What is the FIRST manifestation of most cell injuries?

Cellular swelling is the first manifestation of almost all forms of injury to cells. When it affects many cells, it causes some pallor, increased turgor and increase in weight of the organ. On microscopic examination, small clear vacuoles may be seen within the cytoplasm; these represent distended and pinched-off segments of the ER. This pattern of nonlethal injury is sometimes called hydropic change or vacuolar degeneration. Swelling of cells is reversible. Ref: Robbins 8th edition, Chapter 1.