Liver infection is caused by different types of infectious agents which cause inflammation of liver and is known as hepatitis. Inflammation means swelling of the tissues as a result of injury or infection. If left untreated, hepatitis causes liver damage and further liver failure.
Types of Liver Infections
Liver infection is of two main types as viral and non-viral liver infections. Viral liver infection is the inflammation of liver caused by hepatitis viruses A, B, C, D and E. It is the most common type and highly contagious. Viral liver infections cause cirrhosis and liver failure. Non-viral liver infection is inflammation of liver caused by agents other than viruses such as bacteria, worms and parasites. This type of liver infection has low incidence, is less common and is not contagious. Fungal infections affect immunocompromised patients only. Let us understand the details of each types and sub-types of liver infections.
Viral Liver Infections
The five major types of viruses that cause liver infections or hepatitis include Hepatitis A, B, C, D and E. These viruses are unrelated to each other. Viral inflammation is mostly caused by Hepatitis A, B and C viruses. These three types of viruses cause acute hepatitis. However, B and C can cause chronic hepatitis which lasts for a long time. Patients with liver infection due to hepatitis B or C have severe liver damage due to cirrhosis. Although each type is transmitted in a different way, the symptoms for all hepatitis viruses are nearly similar which includes:
Let us discuss each type of hepatitis in details.
Liver Infection Due to Hepatitis A Virus
Hepatitis A virus (HAV) enters the body through intake of water or food contaminated with faeces of patient infected with hepatitis A and consumption of raw fish food. This virus is observed in developing countries where there is poor sanitation. It is most likely contracted while travelling to such countries. HAV causes acute and short term liver inflammation. It causes mild hepatitis which resolves within two months. In some rare cases it progresses to cause liver failure.
Hepatitis A virus is detected by blood test where antibodies to HAV indicate presence of infection.
It is a short term disease hence only bed rest is recommended. The infection clears on its own within one or two months. Patients are advised to take rest, drink plenty of liquids, eat healthy diet and avoid intake of alcohol.
- Hepatitis A vaccine is able to prevent this infection. Children at age of 12-23 months are vaccinated. Hepatitis A vaccine is available for adults. This vaccine is administered as two shots, where second shot is to be taken after 6 to 12 months of the first shot. It is important to take both the shots to prevent HAV infection. This vaccine is able to prevent infection for 10 years.
- While travelling to developing countries it is necessary to get vaccinated with HAV vaccine.
- One should drink bottled water when in developing countries.
- Maintaining a good hygiene is essential.
Liver Infection Due to Hepatitis B Infection
Hepatitis B virus is seen all over the world and is endemic in South East Asian countries. It is responsible for most of the liver inflammations and liver damage. It enters the body through use of contaminated needles, due to contact with infected blood and other body fluids such as vaginal discharge and semen. In addition, the risk is increased while having unprotected sex with HBV infected partner and using HBV infected razors and needles. It is also transmitted from infected mother to her baby. It causes both acute and chronic liver infections. Acute infection is short term where the infection lasts for few weeks since the body is able to fight off the infection. Healthy adults and children are able to recover from HBV infections without any medication. Chronic infection is a long lasting infection and is dangerous. It causes severe inflammation which hinders the normal functioning of the liver. If left untreated, it leads to further complications such as cirrhosis, liver failure and liver cancer.
The patient has to undergo physical examination. Further, both medical history of the patient and his family is noted. Regular blood tests (Liver function tests) are done. Liver biopsy may be advised. Elastography Ultrasound is done to determine liver’s stiffness by using sound waves. Paracentesis is done where the abdominal fluid is removed and tested to determine the cause of its accumulation.
There is no specific treatment for acute hepatitis B infection. While chronic hepatitis is treated with antiviral medicines. There are six treatment options available for chronic hepatitis infection as alpha-interferon, pegylated interferon, Adefovir, entecavir, telbivudine and lamivudine. The interferons are injectable forms while the drugs are to be taken orally. Oral medication helps to suppress the virus growth. The duration of medications differs for different patients. Most of the patients show good response to medicines. There is possibility of side effects due to intake of medicines.
- HBV infection can be prevented by vaccinating newborns, children and adults with HBV vaccine. Adults infected with HBV can also be vaccinated. Similarly HBV vaccine is safe for pregnant women. HBV vaccine confers protection throughout the entire life.
- People should get vaccinated before travelling to countries with high incidence of HBV.
- One should avoid unprotected sexual contact with multiple partners or with HBV infected partners.
- Be careful while undergoing blood transfusions.
- Avoid using reused needles during tattooing, blood transfusions and drug use.
Liver Infection due to Hepatitis C
Hepatitis C virus causes both acute and chronic hepatitis of the liver. Infection by HCV is curable. Hepatitis C infection remains asymptomatic for decades. Patients with HAV and HBV infection are more prone to HCV infection.
