Uremia can generally be divided into central and renal urolithiasis, which is clinically characterized by polyuria, irritable thirst, and low specific gravity urine. Generally, the urine output needs to be more than 2500 ml per day, with a significant increase in nocturia, which in a very few patients may exceed ten liters per day. Uremia is usually caused by hypothalamic neuropituitary lesions that cause varying degrees of antidiuretic hormone deficiency, or by multiple pathologies that cause defects in renal sensitivity to antidiuretic hormone, resulting in dysfunction of renal tubular reabsorption of water.