At Glance
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Hepatitis

 

Hepatitis is a disease of the liver characterized by the presence of inflammatory cells in the tissue of the organ. Hepatitis may occur without symptoms, but can lead to jaundice (a yellow discoloration of the skin, mucous membranes, and conjunctiva of the eyes), poor appetite, and fatigue. Depending on the cause, hepatitis can manifest either as an acute or as a chronic disease. Acute hepatitis can be self-limiting (resolving on its own), can progress to chronic hepatitis, or can cause acute liver failure in rare instances. Chronic hepatitis may have no symptoms, or may progress over time to cirrhosis (scarring of the liver), fibrosis (the formation of extra fibrous connective tissue), and chronic liver failure. Cirrhosis of the liver increases the risk of developing hepatocellular carcinoma (a form of liver cancer).

Worldwide, viral hepatitis is the most common cause, followed closely by alcoholic liver disease and non-alcoholic liver disease (NAFLD).Other less common causes of hepatitis include autoimmune diseases, ingestion of toxic substances, certain medications (such as paracetamol), some industrial organic solvents, and plants.

The word is derived from the Greek hêpar, meaning "liver", and the suffix -itis, meaning "inflammation" (c. 1727).

 

Signs and symptoms

 

Hepatitis has a broad spectrum of presentations that range from a complete lack of symptoms to severe liver failure. The acute form of hepatitis, generally caused by viral infection, is characterized by constitutional symptoms that are typically self-limiting. Chronic hepatitis presents similarly, but can manifest signs and symptoms specific to liver dysfunction with long-standing inflammation and damage to the organ.

 

Acute hepatitis

 

Acute viral hepatitis follows a pattern of infection that involves three distinct phases:

The initial prodromal phase (preceding symptoms) involves non-specific and flu-like symptoms common to many acute viral infections. This includes fatigue, nausea, vomiting, poor appetite, joint pain, and headaches. Fever, when present, is most common in cases of hepatitis A and E. Late in this phase, people can experience liver-specific symptoms, including choluria (dark urine) and clay-colored stools.

Clinical jaundice (yellowing of the skin) and icterus (yellowing of the eyes) follow the prodrome after about 1–2 weeks and can last for up to 4 weeks. The non-specific symptoms seen in the prodromal typically resolve by this time, but people will develop an enlarged liver and right upper abdominal pain or discomfort. 10–20% of people will also experience an enlarged spleen, while some people will also experience a mild unintentional weight loss.

The recovery phase is characterized by resolution of the clinical symptoms of hepatitis with persistent elevations in liver lab values and potentially a persistently enlarged liver. All cases of hepatitis A and E are expected to fully resolve after 1–2 months. A majority of hepatitis B cases are also self-limited and will resolve in 3–4 months. Few cases of hepatitis C will resolve completely.

Both drug-induced hepatitis and autoimmune hepatitis can present very similarly to acute viral hepatitis, with slight variations in symptoms depending on the cause. Cases of drug-induced hepatitis can manifest with systemic signs of an allergic reaction including rash, fever, serositis (inflammation of membranes lining certain organs), elevated eosinophils (a type of white blood cell), and suppression of bone marrow activity.

 

Fulminant hepatitis

 

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. The complication more frequently occurs in instances of hepatitis B and D co-infection at a rate of 2–20% and in pregnant women with hepatitis E at rate of 15–20% of cases. In addition to the signs of acute hepatitis, people can also demonstrate signs of coagulopathy(abnormal coagulation studies with easy bruising and bleeding) and encephalopathy (confusion, disorientation, andsleepiness). Mortality due to fulminant hepatitis is typically the result of various complications including cerebral edema,gastrointestinal bleeding, sepsis, respiratory failure, or kidney failure.

