(See also Overview of Blood Vessel Disorders of the Liver Overview of Blood Vessel Disorders of the Liver The liver receives the oxygen and nutrients it needs in blood that comes from two large blood vessels: Portal vein Hepatic artery The portal vein provides about two thirds of the blood. This... read more .)
In ischemic hepatitis, liver cells are damaged or die because the liver does not receive enough blood or oxygen.
Ischemic hepatitis differs from other types of hepatitis. Usually, “hepatitis” implies inflammation of the liver, which can have many causes, most commonly a virus (as in hepatitis A or B Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more ). However, in ischemic hepatitis, the liver is not inflamed. Rather, liver cell death (necrosis) occurs. The term hepatitis is used because technically, it refers to any disorder in which liver enzymes called aminotransferases leak from damaged liver cells into the blood.
Ischemic hepatitis develops when the liver’s requirements for blood, oxygen, or both are not being met.
Decreased blood flow throughout the body is the most common cause for such unmet needs. Blood flow may be decreased by the following:
Decreased oxygen levels in the body, as may result from prolonged, severe respiratory disorders, can also cause ischemic hepatitis.
An increased need for oxygen and blood, as occurs during a severe bodywide infection (sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more ), can contribute to ischemic hepatitis.
Blocked blood vessels can cause hepatic ischemia but only when both the hepatic artery and the portal vein are narrowed or blocked. Ischemia does not develop when only one of these blood vessels is narrowed or blocked because the liver receives blood from both the hepatic artery and portal vein, and the blood vessel that is not blocked continues to supply the liver with blood.
The most common cause of blocked blood vessels is a blood clot. (Blockage by a blood clot is called thrombosis.) Blood clots in the hepatic artery can have many causes, such as the following:
A bulge (aneurysm) in the hepatic artery
Use of cocaine (causing spasm of the artery)
Tumors, certain medical procedures, or heart infections (endocarditis Infective Endocarditis Infective endocarditis is an infection of the lining of the heart (endocardium) and usually also of the heart valves. Infective endocarditis occurs when bacteria enter the bloodstream and travel... read more ) that cause emboli—clumps of material, such as a piece of fatty material or blood clot on the wall of an artery—to break off and travel through the bloodstream and become lodged in a blood vessel
Disorders that make blood more likely to clot Overview of Blood Clotting Disorders Blood clotting (coagulation) disorders are dysfunctions in the body's ability to control the formation of blood clots. These dysfunctions may result in Too little clotting, leading to abnormal... read more can cause blockages in the hepatic artery or portal vein. These disorders may be inherited or acquired.
Symptoms include nausea and vomiting. The liver may be tender and enlarged. If people already have severe scarring of the liver (cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more ), ischemic hepatitis can cause liver failure Liver Failure Liver failure is severe deterioration in liver function. Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice (yellow skin and eyes), feel tired... read more .
Doctors suspect ischemic hepatitis when results of liver blood tests (done to determine how well the liver is functioning and whether it is damaged) and/or blood clotting tests are abnormal in people who have a condition that can cause the disorder.
If doctors suspect ischemic hepatitis, they look for a cause. For example, they may do imaging tests to check heart function or for a blockage in the hepatic artery. These imaging tests Imaging Tests of the Liver and Gallbladder Imaging tests of the liver, gallbladder, and biliary tract include ultrasonography, radionuclide scanning, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic retrograde cholangiopancreatography... read more include echocardiogram, ultrasonography, magnetic resonance imaging (MRI) of blood vessels (magnetic resonance angiography Magnetic resonance angiography (MRA) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more ), and arteriography Arteriography In angiography, x-rays are used to produce detailed images of blood vessels. It is sometimes called conventional angiography to distinguish it from computed tomography (CT) angiography and magnetic... read more , which involves taking x-rays after a radiopaque contrast agent Radiopaque Contrast Agents During imaging tests, contrast agents may be used to distinguish one tissue or structure from its surroundings or to provide greater detail. Contrast agents include Radiopaque contrast agents... read more (which is visible on x-rays) is injected into an artery.