Urinary catheters should be used sparingly. Indwelling urethral catheters are the most common; suprapubic catheters require a surgical procedure but have fewer infectious complications (see chapter 92, “Acute Urinary Retention”). Most catheters are made of latex; however, silicone catheters are available for patients with latex allergy.¹ Table 95-1 lists the complications of urinary catheters.

INFECTION

Catheter-associated urinary tract infections (UTIs) are one of the most common causes of nosocomial infections. The risk of infection is approximately 1% to 2% with a catheter in place for <24 hours, with the prevalence of bacteriuria reaching almost 100% for long-term catheterization (by 30 days).² Comorbidities that increase the risk of catheter-associated UTI include female sex, prostatic hypertrophy, creatinine >2 milligrams/dL, diabetes, advanced age, nonsurgical disease, and debilitation.³ Microbial factors associated with an incidence of catheter-associated UTI include the source of the organisms, the specific bacteria, the route of invasion, and the duration of catheterization.

Pathophysiology

In the noncatheterized urinary tract, bacteria are efficiently eliminated. In contrast, most bacterial strains that are introduced into the catheterized urinary tract are able to multiply to high concentrations in 24 hours. Bacteria may be able to gain access to the urinary tract through the catheter lumen (intraluminal) or along the catheter surface (extraluminal). The drainage tube of a urinary catheter must be opened periodically to drain the accumulated urine. If the drainage tube lumen is colonized, bacteria may ascend the collection bag and catheter, causing an infection. An infection from the catheter lumen route begins with the formation of a biofilm on the catheter’s inner surface. This biofilm extends from the uroepithelium through catheters to the drainage bag and allows adherence of bacteria to a catheter or mucosal surface. Organisms become embedded within the biofilm and gain protection from the mechanical flow of urine, host defenses, and antibiotics.² The microbiology of catheter-associated UTI varies according to the duration of catheter placement. During short-term catheterization, infections are usually due to single organisms, most commonly Escherichia coli, followed by Klebsiella, Pseudomonas, Enterobacter, and gram-positive cocci such as staphylococci. With long-term catheterization (≤30 days), catheter-associated UTIs are usually polymicrobial from E. coli, Proteus mirabilis, Pseudomonas, Morganella morganii, and Candida species. These infections are usually difficult to treat due to antibiotic resistance by the infecting bacteria.²

Asymptomatic bacteriuria usually occurs with short-term catheterization, and removal of the catheter clears the bacteriuria. Antibiotic treatment of asymptomatic bacteriuria in a patient with a short-term indwelling urinary catheter is not recommended^2,3,4,5 (unless the patient is pregnant or immediately pending a urologic procedure). Guidelines and reviews recommend antibiotics for symptomatic catheter-associated UTI only.^2,3,4

Clinical Features

Signs and symptoms include fever, rigors, altered mental status, malaise, or lethargy with no other identified cause; flank pain; costovertebral angle tenderness; acute hematuria; pelvic discomfort; and in those whose catheters have been removed, dysuria, urgent or frequent urination, or suprapubic pain or tenderness. In patients with spinal cord injury, increased spasticity, autonomic dysreflexia, and sense of unease are also compatible with catheter-associated UTI.⁴

Diagnosis

Diagnoses of catheter-associated UTI symptoms are listed in Table 95-2.⁴ Pyuria is universal for patients with long-term (>1 month) indwelling catheters; in the absence of clinical symptoms, pyuria should not be used in the diagnosis of symptomatic infection.^2,3,4 Hematuria is a better indicator of infection and also may suggest urinary obstruction. Bedside US can identify urinary obstruction.⁴

Pyelonephritis (complicated UTI; see chapter 91, “Urinary Tract Infections and Hematuria”) is the most common complication of catheter-associated UTI with fever. Other related infections include prostatitis, epididymitis, and scrotal abscess. Obtain urine cultures prior to empiric antibiotic therapy, and obtain blood cultures if the patient is septic or immunocompromised.²

Treatment

Remove the catheter if clinically feasible, or replace the catheter if it has been in place for >7 days.^2,4 Empiric antibiotics should be instituted promptly in most cases⁴ unless the fever is low grade and the clinical condition allows for time to perform cultures and continued observation.² Assess local resistance patterns if available before instituting therapy. Treatment for complicated UTI is reviewed in Table 91-6. Outpatient treatment for patients without clinical toxicity is presented in Table 91-5 in chapter titled “Urinary Tract Infections and Hematuria”. A total of 7 total days is the recommended duration of antimicrobial treatment for patients with catheter-associated UTI who have prompt resolution of symptoms, and a total of 10 to 14 days of treatment is recommended for those with a delayed response.⁴ Alter drug regimens for renal insufficiency. If candiduria exists, remove the catheter, and consider antifungal agents in symptomatic patients.^2,4

CATHETER OBSTRUCTION AND LEAKAGE

Urethral catheters can become obstructed for many reasons, most commonly from the formation of intraluminal encrustations during long-term placement. These concretions are composed of compounds, such as ammonium magnesium sulfate (struvite) and calcium phosphate (apatite), often with urease-splitting organisms, such as Protease and Morganella. Such encrustations can increase the risk of formation of infectious stones and cause bladder trauma, leading to blood clots. A catheter obstruction may lead to urinary leakage around the catheter and acute urinary retention. Management options include repeated bladder irrigations, methenamine treatment, and removal of the catheter if the other methods fail.

