Hepatitis is an inflammation of the liver. It may be caused by drugs, alcohol use, or certain medical conditions. But in most cases, it's caused by a virus. This is known as viral hepatitis. The condition can be self-limiting or can progress to fibrosis (scarring), cirrhosis or liver cancer. Hepatitis viruses are the most common cause of hepatitis in the world but other infections, toxic substances (e.g. alcohol, certain drugs), and autoimmune diseases can also cause hepatitis.
TYPES OF HEPATITIS
There are 5 main hepatitis viruses, referred to as types A, B, C, D and E. The most common forms are the types A, B, C. These 5 types are of greatest concern because of the burden of illness and death they cause and the potential for outbreaks and epidemic spread.
Hepatitis A is highly contagious and can spread from person to person in many different settings. It typically causes only a mild illness, and many people who are infected may never realize they're sick at all. The virus almost always goes away on its own and does not cause long-term liver damage.
Hepatitis A usually passes within a few months, although it can occasionally be severe and even life-threatening. There's no specific treatment for it, other than to relieve symptoms such as pain, nausea and itching.
Treatments for hepatitis A
There's currently no cure for hepatitis A, but it will normally pass on its own within a couple of months. You can usually look after yourself at home.
Hepatitis B is caused by the hepatitis B virus, which is spread in the blood of an infected person. It is transmitted through exposure to infective blood, semen, and other body fluids. HBV can be transmitted from infected mothers to infants at the time of birth or from family member to infant in early childhood. Transmission may also occur through transfusions of HBV-contaminated blood and blood products, contaminated injections during medical procedures, and through injection drug use.
Many adults who get hepatitis B have mild symptoms for a short time and then get better on their own. But some people are not able to clear the virus from the body, which causes a long-term infection. Nearly 90% of infants who get the virus will carry it for life. Over time, hepatitis B can lead to serious problems, such as liver damage, liver failure, and liver cancer.
Symptoms of hepatitis B
Many people with hepatitis B won't experience any symptoms and may fight off the virus without realizing they had it. If symptoms do develop, they tend to occur two or three months after exposure to the hepatitis B virus.
Symptoms of hepatitis B include:
flu-like symptoms, including tiredness, a fever, and general aches and pains
loss of appetite
feeling and being sick
tummy (abdominal) pain
yellowing of the skin and eyes (jaundice)
Treatments for hepatitis B
Treatment for hepatitis B depends on how long you've been infected for:
If you've been exposed to the virus in the past few days, emergency treatment can help stop you becoming infected.
If you've only had the infection for a few weeks or months (acute hepatitis B), you may only need treatment to relieve your symptoms while your body fights off the infection.
If you've had the infection for more than six months (chronic hepatitis B), you may be offered treatment with medicines that can keep the virus under control and reduce the risk of liver damage.
Chronic hepatitis B often requires long-term or lifelong treatment and regular monitoring to check for any further liver problems.
Hepatitis C is caused by the hepatitis C virus and is usually spread through blood-to-blood contact with an infected person. Hepatitis C often causes no noticeable symptoms, or only flu-like symptoms, so many people are unaware they're infected.
Around one in four people will fight off the infection and be free of the virus. In the remaining cases, it will stay in the body for many years. This is known as chronic hepatitis C and can cause cirrhosis and liver failure.
Chronic hepatitis C can be treated with very effective antiviral medications, but there's currently no vaccine available.
Hepatitis D is caused by the hepatitis D virus. It only affects people who are already infected with hepatitis B, as it needs the hepatitis B virus to be able to survive in the body.
Hepatitis D is usually spread through blood-to-blood contact or sexual contact. It's uncommon in the UK, but is more widespread in other parts of Europe, the Middle East, Africa and South America. Long-term infection with hepatitis D and hepatitis B can increase your risk of developing serious problems, such as cirrhosis and liver cancer.
There's no vaccine specifically for hepatitis D, but the hepatitis B vaccine can help protect you from it.
Hepatitis E is caused by the hepatitis E virus. is mostly transmitted through consumption of contaminated water or food. HEV is a common cause of hepatitis outbreaks in developing parts of the world and is increasingly recognized as an important cause of disease in developed countries.
Hepatitis E is generally a mild and short-term infection that doesn't require any treatment, but it can be serious in some people, such as those who have a weakened immune system.
There's no vaccine for hepatitis E. When travelling to parts of the world with poor sanitation, where epidemic hepatitis E may be common, you can reduce your risk by practicing good food and water hygiene measures.
Parasites can also infect the liver and activate the immune response, resulting in symptoms of acute hepatitis with increased serum IgE (though chronic hepatitis is possible with chronic infections). Protozoans such as Trypanosoma cruzi, Leishmania species, and the malaria-causing Plasmodium species all can cause liver inflammation. Entamoeba histolytica, causes hepatitis with distinct liver abscesses.
Echinococcus granulosus(dog tapeworm), infects the liver and forms characteristic hepatic hydatid cysts.The liver flukes Fasciola hepatica and Clonorchis sinensis live in the bile ducts and cause progressive hepatitis and liver fibrosis.
