Acute kidney injury caused by disease and/or toxicity can reverse itself. Someone does too much diuretics and lands themselves in the hospital for a week for emergent hemodialysis, that kinda thing.
Chronic kidney disease, the type that involves the progressive death of the nephrons (the functional unit of the kidneys, like neurons in the brain), cannot be reversed. The filtration rate of the kidneys decreases w age, and additional factors will of course hasten this progression.
Most likely Bonac had a case of AKI but he’s likely on the road to chronic kidney disease as well.
