acting antiviral drug (DAA) protease inhibitor bocepivir (BOC) or telapivir (TVR), a triple therapy with interferon combined with ribavirin, approved for clinical use in the United States in May 2011 , Recommended for genotype 1 HCV infection, can improve the cure rate. After meals with bocepivir (BOC), three times a day (every 7-9 hours) or after meals with telepivir (TVR) (a non-low-fat diet) three times a day (every 7-9 hours). HCVRNA should be closely monitored during this period, and if a virological breakthrough occurs (serum HCVRNA rises> 1 log after the lowest value), protease inhibitors should be discontinued.

2. Treatment of patients with general hepatitis C virus

(1) Acute viral hepatitis C There is definite evidence suggesting that interferon treatment can reduce the chronicity rate of acute viral hepatitis C. It can be performed 8-12 weeks after the onset of acute hepatitis with HCV infection, and the course of treatment is 12-24 weeks. The optimal treatment plan has not been finalized, but early treatment is more effective for patients with high genotype 1 viral load (> 800,000 logIU / ml).

(2) Patients with chronic viral hepatitis C should be evaluated for the severity of liver disease before treatment. Those with repetitive abnormal liver function or obvious liver necrosis (G2) or moderate fibrosis (S2) ), Easy to progress to cirrhosis, should be given antiviral treatment.

(3) Viral hepatitis C cirrhosis Patients with compensatory cirrhosis (Child-Pugh A), although the tolerance and effect of treatment have been reduced, but in order to stabilize the disease, delay or prevent liver failure and HCC Such as the occurrence of complications, it is recommended to give antiviral treatment under close observation. Patients with decompensated liver cirrhosis: It is difficult to tolerate the adverse reactions of IFN treatment, and those who have the conditions should perform liver transplantation.

3. Treatment of patients with special hepatitis C virus

(1) Children and the elderly Experience in the treatment of chronic viral hepatitis C in children is not sufficient. Preliminary clinical research results show that the SVR rate of IFN monotherapy seems to be higher than that of adults, and the drug is well tolerated. Elderly patients aged 65 or over should also receive antiviral therapy in principle, but they are generally less well tolerated. Therefore, the patient's age, tolerance to the drug, complications (such as hypertension, coronary heart disease, etc.) and the patient's willingness should be fully measured to determine whether to give antiviral treatment.

(2) Alcohol and drug users Chronic alcoholism and drug use may promote HCV replication and exacerbate liver damage, thereby accelerating the development of cirrhosis and even HCC. Because patients with alcohol and drug use have lower compliance, tolerance, and SVR rates for antiviral treatment, treatment of hepatitis C must be accompanied by alcohol and drug withdrawal.

(3) Patients with HBV or HIV infection Combining HBV infection will accelerate the progression of chronic hepatitis C to cirrhosis or HCC. For HCVRNA-positive / HBVDNA-negative patients, anti-HCV treatment should be given first; for those who have active replication of both viruses, it is recommended to clear HCV with IFN plus ribavirin, and anti-HBV can be given to those who remain positive after treatment treatment. The treatment of such patients requires further research to determine the best treatment options.

Combining HIV infection can also accelerate the progression of chronic hepatitis C. Anti-HCV treatment mainly depends on the patient's CD4 + cell count and fibrosis stage of the liver tissue. Those with normal immune function and who have not yet initiated high-activity antiretroviral therapy (HAART) should treat HCV infection first; patients who are receiving HAART and have liver fibrosis with S2 or S3 must also be given anti-HCV therapy; However, special attention should be paid to the possibility of interactions between ribavirin and anti-HIV nucleoside analogs, including lactic acidosis. For patients with severe immunosuppression (CD4 + positive lymphocytes <2 × 108 / L), anti-HIV treatment should be given first, and anti-HCV treatment should be considered after the immune function is restored.

(4) Chronic renal failure Antiviral therapy should not be performed for patients with chronic hepatitis C with renal failure who have not received dialysis. Patients who have undergone dialysis and who have no cirrhosis histopathologically (especially those who are preparing for kidney transplantation) can be treated with IFN alone (care should be taken after dialysis). Because severe hemolysis can occur in patients with renal insufficiency, combined ribavirin therapy is generally not used.

(5) Recurrence of HCV-related cirrhosis in patients with hepatitis C virus recurrence after liver transplantation or HCC after liver transplantation has a high recurrence rate of HCV infection. IFN treatment is effective in such patients, but it may promote the rejection of liver transplantation. Antiviral treatment can be performed under the guidance and close observation of experienced specialists.

Antiviral treatment for hepatitis C virus has a long course of treatment and has large side effects. It is necessary to use the drug safely under the guidance of experienced experts. During the treatment period, it is necessary to evaluate the efficacy in a timely manner, guide the treatment according to the response, and closely monitor the adverse reactions of the drug. Avoid serious adverse reactions.

4. Contraindications for antiviral therapy

(1) Absolute contraindications to interferon Pregnancy; A history of mental illness such as severe depression; Uncontrolled epilepsy, Unabstained alcoholics or drug users; Uncontrolled autoimmune diseases Decompensated liver cirrhosis; Symptomatic heart disease; Granulocytes <1.0 × 10 ⁹ / L before treatment; Platelets <50 × 10 ⁹ / L before treatment; Organ transplantation patients in the acute phase (except liver transplantation) ).

(2) Relative contraindications to interferon: thyroid disease, retinopathy, psoriasis, past depression history, uncontrolled diabetes, uncontrolled hypertension.

(3) Absolute contraindications for ribavirin Pregnancy, severe heart disease, renal insufficiency, hemoglobinopathy, HB <80g / L.

(4) Relative contraindications for ribavirin Uncontrolled hypertension, uncontrolled coronary heart disease, HB <100g / L.

Prognosis of hepatitis C virus

Acute hepatitis C interferon has a good antiviral effect, and 90% of patients can get a complete response and be completely cured. Chronic hepatitis C is relatively milder than viral hepatitis B. With standard antiviral treatment, there is a chance Get rid of the virus and get healed. Cirrhosis or liver cancer can develop in some patients 20-30 years after infection.