Compartment syndrome occurs when hemorrhage or edema usually from trauma results in volume expansion of the tissues within a compartment leading to increased pressures and eventually tissue ischemia and cell death. The borders of the muscle compartments in the human body are defined by bone and fascia which have limited ability to stretch, so when the volume of the tissue within that space increases due to edema, the pressures in that space also increase. Increased pressure within a limited space limits circulation and eventually results in ischemia.

Most common sites are the anterior compartment of the lower leg and the volar compartment of the forearm.  But compartment syndrome can occur in any muscle compartment.

Clinically compartment syndrome presents with the 6 P’s:

• Pain  - out of proportion to exam**
• Paresthesia
• Pallor
• Paralysis
• Poikilothermia – affected limb is colder
• Pulselessness – occurs late

Compartment pressure

Normal below 10mmHg, but the body can usually tolerate up to 20mmHg without damage

Usually >30mmHg is considered the conservative threshold for the level at which tissue death starts to occur

Newer criteria use the delta pressure to define compartment syndrome:

Delta Pressure = Diastolic Pressure – Compartment Pressure

With a delta pressure <30mmHg indicating Compartment syndrome

Treatment is Emergent Surgical Fasciotomy

If you suspect compartment syndrome, you need to call your surgical consultants immediately as this is a very time sensitive surgical emergency with permanent damage occurring some time around 4-8hrs after the onset of ischemia.  Consider adding pre-op labs and EKG and CXR if not already done. Also work the patient up for Rhabdomyolysis by adding CK and UA as Rhabdomyolysis often goes in tandem with Compartment Syndrome.

compartment syndrome from Alexis Pelletier-Bui on Vimeo.

Got this down but don't know how to measure a compartment?  We got you covered on one of EM Daily's first posts.

Sources

1.  Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 8e.

2.  Compartment Syndrome. Life in the Fastlane. Chris Nickson. Web.

3.   Compartments of the Lower Leg. Digital image. Approach to the Posteromedial Surface of the Tibia. AO Foundation, n.d. Web.

4.  Intra-Compartmental Pressure Monitor. Digital image. Stryker Intra-Compartmental Pressure Monitor. Stryker, n.d. Web.

5.  Scalpel. Digital image. Wikimedia Commons. Petit B, 17 July 2015. Web.