Compartment syndrome

Background

• Increased pressure within a closed fascial compartment compromising perfusion to muscles and nerves
• Surgical emergency — irreversible damage begins within 6-8 hours of ischemia
• Most common location: anterior compartment of the leg (tibia fractures)
• Causes:
  • Fractures (most common — especially tibia, forearm, supracondylar humerus in children)
  • Crush injuries, reperfusion injury after vascular repair
  • Burns (circumferential), tight casts/splints/dressings
  • Hemorrhage (anticoagulation), rhabdomyolysis
  • Envenomation (snakebite)
  • IV/IO infiltration
• Normal tissue pressure: 0-8 mmHg
• Ischemia begins when compartment pressure exceeds capillary perfusion pressure

Clinical Features

• The 6 P's (pain is earliest and most reliable; pulselessness is latest):
  • Pain — out of proportion to exam (most sensitive early finding)
  • Pain with passive stretch of muscles in affected compartment (most sensitive exam finding)
  • Pressure — tense, firm compartment on palpation
  • Paresthesias — indicates nerve ischemia
  • Paralysis — late finding; indicates significant ischemia
  • Pulselessness — very late finding; presence of pulses does NOT exclude compartment syndrome
• Key pearls:
  • Increasing analgesic requirements should raise suspicion
  • Normal pulses and capillary refill do NOT rule out compartment syndrome
  • Obtunded, intubated, or pediatric patients cannot report pain — maintain high index of suspicion

Differential Diagnosis

• Deep vein thrombosis
• Cellulitis / necrotizing fasciitis
• Fracture pain
• Peripheral vascular injury
• Neuropraxia
• Rhabdomyolysis without compartment syndrome
• Acute arterial occlusion

Evaluation

Clinical Diagnosis

• Compartment syndrome is primarily a CLINICAL diagnosis
• Serial examinations are essential
• Do not delay fasciotomy for pressure measurement if clinical picture is clear

Compartment Pressure Measurement

• Indicated when clinical exam is unreliable (obtunded, pediatric, equivocal exam)
• Methods: Stryker needle (most common in ED), arterial line transducer
• Absolute pressure >30 mmHg: concerning
• Delta pressure (diastolic BP minus compartment pressure) <30 mmHg: indicates need for fasciotomy
• Delta pressure is more reliable than absolute pressure (accounts for patient's perfusion status)
• Measure all compartments in the affected extremity (leg has 4: anterior, lateral, deep posterior, superficial posterior)

Labs

• CK (elevated in rhabdomyolysis)
• BMP (monitor renal function, hyperkalemia)
• Urinalysis (myoglobinuria)

Management

Immediate

• Remove all circumferential dressings, casts, and splints immediately
• Keep extremity at heart level (elevation may decrease arterial perfusion; dependent position worsens edema)
• Avoid hypotension — maintain adequate perfusion pressure
• IV fluid resuscitation if rhabdomyolysis

Fasciotomy

• Definitive treatment — emergent surgical consultation
• Four-compartment fasciotomy for lower leg
• Delay >6-8 hours: significantly increased risk of permanent neuromuscular damage, amputation
• Do NOT delay for imaging if diagnosis is clinically apparent
• Wound typically left open with delayed primary closure or skin grafting at 48-72 hours

Post-Fasciotomy Monitoring

• Serial CK, renal function, electrolytes
• Monitor for reperfusion injury (hyperkalemia, metabolic acidosis, rhabdomyolysis)
• Broad-spectrum antibiotics if contaminated wound

Disposition

• All suspected cases require admission and emergent orthopedic/surgical consultation
• ICU if rhabdomyolysis or hemodynamic instability
• Missed compartment syndrome is a significant medicolegal risk

See Also

• Rhabdomyolysis
• Fractures
• Crush syndrome
• Snakebite

References

• Via AG, et al. Acute compartment syndrome. Muscles Ligaments Tendons J. 2015;5(1):18-22. PMID 25878982
• Shadgan B, et al. Diagnostic techniques in acute compartment syndrome of the leg. J Orthop Trauma. 2008;22(8):581-587. PMID 18758292
• Schmidt AH. Acute compartment syndrome. Orthop Clin North Am. 2016;47(3):517-525. PMID 27241376