Misplaced Pages

#314685

89-481: Hepatitis is most commonly caused by the virus hepatovirus A , B , C , D , and E . Other viruses can also cause liver inflammation , including cytomegalovirus , Epstein–Barr virus , and yellow fever virus . Other common causes of hepatitis include heavy alcohol use , certain medications, toxins, other infections, autoimmune diseases , and non-alcoholic steatohepatitis (NASH). Hepatitis A and E are mainly spread by contaminated food and water. Hepatitis B

178-474: 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 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

267-417: 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

356-448: A cascade of events that began with injury. In the case of non-alcoholic steatohepatitis , this cascade is initiated by changes in metabolism associated with obesity, insulin resistance, and lipid dysregulation. In alcoholic hepatitis , chronic excess alcohol use is the culprit. Though the inciting event may differ, the progression of events is similar and begins with accumulation of free fatty acids (FFA) and their breakdown products in

445-765: A clotting disorder is the opposite, defined as a predisposition to excessive clot formation ( thrombus ), also known as a hypercoagulable state or thrombophilia . External Research: - Hematologic and coagulopathy parameter as a survival predictor among moderate to severe COVID-19 patients in non- ICU ward: a single-center study at the main referral hospital in Surabaya, East Java, Indonesia Coagulopathy may cause uncontrolled internal or external bleeding. Left untreated, uncontrolled bleeding may cause damage to joints, muscles, or internal organs and may be life-threatening. People should seek immediate medical care for serious symptoms, including heavy external bleeding, blood in

534-452: A higher level of detail, allowing visualization and characterize such structures as vessels and tumors within the liver. Unlike steatosis and cirrhosis, no imaging test is able to detect liver inflammation (i.e. hepatitis) or fibrosis. Liver biopsy is the only definitive diagnostic test that is able to assess inflammation and fibrosis of the liver. Viral hepatitis is primarily diagnosed through blood tests for levels of viral antigens (such as

623-418: A human has also been described but has been reclassified as subgenotype IIB. Genotype III has been isolated from both humans and owl monkeys . Most human isolates are of genotype I. Of genotype I isolates, subtype IA accounts for the majority. The mutation rate in the genome has been estimated to be 1.73–9.76 × 10 nucleotide substitutions per site per year. The human strains appear to have diverged from

712-574: A milder form of the disease, usually lasting 1–3 weeks, whereas adults tend to experience a much more severe form of the disease. Globally, symptomatic HAV infections are believed to occur in around 1.4 million people a year. About 114 million infections (asymptomatic and symptomatic) occurred all together in 2015. Acute hepatitis A resulted in 11,200 deaths in 2015. Developed countries have low circulating levels of hepatovirus A, while developing countries have higher levels of circulation. Most adolescents and adults in developing countries have already had

801-467: A poor internal ribosome entry site . In the region that codes for the HAV capsid, highly conserved clusters of rare codons restrict antigenic variability. Vertebrates such as humans serve as the natural hosts. Transmission routes are fecal-oral and blood. Following ingestion, HAV enters the bloodstream through the epithelium of the oropharynx or intestine. The blood carries the virus to its target,

890-663: A reduction in clotting factors. Anticoagulants such as warfarin will also prevent clots from forming properly. Coagulopathy may also occur as a result of dysfunction or reduced levels of platelets (small disk-shaped bodies in the bloodstream that aid in the clotting process). In 2003, Karim Brohi, Professor of Trauma Sciences at Queen Mary University of London , first introduced the term Acute Traumatic Coagulopathy (ATC), establishing that coagulopathy induced by trauma results in: If someone has coagulopathy, their health care provider may help them manage their symptoms with medications or replacement therapy. In replacement therapy,

979-733: A rodent origin for human Hepatitis A. A member virus of hepatovirus B ( Phopivirus ) has been isolated from a seal. This virus shared a common ancestor with Hepatovirus A about 1800 years ago. Another hepatovirus – Marmota himalayana hepatovirus – has been isolated from the woodchuck Marmota himalayana . This virus appears to have had a common ancestor with the primate-infecting species around 1000 years ago. One serotype and six different genotypes (three human and three simian) have been described. The human genotypes are numbered I–III. Six subtypes have been described (IA, IB, IIA, IIB, IIIA, IIIB). The simian genotypes have been numbered IV–VI. A single isolate of genotype VII isolated from

