Kidney–brain crosstalk in the acute and chronic setting

Patients with kidney disease often exhibit multiple organ dysfunction that is caused, in part, by marked connectivity between the kidney and other organs and tissues. Substantial crosstalk occurs between the kidney and the brain, as indicated by the frequent presentation of neurological disorders, such as cerebrovascular disease, cognitive impairment, and neuropathy during the natural history of chronic kidney disease. The underlying pathophysiology of such comorbid neurological disorders in kidney disease is governed by shared anatomic and vasoregulatory systems and humoral and non-humoral bidirectional pathways that affect both the kidney and the brain. During acute kidney injury, the brain and kidney might interact through the amplification of cytokine-induced damage, extravasation of leukocytes, oxidative stress, and dysregulation of sodium, potassium, and water channels. The advent of dialysis and renal transplantation programmes has led to a reduction in the rate of neurological complications associated with uraemia, but a new set of complications have arisen as a consequence of the effects of dialysis on the central nervous system over the short and long term. This Review discusses the clinical complications of acute and chronic renal failure from a neurologic perspective, and highlights current understanding of the underlying pathophysiologies.