Acute liver failure is loss of liver function that occurs rapidly — in days or weeks — usually in a person who has no preexisting liver disease. It's most commonly caused by a hepatitis virus or drugs, such as acetaminophen. Acute liver failure is less common than chronic liver failure, which develops more slowly.

Acute liver failure, also known as fulminant hepatic failure, can cause serious complications, including excessive bleeding and increasing pressure in the brain. It's a medical emergency that requires hospitalization.

Depending on the cause, acute liver failure can sometimes be reversed with treatment. In many situations, though, a liver transplant may be the only cure.

Signs and symptoms of acute liver failure may include:

• Yellowing of your skin and eyeballs (jaundice)
• Pain in your upper right abdomen
• Abdominal swelling (ascites)
• Nausea
• Vomiting
• A general sense of feeling unwell (malaise)
• Disorientation or confusion
• Sleepiness
• Breath may have a musty or sweet odor
• Tremors

When to see a doctor

Acute liver failure can develop quickly in an otherwise healthy person, and it is life-threatening. If you or someone you know suddenly develops a yellowing of the eyes or skin; tenderness in the upper abdomen; or any unusual changes in mental state, personality or behavior, seek medical attention right away.

Acute liver failure occurs when liver cells are damaged significantly and are no longer able to function. Potential causes include:

• Acetaminophen overdose. Taking too much acetaminophen (Tylenol, others) is the most common cause of acute liver failure in the United States. Outside of the United States, acetaminophen is known as paracetamol. Acute liver failure can occur after one very large dose of acetaminophen, or after higher than recommended doses every day for several days.

  If you or someone you know has taken an overdose of acetaminophen, seek medical attention as quickly as possible. Treatment may prevent liver failure. Don't wait for the signs of liver failure.

• Prescription medications. Some prescription medications, including antibiotics, nonsteroidal anti-inflammatory drugs and anticonvulsants, can cause acute liver failure.
• Herbal supplements. Herbal drugs and supplements, including kava, ephedra, skullcap and pennyroyal, have been linked to acute liver failure.
• Hepatitis and other viruses. Hepatitis A, hepatitis B and hepatitis E can cause acute liver failure. Other viruses that can cause acute liver failure include Epstein-Barr virus, cytomegalovirus and herpes simplex virus.
• Toxins. Toxins that can cause acute liver failure include the poisonous wild mushroom Amanita phalloides, which is sometimes mistaken for one that is safe to eat. Carbon tetrachloride is another toxin that can cause acute liver failure. It is an industrial chemical found in refrigerants and solvents for waxes, varnishes and other materials.
• Autoimmune disease. Liver failure can be caused by autoimmune hepatitis — a disease in which your immune system attacks liver cells, causing inflammation and injury.
• Diseases of the veins in the liver. Vascular diseases, such as Budd-Chiari syndrome, can cause blockages in the veins of the liver and lead to acute liver failure.
• Metabolic disease. Rare metabolic diseases, such as Wilson's disease and acute fatty liver of pregnancy, infrequently cause acute liver failure.
• Cancer. Cancer that either begins in or spreads to your liver can cause your liver to fail.
• Shock. Overwhelming infection (sepsis) and shock can severely impair blood flow to the liver, causing liver failure.
• Heat stroke. Extreme physical activity in a hot environment can trigger acute liver failure.

Some cases of acute liver failure have no apparent cause.

Acute liver failure often causes complications, including:

• Excessive fluid in the brain (cerebral edema). Too much fluid causes pressure to build up in your brain, which can lead to disorientation, severe mental confusion and seizures.
• Bleeding and bleeding disorders. A failing liver cannot make enough clotting factors, which help blood to clot. Bleeding in the gastrointestinal tract is common with this condition. It may be difficult to control.
• Infections. People with acute liver failure are more likely to develop infections, particularly in the blood and in the respiratory and urinary tracts.
• Kidney failure. Kidney failure often occurs after liver failure, especially if you had an acetaminophen overdose, which damages both your liver and your kidneys.

Reduce your risk of acute liver failure by taking care of your liver.

• Follow instructions on medications. If you take acetaminophen or other medications, check the package insert for the recommended dosage, and don't take more than that. If you already have liver disease, ask your doctor if it is safe to take any amount of acetaminophen.
• Tell your doctor about all your medicines. Even over-the-counter and herbal medicines can interfere with prescription drugs you're taking.
• Drink alcohol in moderation, if at all. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women and up to two drinks a day for men.
• Avoid risky behavior. Get help if you use illicit intravenous drugs. Don't share needles. Use condoms during sex. If you get tattoos or body piercings, make sure the shop you choose is clean and safe. Don't smoke.
• Get vaccinated. If you have chronic liver disease, a history of any type of hepatitis infection or an increased risk of hepatitis, talk to your doctor about getting the hepatitis B vaccine. A vaccine also is available for hepatitis A.
• Avoid contact with other people's blood and body fluids. Accidental needle sticks or improper cleanup of blood or body fluids can spread hepatitis viruses. Sharing razor blades or toothbrushes also can spread infection.
• Don't eat wild mushrooms. It can be difficult to tell the difference between a poisonous mushroom and one that is safe to eat.
• Take care with aerosol sprays. When you use an aerosol cleaner, make sure the room is ventilated, or wear a mask. Take similar protective measures when spraying insecticides, fungicides, paint and other toxic chemicals. Follow product instructions carefully.
• Watch what gets on your skin. When using insecticides and other toxic chemicals, cover your skin with gloves, long sleeves, a hat and a mask.
• Maintain a healthy weight. Obesity can cause a condition called nonalcoholic fatty liver disease, which may include fatty liver, hepatitis and cirrhosis.

