Hepatitis is

inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...

of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (

jaundice Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme meta ...

poor appetite Anorexia is a medical term for a loss of appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a loss of appetite, some of which may be harmless, while others i ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

tiredness Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than ...

, and

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

. Hepatitis is ''

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse eff ...

'' if it resolves within six months, and '' chronic'' if it lasts longer than six months. Acute hepatitis can resolve on its own, progress to chronic hepatitis, or (rarely) result in

acute liver failure Acute liver failure is the appearance of severe complications rapidly after the first signs (such as jaundice) of liver disease, and indicates that the liver has sustained severe damage (loss of function of 80–90% of liver cells). The complicati ...

. Chronic hepatitis may progress to scarring of the liver (

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

), liver failure, and

liver cancer Liver cancer (also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy) is cancer that starts in the liver. Liver cancer can be primary (starts in liver) or secondary (meaning cancer which has spread from elsewhere to th ...

. Hepatitis is most commonly caused by the virus ''

hepatovirus A Hepatitis A is an infectious disease of the liver caused by ''Hepatovirus A'' (HAV); it is a type of viral hepatitis. Many cases have few or no symptoms, especially in the young. The time between infection and symptoms, in those who develop them ...

'', '' B'', '' C'', '' D'', and '' E''. Other viruses can also cause liver inflammation, including

cytomegalovirus ''Cytomegalovirus'' (''CMV'') (from ''cyto-'' 'cell' via Greek - 'container' + 'big, megalo-' + -''virus'' via Latin 'poison') is a genus of viruses in the order ''Herpesvirales'', in the family ''Herpesviridae'', in the subfamily ''Betaherpe ...

Epstein–Barr virus The Epstein–Barr virus (EBV), formally called ''Human gammaherpesvirus 4'', is one of the nine known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. EBV is a double-stranded DNA virus. It is b ...

, and

yellow fever virus Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In ...

. Other common causes of hepatitis include heavy alcohol use, certain medications, toxins, other infections,

autoimmune diseases An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...

, and

non-alcoholic steatohepatitis Non-alcoholic fatty liver disease (NAFLD), also known as metabolic (dysfunction) associated fatty liver disease (MAFLD), is excessive fat build-up in the liver without another clear cause such as alcohol use. There are two types; non-alcoholic ...

(NASH). Hepatitis A and E are mainly spread by contaminated food and water. Hepatitis B is mainly sexually transmitted, but may also be passed from mother to baby during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...

childbirth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births globall ...

and spread through infected

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

. Hepatitis C is commonly spread through infected blood such as may occur during

needle sharing Needle sharing is the practice of intravenous drug-users by which a needle or syringe is shared by multiple individuals to administer intravenous drugs such as heroin, steroids, and hormones. This is a primary vector for blood-borne diseases which ...

intravenous drug users Recreational drug use indicates the use of one or more psychoactive drugs to induce an altered state of consciousness either for pleasure or for some other casual purpose or pastime by modifying the perceptions and emotions of the user. When a ...

. Hepatitis D can only infect people already infected with hepatitis B. Hepatitis A, B, and D are preventable with

immunization Immunization, or immunisation, is the process by which an individual's immune system becomes fortified against an infectious agent (known as the immunogen). When this system is exposed to molecules that are foreign to the body, called ''non-sel ...

. Medications may be used to treat chronic viral hepatitis. Antiviral medications are recommended in all with chronic hepatitis C, except those with conditions that limit their life expectancy. There is no specific treatment for NASH; physical activity, a

healthy diet A healthy diet is a diet that maintains or improves overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients such as protein, micronutrients such as vitamins, and adequate fibre and food energy. A healthy ...

, and

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...

are recommended.

