Abnormalities in the quantity and/or composition of the urine. Normally, 1 to 2 litres of urine are produced daily. When less than 100 ml are produced, the condition is known as anuria. Low urination can also be the consequence of urine retention. Frequent urination is usually the result of cystitis. Abnormally high urine production occurs in diabetes, chronic kidney failure, the recovery phase of tubule necrosis, and in other conditions. Inability to urinate normally. Difficulty in emptying the bladder may arise from sclerosis of the neck of the bladder, a congenital stricture in the urethra, or narrowing of the urethra, such as often occurs in elderly men with an enlarged prostate. Urine is passed in a thin, weak stream and this requires much time and effort, often with subsequent dribbling. Apart from narrowing of the urethra, another cause can be external pressure on the urethra. In women, this often results from prolapse of the bladder or pregnancy. A swollen pelvis or bladder can also be the cause. In a number of spinal cord disorders, the nerve paths to the bladder are impaired, and in consequence it can be difficult or impossible to empty the bladder. When there is difficulty in passing urine, some urine frequently remains in the bladder (urine retention). A bladder stone can suddenly close the neck of the bladder during urination, and this is accompanied by considerable pain. Pain during urination, as in urethritis, can cause delay in urination. Many people have difficulty in urinating in the presence of others even when they need to do so. It is usually possible to determine the reason for difficulty in urination by taking contrast X-rays of the bladder and by using an instrument to examine the bladder via the urethra (cystoscope).