In a 20-year-old male with acute right flank pain, gross hematuria, vomiting and diarrhea after eating pork, what is the most likely diagnosis and appropriate management?

Diagnosis and Management

The most likely diagnosis is urolithiasis (kidney stone), and you should immediately obtain a non-contrast CT abdomen/pelvis to confirm the diagnosis, followed by NSAIDs for pain control and supportive care while monitoring for complications.

Clinical Reasoning

This 20-year-old male presents with the classic triad of renal colic: right flank pain, hematuria, and associated gastrointestinal symptoms (vomiting). While the history of pork consumption and diarrhea raises consideration of foodborne illness, the combination of flank pain with hematuria strongly points toward urolithiasis as the primary diagnosis 1, 2.

Key Diagnostic Considerations

The gastrointestinal symptoms (vomiting, loose stool) are commonly seen with renal colic due to:

• Ureteral hyperperistalsis causing referred pain
• Shared autonomic innervation between the urinary and GI tracts
• The acute pain response itself

The temporal relationship with pork consumption is likely coincidental rather than causative, though you should remain alert for alternative diagnoses if imaging is negative.

Diagnostic Workup

Imaging (Priority Order)

First-line: Non-contrast CT abdomen/pelvis

• This is the reference standard with 97% sensitivity for detecting stones 2
• Detects stones of all sizes and compositions
• Identifies complications (hydronephrosis, perinephric inflammation)
• Rules out alternative diagnoses
• Use low-dose protocol to minimize radiation exposure 1

Alternative if CT unavailable: Ultrasound

• Initial sensitivity only 45% for ureteral stones but 94% specificity 1
• Can detect hydronephrosis and complications
• Useful for assessing obstruction even if stone not directly visualized 2
• Consider combining with KUB radiography (increases sensitivity to 90%) 2

Laboratory Testing

Obtain immediately 1:

• Urinalysis with dipstick - confirms hematuria, checks for infection
• Complete blood count - assess for infection/complications
• Serum creatinine - evaluate renal function
• C-reactive protein (CRP) - assess inflammatory response
• Uric acid, ionized calcium - metabolic evaluation

Critical: Check for fever and signs of infection - if present, this becomes a urologic emergency requiring urgent intervention 1.

Treatment Approach

Immediate Pain Management

NSAIDs are first-line therapy 1:

• Diclofenac, ibuprofen, or metamizole
• Superior to opioids for renal colic
• Reduce need for additional analgesia
• Caution: Use lowest effective dose due to cardiovascular and GI risks

Definitive Management Strategy

Treatment depends on stone characteristics identified on imaging 1:

Stones <5mm:

• High likelihood of spontaneous passage
• Conservative management with hydration
• Pain control as needed
• Outpatient follow-up

Stones 5-10mm:

• Moderate passage rates
• Consider medical expulsive therapy
• Close monitoring for complications

Stones >10mm or complications:

• Likely require intervention (ureteroscopy, lithotripsy, or percutaneous nephrolithotomy)
• Urgent urology consultation

Critical Red Flags Requiring Immediate Intervention

Watch for 1:

• Fever with obstructing stone - indicates infected hydronephrosis (urosepsis risk)
• Solitary kidney - any obstruction is an emergency
• Bilateral obstruction - acute renal failure risk
• Intractable pain or vomiting - may require admission
• Acute renal failure (elevated creatinine)

Alternative Diagnoses to Consider

If imaging is negative for stones, consider 3, 4, 5:

• Hemolytic uremic syndrome - especially with bloody diarrhea history (though typically presents with more systemic findings)
• Renal artery thrombosis - sudden onset, elevated LDH, but patient is young without typical risk factors
• Subcapsular hematoma (Page kidney) - can mimic stone presentation
• Gastrointestinal pathology - though less likely with hematuria

Common Pitfalls to Avoid

• Don't anchor on the GI symptoms - the hematuria with flank pain makes urolithiasis most likely
• Don't skip imaging - clinical diagnosis alone is insufficient
• Don't use contrast-enhanced CT initially - it obscures stone visualization 2
• Don't dismiss fever - infected obstructed kidney requires emergency decompression
• Don't forget stone analysis - if stone passes or is retrieved, send for composition analysis to guide prevention 1