Heather Winterstein’s life possibly could have been saved if she’d received a different and sooner treatment at the St. Catharines, Ont., hospital before she died of sepsis, an infectious disease specialist told the inquest into her 2021 death.
Dr. Dominik Mertz, a professor in McMaster University’s department of medicine, said the best chance at saving Winterstein’s life came on Dec. 9, the first day the 24-year-old went to the emergency department of what is now known as Marotta Family Hospital.
Winterstein was seeking help for severe body pain, the inquest that began March 30 has heard. But the emergency department doctor who assessed her ruled out an infection, and she was sent home with a Tylenol and instructions to return to hospital if her condition deteriorated. The doctor determined “social issues” were behind her hospital visit.
She returned to the hospital the next day and was sent to a waiting room, where she collapsed after spending 2½ hours there.
On Monday, Mertz said while Winterstein’s vital signs didn’t trigger protocols under hospital screening tools for treating sepsis on her Dec. 9 visit, he most likely would have ordered bloodwork and possibly extra lab tests to search for signs of an infection, such as inflammation or organ dysfunction.
“Those screening tools are not perfect,” he said. “You miss 10 to 20 per cent of patients” with sepsis.
Sepsis is the result of a severe reaction to a bacterial infection, causing the immune system to harm healthy tissues and organs.
Since Winterstein’s death, family members and community organizations have expressed concern that addiction discrimination and anti-Indigenous racism may have played a role in how she was treated.

Earlier in the inquest, one witness who was in the waiting room at the same time as Winterstein testified that she figured Winterstein was Indigenous; a triage nurse told the hearing that she didn’t know Winterstein’s background.
Mertz is among some 22 people expected to testify over 13 days before the coroner’s jury. Jurors are tasked with determining the facts in a case and may make recommendations to prevent similar deaths, but don’t assign blame or make findings of guilt or innocence.
Infection ‘could have been identified’
An autopsy found Winterstein’s sepsis was due to two types of bacteria: streptococcus pyogenes and staphylococcus aureus.
The fact she used intravenous drugs, which could lead to an elevated risk of a blood infection from contaminated syringes, should also have been a red flag, said Mertz.
Had an infection been confirmed or strongly suspected, Winterstein could have been put on an antibiotic treatment that potentially could have halted the progress of her condition before it escalated to septic shock, he said.
“You want to start the antibiotics before that septic shock actually happens because that’s when the mortality starts to increase quite significantly,” he said.
“If there was any suspicion there that something infectious might have been going on, which in hindsight I believe could have been identified, then that would have been the moment when we could have had the best chances to intervene successfully.”

While there was potential to save her life with timely medical interventions on both Dec. 9 and 10, the first day was “the best opportunity to change the outcome,” he said.
“If there was enough suspicion at the time or if additional testing had been done, that would have identified a concern, then she would have had a reasonable chance to survive this,” even if she’d had necrotizing fasciitis.
Necrotizing fasciitis, also known as flesh-eating disease, is a rare bacterial infection that can quickly develop into a life-threatening emergency. It can also lead to sepsis.
Sepsis may come with normal temperature, inquest told
With each passing hour without proper treatment, sepsis is likely to continue to worsen and decrease the chance of staying alive, said Mertz.
By the time Winterstein arrived at the hospital on Dec. 10, her survival chances were already declining, he added.
While the doctor who saw Winterstein on Dec. 9 ruled out infection in part because she didn’t have a fever, Mertz said, “We do see patients who present with sepsis and a normal temperature.”
The fact Winterstein’s skin was described as grey, she was having trouble walking and she answered questions slowly in a 911 call on Dec. 10 would also have indicated something serious was happening, said Mertz.
A prompt blood test upon arrival at the hospital on Dec. 10 might have identified she was having multi-organ failure, he said.
When she collapsed at 2:41 p.m. ET and doctors spent hours trying to resuscitate her, Mertz said, “The chances to change things at this time were very close to nothing. Your window of opportunity has almost closed.”
Winterstein was declared dead at 8:42 p.m.
Jaan Lilles, a lawyer representing several doctors, including the emergency department physician who assessed Winterstein on Dec. 9, asked Mertz if bloodwork might have shown no organ dysfunction that day.
“It’s impossible,” Mertz answered. Because the onset of sepsis to full-blown septic shock typically takes 24 to 48 hours, “it’s more likely than not that something would have been not normal on the 9th.
“The first step would have been basic bloodwork to see if there’s any signs of inflammation and organ dysfunction.”
The inquest continues today.








