Steve Harwell, former lead singer for rock band Smash Mouth, died at age 56 on Sept. 4, 2023, due to acute liver failure.
"He was surrounded by family and friends and passed peacefully and comfortably," the band's manager, Robert Hayes, said in a statement to NBC News. "Steve Harwell was a true American Original. A larger than life character who shot up into the sky like a Roman candle," the statement continues.
Best known for the 1999 hit "All Star," Harwell's "iconic voice is one of the most recognizable voices from his generation. He loved the fans and loved to perform," the statement said.
Steve Harwell's cause of death
Steve Harwell died from acute liver failure, his band's manager told NBC News. He added that Harwell "had many health issues."
Harwell retired from performing with the band two years ago and passed away after a short stay in hospice care.
What is acute liver failure?
Liver failure is a condition in which the liver can no longer keep functioning at normal levels.
Liver failure generally falls into two categories: chronic or acute, Dr. Tatyana Kushner, professor of medicine in the division of liver diseases at the Icahn School of Medicine at Mount Sinai, tells TODAY.com.
"The way we distinguish between the two is largely based on history," she explains. That means "knowing whether they had a chronic ongoing liver injury or confirming that they've never had any liver injury, but now come in with a new situation where their liver's not working."
With chronic liver disease, people may lose their liver function slowly, often over a period of many years — even decades, Kushner explains. Chronic liver failure, also called decompensated liver disease, can cause symptoms like nausea, vomiting, fatigue, diarrhea and loss of appetite, the Cleveland Clinic says. Over time, the symptoms may become more severe as the disease advances.
People who have certain long-term medical issues, or who currently or previously consumed an excessive amount of alcohol are at higher risk for liver failure, Cleveland Clinic says. But with acute liver failure, liver function deteriorates much more quickly, usually over days or weeks, the Mayo Clinic says.
"Acute liver failure is probably one of the scariest things in my field," Dr. Catherine Lucero, assistant professor of clinical medicine and transplant hepatologist at NewYork-Presbyterian/Weill Cornell Medical Center, tells TODAY.com.
Although the condition is "extremely rare," Lucero says, it's also always an emergency. It occurs when, all of a sudden, the liver just stops working in somebody who has no known liver condition, Lucero says. "And so it does it in a very short time span," she adds.
Once the liver fails, kidney failure and neurologic dysfunction might follow. “All the organs in the body work together, so if one fails, then you start seeing other organs fail, as well,” Kushner explains. "It's a cascade of events that pretty rapidly can lead to multi-organ dysfunction, and ultimately, that's what people pass away from."
What causes acute liver failure?
With chronic liver failure, patients usually have long-standing liver disease, Kushner says, which can be caused by long-term alcohol use, hepatitis viruses, autoimmune conditions and genetic conditions.
Over time, these can cause scarring in the liver. At the most severe stage, this scarring is called cirrhosis, Kushner explains. "You can still have actually a functioning liver that has a lot of scarring," she says, but eventually the scarring will likely impact liver function and lead to liver failure.
However, by definition, acute liver failure only occurs in "someone who has no underlying liver disease and has never had any liver problem,” Kushner says. Instead, it arises most commonly due to an overdose of acetaminophen, Lucero explains.
The classic example is "their eyes turn yellow (due to jaundice), they start to get confused and then they're comatose within a day," Lucero says. That confusion occurs because, as the liver fails, it's no longer able to effectively metabolize the toxin ammonia, which builds up and causes swelling in the brain, Lucero explains.
Recently, some experts have started using the term acute on chronic liver failure. In this situation, a patient "may have underlying long-standing chronic liver disease or cirrhosis," Kushner explains, and then an infection or other issue "on top of that leads to liver failure."
For instance, although chronic alcohol consumption doesn't directly cause acute liver failure, it "decreases the threshold to develop drug-induced liver injury," Lucero says.
Acute liver failure treatments
In some cases, treatments can prevent further complications or help reverse acute liver failure by giving the liver time to heal, the Mayo Clinic says.
If someone gets diagnosed with acetaminophen-induced acute liver failure, "there is an antidote to give," Lucero says. "And if it's given early enough, it can help avoid the need for a liver transplant." Patients may also receive a special form of continual dialysis, which can help decrease the amount of ammonia in their body, she adds.
In many cases, though, a liver transplant is the only effective option.
"Liver failure does not necessarily have to be a death sentence," Kushner says. But, she continues, "it's not that anyone who wants a liver transplant just walks in and gets one." There's a waitlist for transplants and "very stringent criteria to determine who can qualify for a liver transplant," Kushner says.
For example, if someone needed a liver transplant due to long-standing alcohol use and they're still drinking alcohol every day, "they won't be offered a liver transplant because you really have to demonstrate that you can stop drinking," Kushner explains. If they do receive a transplant and continue to drink, "then their new liver will also fail eventually."
Doctors are typically able to decide whether or not a patient is a transplant candidate — and, if so, get them listed for a transplant — within a day, Lucero says. The challenge with acute liver failure patients, though, is that they "have to be able to agree to take lifelong immune suppression to prevent rejection of the organ," Lucero explains.
But at that point, they may already be comatose, which means the hospital's social work team needs to find out who the patient's care team is and if they'd be someone who might agree to that.
Steve Harwell's past health issues
Harwell dealt with multiple health conditions in the years prior to his death, including addiction, according to Hayes.
He'd been diagnosed with cardiomyopathy several years ago, according to previous interviews with People. The condition occurs when the heart muscles can't effectively pump blood to the rest of the body, the Mayo Clinic explains, and it can later lead to heart failure, blood clots and cardiac arrest.
Harwell later developed Wernicke’s encephalopathy, a sudden brain and memory disorder that's caused by a lack of vitamin B1, which causes brain damage, the Cleveland Clinic explains. People with a history of alcohol use disorder are more likely to develop the condition.
Why did Steve Harwell leave Smash Mouth?
Harwell left Smash Mouth in October 2021 to "focus on his physical and mental health," his representative told People at the time.
He made the announcement after he was seen slurring his words during a concert in upstate New York.
“Steve has been dealing with long-term medical issues over the last eight years and during his last performance at the Big Sip stage, he suffered numerous symptoms directly linked with his current medical situation,” the statement from Harwell's rep continued. “As of today, Steve will be retiring from Smash Mouth to focus on his physical and mental health.”
Harwell also addressed his health struggles in a statement to the magazine: "I’ve tried so hard to power through my physical and mental health issues, and to play in front of you one last time, but I just wasn’t able to."
This story has been updated to add comments from Dr. Lucero.