SECTION 10

#1732765504315

1068-560: A single infection, a person is immune for the rest of their life. Diagnosis requires blood testing, as the symptoms are similar to those of a number of other diseases. It is one of five known hepatitis viruses: A, B , C , D , and E . The hepatitis A vaccine is effective for prevention. Some countries recommend it routinely for children and those at higher risk who have not previously been vaccinated. It appears to be effective for life. Other preventive measures include hand washing and properly cooking food. No specific treatment

1157-585: A variety of causes, some of which are not typically seen in adults. Congenital or perinatal infection with the hepatitis viruses, toxoplasma , rubella , cytomegalovirus , and syphilis can cause neonatal hepatitis. Structural abnormalities such as biliary atresia and choledochal cysts can lead to cholestatic liver injury leading to neonatal hepatitis. Metabolic diseases such as glycogen storage disorders and lysosomal storage disorders are also implicated. Neonatal hepatitis can be idiopathic , and in such cases, biopsy often shows large multinucleated cells in

1246-489: 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 by person. There are wide variations in the mechanisms of liver injury and latency period from exposure to development of clinical illness. Many types of drugs can cause liver injury, including

1335-604: 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, and sleepiness ). Mortality due to fulminant hepatitis

1424-495: 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 (least severe, most reversible), 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. The most important risk factors for

1513-404: 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, is two–six weeks. When symptoms occur, they typically last eight weeks and may include nausea, vomiting, diarrhea, jaundice , fever, and abdominal pain. Around 10–15% of people experience a recurrence of symptoms during the 6 months after

1602-492: Is also recommended in those who have not been previously immunized and who have been exposed or are likely to be exposed due to travel. The CDC recommends vaccination against infection for men who have sex with men . No specific treatment for hepatitis A is known. Recovery from symptoms following infection may take several weeks or months. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids lost from vomiting and diarrhea. In

1691-513: Is associated with a high risk of infection. HAV can also be spread through sexual contact , specifically oro–anal and digital–rectal sexual acts. Humans are the only natural reservoir and disease vector of the HAV virus; no known insect or other animal vectors can transmit the virus. A chronic HAV state has not been reported. About 40% of all acute viral hepatitis is caused by HAV. Infected individuals are infectious prior to onset of symptoms, roughly 10 days following infection. The virus

1780-422: Is available, with rest and medications for nausea or diarrhea recommended on an as-needed basis. Infections usually resolve completely and without ongoing liver disease. Treatment of acute liver failure, if it occurs, is with liver transplantation . Globally, around 1.4 million symptomatic cases occur each year and about 114 million infections (symptomatic and asymptomatic). It is more common in regions of

1869-583: Is believed to have started in November 2017. By July 2018 48% of the state's counties had reported at least one case of hepatitis A, and the total number of suspected cases was 969 with six deaths (482 cases in Louisville, Kentucky ). By July 2019 the outbreak had reached 5,000 cases and 60 deaths, but had slowed to just a few new cases per month. Another widespread outbreak in the United States,

SECTION 20

#1732765504315

1958-406: Is best understood in the case of hepatitis B and C. The viruses do not directly activate apoptosis (cell death). Rather, infection of liver cells activates the innate and adaptive arms of the immune system leading to an inflammatory response which causes cellular damage and death, including viral-induced apoptosis via the induction of the death receptor-mediated signaling pathway. Depending on

2047-424: Is concurrent obesity, diabetes, and metabolic syndrome. In this case, alcoholic and nonalcoholic hepatitis can be distinguished by the pattern of liver enzyme abnormalities; specifically, in alcoholic steatohepatitis AST>ALT with ratio of AST:ALT>2:1 while in nonalcoholic steatohepatitis ALT>AST with ratio of ALT:AST>1.5:1. Liver biopsies show identical findings in patients with ASH and NASH, specifically,

2136-410: Is considered immune from the virus via either prior infection and recovery or prior vaccination. In the case of hepatitis B, blood tests exist for multiple virus antigens (which are different components of the virion particle ) and antibodies. The combination of antigen and antibody positivity can provide information about the stage of infection (acute or chronic), the degree of viral replication, and

