In a patient with an indwelling Foley catheter who develops dark (amber/brown) urine and abdominal distension, what is the appropriate evaluation and management?

Dark Urine in a Patient with Foley Catheter and Abdominal Distension

The combination of dark urine and abdominal distension in a catheterized patient requires immediate evaluation for bowel obstruction with potential urinary retention or catheter malfunction, followed by assessment for hematuria, infection, and catheter positioning. 1, 2

Immediate Assessment Priority: Rule Out Bowel Obstruction

The abdominal distension is the critical finding that must be addressed first, as it may indicate bowel obstruction with associated complications:

• Check vital signs immediately for tachycardia, tachypnea, hypotension, or signs of shock (cool extremities, altered mental status, oliguria), which suggest ischemia, perforation, or sepsis 1
• Examine the abdomen for peritoneal signs (rigidity, rebound tenderness) indicating ischemia or perforation, which are surgical emergencies 1
• Verify catheter patency and urine output - oliguria combined with abdominal distension may indicate hypovolemic or septic shock from bowel obstruction 1
• Obtain laboratory studies: complete blood count, renal function, electrolytes, lactate, and arterial blood gas to assess for intestinal ischemia (elevated lactate, metabolic acidosis, leukocytosis) 1

Evaluate Catheter Function and Positioning

Dark urine may indicate hematuria, concentrated urine from dehydration, or catheter malposition:

• Assess for "long catheter sign" - excessive catheter length outside the penis (in males) indicates the balloon is inflated in the urethra rather than bladder, causing urethral trauma and potential hematuria 3
• Verify adequate urine drainage - catheter obstruction from blood clots, encrustation, or malposition can cause bladder distension contributing to abdominal findings 4, 3
• Check for gross hematuria - if present with abdominal distension and the patient has history of pelvic trauma or recent catheterization, bladder injury must be excluded 2

Determine the Cause of Dark Urine

If Gross Hematuria is Present:

• Replace the catheter immediately if it appears obstructed or malpositioned to ensure adequate drainage 2
• Obtain imaging urgently if there is history of pelvic trauma, pelvic fracture, or difficult catheterization - retrograde cystography (plain film or CT) is mandatory as 29% of patients with gross hematuria and pelvic fracture have bladder rupture 2
• Look for signs of intraperitoneal bladder rupture: inability to void, low urine output despite adequate resuscitation, elevated BUN/creatinine, abdominal distension, suprapubic pain, or free fluid on imaging 2
• Do not attribute hematuria to catheter trauma alone if it is more than trace amounts - catheterization causes minimal hematuria (typically <4 RBCs per high-power field), so significant hematuria requires investigation for structural causes 5

If Urine is Dark but Not Bloody:

• Consider concentrated urine from hypovolemia - bowel obstruction causes third-spacing of fluids, and the patient may be significantly volume depleted 1
• Assess for infection - dark, cloudy urine with foul odor suggests catheter-associated UTI, though this should not delay evaluation of the abdominal distension 1, 2
• Check for catheter encrustation - chronic catheterization with Proteus mirabilis infection causes crystalline biofilm formation that can darken urine and obstruct flow 4

Management Algorithm

Step 1: Stabilize and Assess Severity

• Begin IV crystalloid resuscitation immediately with isotonic fluids to address hypovolemia from bowel obstruction 1
• Insert nasogastric tube if not already present to decompress the bowel and prevent aspiration 1
• Monitor urine output hourly via the Foley catheter as a marker of adequate resuscitation 1

Step 2: Imaging Based on Clinical Findings

• Obtain abdominal X-ray as first-line imaging for suspected bowel obstruction (sensitivity 74% for small bowel obstruction, 84% for large bowel obstruction) 1
• Obtain renal/bladder ultrasound if catheter malfunction is suspected - this will identify hydronephrosis, bladder distension despite catheter, or free fluid 1
• Obtain CT cystography if gross hematuria is present with pelvic trauma or if bladder injury is suspected - do NOT simply clamp the Foley and rely on IV contrast accumulation, as this inadequate technique misses injuries 2

Step 3: Catheter Management

• Replace the catheter if there is evidence of malposition, obstruction, or if it has been in place long-term and encrustation is suspected 2, 4
• Remove the catheter entirely if it is no longer medically necessary - each day of catheterization increases infection risk by 5%, and catheters should be removed within 24-48 hours when feasible 1, 6, 7
• Use intermittent catheterization (every 4-6 hours) rather than replacing an indwelling catheter if the patient only needs bladder volume monitoring 1, 6

Step 4: Treat Underlying Cause

• Surgical consultation is required if bowel obstruction is confirmed with signs of ischemia, perforation, or complete obstruction 1
• Urology consultation is required for persistent gross hematuria despite conservative measures, suspected bladder/urethral injury, or catheter management complications 2
• Obtain urine culture before antibiotics if catheter-associated UTI is suspected, but do NOT treat asymptomatic bacteriuria in catheterized patients 2, 7

Critical Pitfalls to Avoid

• Do not assume dark urine is simply concentrated or infection-related without first addressing the abdominal distension, which may represent a life-threatening surgical emergency 1
• Do not delay imaging in patients with gross hematuria and pelvic trauma - 29% have bladder rupture requiring immediate diagnosis 2
• Do not continue catheterization beyond 48 hours unless there is a specific ongoing indication (urinary retention, accurate output monitoring in shock, bladder irrigation for clot evacuation) 1, 6, 7
• Do not obtain urinalysis or urine culture in asymptomatic catheterized patients - bacteriuria is universal with long-term catheterization and treatment increases antibiotic resistance without benefit 7, 8
• Do not perform cystography by clamping the Foley and allowing IV contrast to accumulate - this technique is inadequate and misses bladder injuries 2

Follow-Up Considerations

• Monitor for resolution of both the abdominal distension and urine color changes after addressing the underlying cause 1
• Remove the catheter as soon as the acute illness resolves and implement a bladder training protocol if needed 1, 6
• Consider urologic evaluation if microscopic hematuria persists after catheter removal, though this is not urgent 2