Autoimmune hepatitis Autoimmune hepatitis, formerly known as lupoid hepatitis, plasma cell hepatitis, or autoimmune chronic active hepatitis, is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells, causing the liv ...

may be treated with medications to suppress the immune system. A

liver transplant Liver transplantation or hepatic transplantation is the replacement of a Liver disease, diseased liver with the healthy liver from another person (allograft). Liver transplantation is a treatment option for Cirrhosis, end-stage liver disease and ...

may be an option in both acute and chronic liver failure. Worldwide in 2015, hepatitis A occurred in about 114 million people, chronic hepatitis B affected about 343 million people and chronic hepatitis C about 142 million people. In the United States, NASH affects about 11 million people and

alcoholic hepatitis Alcoholic hepatitis is hepatitis (inflammation of the liver) due to excessive intake of alcohol. Patients typically have a history of at least 10 years of heavy alcohol intake, typically 8-10 drinks per day. It is usually found in association wit ...

affects about 5 million people. Hepatitis results in more than a million deaths a year, most of which occur indirectly from liver scarring or liver cancer. In the United States, hepatitis A is estimated to occur in about 2,500 people a year and results in about 75 deaths. The word is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''hêpar'' (), meaning "liver", and ''

-itis Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

'' (), meaning "inflammation".

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 Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

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 three distinct phases: # The initial prodromal phase (preceding symptoms) involves

non-specific Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...

and

flu-like Influenza-like illness (ILI), also known as flu-like syndrome or flu-like symptoms, is a medical diagnosis of possible influenza or other illness causing a set of common symptoms. These include fever, shivering, chills, malaise, dry cough, loss o ...

symptoms common to many acute viral infections. These include

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

, 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 Choluria is abnormal darkness of the urine due to a high bilirubin content. Choluria is a common symptom of liver diseases, such as hepatitis and cirrhosis. It can be described as dark or brown urine, often referred to as the color of Coca-Cola. C ...

(dark urine) and clay-colored stools. # Yellowing of the skin and whites 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 Hepatomegaly is the condition of having an enlarged liver. It is a non-specific medical sign having many causes, which can broadly be broken down into infection, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdomi ...

and right upper abdominal pain or discomfort. 10–20% of people will also experience an

enlarged spleen Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of ''hypersplenism'' which include: some reduction in number of circulating ...

, 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. Most hepatitis B cases are also self-limiting and will resolve in 3–4 months. Few cases of hepatitis C will resolve completely. Both

drug-induced hepatitis Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn fro ...

and

autoimmune hepatitis Autoimmune hepatitis, formerly known as lupoid hepatitis, plasma cell hepatitis, or autoimmune chronic active hepatitis, is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells, causing the liv ...

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 Serositis refers to inflammation of the serous tissues of the body, the tissues lining the lungs (pleura), heart (pericardium), and the inner lining of the abdomen (peritoneum) and organs within. It is commonly found with fat wrapping or creeping ...

(inflammation of membranes lining certain organs), elevated

eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...

(a type of white blood cell), and suppression of bone marrow activity.

Fulminant hepatitis

Fulminant hepatitis, or massive hepatic

cell death Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as dis ...

, 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 Coagulopathy (also called a bleeding disorder) is a condition in which the blood's ability to coagulate (form clots) is impaired. This condition can cause a tendency toward prolonged or excessive bleeding (bleeding diathesis), which may occur spo ...

(abnormal coagulation studies with easy bruising and bleeding) and

encephalopathy Encephalopathy (; from grc, ἐνκέφαλος "brain" + πάθος "suffering") means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but r ...

(confusion, disorientation, and

sleepiness Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...

). Mortality due to fulminant hepatitis is typically the result of various complications including

cerebral edema Cerebral edema is excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain. This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compressio ...

gastrointestinal bleeding Gastrointestinal bleeding (GI bleed), also called gastrointestinal hemorrhage (GIB), is all forms of bleeding in the gastrointestinal tract, from the mouth to the rectum. When there is significant blood loss over a short time, symptoms may incl ...

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

respiratory failure Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise ...

, or

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

Chronic hepatitis

Acute cases of hepatitis are seen to be resolved well within a six-month period. When hepatitis is continued for more than six months it is termed chronic hepatitis. Chronic hepatitis is often asymptomatic early in its course and is detected only by liver laboratory studies for

screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), a ...

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 can occur as well, but much later in the disease process and is typically a sign of advanced disease. Chronic hepatitis interferes with hormonal functions of the liver which can result in acne,

hirsutism Hirsutism is excessive body hair on parts of the body where hair is normally absent or minimal. The word is from early 17th century: from Latin ''hirsutus'' meaning "hairy". It usually refers to a "male" pattern of hair growth in a female that ...

(abnormal hair growth), and

amenorrhea Amenorrhea is the absence of a menstrual period in a woman of reproductive age. Physiological states of amenorrhoea are seen, most commonly, during pregnancy and lactation (breastfeeding). Outside the reproductive years, there is absence of menses ...

