The difference between a strep A infection and strep throat

An Alberta woman went public this week after nearly dying from a rare strep A infection.

Colleen Watters survived, but spent nine days in a coma and doctors were forced to amputate her left foot, along with all the toes on her right foot and four fingers.

Watters initially went to hospital suffering flu-like symptoms but her condition quickly worsened and she suffered organ failure before falling into the coma.

• Alberta woman loses foot, toes, fingers after rare strep A infection
• Mississauga girl loses 2 limbs after infection doctors thought was influenza

Watters decided to go public after hearing about the ordeal of an 11-year-old girl in Mississauga, Ont. who had her left arm and right leg amputated following a several bacterial infection after contracting the streptococcus A strain. The girl is currently on dialysis at the Hospital for Sick Children in Toronto.

Doctors involved in that case initially thought the girl was suffering from the flu as well.

To learn more about Strep A, CBC Radio's The Calgary Eyeopener spoke with Dr. Lynora Saxinger, an infectious disease specialist at the University of Alberta.

Below is an excerpt of that conversation.

Q: What's the difference between strep throat and strep A?

A: They're the same type of bacteria in a general way, because they look the same on a plate, they have the same kind of name when you get a culture report. But generally, the strains that cause strep throat, which we know as being more of a nuisance infection, are different than the strains that cause invasive group A strep infection and sepsis, like these cases you've been discussing. The more aggressive strains are the ones that cause necrotizing fasciitis, so although it's the same bacteria, it's different strains causing different problems.

Q: Why does strep A sometimes go unnoticed or get misdiagnosed by doctors?

A: It's really an unfortunate thing that the early stages of any severe sepsis are really very difficult to tell from a lot of other conditions and the evolution of it really is the thing that makes the diagnosis. So I think there's a lot of literature on delayed diagnosis in things like necrotizing fasciitis because initially, especially when people are young and healthy like the young girl or the other lady, the early signs are very non-specific so it's not really so much a missed diagnosis as a late diagnosis, and sometimes those hours where people have been reassured and feel like their concerns have been dismissed turn out to be fairly important hours.

Q: Perhaps part of what makes it confusing, doesn't it often present as the flu during flu season?

A: It can present any time of year but especially in cases where there's something like a gastrointestinal component, they feel nauseated, they're vomiting, it can seem like a stomach virus. The early stages otherwise are fever, aches and feeling unwell, so it's really hard to distinguish. And the actual incidents are so rare, most people who have those symptoms do not turn out to have invasive group A strep.

Q: I want to be clear about that, how rare is it to contract an invasive and serious strep A infection?

A: It's somewhere in the realm of two to four per 100,000 people, so that's something like .002 per cent, and of that number, the vast majority actually are not as severe as the cases that were described. It's basically very rare but it's also somewhat unpredictable, which keeps it scary, I would have to say.

Q: What are the warning signs?

A: When we as infection specialists see people at the other end of this, when it's proven to be very severe, the things that seem to cluster together are, they start off non-specific, but there's a clear progression and rapid worsening. To me, the worsening over time, the serious sense that things are changing in a way that's not OK very quickly would be the thing I would highlight. For children, things like becoming lethargic and difficult to wake up, mottled skin, painful hands and feet, those things are all serious signs that should not be ignored. People should not feel bad about requesting the assessment if they think something serious is going on.

Q: If it's recognized early enough, how good is modern science at treating it?

A: There's a window of good success. If people come in very late it can be hard because at that point it's not just the bacteria anymore, but the body's response to bacteria in the form of a whole body inflammatory cascade in sepsis, where you do get multiple organ failure and that can be a lot more challenging to manage. Our modern [intensive care units] are very good at supporting people through that but it's not always fully recoverable in terms of damage to the body. The earlier people come in and  start appropriate antibiotics and appropriate supportive care, the more likely it is they'll come out of it reasonably well. I've seen some really miraculous turnarounds as well. We don't give up on these people, we give them full, active support and hope for the best.

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