2225-410: Is excreted in the feces towards the end of the incubation period, specific diagnosis is made by the detection of HAV-specific IgM antibodies in the blood. IgM antibody is only present in the blood following an acute hepatitis A infection. It is detectable from 1–2 weeks after the initial infection and persists for up to 14 weeks. The presence of IgG antibodies in the blood means the acute stage of

2314-580: 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. Factors accelerating progression from NAFLD to NASH are obesity, older age, non-African American ethnicity, female gender, diabetes mellitus, hypertension, higher ALT or AST level, higher AST/ALT ratio, low platelet count, and an ultrasound steatosis score . In

2403-606: Is mainly sexually transmitted , but may also be passed from mother to baby during pregnancy or childbirth and spread through infected blood . Hepatitis C is commonly spread through infected blood such as may occur during needle sharing by intravenous drug users . Hepatitis D can only infect people already infected with hepatitis B. Hepatitis A, B, and D are preventable with immunization . 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

2492-415: Is most often associated with heart failure but can also be caused by shock or sepsis . Blood testing of a person with ischemic hepatitis will show very high levels of transaminase enzymes ( AST and ALT ). The condition usually resolves if the underlying cause is treated successfully. Ischemic hepatitis rarely causes permanent liver damage. Hepatitis can also occur in neonates and is attributable to

2581-451: Is no specific treatment for NASH; physical activity, a healthy diet , and weight loss are recommended. Autoimmune hepatitis may be treated with medications to suppress the immune system . A liver transplant 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

2670-500: Is present, a second test – usually done on the same blood sample – that detects the antibody for the hepatitis B core antigen (anti- HBcAg ) can differentiate between acute and chronic infection. People who are high-risk whose blood tests negative for HBsAg can receive the hepatitis B vaccine to prevent future infection. The CDC , WHO , USPSTF , AASLD , and ACOG recommend screening people at high risk for hepatitis C infection. These populations include people who are: For people in

2759-511: Is recognized as the third most common cause of liver disease in the United States. 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 antigens involved in the immune response. As in other autoimmune diseases, circulating auto-antibodies may be present and are helpful in diagnosis. Auto-antibodies found in patients with autoimmune hepatitis include

Hepatitis - Misplaced Pages Continue

2848-655: Is resistant to detergent , acid (pH 1), solvents (e.g., ether , chloroform ), drying, and temperatures up to 60 °C. It can survive for months in fresh and salt water. Common-source (e.g., water, food) outbreaks are typical. Infection is common in children in developing countries , reaching 100% incidence, but following infection, lifelong immunity results. HAV can be inactivated by chlorine treatment (drinking water), formalin (0.35%, 37 °C, 72 hours), peracetic acid (2%, 4 hours), beta-propiolactone (0.25%, 1 hour), and UV radiation (2 μW/cm /min). In developing countries , and in regions with poor hygiene standards,

2937-743: Is the gold standard for establishing the diagnosis: histopathologic analysis is able to reveal the precise extent and pattern of inflammation and fibrosis . Biopsy is typically not the initial diagnostic test because it is invasive and is associated with a small but significant risk of bleeding that is increased in people with liver injury and cirrhosis. Blood testing includes liver enzymes , serology (i.e. for autoantibodies), nucleic acid testing (i.e. for hepatitis virus DNA/RNA), blood chemistry , and complete blood count . Characteristic patterns of liver enzyme abnormalities can point to certain causes or stages of hepatitis. Generally, AST and ALT are elevated in most cases of hepatitis regardless of whether

3026-515: Is the most common cause of drug-induced liver injury, and paracetamol toxicity the most common cause of acute liver failure in the United States and Europe. Herbal remedies and dietary supplements are another important cause of hepatitis; these are the most common causes of drug-induced hepatitis in Korea. The United States–based Drug Induced Liver Injury Network linked more than 16% of cases of hepatotoxicity to herbal and dietary supplements. In

3115-971: 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 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 or mucous 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. 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

3204-474: 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. Parasites can also infect

