Fluid and electrolyte disturbances associated with cancer and its treatment.

Individuals with cancer are subject to fluid and electrolyte imbalances because of the original disease process, therapy, and complications resulting from both the disease process and from therapy. These imbalances are life threatening either when they become extreme or when they occur very rapidly. Although almost any fluid and electrolyte disorder or combination of disorders can occur in people with cancer, this article will focus on the following more common, potentially critical imbalances: water excess, decreased vascular volume, hypercalcemia, hypokalemia, and tumor lysis syndrome, which includes hypocalcemia, hyperphosphatemia, hyperuricemia, and hyperkalemia. These imbalances will each be reviewed with a focus on their causes, signs and symptoms, and treatment. Additional readings on fluid and electrolyte imbalances in patients with cancer can be found in several recent articles.