 

Chronic hepatitis

 

Chronic hepatitis is often asymptomatic early on in its course and is detected only by liver laboratory studies for screening purposes or to evaluate non-specific symptoms. As the inflammation progresses, patients can develop constitutional symptoms similar to acute hepatitis including fatigue, nausea, vomiting, poor appetite, and joint pain. Jaundice and icterus can occur as well, but occur much later in the disease process and are typically a sign of advanced disease. Chronic hepatitis interferes with hormonal functions of the liver which can result in acne, hirsutism (abnormal hair growth), andamenorrhea (lack of menstrual period) in women. Extensive damage and scarring of the liver over time defines cirrhosis, a condition in which the liver's ability to function is permanently impeded. This results in jaundice, weight loss, coagulopathy, ascites (abdominal fluid collection), and peripheral edema (leg swelling). Cirrhosis can lead to other life-threatening complications such as hepatic encephalopathy, esophageal varices, hepatorenal syndrome, and liver cancer.

 

Causes

 

Causes of hepatitis can be divided into the following major categories: infectious, metabolic, ischemic, autoimmune, genetic, and other. Infectious agents include viruses, bacteria, and parasites. Toxins, drugs, alcohol, and lipids are metabolic causes of liver injury and inflammation. Autoimmune and genetic causes of hepatitis involve genetic predispositions and tend to affect characteristic populations. Ischemic hepatitis results from reduced blood flow to the liver as in shock, heart failure, or vascular insufficiency.

 

Infectious

 

Viral hepatitis

 

Viral hepatitis is the most common type of hepatitis worldwide. Viral hepatitis is caused by five different viruses (hepatitis A, B, C, D, and E). Hepatitis A and hepatitis E behave similarly: they are both transmitted by the fecal-oral route, are more common in developing countries, and are self-limiting illnesses that do not lead to chronic hepatitis.

Hepatitis B, hepatitis C, and hepatitis D are transmitted when blood ormucus membranes are exposed to infected blood and body fluids, such as semen and vaginal secretions.Viral particles have also been found in saliva and breastmilk. However, kissing, sharing utensils, and breastfeeding do not lead to transmission unless these fluids are introduced into open sores or cuts.

Hepatitis B and C can present either acutely or chronically. Hepatitis D is a defective virus that requires hepatitis B to replicate and is only found with hepatitis B co-infection. In adults, hepatitis B infection is most commonly self-limiting, with less than 5% progressing to chronic state, and 20 to 30% of those chronically infected developing cirrhosis and/or liver cancer. However, infection in infants and children frequently leads to chronic infection.

Unlike hepatitis B, most cases of hepatitis C lead to chronic infection. Hepatitis C is the second most common cause of cirrhosis in the US (second to alcoholic hepatitis). In the 1970s and 1980s, blood transfusions were a major factor in spreading hepatitis C virus. Since widespread screening of blood products for hepatitis C began in 1992, the risk of acquiring hepatitis C from a blood transfusion has decreased from approximately 10% in the 1970s to 1 in 2 million currently.

 

Parasitic hepatitis

 

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). Of the protozoans, Trypanosoma cruzi,Leishmania species, and the malaria-causing Plasmodium species all can cause liver inflammation. Another protozoan, Entamoeba histolytica, causes hepatitis with distinct liver abscesses.

Of the worms, the cestode Echinococcus granulosus, also known as the small 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.

 

Bacterial hepatitis

 

Bacterial infection of the liver commonly results in pyogenic abscesses, acute hepatitis, or granulomatous (or chronic) liver disease. Pyogenic abscesses commonly involve enteric bacteria such as Escherichia coli and Klebsiella pneumoniae and are composed of multiple bacteria up to 50% of the time. Acute hepatitis is caused by Neisseria meningitidis, Neisseria gonorrhoeae, 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.

 

Prevention

 

Vaccines

Hepatitis A

 

The CDC recommends the hepatitis A vaccine for all children beginning at age one, as well as for those who have not been previously immunized and are at high risk for contracting the disease.

For children 12 months of age or older, the vaccination is given as a shot into the muscle in two doses 6–18 months apart and should be started before the age 24 months. The dosing is slightly different for adults depending on the type of the vaccine.  If the vaccine is for hepatitis A only, two doses are given 6–18 months apart depending on the manufacturer.[66]  If the vaccine is combined hepatitis A and hepatitis B, up to 4 doses may be required.

 

Hepatitis B

 

The CDC recommends the routine vaccination of all children under the age of 19 with the hepatitis B vaccine. They also recommend it for those who desire it or are at high risk.