3293-502: Is typically the result of various complications including cerebral edema , gastrointestinal bleeding , sepsis , respiratory failure , or kidney failure . 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 purposes or to evaluate non-specific symptoms. As

3382-605: The 2003 US hepatitis outbreak , affected at least 640 people (killing four) in northeastern Ohio and southwestern Pennsylvania in late 2003. The outbreak was blamed on tainted green onions at a restaurant in Monaca, Pennsylvania . In 1988, more than 300,000 people in Shanghai , China, were infected with HAV after eating clams ( Anadara subcrenata ) from a contaminated river. In June 2013, frozen berries sold by US retailer Costco and purchased by around 240,000 people were

3471-427: The analgesic paracetamol; antibiotics such as isoniazid, nitrofurantoin , amoxicillin-clavulanate , erythromycin , and trimethoprim-sulfamethoxazole ; anticonvulsants such as valproate and phenytoin ; cholesterol-lowering statins ; steroids such as oral contraceptives and anabolic steroids ; and highly active anti-retroviral therapy used in the treatment of HIV/AIDS . Of these, amoxicillin-clavulanate

3560-467: The hepatitis A vaccine . Those at high risk and in need of screening include: The presence of anti-hepatitis A IgG in the blood indicates past infection with the virus or prior vaccination. The CDC , WHO , USPSTF , and ACOG recommend routine hepatitis B screening for certain high-risk populations. Specifically, these populations include people who are: Screening consists of a blood test that detects hepatitis B surface antigen ( HBsAg ). If HBsAg

3649-441: The hepatitis B surface or core antigen), anti-viral antibodies (such as the anti-hepatitis B surface antibody or anti-hepatitis A antibody), or viral DNA/RNA. In early infection (i.e. within 1 week), IgM antibodies are found in the blood. In late infection and after recovery, IgG antibodies are present and remain in the body for up to years. Therefore, when a patient is positive for IgG antibody but negative for IgM antibody, he

Hepatitis - Misplaced Pages Continue

3738-604: 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 nitrofurantoin , hydralazine , and methyldopa ), after liver transplant, or by viruses (such as hepatitis A, Epstein-Barr virus , or measles ). Autoimmune hepatitis can present anywhere within

3827-430: The United States in 1991, the mortality rate for hepatitis A was estimated to be 0.015% for the general population, but ranged up to 1.8–2.1% for those aged 50 and over who were hospitalized with icteric hepatitis. The risk of death from acute liver failure following HAV infection increases with age and when the person has underlying chronic liver disease. Young children who are infected with hepatitis A typically have

3916-546: The United States, NASH affects about 11 million people and alcoholic hepatitis 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 hêpar ( ἧπαρ ), meaning "liver", and -itis ( -ῖτις ), meaning "inflammation". Hepatitis has

4005-718: The United States, herbal and dietary supplements – unlike pharmaceutical drugs – are unregulated by the Food and Drug Administration . The National Institutes of Health maintains the LiverTox Archived 2019-07-24 at the Wayback Machine database for consumers to track all known prescription and non-prescription compounds associated with liver injury. Exposure to other hepatotoxins can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. The industrial toxin carbon tetrachloride and

4094-481: The United States, the vaccine developed by Maurice Hilleman and his team was licensed in 1995, and the vaccine was first used in 1996 for children in high-risk areas, and in 1999 it was spread to areas with elevating levels of infection. The vaccine is given by injection. An initial dose provides protection lasting one year starting 2–4 weeks after vaccination; the second booster dose, given six to 12 months later, provides protection for over 20 years. The vaccine

4183-542: The bile and released in stool. HAV is excreted in large numbers about 11 days prior to the appearance of symptoms or anti-HAV IgM antibodies in the blood. The incubation period is 15–50 days and risk of death in those infected is less than 0.5%. Within the liver hepatocytes, the RNA genome is released from the protein coat and is translated by the cell's own ribosomes . Unlike other picornaviruses, this virus requires an intact eukaryotic initiation factor 4G (eIF4G) for

4272-729: 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 (enlarged liver) to symptoms of acute or chronic hepatitis to liver failure. 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