(lack of menstrual period) in women. Extensive damage and scarring of the liver over time defines

, a condition in which the liver's ability to function is permanently impeded. This results in jaundice, weight loss, coagulopathy,

ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, ab ...

(abdominal fluid collection), and

peripheral edema Peripheral edema is edema (accumulation of fluid causing swelling) in tissues perfused by the peripheral vascular system, usually in the lower limbs. In the most dependent parts of the body (those hanging distally), it may be called dependent edem ...

(leg swelling). Cirrhosis can lead to other life-threatening complications such as

hepatic encephalopathy Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stages ...

esophageal varices Esophageal varices are extremely dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis. People with esophageal varices have a strong tendency to develop ...

hepatorenal syndrome Hepatorenal syndrome (often abbreviated HRS) is a life-threatening medical condition that consists of rapid deterioration in kidney function in individuals with cirrhosis or fulminant liver failure. HRS is usually fatal unless a liver transplan ...

, and

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. Metabolic causes include prescription medications, toxins (most notably

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

), and

non-alcoholic fatty liver disease Non-alcoholic fatty liver disease (NAFLD), also known as metabolic (dysfunction) associated fatty liver disease (MAFLD), is excessive fat build-up in the liver without another clear cause such as alcohol use. There are two types; non-alcoholic ...

Autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...

and genetic causes of hepatitis involve genetic predispositions and tend to affect characteristic populations.

Infectious

Viral hepatitis

Viral hepatitis Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form. The most common causes of viral hepatitis are the five unrelated hepatotropic v ...

is the most common type of hepatitis worldwide, especially in Asia and Africa. Viral hepatitis is caused by five different viruses (hepatitis A, B, C, D, and E).

Hepatitis A Hepatitis A is an infectious disease of the liver caused by ''Hepatovirus A'' (HAV); it is a type of viral hepatitis. Many cases have few or no symptoms, especially in the young. The time between infection and symptoms, in those who develop them ...

and

hepatitis E Hepatitis E is inflammation of the liver caused by infection with the hepatitis E virus (HEV); it is a type of viral hepatitis. Hepatitis E has mainly a fecal-oral transmission route that is similar to hepatitis A, although the viruses are unrel ...

behave similarly: they are both transmitted by the

fecal–oral route The fecal–oral route (also called the oral–fecal route or orofecal route) describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal ...

, are more common in developing countries, and are self-limiting illnesses that do not lead to chronic hepatitis.

Hepatitis B Hepatitis B is an infectious disease caused by the ''Hepatitis B virus'' (HBV) that affects the liver; it is a type of viral hepatitis. It can cause both acute and chronic infection. Many people have no symptoms during an initial infection. Fo ...

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...

, and

hepatitis D Hepatitis D is a type of viral hepatitis caused by the hepatitis delta virus (HDV). HDV is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a satellite (a type of subviral agent) because it can propagate only in ...

are transmitted when blood or

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...

s are exposed to infected blood and body fluids, such as semen and vaginal secretions. Viral particles have also been found in saliva and breastmilk. Kissing, sharing utensils, and breastfeeding do not lead to transmission unless these fluids are introduced into open sores or cuts. Many families who do not have safe drinking water or live in unhygienic homes have contracted hepatitis because saliva and blood droplets are often carried through the water and blood-borne illnesses spread quickly in unsanitary settings. 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 or liver cancer. 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 Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...

can also infect the liver and activate the immune response, resulting in symptoms of acute hepatitis with increased serum

IgE Immunoglobulin E (IgE) is a type of antibody (or immunoglobulin (Ig) " isotype") that has been found only in mammals. IgE is synthesised by plasma cells. Monomers of IgE consist of two heavy chains (ε chain) and two light chains, with the ε c ...

(though chronic hepatitis is possible with chronic infections). Of the

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

ns,

Trypanosoma cruzi ''Trypanosoma cruzi'' is a species of parasitic euglenoids. Among the protozoa, the trypanosomes characteristically bore tissue in another organism and feed on blood (primarily) and also lymph. This behaviour causes disease or the likelihood of ...

