Compartment syndrome

Pathophysiology

• Increased pressure>impaired perfusion>disruption of cellular metabolism>cytolysis with release of osmotically active contents into compartment>additional fluid drawn into compartment>increased pressure

Presentation

• Five Ps:
  • Pain, paresthesia, pallor, poikilothermia, pulselessness
    • Pain, paresthesias are NOT reliable
• Pain at rest or with passive ROM
• Sensory nerves are first to lose conductive ability

Etiology

• Usually develops soon after sig. trauma
  • (Particularly involving long bone fractures of the lower leg or forearm)
• May also occur following minor trauma or from nontraumatic causes:
  • Ischemia-reperfusion injury
  • Coagulopathy
  • Certain animal envenomations and bites
  • Extravasation of IV fluids
  • Injection of recreational drugs
  • Prolonged limb compression

Diagnosis

• Non-invasive tests are NOT reliable
• Stryker
  • Normal = 0-8mm Hg
  • Capillary blod flow begins to be compromised at 20mmHg
  • Signs/symptoms may develop with pressures above 20mmHg
  • Muscles and nerve fibers at risk at >30-40mmHg
  • Must interpret in light of SBP
    • Higher pressures may be necessary with systemic hypertension
      • May develop at lower pressures in those with hypotension or peripheral vascular disease
  • A single nl compartment pressure reading, early in course of disease, does NOT rule out comp sy.
  • Serial measurements important when pt risk is mod to high or clinical suspicion exists

Specific Syndromes

Forearm (<5%)

• Supracondylar humerus fracture (children)
• Distal radius fractures (adults)
• Deep volar
  • At highest risk for comp sy
  • Contains the digital flexors
    • Includes flexor digitorum profundus (responsible for distal interphalangeal joint flexion) and the flexor pollicis longus (responsible for interphalangeal joint flexion of the thumb)
  • Decreased wrist extension
• Superficial volar
• Dorsal
  • Contains the digital extensors
• Lateral

Lower (Leg 2-12% tibia)

• Anterior
  • Most common site compartment sy
  • contains the four extensor muscles of the foot, the anterior tibial artery, and the deep peroneal nerve
  • sx include loss of sensation between the 1st and 2nd toes and weakness of foot dorsiflexion
  • late sequelae include foot drop, claw foot, and deep peroneal nerve dysfunction
• Lateral
  • contains muscles for foot eversion and some plantar flexion (ie, peroneus brevis, peroneus longus), the peroneal artery, the superficial peroneal nerve, and the proximal portion of the deep peroneal nerve
  • sx include deep peroneal nerve deficit (weakness in dorsiflexion and inversion of the foot and sensory loss in the web space between the great toe and the adjacent toe)
  • superficial peroneal nerve also travels through this compartment and supplies sensation to the lower leg and foot
• Deep posterior
  • Muscles that aid in foot plantar flexion, as well as the posterior tibial artery, peroneal artery, and the tibial nerve
  • sx include plantar hypesthesia, weakness of toe flexion, and pain with passive extension of the toes
• Superficial posterior
  • Major muscles of plantar flexion (ie, gastrocnemius, soleus)
  • No major arteries or nerves in this compartment.
  • Least likely to develop ACS in lower leg
  • Sx include pain and a palpably tense and tender compartment

Treatment

• Raise limb to level of heart
• AVOID ice (will further compromise microcirculation)
• Bivalve or remove cast if present
• Surgery consult
• Definitive: Fasciotomy
  • Goal: <6hr

Source

Adapted from KajiQuestions and Donaldson; Perron (ACEP '09)