Since the pressure ulcer staging system is based on the tissue you can visualize, we get caught up in a bizarre logic. It ought to be possible to describe the steps a wound goes through to get to a stage 4 pressure ulcer. But you can’t, because an ulcer doesn’t become a stage 4 until you can see bone. Prior to that it was probably unstageable (is that even a stage?), or it might have been a DTI, but we know they don’t progress by moving through the stages.
So, how do we “get to” a Stage 4? Well, one day it is a stage 4. Before that, it wasn’t. It was something else. You don’t get to watch Stage 4 ulcers actually happen very often, starting with the deep tissue injury which IS the way that they begin – but every now and then you might be taking care of a patient and get to photograph the whole thing week by week. I have several of these cases, and I thought I would post two of them.
Both patients developed a deep tissue injury – one from a tight stump trainer after a below the knee amputation, and the other from a splint that was placed to protect a heel (he’s paralyzed). In both cases, the only thing visible was a rather innocuous skin discoloration. The second one might have been mistaken for a Stage 1. In both cases, the thing that caused the problem was removed immediately so there was no more pressure, but the ulceration evolved anyway. In both cases, muscle died.
Case #1:

By the time the erythematous area in the top photo was visible, it was too late to stop the bottom wound from occurring.

The tissue damage had already happened, and the evolution of the ulcer over the next several months was inevitable.
These ulcers do not progress but rather evolve.

Case #2:

It took about 4 weeks for this DTI to EVOLVE into a Stage 4 pressure ulcer.

This area was protected from any further pressure from the moment the discoloration was noted.

What do these pictures tell you about the way a Stage 4 pressure ulcer forms? Yep – they form from the inside out. And once the skin discoloration was noticed in these patients – what could I have done to stop the tissue below it from dying? As far as I know, nothing. It was already too late. Both patients were outpatients and living at home, so, alas for them – there’s no hospital or doctor to sue for failing to keep these pressure ulcers from worsening.