What is the best course of treatment for an elderly woman with a recent history of open reduction internal fixation (ORIF) surgery, presenting with weakness and leukocytosis (elevated white blood cell count)?

Postoperative Leukocytosis After ORIF in Elderly Patients

Leukocytosis to 22,000 cells/mm³ after ORIF in an elderly patient is most commonly a normal physiologic stress response to surgery rather than infection, but requires clinical correlation with fever, wound signs, and left shift to determine if infection workup is warranted. 1, 2, 3

Understanding Postoperative Leukocytosis

Postoperative leukocytosis is extremely common after orthopedic surgery and represents normal surgical stress response in most cases:

• After total hip and knee arthroplasty, 38% of patients develop postoperative leukocytosis, with WBC counts typically peaking at approximately 3 × 10⁶ cells/μL over the first 2 postoperative days before declining by day 4 3
• The sensitivity of WBC count alone for diagnosing early periprosthetic infection is only 79% with specificity of just 46%, making it a poor standalone marker 3
• Leukocytosis >17 × 10⁹/L may indicate infection (commonly chest or urinary), but leucocytosis and neutrophilia are common (45% and 60% respectively) at presentation as a reactive response to trauma rather than infection 1

Critical Clinical Assessment Required

You must evaluate specific clinical parameters beyond the WBC count to determine infection probability:

High-Risk Features Suggesting Infection 1, 2, 4

• Fever ≥38.0°C - obtain blood cultures and start antibiotics immediately 2
• Left shift with band neutrophils ≥16% or absolute band count ≥1,500 cells/mm³ - likelihood ratio of 4.7 and 14.5 respectively for bacterial infection, even with normal total WBC 4
• Wound erythema, drainage, or dehiscence 2
• Respiratory symptoms with productive cough 2
• Urinary symptoms with dysuria or increased incontinence 1, 4

Laboratory Markers with Better Specificity 2

• C-reactive protein (CRP) ≥5 mg/dL has higher sensitivity and specificity than WBC for detecting postoperative complications 2
• Procalcitonin has higher diagnostic accuracy than CRP for bacterial sepsis, though more expensive 2
• Serum lactate, renal function, and blood gas analysis should be obtained if infection suspected 2

Recommended Diagnostic Algorithm

If Patient Has Fever, Wound Signs, or Left Shift 2, 4

1. Obtain blood cultures before starting antibiotics 2
2. Check manual differential for band count (automated analyzers are insufficient) 4
3. Measure CRP and consider procalcitonin 2
4. Obtain site-specific cultures:
   • Urinalysis with culture if urinary symptoms 4
   • Chest X-ray if respiratory symptoms 1, 4
   • Wound aspiration if fluctuance or drainage 4
5. Initiate empiric broad-spectrum antibiotics immediately without waiting for culture results 2

If Patient is Afebrile Without Clinical Signs 1, 2, 3

• No additional workup warranted - postoperative leukocytosis represents normal physiologic response 3
• Observe clinically and repeat CBC in 24-48 hours to confirm downtrending 3
• Do not start empiric antibiotics based on leukocytosis alone 3

Special Considerations in Elderly Patients

Elderly patients present unique diagnostic challenges that require heightened vigilance:

• Older patients may have decreased basal body temperature and frequently lack typical infection symptoms despite serious infection 4
• Age >70 years, ASA ≥3, diabetes, and chronic heart disease are risk factors for surgical site infection after ORIF 1
• Elderly patients have higher baseline functional limitations and may not manifest typical signs of sepsis 5
• Hypokalaemia, hypomagnesaemia, hypovolaemia, and hypoxaemia can all cause physiologic stress leukocytosis and should be corrected 1

Common Pitfalls to Avoid

Critical errors that lead to inappropriate management:

• Do not pursue extensive infection workup for isolated leukocytosis without fever, left shift, or clinical signs - this leads to unnecessary antibiotics and resistant organism colonization 3, 6
• Do not rely on automated differential alone - manual differential is essential for accurate band assessment 4
• Do not ignore fever ≥38.0°C even if WBC is only mildly elevated - obtain cultures and start antibiotics 2
• Do not use leukocytosis as a single marker to diagnose or exclude specific surgical complications 2
• Do not continue empiric broad-spectrum antibiotics without documented infection, as this promotes C. difficile colonization and resistant organisms 6

Persistent Unexplained Leukocytosis

If leukocytosis persists beyond 4-5 days without identified source:

• Consider persistent inflammation-immunosuppression and catabolism syndrome (PICS), particularly in patients with major trauma or extensive tissue damage 6
• Look for eosinophilia >500 cells/mm³ developing around hospital day 12, which supports PICS rather than active infection 6
• Avoid prolonged empiric antibiotics - these patients have tissue damage driving inflammation rather than active infection 6
• Monitor for opportunistic colonization including C. difficile, which occurred in 21% of patients with persistent unexplained leukocytosis 6