Leishmania ''Leishmania'' is a parasitic protozoan, a single-celled organism of the genus '' Leishmania'' that are responsible for the disease leishmaniasis. They are spread by sandflies of the genus ''Phlebotomus'' in the Old World, and of the genus '' ...

species, and the

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

-causing

Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a vert ...

species all can cause liver inflammation. Another protozoan,

Entamoeba histolytica ''Entamoeba histolytica'' is an anaerobic parasitic amoebozoan, part of the genus ''Entamoeba''. Predominantly infecting humans and other primates causing amoebiasis, ''E. histolytica'' is estimated to infect about 35-50 million people worldwid ...

, causes hepatitis with distinct liver abscesses. Of the worms, the

cestode Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of man ...

Echinococcus granulosus ''Echinococcus granulosus,'' also called the hydatid worm, hyper tape-worm or dog tapeworm, is a cyclophyllid cestode that dwells in the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and huma ...

, also known as the dog tapeworm, infects the liver and forms characteristic hepatic hydatid cysts. The liver flukes

Fasciola hepatica ''Fasciola hepatica'', also known as the common liver fluke or sheep liver fluke, is a parasitic trematode (fluke or flatworm, a type of helminth) of the class Trematoda, phylum Platyhelminthes. It infects the livers of various mammals, inc ...

and

Clonorchis sinensis ''Clonorchis sinensis'', the Chinese liver fluke, is a liver fluke belonging to the class Trematoda, phylum Platyhelminthes. It infects fish-eating mammals, including humans. In humans, it infects the common bile duct and gall bladder, feeding on ...

live in the bile ducts and cause progressive hepatitis and liver fibrosis.

Bacterial hepatitis

Bacterial infection of the liver commonly results in pyogenic liver abscesses, acute hepatitis, or

granuloma A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious ...

tous (or chronic) liver disease. Pyogenic abscesses commonly involve

enteric The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

bacteria such as ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

'' and ''

Klebsiella pneumoniae ''Klebsiella pneumoniae'' is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar. Although found in the normal flora of the mouth ...

'' and are composed of multiple bacteria up to 50% of the time. Acute hepatitis is caused by ''

Neisseria meningitidis ''Neisseria meningitidis'', often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a ...

'', ''

Neisseria gonorrhoeae ''Neisseria gonorrhoeae'', also known as ''gonococcus'' (singular), or ''gonococci'' (plural), is a species of Gram-negative diplococci bacteria isolated by Albert Ludwig Sigesmund Neisser, Albert Neisser in 1879. It causes the sexually transmit ...

'', ''

Bartonella henselae ''Bartonella henselae'', formerly ''Rochalimæa henselae'', is a bacterium that is the causative agent of cat-scratch disease ( bartonellosis). ''Bartonella henselae'' is a member of the genus ''Bartonella'', one of the most common types of bacte ...

'', ''

Borrelia burgdorferi ''Borrelia burgdorferi'' is a bacterial species of the spirochete class in the genus ''Borrelia'', and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it make ...

'',

salmonella ''Salmonella'' is a genus of rod-shaped (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two species of ''Salmonella'' are ''Salmonella enterica'' and ''Salmonella bongori''. ''S. enterica'' is the type species and is fur ...

species,

brucella ''Brucella'' is a genus of Gram-negative bacteria, named after David Bruce (1855–1931). They are small (0.5 to 0.7 by 0.6 to 1.5 µm), non encapsulated, nonmotile, facultatively intracellular coccobacilli. ''Brucella'' spp. are the caus ...

species and

campylobacter ''Campylobacter'' (meaning "curved bacteria") is a genus of Gram-negative bacteria. ''Campylobacter'' typically appear comma- or s-shaped, and are motile. Some ''Campylobacter'' species can infect humans, sometimes causing campylobacteriosis, a d ...

species. Chronic or granulomatous hepatitis is seen with infection from

mycobacteria ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and ...

species, '' Tropheryma whipplei'', ''

Treponema pallidum ''Treponema pallidum'', formerly known as ''Spirochaeta pallida'', is a spirochaete bacterium with various subspecies that cause the diseases syphilis, bejel (also known as endemic syphilis), and yaws. It is transmitted only among humans. It is ...

'', ''

Coxiella burnetii ''Coxiella burnetii'' is an obligate intracellular bacterial pathogen, and is the causative agent of Q fever. The genus ''Coxiella'' is morphologically similar to ''Rickettsia'', but with a variety of genetic and physiological differences. ''C. ...

