What are the implications and necessary actions for a patient with a creatinine level of 1.11, left-sided hip and groin pain, and a significant drop in a related measurement from 64 to 49 in one day?

Immediate Evaluation for Occult Hip Fracture

This patient requires urgent MRI of the left hip to rule out an occult femoral neck fracture, as the combination of acute hip/groin pain following trauma with normal initial radiographs is a classic presentation that can progress to displacement if missed. 1

Critical Clinical Context

The creatinine of 1.11 mg/dL is mildly elevated but does not meet criteria for acute kidney injury (which requires ≥0.3 mg/dL increase within 48 hours or 50% increase within 7 days). 2 However, the unclear measurement that "went from 64 to 49 in one day" requires clarification—if this represents hemoglobin dropping from 64 g/L to 49 g/L (6.4 to 4.9 g/dL), this indicates significant acute blood loss requiring immediate transfusion. 1

Primary Concern: Occult Hip Fracture

The left-sided hip and groin pain is the dominant clinical concern that must be addressed immediately, as occult hip fractures can become displaced and lead to significant morbidity if not diagnosed early. 1

Why Hip Fracture Must Be Ruled Out:

• Initial radiographs miss 2-10% of hip fractures, particularly basicervical and nondisplaced femoral neck fractures 1
• MRI is the gold standard for detecting occult hip fractures when plain radiographs are negative but clinical suspicion remains high 1
• Delayed diagnosis leads to fracture displacement, converting a potentially stable injury requiring simple fixation into one requiring arthroplasty 1
• Hip joint pathology is the most common cause of groin pain in active populations (56% of cases), with femoroacetabular impingement, labral tears, and fractures being primary considerations 3

Immediate Actions Required:

• Obtain MRI of the left hip within 24-48 hours if patient cannot bear weight or has significant pain with hip rotation 1
• Keep patient non-weight bearing until fracture is definitively excluded 1
• Provide adequate analgesia to allow proper clinical assessment 1

Creatinine Assessment

The creatinine of 1.11 mg/dL requires contextualization:

If This Represents Baseline Kidney Function:

• Calculate eGFR using the MDRD equation rather than relying on creatinine alone, as serum creatinine grossly overestimates kidney function 1
• A creatinine of 1.11 mg/dL may represent significantly reduced GFR depending on age, sex, race, and body size 1
• For a 71-year-old male with creatinine 1.42 mg/dL (as in the case example), this was considered acceptable for proceeding with hip surgery 1

If This Represents Acute Change:

• Review all nephrotoxic medications including NSAIDs, ACE inhibitors, and contrast agents 1
• Assess volume status and ensure adequate hydration, particularly if patient has been immobile due to pain 1
• Recheck creatinine within 1-2 weeks to determine trajectory 4

Management of Potential Blood Loss

If the "64 to 49" represents hemoglobin:

• Transfuse to maintain hemoglobin ≥8 g/dL in the setting of hip fracture, though avoid overtransfusion 1
• Identify source of bleeding: occult hip fractures can cause significant blood loss into the thigh (500-1500 mL) 1
• Monitor for compartment syndrome if significant bleeding into the thigh is suspected, checking for pain with passive stretch, paresthesias, and paresis every 30-60 minutes 1

Surgical Planning Considerations (If Fracture Confirmed)

Timing:

• Surgery should be performed as soon as medically optimized, ideally within 24-48 hours 1
• The creatinine of 1.11 mg/dL does not contraindicate surgery unless it represents acute kidney injury requiring intervention 1

Anesthesia:

• Either spinal or general anesthesia is appropriate for hip fracture surgery (strong evidence, strong recommendation) 1

VTE Prophylaxis:

• Initiate pharmacological thromboprophylaxis with LMWH within 6-36 hours after hemorrhage control 1
• Continue VTE prophylaxis for 4 weeks postoperatively (strong recommendation) 1

Common Pitfalls to Avoid

• Do not discharge the patient without MRI if they cannot bear weight or have pain with hip rotation—this is how occult fractures become displaced 1
• Do not delay imaging for "conservative management"—the case example shows a patient who returned 2 days later with worsened pain and was found to have a displaced fracture 1
• Do not attribute groin pain solely to muscle strain without excluding hip joint pathology, as 56% of chronic hip/groin pain relates to intra-articular pathology 3
• Do not stop necessary medications based solely on creatinine 1.11 mg/dL unless there is evidence of acute kidney injury or the value represents significant change from baseline 1

Follow-Up Monitoring

If Fracture Excluded:

• Consider alternative diagnoses including femoroacetabular impingement, labral tears, adductor-related pain, or iliopsoas pathology 3
• Recheck creatinine in 1-2 weeks to ensure stability 4
• Physical therapy referral if musculoskeletal cause identified 5

If Fracture Confirmed:

• Proceed with surgical fixation or arthroplasty based on fracture pattern and patient factors 1
• Monitor renal function perioperatively, particularly if contrast or nephrotoxic antibiotics required 1
• Long-term osteoporosis evaluation and treatment (strong recommendation) 1