What killed Muhammad Ali?

Story highlights

  • Muhammad Ali died of septic shock, according to his family's spokesman
  • Sepsis is not typically linked to Parkinson's disease but rather an infection

(CNN)Boxing legend Muhammad Ali will be laid to rest Friday, one week after he died at age 74. Ali had been publicly battling Parkinson's disease for more than three decades, so it came as a surprise to many that his official cause of death, according to family spokesman Bob Gunnell, was "septic shock due to unspecified natural causes."

"Sepsis is the body's overwhelming and life-threatening response to an infection, which can lead to tissue damage, organ failure and death," according to the Centers for Disease Control and Prevention.
    "A direct link from Parkinson's to sepsis is a long jump. However, there are several features of Parkinson's -- especially later in the course of the illness -- that can place a patient at higher risk for [developing] an infection, which can get into the bloodstream and cause them to become septic," said Dr. Michael S. Okun, national medical director of the National Parkinson Foundation.
    Parkinson's patients are at higher risk when hospitalized because the disease "can set up a scenario that decreases the threshold for getting an infection and makes it more difficult to clear the infection," said Okun, who is also the chairman of neurology at the University of Florida.
    The origin of Ali's infection has not been revealed, but the CDC stresses that an infection that starts anywhere in your body can lead to sepsis, even if it is only a minor one to begin with. The agency says there are more than 1 million documented cases of sepsis every year in the United States, including more than a quarter-million deaths.
    According to the CDC, the number of sepsis cases is on the rise in the United States because the population is aging; people have more chronic illness; people are getting more invasive procedures, immunosuppressive drugs, chemotherapy and organ transplants; and because of increasing antibiotic resistance. There's also increasing awareness and tracking of sepsis.
    Anyone can get sepsis from an infection, but the CDC says the risk is higher in:
    • People with weakened immune systems.
    • Babies and very young children.
    • Elderly people.
    • People with chronic illnesses, such as diabetes, AIDS, cancer, and kidney or liver disease.
    • People suffering from a severe burn or wound.
    "Many doctors view sepsis as a three-stage syndrome, starting with sepsis and progressing through severe sepsis to septic shock," according to the Mayo Clinic. "The goal is to treat sepsis during its early stage, before it becomes more dangerous."
    Symptoms of sepsis
    If you think you have an infection or sepsis, the CDC recommends that you call your doctor or go to the emergency room right away. Doctors diagnose sepsis by assessing vital signs, looking for high body temperature, increased heart rate and increased breathing rate. Many of the symptoms of sepsis, though -- such as fever and difficulty breathing -- are the same as with other conditions, making it difficult to diagnose early on.
    "If you are continuing to feel worse or not getting better in the days after surgery, ask your doctor about sepsis," the CDC says. "Sepsis is a common complication of people hospitalized for other reasons."
    Initial reports of Ali's illness, for example, put him in the hospital just one day before his death to be treated for a "respiratory issue," according to the family's spokesman.
    Muhammad Ali dies at 74
    Muhammad Ali dies at 74

      JUST WATCHED

      Muhammad Ali dies at 74

    MUST WATCH

    Muhammad Ali dies at 74 01:31
    Okun calls Parkinson's the most complex disease in clinical medicine, because it has so many symptoms and such a wide variety of treatments. "Physically, a patient can experience motor tremors, stiffness, slowness and shuffling of the feet," he said. "Non-motor conditions include depression, anxiety and sleeping problems, just to name a few. Multiple studies show that the more disabling features are the non-motor features."
    "Once you have an infection in the system, it makes it more difficult for Parkinson's patients to exist," Okun said. "It's harder to walk, their tremors get worse, but it is rare for them to die of sepsis."
    Okun encourages Parkinson's patients and their families to avoid hospitalizations whenever possible, opting instead for an outpatient setting. Of course, that won't be feasible in all cases, such as when a patient develops a breathing problem or pneumonia. In Ali's case, Okun says, "Sepsis wasn't caused by the hospitalization; it happened as the result of an infection."
    Join the conversation

    See the latest news and share your comments with CNN Health on Facebook and Twitter.

    For all patients, with and without Parkinson's -- and there are certainly far more without -- "Early, aggressive treatment boosts your chances of surviving sepsis," according to the Mayo Clinic. That treatment might include medications like antibiotics, administering oxygen or IV fluids, or being placed on dialysis. In some extreme cases, surgery might even be needed to remove an infection.
    When it comes to preventing sepsis, the CDC recommends getting vaccinated against the flu, pneumonia and other infections that can lead to sepsis. It also says people can prevent infections that can lead to sepsis by cleaning scrapes and wounds, and practicing good hygiene, such as regular bathing and hand washing.