What is the diagnosis and appropriate treatment for a patient experiencing consistent groin pain over the last few weeks, with a history of intermittent groin pain for a few months, accompanied by discolored urine and lower back pain radiating to the anterior left side?

Diagnosis: Urolithiasis (Kidney Stone) with Possible Obstruction

This patient most likely has urolithiasis causing ureteral obstruction, and requires urgent imaging with non-contrast CT abdomen/pelvis and immediate urology referral if obstruction is confirmed.

Clinical Presentation Analysis

The constellation of symptoms—groin pain, discolored urine (likely hematuria), and left-sided lower back pain radiating anteriorly—represents the classic triad of urolithiasis 1, 2. This presentation pattern has over 80% likelihood of representing renal colic from a ureteral stone 3.

Key diagnostic features present:

• Radiation pattern: Left flank pain radiating anteriorly to the groin is pathognomonic for ureteral calculus, as stones migrate down the ureter causing referred pain along the nerve distribution 2, 4
• Discolored urine: Strongly suggests hematuria from ureteral trauma, though absence of visible hematuria does not exclude stone disease 5, 6
• Progressive pain pattern: Intermittent pain over months progressing to constant pain suggests stone migration with possible impaction 2

Immediate Diagnostic Workup Required

Imaging (Gold Standard):

• Non-contrast CT abdomen/pelvis is mandatory with 98-100% sensitivity and specificity for urolithiasis 5, 3
• This imaging will identify stone size, location, degree of obstruction, and alternative diagnoses 1
• Ultrasound can detect hydronephrosis but misses many stones; CT is superior 4

Laboratory evaluation:

• Urinalysis with microscopy (though 20% of confirmed stones have negative urinalysis) 5
• Urine culture if infection suspected 1, 6
• Serum creatinine to assess renal function 1
• Complete blood count if infection suspected 7

Red Flags Requiring Emergency Department Referral

This patient requires immediate ED evaluation if ANY of the following are present:

• Fever or chills: Suggests infected obstructed system (pyonephrosis)—a urologic emergency requiring immediate decompression 5, 3
• Inability to urinate or significantly decreased urine output: Indicates possible complete obstruction 5
• Hemodynamic instability: Requires urgent evaluation regardless of other findings 5
• Failure of analgesia after 1 hour: Mandates immediate hospital admission 5, 3
• Constant non-colicky pain: May indicate complete obstruction or alternative diagnosis 5

Treatment Algorithm

Immediate management (within 30 minutes):

• Provide rapid analgesia and reassess within 1 hour 5, 3
• If pain control fails, immediate hospital admission is required 5, 3

Based on imaging results:

Stones >5mm or complete obstruction:

• Urgent urology referral for intervention (ureteroscopy, stent placement, or percutaneous nephrolithotomy) 1, 5
• Complete obstruction with concurrent infection represents a urologic emergency requiring immediate decompression 5

Stones ≤5mm without obstruction:

• Conservative management with hydration and analgesia 2
• Spontaneous passage rates are higher for smaller, more distal stones 1
• Outpatient follow-up with repeat imaging if symptoms persist 2

Critical Differential Diagnoses to Exclude

While urolithiasis is most likely, the following life-threatening conditions must be ruled out:

• Abdominal aortic aneurysm (if patient >60 years): Can present with flank pain radiating to groin 3
• Pyelonephritis: Distinguished by fever, chills, and pain worsening with external flank pressure 5, 6
• Ectopic pregnancy (if female of reproductive age): Must be excluded with pregnancy test 5
• Lumbar compartment syndrome: Rare but presents with severe loin-to-groin pain, typically after exercise 8

Common Pitfalls to Avoid

• Do not rely on urinalysis alone: Over 20% of confirmed stones have negative urinalysis 5
• Do not delay imaging: Clinical diagnosis alone is insufficient; CT is required for definitive diagnosis and treatment planning 1, 3
• Do not miss infection: Fever with obstruction is an emergency requiring immediate decompression and antibiotics 1, 5
• Do not assume musculoskeletal cause: The anterior radiation pattern and discolored urine make visceral pathology (urolithiasis) far more likely than musculoskeletal back pain 1, 2