Laboratory Tests for Compartment Syndrome in Arterial Thrombosis
Monitoring for compartment syndrome is essential in patients with arterial thrombosis, with serum creatine kinase being the most important laboratory marker to assess muscle damage. 1
Clinical Context
Compartment syndrome is a serious complication following arterial thrombosis and revascularization, characterized by increased pressure within a fascial compartment that can lead to tissue necrosis, functional impairment, and limb loss if not promptly diagnosed and treated 2.
Primary Laboratory Tests
Serum creatine kinase (CK): Elevated levels indicate muscle damage and are a key marker for compartment syndrome. CK levels may not peak until up to 24 hours after the initial event 1
Myoglobin: Elevated serum and urine myoglobin levels indicate muscle breakdown and are associated with compartment syndrome following revascularization 1
Serum lactate: Should be measured to estimate and monitor the extent of ischemia and shock 1
Base deficit: Useful to estimate and monitor the severity of ischemia and shock 1
Additional Laboratory Tests
Serum potassium: Elevated levels may indicate significant muscle damage and cell lysis. Treatment with sodium bicarbonate and/or glucose with insulin may be necessary for hyperkalaemia 1
Renal function tests (creatinine, BUN): Important to monitor for acute kidney injury secondary to myoglobinuria 1
Coagulation profile (PT, PTT, INR, fibrinogen): To assess for coagulopathy which may develop in severe cases 1
Complete blood count: To evaluate for evidence of hemolysis or infection 1
Monitoring Approach
Laboratory tests should be performed at regular intervals (every 4-6 hours initially) in patients with arterial thrombosis, especially following revascularization 1
Trending of CK levels is more valuable than a single measurement, as levels may continue to rise for 24-48 hours 1
Persistent elevation or rapid increase in CK levels should prompt immediate clinical reassessment for compartment syndrome 1
Clinical Correlation
Laboratory tests should always be correlated with clinical findings. The diagnosis of compartment syndrome is primarily clinical and is based on:
- Pain out of proportion to injury, especially pain on passive stretch 3
- Paresthesia, pallor, paralysis, and pulselessness (the "5 Ps" - though these are often late findings) 4
- Direct measurement of compartment pressures when clinical diagnosis is uncertain 3
Special Considerations
In patients with arterial thrombosis who have undergone revascularization (surgical or endovascular), the risk of compartment syndrome is particularly high due to reperfusion injury 1
Patients with prolonged ischemia (>2.5 hours) are at higher risk for developing compartment syndrome and should have more frequent laboratory monitoring 2
Patients with popliteal artery involvement are at particularly high risk and require close monitoring 2
Compartment syndrome can develop even after successful revascularization due to reperfusion injury 5
Remember that while laboratory tests are valuable, they should not delay treatment if clinical signs of compartment syndrome are present. Fasciotomy is the definitive treatment for established compartment syndrome 1.