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Some procedures are used for diagnosis alone, and others can be used for either diagnosis or therapy.
Bladder Catheterization
Bladder catheterization is used to do the following:
Catheterization may be urethral or suprapubic.
Catheters:
Catheters vary by caliber, tip configuration, number of ports, balloon size, type of material, and length.
Caliber is standardized in French (F) units—also known as Charrière (Ch) units. Each unit is 0.33 mm, so a 14-F catheter is 4.6 mm in diameter. Sizes range from 14 to 24 F for adults and 8 to 12 F for children. Smaller catheters are usually sufficient for uncomplicated urinary drainage and useful for urethral strictures and bladder neck obstruction; bigger catheters are indicated for bladder irrigation and some cases of hemorrhage (eg, postoperatively or in hemorrhagic cystitis) and pyuria, because clots could obstruct smaller caliber catheters.
Tips are straight in most catheters (eg, Robinson, whistle-tip) and are used for intermittent urethral catheterization (ie, catheter is removed immediately after bladder drainage). Foley catheters have a straight tip and an inflatable balloon for self-retention. Other self-retaining catheters may have an expanded tip shaped like a mushroom (de Pezzer catheter) or a 4-winged perforated mushroom (Malecot catheter); they are used in suprapubic catheterization or nephrostomy. Elbowed (coudé) catheters, which may have balloons for self-retention, have a bent tip to ease catheterization through strictures or obstructions (eg, prostatic obstruction).
Ports are present in all catheters used for continuous urinary drainage. Many catheters have ports for balloon inflation, irrigation, or both (eg, 3-way Foley).
Balloons on self-retaining catheters have different volumes, from 2.5 to 5 mL in balloons intended for use in children and 10 to 30 mL in balloons used in adults. Larger balloons and catheters are generally used to manage bleeding; traction on the catheter pulls the balloon against the base of the bladder and puts pressure on vessels.
Stylets are flexible metal guides inserted through the catheter to give stiffness and to facilitate insertion through strictures or obstructions.
Catheter material chosen depends on the intended use. Plastic, latex, or polyvinyl chloride catheters are for intermittent use. Latex with silicone, hydrogel, or polymer (to diminish bacterial colonization) catheters are for continuous use. Silicone catheters are used in patients with latex allergy.
Urethral catheterization:
A urethral catheter can be inserted by any health care practitioner and sometimes by patients themselves. No prior patient preparation is necessary; thus, the bladder is catheterized through the urethra unless the urethral route is contraindicated. Relative contraindications are the following:
After the urethral meatus is carefully cleaned with an antibacterial solution, using strict sterile technique, the catheter is lubricated with sterile gel and gently advanced through the urethra into the bladder. Lidocaine jelly may be injected through the male urethra before the catheter is passed to help relieve discomfort.
Complications of bladder catheterization include all of the following:
Suprapubic catheterization:
Suprapubic catheterization via percutaneous cystostomy is done by a urologist or another experienced physician. No prior patient preparation is necessary. General indications include need for long-term bladder drainage and inability to pass a catheter through the urethra or contraindication to catheter use when bladder catheterization is necessary.
Contraindications include the following:
After the abdomen above the pubic area is numbed with a local anesthetic, a spinal needle is inserted into the bladder; ultrasound guidance is used if available. A catheter is then placed through a special trocar or over a guide wire threaded through the spinal needle. Prior lower abdominal surgery contraindicates blind insertion. Complications include UTI, intestinal injury, and bleeding.
Cystoscopy
Cystoscopy is insertion of a rigid or flexible fiberoptic instrument into the bladder.
Indications include the following:
The main contraindication is active UTI.
Cystoscopy is usually done in an outpatient setting with use of local anesthesia or, when necessary, conscious sedation or general anesthesia. Complications include UTI, bleeding, and bladder and urethral trauma.
Biopsy
Biopsy requires a trained specialist (nephrologist, urologist, or interventional radiologist).
Renal biopsy:
Indications for diagnostic biopsy include unexplained nephritic or nephrotic syndrome or acute kidney injury. Biopsy is occasionally done to assess response to treatment. Relative contraindications include bleeding diathesis and uncontrolled hypertension. Mild preoperative sedation with a benzodiazepine may be needed. Complications are rare but may include renal bleeding requiring transfusion or radiologic or surgical intervention.
Bladder biopsy:
Bladder biopsy is indicated to diagnose certain disorders (eg, bladder cancer, sometimes interstitial cystitis or schistosomiasis) and occasionally to assess response to treatment. Contraindications include bleeding diathesis and acute tuberculous cystitis. Preoperative antibiotics are necessary only if active UTI is present. The biopsy instrument is inserted into the bladder through a cystoscope; rigid or flexible instruments can be used. The biopsy site is cauterized to prevent bleeding. A drainage catheter is left in place to facilitate healing and drainage of clots. Complications include excessive bleeding, UTI, and bladder perforation.
Prostate biopsy:
Prostate biopsy is usually done to diagnose prostate cancer. Contraindications include bleeding diathesis, acute prostatitis, and UTIs. Patient preparation includes stopping maintenance aspirin a week before biopsy, preoperative antibiotics (usually a fluoroquinolone), and an enema to clear the rectum. With the patient in a lateral position, the prostate is located by palpation or, preferably, ultrasonography. Overlying structures (perineum or rectum) are anesthetized, a spring-loaded biopsy needle is inserted into the prostate, and usually 12 tissue cores are obtained. Complications include the following:
Urethral Dilation
Urethral dilation is used to treat the following:
Contraindications include untreated infection, bleeding diathesis, a long segment stenosis, and severe scarring of the urethra. In cases of stricture, a fine filiform probe is passed through, then followers (dilators) of progressively larger diameter are attached to the distal end of the filiform probe and passed behind the probe to dilate the stricture until urine stream becomes adequate; the procedure is usually done over several sessions.
Last full review/revision September 2009 by Seyed-Ali Sadjadi, MD
Content last modified September 2009
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