Robbins is wrong (or at least misleading).

In my previous post, I suggested a central dogma for students of pathology. After injury, a physiologic response maintains homeostasis without loss of function while a pathologic response leads to reduced function, even if a new homeostatic set point is reached. 

With that in mind, let us turn to the first figure in the textbook that most of us consider the “standard of care” for pre-clinical instruction, Robbin’s textbook of pathology. The first figure is an opportunity for pathology to state the central dogma of the field.  Unfortunately, this figure is terrible.  The figure lists various names such as cell injury and death, homeostasis and adaption, reversible and irreversible injury. The relationship of these to each other seems arbitrary, ignoring definitions or time course. At most, one learns that some how a cell at rest maintains homeostasis, but that the cell can be injured, that sometimes this injury is mild and can be repaired, sometimes there is something called adaption and sometimes the cell dies.




Why is stress and injury related by two different arrows in different directions? Stress leads to injury; this is not an either or situation. The diagram suggests that under conditions of stress, the cell undergoes “adaption”. Presumably that means that the cell has an active response (e.g. upregulation of anti-oxidants in an oxidant rich environment) but that homeostasis is still maintained. How does that differ from homeostasis listed on the initial cell?  The figure does not indicate what happens to the adapted cell when the stress is removed. Is this reversible? If so, wouldn’t that mean this is reversible injury? How do we distinguish mild injury from strong repair? Finally, and most importantly, this diagram does nothing to distinguish how pathology differs from physiology or cell biology.

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