Fulminant hepatitis or massive hepatic cell death is a rare and life-threatening complication of acute hepatitis that can occur in cases of hepatitis B, D, and E, in addition to drug-induced and autoimmune hepatitis.
Bacterial infection of the liver commonly results in pyogenic liver abscesses, acute hepatitis, or granulomatous (or chronic) liver disease. This involves enteric bacteria such as Escherichia coli and Klebsiella pneumonia. Acute hepatitis is caused by Neisseria meningitidis, Neisseria gonorrhea, Bartonella henselae, Borrelia burgdorferi, salmonella species, brucella species and campylobacter species. Chronic or granulomatous hepatitis is seen with infection from mycobacteria species, Tropheryma whipplei, Treponema pallidum, Coxiella burnetii, and rickettsia species.
This form of Hepatitis includes:
Excessive alcohol consumption is a significant cause of hepatitis and is the most common cause of cirrhosis in the U.S. Alcoholic hepatitis is within the spectrum of alcoholic liver disease. This ranges in order of severity and reversibility from alcoholic steatosis, alcoholic hepatitis, cirrhosis, and liver cancer (most severe, least reversible). Hepatitis usually develops over years-long exposure to alcohol, occurring in 10 to 20% of alcoholics. Long-term alcohol intake (in excess of 80 grams of alcohol a day in men and 40 grams a day in women) is associated with development of alcoholic hepatitis.
Toxic and drug-induced hepatitis
Many chemical agents, including medications, industrial toxins, and herbal and dietary supplements, can cause hepatitis. Toxins and medications can cause liver injury through a variety of mechanisms, including direct cell damage, disruption of cell metabolism, and causing structural changes. Some drugs such as paracetamol exhibit predictable dose-dependent liver damage while others such as isoniazid cause idiosyncratic and unpredictable reactions that vary among individuals.
Exposure to other hepatotoxins can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. Examples of such toxins are carbon tetrachloride and the wild mushroom Amanita phalloides.
Non-alcoholic fatty liver disease
Non-alcoholic liver disease occurs in people with little or no history of alcohol use, and is instead strongly associated with metabolic syndrome, obesity, insulin resistance and diabetes, and hypertriglyceridemia. Over time, non-alcoholic fatty liver disease can progress to non-alcoholic steatohepatitis, which additionally involves liver cell death, liver inflammation and possible fibrosis.
Autoimmune hepatitis is a rare cause of long-term hepatitis in which the immune system attacks and damages the liver. The liver can get so damaged that it stops working properly. As in other autoimmune diseases, circulating auto-antibodies may be present and are helpful in diagnosis. Treatment for autoimmune hepatitis involves very effective medicines that suppress the immune system and reduce inflammation. The causes of autoimmune hepatitis are still unclear and it's not known whether anything can be done to prevent it.
Other forms include:
DIAGNOSIS OF HEPATITIS
Diagnosis of hepatitis is made on the basis of some or all of the following:
*a patient's signs and symptoms
* medical history including sexual and substance use history.
* Blood tests, imaging, and liver biopsy.
In general, for viral hepatitis and other acute causes of hepatitis, the patient's blood tests and clinical picture are sufficient for diagnosis but in chronic hepatitis, blood tests may not be useful, instead, liver biopsy is used for establishing the diagnosis as histopathology analysis is able to reveal the precise extent and pattern of inflammation and fibrosis.
PROGNOSIS OF HEPATITIS
Nearly all patients with hepatitis A infections recover completely without complications if they were healthy prior to the infection. Similarly, acute hepatitis B infections have a favorable course towards complete recovery in 95–99% of patients. However, certain factors may portend a poorer outcome, such as co-morbid medical conditions or initial presenting symptoms of ascites, edema, or encephalopathy. Overall, the mortality rate for acute hepatitis is low:
In contrast to hepatitis A & B, hepatitis C carries a much higher risk of progressing to chronic hepatitis, approaching 85–90%. Cirrhosis has been reported to develop in 20–50% of patients with chronic hepatitis C. Rare complications of acute hepatitis include pancreatitis, aplastic anemia, peripheral neuropathy, and myocarditis.
Fulminant hepatitis represents a rare but feared complication. Mortality rates in cases of fulminant hepatitis rise over 80%, but those patients that do survive often make a complete recovery. Liver transplantation can be life-saving in patients with fulminant liver failure. Hepatitis D infections can transform benign cases of hepatitis B into severe, progressive hepatitis, (superinfection).
Overall, the 5-year survival rate for chronic hepatitis B ranges from 97% in mild cases to 55% in severe cases with cirrhosis. Most patients who acquire hepatitis D at the same time as hepatitis B (co-infection) recover without developing a chronic infection; however, in people with hepatitis B who later acquire hepatitis D (superinfection), chronic infection is much more common at 80-90%, and liver disease progression is accelerated.
Chronic hepatitis C progresses towards cirrhosis, with estimates of cirrhosis prevalence of 16% at 20 years after infection. While the major causes of mortality in hepatitis C is end stage liver disease, hepatocellular carcinoma is an important additional long term complication and cause of death in chronic hepatitis.
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