4361-451: The disease, thus are immune. Adults in midlevel countries may be at risk of disease with the potential of being exposed. Over 30,000 cases of hepatitis A were reported to the CDC in the US in 1997, but the number has since dropped to less than 2,000 cases reported per year. The most widespread hepatitis A outbreak in the United States occurred in 2018, in the state of Kentucky. The outbreak

4450-452: The early stages (as with NAFLD and early NASH), most patients are asymptomatic or have mild right upper quadrant pain, and diagnosis is suspected on the basis of abnormal liver function tests . As the disease progresses, symptoms typical of chronic hepatitis may develop. While imaging can show fatty liver, only liver biopsy can demonstrate inflammation and fibrosis characteristic of NASH. 9 to 25% of patients with NASH develop cirrhosis. NASH

4539-424: 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 ), and non-alcoholic fatty liver disease . Autoimmune and genetic causes of hepatitis involve genetic predispositions and tend to affect characteristic populations. Viral hepatitis

SECTION 50

#1732765504315

4628-441: The groups above whose exposure is ongoing, screening should be periodic, though there is no set optimal screening interval. The AASLD recommends screening men who have sex with men who are HIV-positive annually. People born in the US between 1945 and 1965 should be screened once (unless they have other exposure risks). Hepatovirus A Hepatitis A is an infectious disease of the liver caused by Hepatovirus A (HAV); it

4717-403: The illness has passed and the person is immune to further infection. IgG antibodies to HAV are also found in the blood following vaccination , and tests for immunity to the virus are based on the detection of these antibodies. During the acute stage of the infection, the liver enzyme alanine transferase (ALT) is present in the blood at levels much higher than is normal. The enzyme comes from

4806-424: The infectivity of the virus. The most apparent distinguishing factor between alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) is a history of excessive alcohol use. Thus, in patients who have no or negligible alcohol use, the diagnosis is unlikely to be alcoholic hepatitis. In those who drink alcohol, the diagnosis may just as likely be alcoholic or nonalcoholic hepatitis especially if there

4895-495: 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 (abnormal hair growth), and amenorrhea (lack of menstrual period) in women. Extensive damage and scarring of

4984-436: The initial infection. Acute liver failure may rarely occur, with this being more common in the elderly. It is usually spread by eating food or drinking water contaminated with infected feces. Undercooked or raw shellfish are relatively common sources. It may also be spread through close contact with an infectious person. While children often do not have symptoms when infected, they are still able to infect others. After

5073-607: The initial infection. About 90% of children do not have symptoms. The time between infection and symptoms, in those who develop them, is two–six weeks, with an average of 28 days. The risk for symptomatic infection is directly related to age, with more than 80% of adults having symptoms compatible with acute viral hepatitis and the majority of children having either asymptomatic or unrecognized infections. Symptoms usually last less than 2 months, although some people can be ill for as long as 6 months: Joint pains , red cell aplasia , pancreatitis and generalized lymphadenopathy are

5162-634: The initiation of translation. The requirement for this factor results in an inability to shut down host protein synthesis , unlike other picornaviruses. The virus must then inefficiently compete for the cellular translational machinery, which may explain its poor growth in cell culture . Aragonès et al. (2010) theorize that the virus has evolved a naturally highly deoptimized codon usage with respect to that of its cellular host in order to negatively influence viral protein translation kinetics and allow time for capsid proteins to fold optimally. No apparent virus-mediated cytotoxicity occurs, presumably because of

5251-413: The likelihood of transmission to others. Hepatitis A causes an acute illness that does not progress to chronic liver disease. Therefore, the role of screening is to assess immune status in people who are at high risk of contracting the virus, as well as in people with known liver disease for whom hepatitis A infection could lead to liver failure. People in these groups who are not already immune can receive

5340-537: The liver , variable degrees of fibrosis and Mallory bodies . Diagnosis of hepatitis is made on the basis of some or all of the following: a person'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 person's blood tests and clinical picture are sufficient for diagnosis. For other causes of hepatitis, especially chronic causes, blood tests may not be useful. In this case, liver biopsy

5429-417: 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

SECTION 60

#1732765504315

5518-474: 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 (also known as shock liver) results from reduced blood flow to the liver as in shock, heart failure, or vascular insufficiency. The condition

