the bladder can cause pain in the lower abdomen (above the pubic symphysis, so called "suprapubic" pain), particularly before and after passing urine, and a desire to pass urine frequently and with little warning (urinary urgency). Infections are usually due to bacteria, of which the most common is E coli. When a urinary tract infection or cystitis is suspected, a medical practitioner may request a urine sample. A dipstick placed in the urine may be used to see if the urine has white blood cells, or the presence of nitrates which may indicate an infection. The urine specimen may be also sent for microbial culture and sensitivity to assess if a particular bacteria grows in the urine, and identify its antibiotic sensitivities. Sometimes, additional investigations may be requested. These might include testing the function of the kidneys by assessing electrolytes and creatinine; investigating for blockages or narrowing of the renal tract with an ultrasound, and testing for an enlarged prostate with a digital rectal examination. Urinary tract infections or cystitis are treated with antibiotics, many of which are consumed by mouth. Serious infections may require treatment with intravenous antibiotics. Interstitial cystitis refers to a condition in which the bladder is infected due to a cause that is not bacteria. Incontinence and retention Frequent urination can be due to excessive urine production, small bladder capacity, irritability or incomplete emptying. Males with an enlarged prostate urinate more frequently. One definition of an overactive bladder is when a person urinates more than eight times per day. An overactive bladder can often cause urinary incontinence. Though both urinary frequency and volumes have been shown to have a circadian rhythm, meaning day and night cycles, it is not entirely clear how these are disturbed in the overactive bladder. Urodynamic testing can help to explain the symptoms. An underactive bladder is the condition where there is a difficulty in passing urine and is the main symptom of a neurogenic bladder. Frequent urination at night may indicate the presence of bladder stones. Disorders of or related to the bladder include: Bladder exstrophy Bladder sphincter dyssynergia, a condition in which the sufferer cannot coordinate relaxation of the urethra sphincter with the contraction of the bladder muscles Paruresis Trigonitis Underactive bladder, a condition with its main symptom being urinary retention. Disorders of bladder function may be dealt with surgically, by re-directing the flow of urine or by replacement with