A 31-year-old obese Caucasian female presents to the Emergency Department late in the evening for left lower quadrant pain that has progressively worsened over the last several hours. She describes the pain as sharp and shooting, coming and going. Her last bowel movement was this morning. She has also had dysuria and urgency. Her surgical history is notable for gastric bypass surgery 2 years prior and an appendectomy at age 9. She is sexually active with her boyfriend and uses condoms. Her temperature is 99.5 deg F (37.5 deg C), blood pressure is 151/83 mmHg, pulse is 86/min, respirations are 14/minute, BMI 32. On physical exam, she has left lower quadrant tenderness to palpation with pain radiating to the left groin and left flank tenderness on palpation. Her urinalysis shows 324 red blood cells/high power field. Her pregnancy test is negative. What is the next best step in management?

A KUB (kidneys, ureters and bladder) plain film

A 79-year-old man with a history of prostate cancer is brought to the emergency department because of lower abdominal pain for 1 hour. He has not urinated for 24 hours. Abdominal examination shows a palpable bladder that is tender to palpation. A pelvic ultrasound performed by the emergency department resident confirms the diagnosis of acute urinary retention. An attempt to perform transurethral catheterization is unsuccessful. A urology consultation is ordered and the urologist plans to attempt suprapubic catheterization. As the urologist is called to see a different emergency patient, she asks the emergency department resident to obtain informed consent for the procedure. The resident recalls a lecture about the different modes of catheterization, but he has never seen or performed a suprapubic catheterization himself. Which of the following statements by the emergency department resident is the most appropriate?

“I would prefer that you obtain informed consent when you become available again.”

“Suprapubic catheterization is not the treatment of choice for this patient.”

“I would be happy to obtain informed consent on your behalf, but I'm not legally allowed to do so during my residency.”

“I will make sure the patient reads and signs the informed consent form.”

“I will ask the patient to waive informed consent because this is an urgent procedure.”

A 61-year-old man comes to the physician because of several episodes of dark urine over the past 2 weeks. He does not have dysuria or flank pain. He works in a factory that produces dyes. Since an accident at work 5 years ago, he has had moderate hearing loss bilaterally. He takes no medications. He has smoked a pack of cigarettes daily for 29 years and drinks one alcoholic beverage daily. Vital signs are within normal limits. Physical examination shows no abnormalities. His urine is pink; urinalysis shows 80 RBC/hpf but no WBCs. Cystoscopy shows a 3-cm mass in the bladder mucosa. The mass is resected. Pathologic examination shows an urothelial carcinoma with penetration into the muscular layer. An x-ray of the chest and a CT scan of the abdomen and pelvis with contrast show a normal upper urinary tract and normal lymph nodes. Which of the following is the most appropriate next step in management?

Transurethral resection of tumor with intravesical BCG instillation

Transurethral resection of tumor with intravesical chemotherapy

Three hours after undergoing open proctocolectomy for ulcerative colitis, a 42-year-old male complains of abdominal pain. The pain is localized to the periumbilical and hypogastric regions. A total of 20 mL of urine has drained from his urinary catheter since the end of the procedure. Temperature is 37.2°C (98.9°F), pulse is 92/min, respirations are 12/min, and blood pressure is 110/72 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 99%. Physical examination shows a 20 cm vertical midline incision and an ileostomy in the right lower quadrant. There is no fluid drainage from the surgical wounds. The urinary catheter flushes easily and is without obstruction. Cardiopulmonary examination shows no abnormalities. Serum studies show a blood urea nitrogen of 30 mg/dL and a creatinine of 1.3 mg/dL. Which of the following is the most appropriate next step in management?

Administer intravenous furosemide

A 50-year-old man is brought to the emergency department because of a 3-day history of left flank pain. The patient has had two episodes of urolithiasis during the last year. He initially had pain with urination that improved with oxycodone. Over the past day, the pain has worsened and he has additionally developed fever and chills. He has hypertension and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 20 years. He does not drink alcohol. His current medications include metformin and lisinopril. The patient appears ill and uncomfortable. His temperature is 39.1°C (102.3°F), pulse is 108/min, respirations are 22/min, and blood pressure is 90/62 mm Hg. The lungs are clear to auscultation. Cardiac examination shows no murmurs, rubs, or gallops. Examination of the back shows left costovertebral angle tenderness. Physical and neurologic examinations show no other abnormalities. Laboratory studies show: Hemoglobin 14.2 g/dL Leukocyte count 13,900/mm3 Hemoglobin A1c 8.2% Serum Na+ 138 mEq/L K+ 3.8 mEq/L Cl- 98 mEq/L Calcium 9.3 mg/dL Glucose 190 mg/dL Creatinine 2.1 mg/dL Urine pH 8.3 Urine microscopy Bacteria moderate RBC 6–10/hpf WBC 10–15/hpf WBC casts numerous Ultrasound shows enlargement of the left kidney with a dilated pelvis and echogenic debris. CT scan shows a 16-mm stone at the left ureteropelvic junction, dilation of the collecting system, thickening of the wall of the renal pelvis, and signs of perirenal inflammation. Intravenous fluid resuscitation and intravenous ampicillin, gentamicin, and morphine are begun. Which of the following is the most appropriate next step in the management of this patient?

