Ten years ago, I watched a 37-year-old man lose his battle with sepsis, a life-threatening condition caused by the body attacking its own tissues and organs in an abnormal response to an infection. I had to tell his young wife and his two young children. That day changed my life, as well as theirs.
A decade on, sepsis is still a relatively unknown condition, yet it affects more than 100,000 people every year in the UK, of which more than one in three don't survive. Sepsis doesn't discriminate by age, gender or ethnicity either - it can affect anyone at any time.
I recently heard the story of 25 year-old Tom Perry who was struck by sepsis on Christmas morning and was left fighting for his life after he was misdiagnosed with a not-so-serious spell of winter flu. After being sent home with antibiotics, Tom was later rush back to hospital with a racing heart, high temperature, and failing kidneys. He had to be put into a medical coma.
Tom's story had a happy ending but, just a few weeks later I read about a woman who died of sepsis after a Cardiff hospital delayed her treatment. The ombudsman found hospital staff failed to follow guidelines on treating sepsis.
So what's the problem? Why are even trained medical professionals missing the signs of this life-threatening condition?
Sepsis is the ultimate mimic. Its symptoms can be confused with flu, gastroenteritis or a chest infection. That means patients tend to stay at home and call their doctor or NHS Direct, instead of an ambulance.
If the general public and NHS staff are missing the signs of sepsis then stories like Tom's are all the more common. Misdiagnosis and the failure to recognise sepsis and intervene early means that it kills far more people, in the UK and globally, than it should.
All this is costing the NHS an estimated £2.5billion each year.
When I was studying medicine in 1989 to 1994, we graduated with absolutely no idea of what sepsis was. Despite how common it is, sepsis simply didn't feature in our training at all. And yet we learnt all about extremely rare conditions like Reye's Syndrome, which I've never even come across in all my years in medicine.
It's not all doom and gloom. The outlook has already improved. We've now developed a procedure for treating sepsis called the Sepsis Six, which includes administering intravenous fluids and antibiotics.
And if sepsis is spotted and treated in this way within the first hour of infection, it can double a patient's chance of survival.
But there's still a very long way to go. We're pushing, right now, for a national educational programme for sepsis, as well as a national register of survivors.
Public awareness is still far too low, but the symptoms - which include diarrhoea, muscle pain, mottled or discoloured skin, itching, difficulty passing urine, chills and shivering, fever, and fast breathing - can be spotted by friends and family, or even the patient themselves.
Until we all start to suspect sepsis, and say sepsis, the outlook won't get better.