Your liver is a powerhouse, performing over 500 life-sustaining functions. This 3-pound organ — the largest internal organ in the body — is located in the upper-right part of your abdomen. It does the following:
- filters toxins from your blood
- produces digestive enzymes called bile
- stores vitamins and minerals
- regulates hormones and the immune response
- helps clot blood
Your liver is the only organ in your body that can regrow after parts of it have been removed or damaged. In fact, your liver can grow back to its full size in just a matter of months.
So, if the liver regenerates, can you live without one for any period of time? Let’s take a closer look.
No. The liver is so crucial to existence that while you can live with only part of a liver, you can’t live without any liver at all. Without a liver:
- your blood won’t properly clot, causing uncontrolled bleeding
- toxins and chemical and digestive byproducts will build up in the blood
- you’ll have fewer defenses against bacterial and fungal infections
- you can have swelling, including deadly swelling of the brain
Without a liver, death would occur in a matter of days.
A liver can fail for a number of reasons.
Acute liver failure, also called fulminant hepatic failure, leads to rapid liver deterioration, often when the liver was previously perfectly healthy. According to research, it’s exceedingly rare, occurring yearly in fewer than 10 people per million. The most common causes are:
- viral infections
- drug toxicity, often due to overdoses of acetaminophen (Tylenol)
- jaundice, which causes yellowing of the skin and whites of the eyes
- abdominal pain and swelling
- mental disorientation
The other type of liver failure is known as chronic liver failure. It’s caused by inflammation and scarring that occurs over a period of months or years. This overall liver deterioration is often due to things like:
- alcohol misuse
- infections, including hepatitis A, B and C
- liver cancer
- genetic diseases, such as Wilson’s disease
- nonalcoholic fatty liver disease
- swollen abdomen
- vomiting blood
- easy bruising
- muscle loss
Not a death sentence
But a failing liver isn’t a death sentence. Depending on your health and the health of your liver, you may be a candidate for a liver transplant, a surgery in which a diseased liver is removed and replaced with a piece of or an entire healthy one from a donor.
There are two types of liver donor transplants:
Deceased donor transplant
This means the liver is taken from a person who’s recently passed away.
The person would have signed a donor organ card before their death. The organ may also be donated postmortem with the consent of the family.
Living donor transplant
In this process, someone who is still alive — often a family member or close friend — agrees to donate part of their healthy liver.
Your doctor may recommend an orthotopic or heterotopic transplant. In an orthotopic transplant, the diseased liver is entirely removed and replaced with a healthy donor liver or segment of liver.
In a heterotopic transplant, the damaged liver is left in place and a healthy liver or segment of liver is put in. While orthotopic transplants are the most common, a heterotopic one may be suggested if:
- your health is so poor you may not be able to withstand complete liver-removal surgery
- your liver disease has a genetic cause
A doctor may opt for a heterotopic transplant if your liver failure is caused by a genetic condition that future gene research may find a cure or viable treatment for. With your liver intact, you may be able to take advantage of these new advances.
Even though you may receive only a partial liver, your doctors will make sure it’s big enough to perform all necessary functions. In fact, one transplant surgeon at the University of Pittsburgh estimates that you only need 25 to 30 percent of your liver to maintain normal functions.
Over time, the liver will grow to about its normal size. Experts aren’t sure exactly how liver regeneration occurs, but they do know that when a liver is surgically reduced in size, a cellular response is activated that produces rapid regrowth.
People who receive a liver from a deceased donor tend to get transplanted with the entire organ. The liver might be split, however, if it’s very large or it’s being divided between a child and an adult.
Those who have a living liver donation — which often comes from a healthy relative or friend who’s matched for size and blood type — receive only a piece of the liver. Some people select this option because they don’t want to risk getting sicker as they wait on a list for an organ that may or may not come in time.
According to the University of Wisconsin School of Medicine and Public Health:
- About 40 to 60 percent of the donor liver is removed and transplanted into the recipient.
- Both the recipient and the donor will have enough of a liver to ensure proper functioning.
- Regrowth of the liver begins almost immediately.
- Within two weeks, the liver is nearing its normal size.
- Total — or near total — regrowth is achieved within a year.
In the United States, 14,000 people are currently on a waiting list for a transplanted liver. Of those, 1,400 will die before they ever receive one.
While still not common, living liver donation is being seen more and more. In 2017, some 367 livers were donated by living donors.
A major benefit of a living liver donation is that the surgery can be scheduled when it’s mutually convenient for both parties. What’s more, the liver can be donated before the recipient becomes gravely ill. This can boost survival rates.
To be considered for living liver donation you must:
- be between the ages of 18 and 60
- have a blood type that’s compatible with the recipient
- undergo extensive physical and psychological testing
- have a healthy weight, since obesity is a risk factor for fatty liver disease, which damages the liver
- be willing to abstain from alcohol until recovered
- be in good general health
The liver performs essential, life-sustaining functions. While you can’t live without a liver completely, you can live with only part of one.
Many people can function well with just under half of their liver. Your liver can also grow back to full size within a matter of months.
If you or someone you know has liver disease and in need of a transplant, living liver donation may be an option to consider.