A 20-year-old male distance runner who was jogging and happened to be running past the emergency department presented with severe bilateral leg pain, foot pain, and foot numbness that had resolved by the time he was evaluated in the ED. The x-ray above was obtained (Image 1. X-ray of the leg. Case courtesy of Andrew Murphy, Radiopaedia.org, rID: 41408).
Chronic exertional compartment syndrome (CECS). It is defined as “reversible ischemia secondary to a non-compliant osseofascial compartment that is unresponsive to the expansion of muscle volume that occurs with exercise .” The x-ray will likely appear normal in CECS as is seen in Image 1.
Pearl: CECS is most commonly seen in younger age groups and affects distance runners and military personnel. It is often reproducible by the patient and they will begin to recognize a pattern in the onset of symptoms after a certain amount of time or distance.
Pearl: The MR imaging below shows swelling and increased signal intensity in the anterior and lateral compartments following exercise. MR imaging is not routinely used for the diagnosis of CECS and likely will not be obtained in the ED to make the diagnosis.
Image 2. MR of the bilateral legs. Case courtesy of Dr. Owen Kang, Radiopaedia.org, rID:22182.
Typically the patient will report symptoms of pain, tightness, cramps, weakness, and diminished sensation typically over a specific compartment or compartments of the lower leg commonly experienced bilaterally . Other neurologic symptoms can include temporary foot drop and/or paresthesias secondary to affected nerves in those compartments. The physical exam is often benign as the symptoms the patient experiences will resolve with rest [2,3]. Complete resolution of the pain is key to making this diagnosis and will occur within 45 minutes or less of rest 
Pearl:Ortho bullets has a great review of the anatomy of the lower leg and the associated compartments.
The diagnosis of CECS is made by an exercise challenge provoking symptoms and elevated compartment pressures following the exercise challenge. A convincing history and physical along with one or more of the following are used to make the diagnosis :
Pre-exercise pressure 15mmHg or higher
1-minute post-exercise pressure 30mmHg or higher
5-minute post-exercise pressure 20mmHg or higher
Pearl: Compartment pressures should be measured bilaterally in the following anatomic locations:
Anterior compartment: 1 cm lateral to the anterior border of the tibia
Lateral compartment: just anterior to the posterior border of the fibula
Deep posterior compartment: just posterior to the medial border of the tibia
Superficial posterior compartment: middle of the gastrocnemius
Image 3. Landmarks for measuring compartment pressures. Author’s own image.
If the patient is evaluated immediately after exercise and symptoms are still ongoing, compartment pressure can be measured based on institutional practice and provider skillset, though proper timing after exercise is crucial for a valid test. In this case, the patient can be discharged and referred for outpatient follow-up with sports medicine to confirm the diagnosis. No further ED management is needed.
Pearl: Caution the patient to avoid exercise that provokes their symptoms as it can lead to significant morbidity such as permanent nerve damage or even amputation. A sports physician can properly guide the patient back to sports with outpatient management.
Management can be surgical or non-surgical. Nonsurgical management includes rest, anti-inflammatories, manual therapy and soft tissue release, stretching and strengthening of the involved muscles, and orthotics . Surgical management includes fasciotomy of the affected compartment .
Resources & References:
Are you a visual learner? If so, be sure to check out our infographic on Compartment Syndrome.