What is the appropriate management for a patient with acute kidney injury presenting with left groin pain?

Acute Kidney Injury with Left Groin Pain: Management Approach

This patient requires immediate hospital admission for evaluation of acute kidney injury (AKI) with concurrent left groin pain, as the rapid decline in GFR (64→49 in one day) with rising creatinine (1.11) and BUN (24) indicates acute renal dysfunction that may be complicated by urinary obstruction from nephrolithiasis. 1

Immediate Assessment and Red Flags

The combination of AKI and left groin pain strongly suggests renal colic with possible obstructive uropathy, which requires urgent evaluation within 30 minutes. 1

Critical exclusions requiring immediate admission:

• Shock or hemodynamic instability 1
• Fever or signs of systemic infection (infected obstructed kidney requires emergency decompression) 1, 2
• Age >60 years (must exclude leaking abdominal aortic aneurysm) 1
• Failure to respond to analgesia within 60 minutes 1

Physical examination priorities:

• Vital signs to exclude shock and systemic infection 1
• Abdominal examination for maximal tenderness, peritonitis, or pulsatile mass 1
• Volume status assessment (prerenal vs intrinsic renal AKI) 3, 4

Diagnostic Workup

Laboratory evaluation:

• Urinalysis for hematuria (present in >80% of renal colic cases, though absence doesn't exclude diagnosis) 1, 5
• Urine sodium, urine specific gravity, and renal failure index to differentiate prerenal from intrinsic AKI 6
• Complete blood count and electrolytes 4
• Fractional excretion of sodium (FENa) and urea (FEUrea) 3, 6

Imaging:

• Renal ultrasonography is mandatory to rule out obstructive uropathy, particularly given the groin pain and acute renal function decline 3, 4
• CT with IV contrast may be needed if ultrasound is inconclusive, though contrast exposure must be carefully considered given AKI 5

Pain Management Protocol

Administer intramuscular diclofenac 75 mg immediately to provide pain relief within 30 minutes, as this is first-line therapy for renal colic. 1, 2, 5

Important considerations:

• NSAIDs may be contraindicated in AKI - if so, use morphine sulfate plus cyclizine (opiate with antiemetic) 1, 2
• Avoid morphine, codeine, or tramadol in renal failure due to accumulation of active metabolites 2
• Consider fentanyl if opiates are needed as it doesn't accumulate metabolites in renal impairment 2
• Maintain pain control for at least 6 hours 1, 2

Follow-up assessment:

• Telephone follow-up 1 hour after analgesia administration 1, 2
• If pain not controlled within 60 minutes, arrange immediate hospital admission 1, 2
• Abrupt recurrence of severe pain warrants immediate admission 1

Management of Acute Kidney Injury

Volume management:

• Determine volume status carefully - prerenal AKI requires fluid resuscitation with isotonic crystalloid 3, 4
• Volume overload requires diuretics 3
• Avoid nephrotoxic medications (NSAIDs, ACE inhibitors, contrast agents) 3, 4

Indications for nephrology consultation:

• Stage 3 or higher AKI 3
• Inadequate response to supportive treatment 3
• AKI without clear cause 3
• Preexisting stage 4 or higher chronic kidney disease 3
• Potential need for renal replacement therapy 3, 4

Renal replacement therapy indications:

• Refractory hyperkalemia 4
• Volume overload unresponsive to diuretics 4
• Intractable acidosis 4
• Uremic encephalopathy, pericarditis, or pleuritis 4

Specific Management for Obstructive Uropathy

If imaging confirms urinary obstruction with infection, urgent decompression via percutaneous nephrostomy or ureteral stenting is required. 2

Stone management:

• 90% of stones pass spontaneously 5
• Instruct patient to drink copious fluids 1
• Void urine through strainer to catch calculus for analysis 1
• Arrange imaging within 7 days if managed as outpatient 1
• Urgent urology consultation within 1 week if intervention needed 1

Common Pitfalls to Avoid

• Never delay analgesia while waiting for diagnostic tests 2, 7
• Don't discharge before ensuring adequate pain control for 6 hours 2, 7
• Don't miss signs of infected obstructed kidney (requires emergency decompression) 2
• Don't use NSAIDs without considering AKI severity (may worsen renal function) 3, 4
• Don't assume absence of hematuria excludes renal colic 1, 5