'', and

rickettsia ''Rickettsia'' is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci (0.1 μm in diameter), bacilli (1–4 μm long), or threads (up to about 10 μm long). The term "rickett ...

species.

Metabolic

Alcoholic hepatitis

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 Alcoholic liver disease (ALD), also called alcohol-related liver disease (ARLD), is a term that encompasses the liver manifestations of alcohol overconsumption, including fatty liver, alcoholic hepatitis, and chronic hepatitis with liver fibrosis ...

. This ranges in order of severity and reversibility from alcoholic steatosis (least severe, most reversible),

, cirrhosis, and liver cancer (most severe, least reversible). Hepatitis usually develops over years-long exposure to alcohol, occurring in 10 to 20% of alcoholics. The most important risk factors for the development of alcoholic hepatitis are quantity and duration of alcohol intake. 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 (1 beer or 4 ounces of wine is equivalent to 12g of alcohol). Alcoholic hepatitis can vary from asymptomatic

hepatomegaly Hepatomegaly is the condition of having an enlarged liver. It is a non-specific medical sign having many causes, which can broadly be broken down into infection, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdomi ...

(enlarged liver) to symptoms of acute or chronic hepatitis to liver failure.

Toxic and drug-induced hepatitis

Many chemical agents, including medications, industrial toxins, and herbal and dietary supplements, can cause hepatitis. The spectrum of drug-induced liver injury varies from acute hepatitis to chronic hepatitis to acute liver failure. Toxins and medications can cause liver injury through a variety of mechanisms, including direct

cell damage Cell damage (also known as cell injury) is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritiona ...

, disruption of cell metabolism, and causing structural changes. Some drugs such as

paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior ...

exhibit predictable dose-dependent liver damage while others such as

isoniazid Isoniazid, also known as isonicotinic acid hydrazide (INH), is an antibiotic used for the treatment of tuberculosis. For active tuberculosis it is often used together with rifampicin, pyrazinamide, and either streptomycin or ethambutol. For l ...

cause idiosyncratic and unpredictable reactions that vary by person. There are wide variations in the mechanisms of liver injury and

latency period In epidemiology, particularly in the discussion of infectious disease dynamics (modeling), the latent period (also known as the latency period or the pre-infectious period) is the time interval between when an individual or host is infected by a p ...

from exposure to development of clinical illness. Many types of drugs can cause liver injury, including the

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

paracetamol;

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

s such as isoniazid,

nitrofurantoin Nitrofurantoin is an antibacterial medication used to treat urinary tract infections, but it is not as effective for kidney infections. It is taken by mouth. Common side effects include nausea, loss of appetite, diarrhea, and headaches. Rarely ...

amoxicillin-clavulanate Amoxicillin/clavulanic acid, also known as co-amoxiclav or amox-clav, sold under the brand name Augmentin, among others, is an antibiotic medication used for the treatment of a number of bacterial infections. It is a combination consisting of a ...

erythromycin Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used duri ...

, and

trimethoprim-sulfamethoxazole Trimethoprim/sulfamethoxazole, sold under the brand name Bactrim among others, is a fixed-dose combination antibiotic medication used to treat a variety of bacterial infections. It consists of one part trimethoprim to five parts sulfamethoxazo ...

;

anticonvulsant Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of b ...

s such as

valproate Valproate (VPA) and its valproic acid, sodium valproate, and valproate semisodium forms are medications primarily used to treat epilepsy and bipolar disorder and prevent migraine headaches. They are useful for the prevention of seizures in those ...

and

phenytoin Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures (also known as grand mal seizures) and focal seizures, but not absence seizures. The intr ...

; cholesterol-lowering

statin Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low- ...

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...

s such as

oral contraceptives Oral contraceptives, abbreviated OCPs, also known as birth control pills, are medications taken by mouth for the purpose of birth control. Female Two types of female oral contraceptive pill, taken once per day, are widely available: * The combin ...

and

anabolic steroid Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroidal androgens that include natural androgens like testosterone (medication), testosterone as well as synthetic androgens that are structurally related ...

s; and

highly active anti-retroviral therapy The management of HIV/AIDS normally includes the use of multiple Antiviral drug, antiretroviral drugs as a strategy to control HIV/AIDS, HIV infection. There are several classes of antiretroviral agents that act on different stages of the HIV life- ...

used in the treatment of

HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...