Tests and procedures used to diagnose acute liver failure include:

• Blood tests. Blood tests are done to determine how well your liver works. A prothrombin time test measures how long it takes your blood to clot. With acute liver failure, blood doesn't clot as quickly as it should.
• Imaging tests. Your doctor may recommend an ultrasound exam to look at your liver. Such testing may show liver damage and help your doctor determine the cause of your liver problems. Your doctor may also recommend abdominal computerized tomography (CT) scanning or magnetic resonance imaging (MRI) to look at your liver and blood vessels. These tests can look for certain causes of acute liver failure, such as Budd-Chiari syndrome or tumors. They may be used if your doctor suspects a problem and ultrasound testing is negative.
• Examination of liver tissue. Your doctor may recommend removing a small piece of liver tissue (liver biopsy). Doing so may help your doctor understand why your liver is failing. Since people with acute liver failure are at risk of bleeding during biopsy, the doctor may perform a transjugular liver biopsy. The doctor makes a tiny incision on the right side of your neck, and then passes a thin tube (catheter) into a neck vein, through your heart and into a vein exiting your liver. Your doctor then inserts a needle through the catheter and retrieves a sample of liver tissue.

People with acute liver failure are often treated in the intensive care unit of a hospital in a facility that can perform a liver transplant, if necessary. Your doctor may try to treat the liver damage itself, but in many cases, treatment involves controlling complications and giving your liver time to heal.

Acute liver failure treatments may include:

• Medications to reverse poisoning. Acute liver failure caused by acetaminophen overdose is treated with a medication called acetylcysteine. This medication may also help treat other causes of acute liver failure. Mushroom and other poisonings also may be treated with drugs that can reverse the effects of the toxin and may reduce liver damage.

  Your doctor will also work to control signs and symptoms you're experiencing and try to prevent complications caused by acute liver failure. Your care may include:

• Relieving pressure caused by excess fluid in the brain. Cerebral edema caused by acute liver failure can increase pressure on your brain. Medications can help reduce the fluid buildup in your brain.
• Liver transplant. When acute liver failure can't be reversed, the only treatment may be a liver transplant. During a liver transplant, a surgeon removes your damaged liver and replaces it with a healthy liver from a donor.
• Screening for infections. Your medical team will take samples of your blood and urine every now and then to be tested for infection. If your doctor suspects that you have an infection, you'll receive medications to treat the infection.
• Preventing severe bleeding. Your doctor can give you medications to reduce the risk of bleeding. If you lose a lot of blood, your doctor may perform tests to find the source of the blood loss. You may require blood transfusions.
• Providing nutritional support. If you're unable to eat, you may need supplements to treat nutritional deficiencies.

Future treatments

Scientists continue to research new treatments for acute liver failure, especially those that could reduce or delay the need for a liver transplant. While several potential future treatments are in the pipeline, it's important to remember they are experimental and may not yet be available.

Among those being studied are:

• Artificial hepatic assist devices. A machine would do the job of the liver, much like dialysis helps when the kidneys stop working. There are many different types of devices being studied. Research suggests that some, but not all, devices may improve survival. A well-controlled multicenter trial showed that one system, called an extracorporeal liver support system, helped some people with acute liver failure survive without a transplant. The treatment is also called high-volume plasma exchange. However, more study is needed for this therapy.
• Hepatocyte transplantation. Transplanting only the cells of the liver — not the entire organ — may temporarily delay the need for a liver transplant. In some cases, it could lead to a complete recovery. A shortage of good-quality donor livers has limited the use of this treatment.
• Auxiliary liver transplantation. This procedure involves removing a small piece of your liver and replacing it with a similarly sized graft. This allows your own liver to regenerate without the need for immunosuppressant drugs. At this time, auxiliary liver transplantation is a difficult procedure that needs more time to be evaluated.
• Xenotransplantation. This type of transplant replaces the human liver with one from an animal or other nonhuman source. Doctors performed experimental liver transplants using pig livers several decades ago, but results were disappointing. However, advancements in immune and transplant medicine have prompted researchers to consider this treatment again. It may help provide support for those waiting for a human liver transplant.

If your doctor suspects you have acute liver failure, you'll likely be admitted to a hospital for treatment. Most people with acute liver failure are treated in an intensive care unit.

What you can do

If you have been diagnosed with acute liver failure, here are some questions to ask the doctor:

• What caused my acute liver failure?
• Can it be reversed?
• If it can be reversed, will my liver completely heal?
• What are the treatments?
• Will I need a liver transplant?
• Does this hospital have a liver transplant unit?
• Should I transfer to a hospital that performs liver transplants?

What to expect from your doctor

Your doctor will ask you or your family questions to try to determine the cause of your acute liver failure. Your doctor may ask:

• When did symptoms begin?
• What prescription medications do you take?
• What over-the-counter medications do you take?
• What herbal supplements do you take?
• Do you use illegal drugs?
• Have you had liver problems before?
• Have you been diagnosed with hepatitis or jaundice?
• Do you have a history of depression or suicidal thoughts?
• How much alcohol do you drink?
• Have you recently started taking new medications?
• Do you take acetaminophen? How much?
• Do liver problems run in your family?