NONDEFLATION OF FOLEY RETENTION BALLOON

The Foley balloon is typically inflated with 10 mL of sterile water after successful insertion. Nondeflation of the retention balloon on the catheter can be caused by a faulty valve mechanism or crystallization of balloon fluid, yielding entrapment of the Foley catheter.⁶ One noninvasive method is introduction of a flexible guidewire into the balloon inflation channel after cutting off the plastic cylindrical valve from the catheter just below its head. The guidewire dilates the channel and may allow the balloon to deflate. If unsuccessful, try step 2; a 22-gauge central venous catheter can be passed over the guidewire. When the catheter tip is into the balloon, the wire can be removed, and the balloon may drain. If step 2 is unsuccessful, instill 10 mL of mineral oil and leave for 15 minutes in an attempt to dissolve the balloon. Repeat once (10 more mL of mineral oil) if unsuccessful. If simple methods do not work, urologic consultation for intervention and potential cystoscopy is recommended.⁷ Another alternative is US-guided percutaneous rupture of the balloon using a needle, typically done by the radiologist in the US suite with input from urology.

Percutaneous nephrostomy is a urinary drainage procedure used for supravesical or ureteral obstruction secondary to malignancy, pyonephrosis, GU stones, and ureteral strictures. It is also adjunctive to lithotripsy and ureteral stents. Nephrostomy tubes are also used for urinary diversion associated with vesical fistula, ureteral transection, and trauma. The percutaneous procedure to remove renal calculi is known as percutaneous nephrolithotomy. Nephrostomy tubes or stents are commonly left in place, but the tubeless percutaneous nephrolithotomy technique may have less risk of morbidity.⁸ Patients develop postoperative complications days or months after the percutaneous nephrostomy. In general, the risk of complications is low and includes bleeding, infection, mechanical complications related to the catheter (dislodgement or obstruction), and accidental punctures of adjacent organs.⁸

During insertion, injury can occur to the renal collecting system (subintimal dissection), lungs (pneumothorax), liver, spleen, and bowel (perforation).⁹ This complication usually is clinically apparent during or immediately after the procedure, but recognition may be delayed a few days.⁹

Bleeding and hemorrhage can occur, especially if the patient has a coagulopathy. Check hemoglobin, hematocrit, and renal function. Obtain coagulation studies (prothrombin time, partial thromboplastin time, and platelet count) and type and cross-match if bleeding is excessive or if coagulopathy is suspected. Most bleeding episodes are mild and can be managed with irrigation to clear nephrostomy tube blood clots. More severe bleeding can be handled by catheter tamponade, a procedure undertaken by the urologist and radiologist. Severe hemorrhage occurs from vascular injury, such as laceration of an artery, formation of an arteriovenous fistula, or bleeding from a pseudoaneurysm, and may occur in the retroperitoneal space or perirenal areas. In such cases, fluid resuscitation and blood transfusion, in addition to more definitive interventions, are required. Angiographic studies with possible embolization may be needed to ascertain the site of bleeding and effect treatment.⁹ Infectious complications from nephrostomy tubes include simple bacteriuria, pyelonephritis, renal abscess, bacteremia, and urosepsis. Signs and symptoms are fever, chills, rigors, pain, and purulent drainage at the site or from the tube. Obtain urine and wound drainage (if present) cultures, and give antibiotics after consultation with the urologist.

Mechanical complications, such as catheter dislodgement, tube blockage, and residual stone fragments, can occur with these devices. CT scan may be helpful for specific diagnosis. The risk of catheter dislodgement increases with increasing duration of the nephrostomy. Dislodgement occurring in the early postoperative period usually requires creation of a new tract at a different site. Dislodgement occurring after some period may be treated by recannulation under fluoroscopic guidance. Tube blockage can occur secondary to encrustations and kinking. The urologist has several techniques available to reestablish access to an obstructed nephrostomy tube.^8,9

The most common method of urinary diversion in the United States is the ileal conduit. With this procedure, a section of small bowel is isolated, and the free ends of the remaining small bowel are reunited, allowing for normal bowel function. The ureters are reimplanted to the isolated section of small bowel, most commonly at the base of the conduit. A stoma is created, typically on the anterior abdominal wall, where a collecting bag is attached. Postoperative complications include bowel obstruction, pyelonephritis, skin breakdown surrounding the stoma, stenosis of the stoma, and inflammatory changes of the upper tract due to reflux of urine back into the ureters. Complications occur in 66% of patients, including deterioration in kidney function (27%), stoma stenosis or infection (24%), bowel obstruction or symptoms (24%), symptomatic UTI/pyelonephritis (23%), conduit/ureteral anastomosis dysfunction (14%), and urolithiasis (9%).¹⁰