The clinical presentation is variable and is determined by the rate of progression of the underlying kidney disease. In patients with a slow decline in eGFR, fatigue, anorexia, weight-loss, and nausea are the presenting signs. Cognitive dysfunction is slow, progressive, and subtle. Psychometric testing is required to identify the involvement of the central nervous system. At the other end of the spectrum are patients with a rapid decline in eGFR. These patients can present with confusion, delirium, seizures, and coma.