. Of these, amoxicillin-clavulanate is the most common cause of drug-induced liver injury, and

paracetamol toxicity Paracetamol poisoning, also known as acetaminophen poisoning, is caused by excessive use of the medication paracetamol (acetaminophen). Most people have few or non-specific symptoms in the first 24 hours following overdose. These include f ...

the most common cause of acute liver failure in the United States and Europe.

Herbal remedies Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedie ...

and

dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...

s are another important cause of hepatitis; these are the most common causes of drug-induced hepatitis in Korea. The United-States-base
Drug Induced Liver Injury Network
linked more than 16% of cases of hepatotoxicity to herbal and dietary supplements. In the United States, herbal and dietary supplements – unlike

pharmaceutical drug A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...

s – are unregulated by the

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

. The

National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...

maintains th
LiverTox
database for consumers to track all known prescription and non-prescription compounds associated with liver injury. Exposure to other

hepatotoxin A hepatotoxin (''Greek language, Gr., hepato = liver'') is a toxic chemical substance that damages the liver. It can be a adverse effect, side-effect, but hepatotoxins are also found naturally, such as microcystins and pyrrolizidine alkaloids, or ...

s can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. The industrial toxin

carbon tetrachloride Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVAC ...

and the wild mushroom

Amanita phalloides ''Amanita phalloides'' (), commonly known as the death cap, is a deadly poisonous basidiomycete fungus, one of many in the genus ''Amanita''. Widely distributed across Europe, but now sprouting in other parts of the world, ''A. phalloides ...

are other known hepatotoxins.

Non-alcoholic fatty liver disease

Non-alcoholic hepatitis is within the spectrum of non-alcoholic liver disease (NALD), which ranges in severity and reversibility from

(NAFLD) to non-alcoholic steatohepatitis (NASH) to cirrhosis to liver cancer, similar to the spectrum of alcoholic 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 Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL). Metabolic syndrome ...

, obesity,

insulin resistance Insulin resistance (IR) is a pathological condition in which cell (biology), cells fail to respond normally to the hormone insulin. Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood gluco ...

and

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

, and hypertriglyceridemia. Over time, non-alcoholic fatty liver disease can progress to non-alcoholic

steatohepatitis Steatohepatitis is a type of fatty liver disease, characterized by inflammation of the liver with concurrent fat accumulation in liver. Mere deposition of fat in the liver is termed steatosis, and together these constitute fatty liver changes. T ...

, which additionally involves liver cell death, liver inflammation and possible fibrosis. Factors accelerating progression from NAFLD to NASH are obesity, older age, non-African American ethnicity, female gender, diabetes mellitus, hypertension, higher

ALT Alt or ALT may refer to: Abbreviations for words * Alt account, an alternative online identity also known as a sock puppet account * Alternate character, in online gaming * Alternate route, type of highway designation * Alternating group, mathema ...

or AST level, higher AST/ALT ratio, low platelet count, and a
ultrasound steatosis score
In the early stages (as with NAFLD and early NASH), most patients are asymptomatic or have mild

right upper quadrant The human abdomen is divided into quadrants and regions by anatomists and physicians for the purposes of study, diagnosis, and treatment. The division into four quadrants allows the localisation of pain and tenderness, scars, lumps, and other ...

pain, and diagnosis is suspected on the basis of abnormal

liver function tests Liver function tests (LFTs or LFs), also referred to as a hepatic panel, are groups of blood tests that provide information about the state of a patient's liver. These tests include prothrombin time (PT/INR), activated partial thromboplastin ti ...

. As the disease progresses, symptoms typical of chronic hepatitis may develop. While imaging can show fatty liver, only

liver biopsy Liver biopsy is the biopsy (removal of a small sample of tissue) from the liver. It is a medical test that is done to aid diagnosis of liver disease, to assess the severity of known liver disease, and to monitor the progress of treatment. Medica ...

can demonstrate inflammation and fibrosis characteristic of NASH. 9 to 25% of patients with NASH develop cirrhosis. NASH is recognized as the third most common cause of liver disease in the United States.

