Compartment syndrome
Pathophysiology
Cycle: 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
-5 Ps: pain, paresthesias, pallor, poikilothermia, pulselessness
NB: pain, paresthesias are NOT reliable
-Pain at rest or with passive ROM
-Sensory nerves are first to lose conductive ability
Etiology==
Most often develops soon after significant 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
Striker
Normal = 0-8mm Hg
Capillary blod flow starts to be compromised at 20mmHg
-Symptoms and signs may develop with pressures above approximately 20 mmHg
Muscles and nerve fibers at risk at >30-40mmHg
- interpret in light of SBP
-The pressure necessary for injury varies
-Higher pressures may be necessary with systemic hypertension
-May develop at lower pressures in those with hypotension or peripheral vascular disease
-A single normal compartment pressure reading, early in the course of the disease, does NOT rule out comp sy.
-Serial or continuous measurements are important when patient risk is moderate to high or clinical suspicion exists.
Specific Syndromes
I. Forearm (<5%)
(most frequent injuries associated with comp sy in forearm are supracondylar humerus fractures in children and distal radius fractures in adults)
1) deep volar
-at highest risk for comp sy
-contains the digital flexors
-decreased wrist extension
-includes flexor digitorum profundus (responsible for distal interphalangeal joint flexion) and the flexor pollicis longus (responsible for interphalangeal joint flexion of the thumb)
2) superficial volar
3) dorsal
-contains the digital extensors
4) lateral
II. Lower (Leg 2-12% tibia)
1) 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
2) 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
3) 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
4) Superficial posterior
-the 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: < 6hours
Source
Adapted from KajiQuestions and Donaldson; Perron (ACEP '09)