Cystoscopy may be needed to explore the urinary passage and rule out blockages.In acute cases of urinary retention where associated symptoms in the lumbar spine are present such as pain, numbness (saddle anesthesia), parasthesias, decreased anal sphincter tone, or altered deep tendon reflexes, an MRI of the lumbar spine should be considered to further assess cauda equina syndrome. Complications
Acute urinary retention is a medical emergency and requires prompt treatment. The pain can be excruciating when urine is not able to flow out. Moreover, one can develop severe sweating, chest pain, anxiety and high blood pressure. Other patients may develop a shock-like condition and may require admission to a hospital. Serious complications of untreated urinary retention include bladder damage and chronic kidney failure. Urinary retention is a disorder treated in a hospital, and the quicker one seeks treatment, the fewer the complications.In the longer term, obstruction of the urinary tract may cause:
Bladder stones
Atrophy of the detrusor muscle (atonic bladder is an extreme form)
Hydronephrosis (congestion of the kidneys)
Hypertrophy of the detrusor muscle (the muscle that squeezes the bladder to empty it during urination)
Diverticula (formation of pouches) in the bladder wall (which can lead to stones and infection)

Treatment
In acute urinary retention, urinary catheterization, placement of a prostatic stent, or suprapubic cystostomy relieves the retention. In the longer term, treatment depends on the cause. BPH may respond to alpha blocker and 5-alpha-reductase inhibitor therapy, or surgically with prostatectomy or transurethral resection of the prostate (TURP).Use of alpha-blockers can provide relief of urinary retention following de-catheterization for both men and women.
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.