Paynter back in clinic; Colitis diagnosed..

[Merlinsky]

I was looking up some things about colitis and it was suggested that Swale actually may've suffered from that, but it sure sounds like he was struck more suddenly than Landaluce or Paynter. Would the effects occur that soon? You could gallop and then drop dead within 30 minutes? I'd always thought it was a heart attack, but apparently the autopsy didn't indicate heart damage.