The symptoms, risk factors, diagnosis, and prevention are same as that of Hepatitis B liver infection.
A patient with chronic Hepatitis C liver infection will be advised to take antiviral medicines such as interferon, with or without antiviral drug ribavirin. Treatment is based on its subtype (genotype) of HCV. These antivirals suppress the growth of virus and are very effective. The duration of medication differs for different patients. They cure the infection within 12-24 weeks. These medicines are very expensive.
There is no vaccine against Hepatitis C virus.
Liver Infection and Hepatitis D
Hepatitis D virus is not common worldwide and occurs only in some places. It causes inflammation of the liver. It infects liver cells only in the presence of hepatitis B virus infection. Hepatitis D virus has no independent existence and requires hepatitis B virus for its survival.
It spreads the same way as Hepatitis B infection. It causes acute or chronic or both types of infection.
The risk factors, symptoms, prevention diagnosis are similar to hepatitis B infection.
Treatment of Hepatitis D is with peginterferon alpha-2a (Pegsys) along with medicines against Hepatitis B virus.
Prevention is by vaccinating against Hepatitis B virus. There is no vaccine against Hepatitis D virus.
Liver Infection Due to Hepatitis E Virus
Hepatitis E virus causes acute hepatitis. It is transmitted through water or food contaminated with faeces of person suffering from Hepatitis E infection. It also spreads on eating undercooked pork or deer. Hepatitis E virus is seen all over the world with a high incidence in developing countries where sanitation is poor. The risk factors, diagnosis and treatment are similar to hepatitis A infection. There is no vaccine against Hepatitis E virus although some reports mention it being developed and used in China.
The other viruses which cause hepatitis are cytomegalovirus, Epstein Barr Virus (EBV), Herpes Simplex virus (HSV).
Non-viral Liver Infections
Bacterial Liver Infections
Certain bacteria such as Escherichia coli, Salmonella species, Staphyloccus aureus can infect liver to cause hepatitis. They cause both acute and chronic type of non-viral liver infection. These bacteria enter liver through contaminated water and food. They cause abscesses and lesions on the liver. Symptoms include fever, pain in the upper right quadrant of the liver and anoxeria. Diagnosis includes liver function tests and microbiological cultures. It also includes radiological investigations or CT scan. ERCP or colonoscopy is done to estimate the cause of liver abscesses. Treatment includes antibiotic medication (specific to the type of organism causing it) and drainage of abscesses.
Parasitic Liver Infections
This can be divided into further sub-types:
- Amoebic Liver Abscess: Entamoeba histolytica commonly causes parasitic infection of liver. It is common in South East Asian countries. This parasite enters the body in cyst form through intake of contaminated water or food. It penetrates the gastrointestinal mucosa and gains access to the liver by the portal venous system. The abscess has characteristic Anchovy paste appearance. Symptoms include fever, malaise, loss of weight and diarrhea. Presence of jaundice is occasional. Diagnosis includes liver function tests, amoebic serology and cultures of the stool sample. The investigation of amoebic infection is further done with ultrasound guided needle aspiration. Treatment involves use of pain killers and good nutrition. Antimicrobial therapy such as metronidazole is also administered.
- Hydatid Diseases: The worms such as Echinococcus granulosus cause hydatid disease. It enters the body in the form of a cyst through intake of food contaminated with faeces of an infected dog. The ova reach the stomach of the humans they hatch due to favourable conditions and penetrate the wall of intestine and pass to the liver by portal vein. Then, the cysts develop in the liver. Symptoms of tapeworm worm infection involve pain in the upper right quadrant of the liver, skin itching, fever and jaundice. Diagnosis involves blood tests such as liver function tests and using serological tests (specifically immunoelectrophoresis). Ultrasound and CT scan are used to assess the size and location of the cysts. ERCP and magnetic resonance cholangiopancretography (MRCP) may be used to diagnose biliary connections. Treatment includes drug therapy and surgery. Drugs such as mebendazole or albendazole are used and can successfully treat 50 % of the cases. Surgery is used for complete removal of the parasite and its cysts.Generally, surgery prevents recurrence of this hydatid disease.
- Liver Fluke Disease: Fasciola hepatica, Ascaris lumbricoides parasites cause liver fluke disease. Fasciola parsite enters the body in the cyst form through eating raw vegetables. They penetrate the intestinal wall and migrate to the liver where they cause liver inflammation. Symptoms include sudden onset of pain in upper right quadrant of liver, fever, allergic reactions, jaundice and anaemia. The condition is treated with drugs such as albendazole or bithional or praziquantel.
Liver is infected by different types of infectious agents such as virus, bacteria, parasites and worms. It is important to recognize the symptoms and start treatment immediately to avoid severe damage to liver in future.