[Circadian rhythm and renal colic]

Many physiological variables show a temporal pattern characterized by rhythmic changes along a time period, e.g. a day, a week, a month, a year, and it is also known that several acute diseases show a rhythmic variability as well. In these last years, high risk periods have been so identified, probably secondary to the temporal overlapping of favouring or triggering mechanisms. Recently, a circadian variability has been reported also for the occurrence of renal colic, with a pattern characterized by a morning peak, independent of gender and presence or not of demonstrable kidney stones. Most, if not all, renal functions exhibit temporal changes e.g. glomerular filtration rate, urine production and renal excretion of solutes, leading to an increased night-time concentration of urine, which could act as a predisposing factor for the morning occurrence of renal colic attacks.