URINARY RETENTION DEFINITION
Stoppage or reduction in the flow of urine either from blockage of a passage with resulting retention in the bladder or from disease of the kidneys.
URINARY RETENTION CAUSES
Causes of urinary retention include an obstruction in the urinary tract such as an enlarged prostate or bladder stones, infections that cause swelling or irritation, nerve problems that interfere with signals between the brain and the bladder, medications, constipation, urethral stricture, or a weak bladder muscle.
URINARY RETENTION PATHOPHYSIOLOGY
Normal urine production in an adult is about 1.5-2 L/day. Urine flow depends on 3 factors—a pressure gradient from the glomerulus to the Bowman capsule, peristalsis of the renal pelvis and ureters, and the effects of gravity (ie, hydrostatic pressure).
Obstruction of the urinary tract at any level eventually results in elevation of intraluminal ureteral pressure. With prolonged obstruction, ureteral peristalsis is overcome and increased hydrostatic pressures are transmitted directly to the nephron tubules.
As pressures in the proximal tubule and Bowman space increase, glomerular filtration rate (GFR) falls. After 12-24 hours of complete obstruction, intratubular pressure decreases to preobstruction levels. If complete obstruction is not relieved, a depressed GFR is maintained by decreases in renal blood flow mediated by thromboxane A2 and angiotensin II (AII). With continued obstruction, renal blood flow progressively falls, resulting in ischemia and incremental nephron loss. Thus, obstructive uropathy may lead to obstructive nephropathy. Several phases of obstructive nephropathy may be seen, including an early hyperemia and a late vasoconstriction followed by regulation of GFR post obstruction. Recovery of GFR depends on the duration and level of obstruction, preobstruction blood flow, and coexisting medical illness or infection.
URINARY RETENTION SYMPTOMS
With urinary retention, there is an inability to empty the bladder despite an urge to urinate. Some people have the following symptoms:
- Most people with acute urinary retention also feel pain in the lower abdomen (pelvis) along with inability to urinate. Chronic urinary retention is usually painless because some amount of urine is able to get out of the bladder. This can become painful with the absence of urination or if the amount of retained urine increases.
- A small amount of urine may leak out of the bladder but generally not enough to relieve symptoms.
- With chronic urinary retention or sensory problems, there may be no symptoms.
URINARY RETENTION DIAGNOSIS
Urinary retention is the inability to voluntarily void urine. This condition can be acute or chronic. Causes of urinary retention are numerous and can be classified as obstructive, infectious and inflammatory, pharmacologic, neurologic, or other. The most common cause of urinary retention is benign prostatic hyperplasia. Other common causes include prostatitis, cystitis, urethritis, and vulvovaginitis; receiving medications in the anticholinergic and alpha-adrenergic agonist classes; and cortical, spinal, or peripheral nerve lesions. Obstructive causes in women often involve the pelvic organs. A thorough history, physical examination, and selected diagnostic testing should determine the cause of urinary retention in most cases. Initial management includes bladder catheterization with prompt and complete decompression. Men with acute urinary retention from benign prostatic hyperplasia have an increased chance of returning to normal voiding if alpha blockers are started at the time of catheter insertion. Suprapubic catheterization may be superior to urethral catheterization for short-term management and silver alloy-impregnated urethral catheters have been shown to reduce urinary tract infection. Patients with chronic urinary retention from neurogenic bladder should be able to manage their condition with clean, intermittent self-catheterization; low-friction catheters have shown benefit in these patients. Definitive management of urinary retention will depend on the etiology and may include surgical and medical treatments.
URINARY RETENTION TREATMENT
Your doctor/specialist may treat your urinary retention with
- bladder drainage
- urethral dilation
- urethral stents
- prostate medications
The type and length of treatment will depend on the type and cause of urinary retention.