In a 73-year-old female undergoing chemotherapy who now has abdominal cramping, right‑sided flank pain, increased urinary urgency and frequency, and a normal urinalysis performed two days ago, what is the appropriate evaluation and management?

Immediate Imaging with CT Scan is Essential—This is Likely Urolithiasis or Chemotherapy-Related Urothelial Toxicity

In a 73-year-old woman on chemotherapy presenting with right flank pain, abdominal cramping, and urinary urgency/frequency despite a normal UA 2 days ago, you must obtain urgent imaging with ultrasound followed by non-contrast CT scan to rule out urolithiasis and assess for hydronephrosis or chemotherapy-induced inflammatory ureteritis/cystitis. 1, 2

Diagnostic Approach

Why the Normal UA Doesn't Rule Out Serious Pathology

• Urolithiasis remains highly likely despite the recent normal urinalysis. Urine dipstick has limited sensitivity (45% for ultrasound detection of stones), and a stone can cause obstruction and pain without immediate pyuria or hematuria 1
• Chemotherapy-associated urothelial toxicity can present with these exact symptoms and may not show abnormalities on routine urinalysis initially 2
• In elderly patients, urinary symptoms are often atypical and non-specific 3

Immediate Diagnostic Steps

1. Start with bedside ultrasound to assess for:

   • Hydronephrosis (sensitivity 45%, specificity 94% for ureteral stones) 1
   • Free fluid suggesting other pathology
   • This should not delay further workup 1

2. Proceed directly to non-contrast CT scan (the gold standard):

   • Sensitivity 93.1%, specificity 96.6% for stone disease 1
   • Will identify stone location, size, density, and degree of obstruction
   • Can also detect inflammatory changes in the ureter/bladder wall suggesting chemotherapy toxicity 2
   • Low-dose protocol is appropriate to minimize radiation 1

3. Obtain fresh urinalysis with microscopy (not just dipstick):

   • Negative dipstick for nitrite AND leukocyte esterase has reasonable negative predictive value 3
   • However, microscopy may reveal findings missed on dipstick
   • Send urine culture if any abnormality detected

4. Blood work: creatinine, CBC, CRP to assess for:

   • Acute kidney injury from obstruction
   • Systemic inflammation
   • Infection markers 1

Critical Differential Diagnoses to Consider

Most Likely: Urolithiasis

• Right-sided flank pain with urinary symptoms is classic
• Stone passage can occur with intermittently normal UA
• Requires urgent imaging to assess for obstruction 1

Chemotherapy-Induced Urothelial Toxicity

• This is an underrecognized but serious complication 2
• Can present with hematuria, flank pain, urinary urgency/frequency
• May show hydronephrosis and inflammatory fat stranding on CT
• A recent case report documented severe inflammatory cystitis and ureteritis after docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP) therapy requiring corticosteroids 2
• If CT shows hydroureter with inflammatory changes but no stone, consider this diagnosis

Less Likely but Important

• Complicated UTI (pyelonephritis) - though less likely with normal recent UA
• Tumor-related obstruction (given cancer history)
• Radiation cystitis if she has had pelvic radiation 4, 5

Management Algorithm

If Stone Disease Confirmed:

1. Pain control: NSAIDs (diclofenac, ibuprofen) are first-line over opioids 1

   • Use lowest effective dose given cardiovascular/GI risks in elderly

2. Stone size determines management:

   • <5mm: Conservative management with hydration, analgesia
   • 5-10mm: Consider medical expulsive therapy

   • 10mm or signs of obstruction: Urology consultation for intervention 1

3. Monitor for complications: fever, worsening renal function, intractable pain requiring urgent intervention

If Inflammatory Ureteritis/Cystitis Suspected:

1. Rule out infection with culture
2. Consider corticosteroids (prednisolone 60mg daily) if imaging shows inflammatory changes without stone and symptoms persist despite supportive care 2
3. Oncology consultation regarding chemotherapy continuation
4. Supportive care: hydration, bladder irrigation if hematuria develops

If Imaging is Negative:

• Reassess for non-urological causes of abdominal pain
• Consider gynecological pathology
• Evaluate for constipation (common in elderly on chemotherapy)

Critical Pitfalls to Avoid

• Don't assume the normal UA from 2 days ago excludes current pathology—clinical picture trumps old labs
• Don't anchor on UTI in elderly patients with atypical presentations; broader differential is essential 3
• Don't miss chemotherapy-related complications—this is increasingly recognized with modern regimens 2
• Don't delay imaging waiting for symptoms to evolve—obstruction can cause permanent renal damage
• Don't use empiric antibiotics without clear evidence of infection (no fever, no systemic signs, normal recent UA) 3

The key is urgent imaging to differentiate between obstructive uropathy (stone), inflammatory toxicity (chemotherapy), and other causes—management diverges significantly based on this distinction.