Autoimmune

Autoimmune hepatitis is a chronic disease caused by an abnormal immune response against liver cells. The disease is thought to have a genetic predisposition as it is associated with certain

human leukocyte antigen The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for the regulation of the immune system. The HLA system is also known as the human version of th ...

s involved in the immune response. As in other autoimmune diseases, circulating

auto-antibodies An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own proteins. Many autoimmune diseases (notably lupus erythematosus) are associated with such antibodies. Pr ...

may be present and are helpful in diagnosis. Auto-antibodies found in patients with autoimmune hepatitis include the sensitive but less specific anti-nuclear antibody (ANA), smooth muscle antibody (SMA), and atypical perinuclear antineutrophil cytoplasmic antibody (p-ANCA). Other autoantibodies that are less common but more specific to autoimmune hepatitis are the antibodies against liver kidney microsome 1 (LKM1) and soluble liver antigen (SLA). Autoimmune hepatitis can also be triggered by drugs (such as

hydralazine Hydralazine, sold under the brand name Apresoline among others, is a medication used to treat high blood pressure and heart failure. This includes high blood pressure in pregnancy and very high blood pressure resulting in symptoms. It has bee ...

, and

methyldopa Methyldopa, sold under the brand name Aldomet among others, is a medication used for high blood pressure. It is one of the preferred treatments for high blood pressure in pregnancy. For other types of high blood pressure including hypertensive e ...

), after liver transplant, or by viruses (such as hepatitis A, Epstein-Barr virus, or

measles Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than , cough, ...

). Autoimmune hepatitis can present anywhere within the spectrum from asymptomatic to acute or chronic hepatitis to fulminant liver failure. Patients are asymptomatic 25–34% of the time, and the diagnosis is suspected on the basis of abnormal liver function tests. Some studies show between 25% and 75% of cases present with signs and symptoms of acute hepatitis. As with other autoimmune diseases, autoimmune hepatitis usually affects young females (though it can affect patients of either sex of any age), and patients can exhibit classic signs and symptoms of autoimmunity such as fatigue, anemia, anorexia,

, acne, arthritis,

pleurisy Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other sy ...

thyroiditis Thyroiditis is the inflammation of the thyroid gland. The thyroid gland is located on the front of the neck below the laryngeal prominence, and makes hormones that control metabolism. Signs and symptoms There are many different signs and symptom ...

ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and a ...

nephritis Nephritis is inflammation of the kidneys and may involve the glomeruli, tubules, or interstitial tissue surrounding the glomeruli and tubules. It is one of several different types of nephropathy. Types * Glomerulonephritis is inflammation of th ...

, and

maculopapular rash A maculopapular rash is a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps. It may only appear red in lighter-skinned people. The term "maculopapular" is a compound: ''macules'' are small, flat ...

. Autoimmune hepatitis increases the risk for cirrhosis, and the risk for liver cancer is increased by about 1% for each year of the disease. Many people with autoimmune hepatitis have other

autoimmune disease An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...

s. Autoimmune hepatitis is distinct from the other autoimmune diseases of the liver,

primary biliary cirrhosis Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to build ...

and

primary sclerosing cholangitis Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts, which normally allow bile to drain from the gallbladder. Affected individuals may ha ...

, both of which can also lead to scarring, fibrosis, and cirrhosis of the liver.

Genetic

Genetic causes of hepatitis include alpha-1-antitrypsin deficiency,

hemochromatosis Iron overload or hemochromatosis (also spelled ''haemochromatosis'' in British English) indicates increased total accumulation of iron in the body from any cause and resulting organ damage. The most important causes are hereditary haemochromatosi ...

, and

Wilson's disease Wilson's disease is a genetic disorder in which excess copper builds up in the body. Symptoms are typically related to the brain and liver. Liver-related symptoms include vomiting, weakness, fluid build up in the abdomen, swelling of the legs, ...

. In alpha-1-antitrypsin deficiency, a co-dominant mutation in the gene for alpha-1-antitrypsin results in the abnormal accumulation of the mutant AAT protein within liver cells, leading to liver disease. Hemochromatosis and Wilson's disease are both

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

diseases involving abnormal storage of minerals. In hemochromatosis, excess amounts of iron accumulate in multiple body sites, including the liver, which can lead to cirrhosis. In Wilson's disease, excess amounts of copper accumulate in the liver and brain, causing cirrhosis and dementia. When the liver is involved, alpha-1-antitrypsin deficiency and Wilson's disease tend to present as hepatitis in the neonatal period or in childhood. Hemochromatosis typically presents in adulthood, with the onset of clinical disease usually after age 50.