5607-503: The liver cells damaged by the virus. Hepatovirus A is present in the blood ( viremia ) and feces of infected people up to 2 weeks before clinical illness develops. Hepatitis A can be prevented by vaccination , good hygiene , and sanitation . The two types of vaccines contain either inactivated Hepatovirus A or a live but attenuated virus. Both provide active immunity against a future infection. The vaccine protects against HAV in more than 95% of cases for longer than 25 years. In

5696-508: The liver cells in a process called steatosis . This initially reversible process overwhelms the hepatocyte 's ability to maintain lipid homeostasis leading to a toxic effect as fat molecules accumulate and are broken down in the setting of an oxidative stress response . Over time, this abnormal lipid deposition triggers the immune system via toll-like receptor 4 (TLR4) resulting in the production of inflammatory cytokines such as TNF that cause liver cell injury and death. These events mark

5785-451: 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 of hepatitis can be divided into

5874-478: The liver tissue. This disease is termed giant cell hepatitis and may be associated with viral infection, autoimmune disorders, and drug toxicity. 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 and cirrhosis . The pathway by which hepatic viruses cause viral hepatitis

5963-440: The liver, where it multiplies within hepatocytes and Kupffer cells (liver macrophages). Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the virus to host receptors, which mediates endocytosis . Replication follows the positive-stranded RNA virus replication model. Translation takes place by viral initiation. The virus exits the host cell by lysis and viroporins . Virions are secreted into

6052-563: The organ. Acute viral hepatitis follows three distinct phases: 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, or massive hepatic cell death ,

6141-416: The person shows any symptoms. The degree of elevation (i.e. levels in the hundreds vs. in the thousands), the predominance for AST vs. ALT elevation, and the ratio between AST and ALT are informative of the diagnosis. Ultrasound , CT , and MRI can all identify steatosis (fatty changes) of the liver tissue and nodularity of the liver surface suggestive of cirrhosis. CT and especially MRI are able to provide

6230-525: The possible extrahepatic manifestations. Kidney failure and pericarditis are very uncommon. If they occur, they show an acute onset and disappear upon resolution of the disease. Hepatovirus A is a species of virus in the order Picornavirales , family Picornaviridae , genus Hepatovirus . Humans and other vertebrates serve as natural hosts of this genus. Nine members of Hepatovirus are recognized. These species infect bats , rodents , hedgehogs , and shrews . Phylogenetic analysis suggests

6319-458: The presence of polymorphonuclear infiltration, hepatocyte necrosis and apoptosis in the form of ballooning degeneration , Mallory bodies , and fibrosis around veins and sinuses. The purpose of screening for viral hepatitis is to identify people infected with the disease as early as possible, even before symptoms and transaminase elevations may be present. This allows for early treatment, which can both prevent disease progression and decrease

6408-416: The primary drivers of the initial innate response and create a cytokine environment that results in the recruitment of CD4 T-helper and CD8 cytotoxic T-cells . Type I interferons are the cytokines that drive the antiviral response. In chronic Hepatitis B and C, natural killer cell function is impaired. Steatohepatitis is seen in both alcoholic and non-alcoholic liver disease and is the culmination of

6497-614: The product. In 2017, California (particularly around San Diego), Michigan, and Utah reported outbreaks of hepatitis A that have led to over 800 hospitalizations and 40 deaths. 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 spontaneously or following an injury or medical and dental procedures. Coagulopathies are sometimes erroneously referred to as "clotting disorders", but

6586-455: The rates of infection with this virus are high and the illness is usually contracted in early childhood. As incomes rise and access to clean water increases, the incidence of HAV decreases. In developed countries, though, the infection is contracted primarily by susceptible young adults, most of whom are infected with the virus during trips to countries with a high incidence of the disease or through contact with infectious persons. Although HAV

6675-408: The reduced or absent clotting factors are replaced with proteins derived from human blood or created in the laboratory. This therapy may be given either to treat bleeding that has already begun or to prevent bleeding from occurring. One area of treatment is managing people with major bleeding in a critical setting, like an emergency department. In these situations, the common treatment is transfusing

