Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladder control, mild lower abdominal pain, and a weak urine stream. Those with long-term problems are at risk of urinary tract infections. Causes include blockage of the urethra, nerve problems, certain medications, and weak bladder muscles. Blockage can be caused by benign prostatic hyperplasia (BPH), urethral strictures, bladder stones, a cystocele, constipation, or tumors. Nerve problems can occur from diabetes, trauma, spinal cord problems, stroke, or heavy metal poisoning. Medications that can cause problems include anticholinergics, antihistamines, tricyclic antidepressants, cyclobenzaprine, diazepam, nonsteroidal anti-inflammatory drugs (NSAID), amphetamines, and opioids. Diagnosis is typically based on measuring the amount of urine in the bladder after urinating. Treatment is typically with a catheter either through the urethra or lower abdomen. Other treatments may include medication to decrease the size of the prostate, urethral dilation, a urethral stent, or surgery. Males are more often affected than females. In males over the age of 40 about 6 per 1,000 are affected a year. Among males over 80 this increases 30%. Signs and symptoms Onset can be sudden or gradual. When the onset is sudden, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladder control, mild lower abdominal pain, and a weak urine stream. Those with long-term problems are at risk of urinary tract infections. Causes Bladder Infection Detrusor sphincter dyssynergia Neurogenic bladder (commonly spinal cord damage, pelvic splanchic nerve damage, cauda equina syndrome, pontine micturition or storage center lesions, demyelinating diseases or Parkinson's disease) Iatrogenic (caused by medical treatment/procedure) scarring of the bladder neck (commonly from removal of indwelling catheters or cystoscopy operations) Damage to the bladder Prostate Benign prostatic hyperplasia (BPH) Prostate cancer and other pelvic malignancies Prostatitis Penile urethra Congenital urethral valves Phimosis or pinhole meatus Circumcision Obstruction in the urethra, for example a stricture (usually caused either by injury or STD), a metastasis or a precipitated pseudogout crystal in the urine Pseudodyssynergia STD lesions (gonorrhoea causes numerous strictures, leading to a "rosary bead" appearance, whereas chlamydia usually causes a single stricture) Emasculation Postoperative Risk factors include Age: Older people may have degeneration of neural pathways involved with bladder function and it can lead