Ischemic hepatitis

Ischemic hepatitis Ischemic hepatitis, also known as shock liver, is a condition defined as an acute liver injury caused by insufficient blood flow (and consequently insufficient oxygen delivery) to the liver. The decreased blood flow (perfusion) to the liver is usu ...

(also known as shock liver) results from reduced blood flow to the liver as in shock, heart failure, or vascular insufficiency. The condition is most often associated with

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

but can also be caused by

shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emerge ...

Blood testing A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a cholester ...

of a person with ischemic hepatitis will show very high levels of transaminase enzymes ( AST and

). The condition usually resolves if the underlying cause is treated successfully. Ischemic hepatitis rarely causes permanent liver damage.

Other

Hepatitis can also occur in neonates and is attributable to a variety of causes, some of which are not typically seen in adults. Congenital or perinatal infection with the hepatitis viruses,

toxoplasma ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...

rubella Rubella, also known as German measles or three-day measles, is an infection caused by the rubella virus. This disease is often mild, with half of people not realizing that they are infected. A rash may start around two weeks after exposure and ...

, and

syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, an ...

can cause neonatal hepatitis. Structural abnormalities such as

biliary atresia Biliary atresia, also known as extrahepatic ductopenia and progressive obliterative cholangiopathy, is a childhood disease of the liver in which one or more bile ducts are abnormally narrow, blocked, or absent. It can be congenital or acquired. I ...

and

choledochal cysts Choledochal cysts (a.k.a. bile duct cyst) are congenital conditions involving cystic dilatation of bile ducts. They are uncommon in western countries but not as rare in East Asian nations like Japan and China. Signs and symptoms Most patients ha ...

can lead to cholestatic liver injury leading to neonatal hepatitis.

Metabolic diseases Inborn errors of metabolism form a large class of genetic diseases involving congenital disorders of enzyme activities. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances (substrat ...

such as glycogen storage disorders and

lysosomal storage disorders Lysosomal storage diseases (LSDs; ) are a group of over 70 rare inherited metabolic disorders that result from defects in lysosomal function. Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other ...

are also implicated. Neonatal hepatitis can be

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent wikt:spontaneous, spontaneous origin. From Ancient Greek, Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approxi ...

, and in such cases, biopsy often shows large multinucleated cells in the liver tissue. This disease is termed giant cell hepatitis and may be associated with viral infection, autoimmune disorders, and drug toxicity.

Mechanism

The specific mechanism varies and depends on the underlying cause of the hepatitis. Generally, there is an initial insult that causes liver injury and activation of an inflammatory response, which can become chronic, leading to progressive

fibrosis Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of perma ...

and

Viral hepatitis

The pathway by which hepatic viruses cause

viral hepatitis Viral hepatitis is liver inflammation due to a viral infection. It may present in acute form as a recent infection with relatively rapid onset, or in chronic form. The most common causes of viral hepatitis are the five unrelated hepatotropic v ...

is best understood in the case of hepatitis B and C. The viruses do not directly activate

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

(cell death). Rather, infection of liver cells activates the

innate {{Short pages monitor 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. 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 Hepatitis B vaccine is a vaccine that prevents hepatitis B. The first dose is recommended within 24 hours of birth with either two or three more doses given after that. This includes those with poor immune function such as from HIV/AIDS and th ...

. 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. In 2015, a group in China published an article regarding the development of a

vaccine for hepatitis E Hepatitis E is inflammation of the liver caused by infection with the hepatitis E virus (HEV); it is a type of viral hepatitis. Hepatitis E has mainly a Fecal–oral route, fecal-oral transmission route that is similar to hepatitis A, although th ...

. As of March 2016, the United States government was in the process of recruiting participants for the

phase IV trial The phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment. For drug development, the clinical phases ...

of the hepatitis E vaccine.

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 Body fluids, bodily fluids, or biofluids, sometimes body liquids, are liquids within the human body. In lean healthy adult men, the total body water is about 60% (60–67%) of the total body weight; it is usually slightly lower in women (52-55%) ...

, prevention is aimed at screening blood prior to transfusion, 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

superinfection A superinfection is a second infection superimposed on an earlier one, especially by a different microbial agent of exogenous or endogenous origin, that is resistant to the treatment being used against the first infection. Examples of this in bact ...

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).