6764-559: 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 diseases . Autoimmune hepatitis is distinct from the other autoimmune diseases of the liver, primary biliary cirrhosis and primary sclerosing cholangitis , both of which can also lead to scarring, fibrosis, and cirrhosis of the liver. Genetic causes of hepatitis include alpha-1-antitrypsin deficiency , hemochromatosis , and Wilson's disease . In alpha-1-antitrypsin deficiency,

6853-456: The simian about 3600 years ago. The mean age of genotypes III and IIIA strains has been estimated to be 592 and 202 years, respectively. Hepatovirus A is a picornavirus ; it is not enveloped and contains a positive-sense, single-strand of RNA packaged in a protein shell . Only one serotype of the virus has been found, but multiple genotypes exist. Codon use within the genome is biased and unusually distinct from its host. It also has

6942-708: 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, amenorrhea , acne, arthritis, pleurisy , thyroiditis , ulcerative colitis , nephritis , and maculopapular rash . Autoimmune hepatitis increases

7031-565: The strength of the immune response, the types of immune cells involved and the ability of the virus to evade the body's defense, infection can either lead to clearance (acute disease) or persistence (chronic disease) of the virus. The chronic presence of the virus within liver cells results in multiple waves of inflammation , injury and wound healing that over time lead to scarring or fibrosis and culminate in hepatocellular carcinoma . People with impaired immune response are at greater risk of developing chronic infection. Natural killer cells are

7120-542: The subject of a recall, after at least 158 people were infected with HAV, 69 of whom were hospitalized. In April 2016, frozen berries sold by Costco were once again the subject of a recall, after at least 13 people in Canada were infected with HAV, three of whom were hospitalized. In Australia in February 2015, a recall of frozen berries was issued after at least 19 people contracted the illness following their consumption of

7209-431: 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. Excessive alcohol consumption

7298-405: The transition to steatohepatitis and in the setting of chronic injury, fibrosis eventually develops setting up events that lead to cirrhosis and hepatocellular carcinoma. Microscopically, changes that can be seen include steatosis with large and swollen hepatocytes ( ballooning ), evidence of cellular injury and cell death (apoptosis, necrosis), evidence of inflammation in particular in zone 3 of

7387-566: The urine or stool , double vision , severe head or neck pain, repeated vomiting , difficulty walking, convulsions, or seizures. They should seek prompt medical care if they experience mild but unstoppable external bleeding or joint swelling and stiffness. The normal clotting process depends on the interplay of various proteins in the blood. Coagulopathy may be caused by reduced levels or absence of blood-clotting proteins, known as clotting factors or coagulation factors. Genetic disorders , such as hemophilia and Von Willebrand disease , can cause

7476-426: The virus' own requirement for an intact eIF4G, and liver pathology is likely immune-mediated. The virus primarily spreads by the fecal–oral route , and infections often occur in conditions of poor sanitation and overcrowding. Hepatitis A can be transmitted by the parenteral route , but very rarely by blood and blood products. Food-borne outbreaks are common, and ingestion of shellfish cultivated in polluted water

7565-613: 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

7654-463: The wild mushroom Amanita phalloides are other known hepatotoxins. Non-alcoholic hepatitis is within the spectrum of non-alcoholic liver disease (NALD), which ranges in severity and reversibility from non-alcoholic fatty liver disease (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

7743-674: The world with poor sanitation and not enough safe water. In the developing world , about 90% of children have been infected by age 10, thus are immune by adulthood. It often occurs in outbreaks in moderately developed countries where children are not exposed when young and vaccination is not widespread. Acute hepatitis A resulted in 11,200 deaths in 2015. World Hepatitis Day occurs each year on July 28 to bring awareness to viral hepatitis . Early symptoms of hepatitis A infection can be mistaken for influenza , but some people, especially children, exhibit no symptoms at all. Symptoms typically appear two–six weeks (the incubation period ) after

7832-603: The worms, the cestode Echinococcus granulosus , also known as the 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 infection of the liver commonly results in pyogenic liver 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

7921-451: Was introduced in 1992 and was initially recommended for persons at high risk. Since then, Bahrain and Israel have embarked on elimination programmes. In countries where widespread vaccination has been practised, the incidence of hepatitis A has decreased dramatically. In the United States, vaccination of children is recommended at 1 and 2 years of age; hepatitis A vaccination is not recommended in those younger than 12 months of age. It

#314685