A burst appendix can be very bad news and can be fatal yes. This is because all the infected material can spread. In the year 1965, I had a big operation called a laparotomy because of intense pains that I was suffering. The thing is I was heavily pregnant with my daughter. They were unsure where my pain was originating from as my pregnancy had shoved organs aside. That is why I had the larger investigation cut ( laparotomy) so that any organ could be reached. This turned out to be a very badly infected appendix and following the op. I was told that had I been left much longer that it would have burst. This was 7 weeks and just 2 days before I gave birth to my daughter. Apparantly she was left intact in the uterus as the infection would have spread into the womb.