This occurs when URINE is produced by the kidneys but not voided by the bladder. It is generally less serious than ANURIA, in which urine is not produced.
Neurological injury, such as trauma to the spinal cord, may cause bladder weakness, leading to retention, although this is rare. Obstruction to outflow is a more common cause: this may be acute and temporary, for example after childbirth or following surgery for piles (HAEMORRHOIDS); or chronic, for example, with prostatic enlargement (see PROSTATE GLAND). Most commonly seen in elderly men, this leads to reduced bladder capacity, with partial, frequent emptying. Total retention is rare, but may result from a stricture, or narrowing, of the URETHRA (see also URETHRA, DISEASES OF AND INJURY TO) – usually the result of infection or injury – or to pressure from a large neighbouring tumour.
Retention is generally treated by regular use of a urethral catheter (see CATHETERS), various types of which are available. ASPIRATION of the bladder with a needle passed above the pubis is rarely necessary, but may occasionally be required in cases of severe stricture.