The exact cause of<unk>  is not yet known. It may occur spontaneously, or following an event such as a surgical procedure or childbirth. Use of opiates also trigger urinary retention. There is not usually any prior history of urological abnormalities in childhood. One hypothesis is that it is due to an abnormality in muscle membrane, possibly hormonally dependent channelopathy. causing excessive excitability of the external urethral sphincter which prevents the adequate relaxation of the muscle necessary for voiding . Another hypothesis in that<unk>  is due to an up-regulation of spinal cord enkephalins and that opiates may compound the functional abnormalities. It has also been hypothesised that there are both local pelvic floor and central neurological causations.
Fowler's syndrome
Wissler's syndrome
Löffler's syndrome
Grisel's syndrome
Rowell's syndrome
Binder's syndrome
Witteveen–Kolk syndrome
Menke-Hennekam syndrome