Routine vaccination for hepatitis B starts with the first dose administered as a shot into the muscle before the newborn is discharged from the hospital. An additional two doses should be administered before the child is 18 months.

For babies born to a mother with hepatitis B surface antigen positivity, the first dose is unique – in addition to the vaccine, the hepatitis immune globulin should also be administered, both within 12 hours of birth.  These newborns should also be regularly tested for infection for at least the first year of life.

There is also a combination formulation that includes both hepatitis A and B vaccines.

Other

There are currently no vaccines available in the United States for hepatitis C or E.

 

Behavioral changes

 

Hepatitis A

 

Because hepatitis A is transmitted primarily through the oral-fecal route, the mainstay of prevention aside from vaccination is good hygiene, access to clean water and proper handling of sewage.

 

Hepatitis B and C

 

As hepatitis B and C are transmitted through blood and multiple bodily fluids, prevention is aimed at screening blood prior totransfusion, abstaining from the use of injection drugs, safe needle and sharps practices in healthcare settings, and safe sex practices.

 

Hepatitis D

 

The hepatitis D virus requires that a person first be infected with hepatitis B virus, so prevention efforts should focus on limiting the spread of hepatitis B. In people who have chronic hepatitis B infection and are at risk for super infection with the hepatitis D virus, the preventive strategies are the same as for hepatitis B.

 

Hepatitis E

 

Hepatitis E is spread primarily through the oral-fecal route but may also be spread by blood and from mother to fetus. The mainstay of hepatitis E prevention is similar to that for hepatitis A (namely, good hygiene and clean water practices).

 

Alcoholic hepatitis

 

As excessive alcohol consumption can lead to hepatitis and cirrhosis, the following are maximal recommendations for alcohol consumption:

  1. Women – ≤ 3 drinks on any given day and ≤ 7drinks per week
  2. Men – ≤ 4 drinks on any given day and ≤ 14 drinks per week

 

Successes

 

Hepatitis A

 

In the United States, universal immunization has led to a two-thirds decrease in hospital admissions and medical expenses due to hepatitis A.

 

Hepatitis B

 

In the United States new cases of hepatitis B decreased 75% from 1990–2004.  The group that saw the greatest decrease was children and adolescents, likely reflecting the implementation of the 1999 guidelines.

 

Hepatitis C

 

Hepatitis C infections each year had been declining since the 1980s, but began to increase again in 2006. The data are unclear as to whether the decline can be attributed to needle exchange programmes.

 

Alcoholic hepatitis

 

Because people with alcoholic hepatitis may have no symptoms, it can be difficult to diagnose and the number of people with the disease is probably higher than many estimates.[85] Programs such as Alcoholics Anonymous have been successful in decreasing death due to cirrhosis, but it is difficult to evaluate their success in decreasing the incidence of alcoholic hepatitis.

 

Treatment

 

Treatment of hepatitis varies based on the form (acute versus chronic), severity of disease, and cause. 

 

Hepatitis A

 

Hepatitis A generally does not progress to a chronic state and rarely requires hospitalization. Treatment is supportive and includes such measures as providing intravenous (IV) hydration and maintaining adequate nutrition.

Rarely, people with the hepatitis A virus can rapidly develop liver failure, termed fulminant hepatic failure, especially the elderly and those who had a pre-existing liver disease, especially hepatitis C. Mortality risk factors include greater age and chronic hepatitis C. In these cases, more aggressive supportive therapy and liver transplant may be necessary.

Hepatitis B

 

Acute

 

In healthy patients, 95–99% recover with no long-lasting effects, and antiviral treatment is not warranted. Age and comorbid conditions can result in a more prolonged and severe illness. Certain patients warrant hospitalization, especially those who present with clinical signs of ascites, peripheral edema, and hepatic encephalopathy, and laboratory signs ofhypoglycemia, prolonged prothrombin time, low serum albumin, and very high serum blirubin.

In these rare, more severe acute cases, patients have been successfully treated with antiviral therapy similar to that used in cases of chronic hepatitis B, with nucleoside analogues such as entecavir or tenofovir. As there is a dearth of clinical trial data and the drugs used to treat are prone to developing resistance, experts recommend reserving treatment for severe acute cases, not mild to moderate.

From  Wikipedia, the free encyclopedia