Ureteroscopy and stent placement

A 22-year-old man is rushed to the emergency department after a motor vehicle accident. The patient states that he feels weakness and numbness in both of his legs. He also reports pain in his lower back. His airway, breathing, and circulation is intact, and he is conversational. Neurologic exam is significant for bilateral lower extremity flaccid paralysis and impaired pain and temperature sensation up to T10-T11 with normal vibration sense. A computerized tomography scan of the spine is performed which shows a vertebral burst fracture of the vertebral body at the level of T11. Which of the following findings is most likely present in this patient?

Flaccid paralysis at the level of the lesion

Urinary diversion procedures Revision – USMLE Surgery

🌊 Why Reroute the Flow?

Urinary diversion creates a new path for urine to exit when the bladder is removed or non-functional. This is necessary to prevent renal damage from obstruction or reflux.

Ileal Conduit with Stoma

Bladder Removal (Cystectomy):
- Muscle-invasive bladder cancer (MIBC).
- Refractory non-muscle invasive disease or carcinoma in situ.
Bladder Dysfunction:
- Neurogenic bladder (e.g., spinal cord injury, spina bifida).
- Severe, intractable incontinence.
Trauma/Obstruction:
- Pelvic trauma damaging bladder/urethra.
- Irreparable fistulas or strictures.

⭐ The most common indication for urinary diversion in adults is radical cystectomy for muscle-invasive bladder cancer.

🛠️ Anatomy - Building New Plumbing

Urinary diversion re-routes urine flow after cystectomy. The choice of procedure balances surgical complexity with patient quality of life, dexterity, and oncologic goals.

Procedure Type	Bowel Segment	Continence & Stoma	Key Features & Complications
Ileal Conduit (Bricker)	Distal Ileum	Incontinent; requires external ostomy bag.	Simplest, fastest. Low pressure system. ⚠️ High risk of uretero-ileal stricture, parastomal hernia, pyelonephritis.
Indiana Pouch	R. Colon & Terminal Ileum	Continent; self-catheterization via abdominal stoma.	Internal reservoir, no bag. Higher surgical complexity. ⚠️ Risk of stone formation, mucus plugging, difficult catheterization.
Orthotopic Neobladder (Studer)	Ileum	Continent; voids via native urethra.	Most "natural" urination. Requires intact urethral sphincter & patient motivation. ⚠️ Risk of nocturnal incontinence, hypercontinence (retention).

⭐ Metabolic Complications: Using bowel segments for diversion leads to reabsorption of urinary solutes. The most common finding is a non-anion gap, hyperchloremic metabolic acidosis due to intestinal chloride absorption in exchange for bicarbonate.

📌 ACIDosis from Absorption of Chloride and Ileal/colonic Diversion.

⚠️ Complications - When Pipes Go Wrong

General Complications:
- Early (<30 days): Infection (UTI, pyelonephritis), anastomotic leak, prolonged ileus, DVT/PE.
- Late (>30 days): Stomal stenosis/hernia, uretero-enteric stricture → hydronephrosis, urolithiasis (struvite, calcium oxalate), vitamin B12 deficiency (if >50 cm of terminal ileum resected).
Metabolic Complications (High-Yield):

⭐ The bowel segment used determines the specific metabolic derangement due to reabsorption of urinary solutes.
- Ileum or Colon (Most Common):
  - Mechanism: Bowel reabsorbs urinary ammonium ($NH_4^+$) and chloride ($Cl^-$) while secreting bicarbonate ($HCO_3^-$).
  - Result: Hyperchloremic, hypokalemic, normal anion gap metabolic acidosis.
- Jejunum (Rarely Used):
  - Mechanism: High osmotic load from urine in the jejunal loop causes fluid and electrolyte shifts.
  - Result: Hyponatremic, hypochloremic, hyperkalemic metabolic acidosis. 📌 Mnemonic: "J" for "Jumpin' K⁺".

⚙️ Management - Keeping Systems Go

Post-Op Monitoring:
- Urine output >0.5 mL/kg/hr.
- Stoma viability: Should be pink and moist.
- Catheters/stents: Ensure patency; typically removed in 2-3 weeks.
Common Complications:
- Early: UTI, urine leak, ileus.
- Late: Uretero-intestinal stricture, stones, parastomal hernia.

⭐ High-Yield: Ileal conduits can cause a hyperchloremic, non-anion gap metabolic acidosis due to Cl⁻ absorption and HCO₃⁻ secretion by the intestinal mucosa.

Troubleshooting Low Output:

⚡ Biggest Takeaways

Radical cystectomy for muscle-invasive bladder cancer is the primary indication for urinary diversion.

Ileal conduit is the most common incontinent diversion, requiring an external ostomy appliance.

Orthotopic neobladder is a continent diversion allowing urethral voiding; risks include incontinence and retention.

Hyperchloremic, non-anion gap metabolic acidosis is a key complication from using bowel segments.

This occurs via Cl⁻ absorption and HCO₃⁻ secretion by the intestinal mucosa.

Long-term risks include uretero-intestinal strictures, recurrent UTIs, and vitamin B12 deficiency.

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