What are the steps to diagnose and manage extremity compartment syndrome?

How to Check for Extremity Compartment Syndrome

Diagnose compartment syndrome clinically based on pain out of proportion to injury and pain with passive muscle stretch; measure compartment pressures only when clinical diagnosis remains uncertain, particularly in obtunded patients. 1

Clinical Diagnosis Algorithm

Step 1: Assess for the Earliest Warning Sign

• Pain out of proportion to the injury is the earliest and most reliable warning sign of acute compartment syndrome (ACS). 1
• Pain on passive stretch of the affected muscle compartment is considered the most sensitive early sign. 1
• However, severe pain alone gives only approximately 25% chance of correctly diagnosing ACS. 1

Step 2: Perform the "5 P's" Examination (Understanding Their Limitations)

• Pain: Assess severity relative to injury mechanism 1
• Pain on passive stretch: Increases positive predictive value to 68% when combined with severe pain 1
• Paresthesia: Results from nerve ischemia 1
• Paralysis: Late sign indicating significant tissue damage 1
• Pulselessness/Pallor/Poikilothermia (coldness): Late signs indicating severe tissue damage 1

Critical Pitfall: When pain, pain on passive stretch, and paralysis are all present, positive predictive value reaches 93%, but paralysis indicates irreversible muscle ischemia may have already occurred. 1 Never wait for late signs. 1

Step 3: Palpate the Compartment (With Caution)

• Assess for increasing firmness/tension of the compartment as intracompartmental pressure rises. 1
• Palpation alone is unreliable (sensitivity 54%, specificity 76% in children). 1

When to Measure Compartment Pressures

Indications for Pressure Measurement

• Clinical diagnosis remains uncertain 1
• Obtunded, confused, or uncooperative patients who cannot report pain 1
• Sedated patients in ICU settings 1
• Consider continuous monitoring in high-risk, obtunded patients 1

Measurement Technique and Interpretation

• Use traditional needle manometry, multiparameter monitors, or dedicated transducer-tipped intracompartmental pressure monitors. 1
• Fasciotomy is indicated when:
  • Compartment pressure ≥30 mmHg, OR 1, 2
  • Differential pressure (diastolic blood pressure minus compartment pressure) ≤30 mmHg 1, 2
• The differential pressure threshold is the most recognized cut-off for intervention in current practice. 1

Immediate Management Steps

When Compartment Syndrome is Suspected

1. Remove all constricting dressings, casts, or splints immediately 1
2. Position the limb at heart level (not elevated) to avoid further decreasing perfusion pressure 1, 3
3. Arrange urgent surgical consultation for fasciotomy without delay 1
4. Measure compartment pressures only if diagnosis remains in doubt 1

Critical Pitfall: Elevating the limb excessively can further decrease perfusion pressure and worsen ACS. 1, 3

Role of Imaging (Limited)

• Plain X-rays should not be used to rule out compartment syndrome and are frequently normal unless infection and necrosis are advanced. 1
• CT has higher sensitivity than plain radiography, showing fat stranding, fluid collections, and fascial thickening. 1
• Ultrasound has no established role in acute compartment syndrome diagnosis. 1
• Never order imaging studies that delay surgical intervention. 1

High-Risk Populations Requiring Heightened Vigilance

• Young men under 35 years with tibial fractures 1, 3
• Tibial shaft fractures (4-5% develop ACS) 3
• Crush injuries or high-energy trauma 1
• Vascular injuries (particularly when combined with fractures) 1, 3
• Burns 1, 3
• Patients on anticoagulation 1, 3

Special Monitoring for Vascular Injury

• Monitor repetitively every 30-60 minutes during the first 24 hours for early signs: pain, tension, paresthesia, and paresis. 3
• Maintain extremely high clinical suspicion when vascular injury is present with fractures. 3
• Prophylactic fasciotomy is reasonable in patients with threatened but salvageable limbs based on clinical findings. 3

Common Diagnostic Pitfalls to Avoid

• Waiting for pulselessness, pallor, and paralysis leads to significant tissue damage 1
• Relying solely on palpation for diagnosis 1
• Delaying diagnosis in obtunded patients 1
• Missing ACS in patients without fractures (can occur with soft tissue injuries alone) 1
• Placing or leaving constricting casts/splints on injured extremities 4