Compartment Syndrome

What is Compartment Syndrome?

Compartment syndrome is a condition where muscles swell against the relatively inflexible fascia that wraps around many muscle groups. This causes a decreased blood supply to the muscles. Since oxygen is delivered through the blood, this high pressure also reduces the flow of oxygen to the affected muscles. Compartment syndrome is potentially limb-threatening. A lack of oxygen can lead to death of the muscle tissue if the pressure from the compartment syndrome is not relieved in an urgent manner. Muscle swelling can occur in two different ways creating two forms of compartment syndrome: acute and chronic (exertional). Acute compartment syndrome occurs when an acute injury such as a lower leg bone (tibia) fracture causes bleeding and rapid swelling of the surrounding muscles that remain confined within their constrictive compartments. Chronic (exertional) compartment syndrome occurs when a repetitively overworked muscle (ex. during a long run) becomes engorged with blood leading to swelling within its constrictive compartment. In both instances, the muscle tissue can lose its’ blood supply and oxygenation unless the constrictive compartment is released to remove the pressure on the swollen muscles.

Acute Compartment Syndrome

Acute compartment syndrome is considered an orthopedic emergency. This is because this form of compartment syndrome can fairly quickly lead to tissue death and potentially consequently amputation of the affected limb. Acute compartment syndrome often develops after a severe injury, like crushed muscles or bone fractures. In these settings, the injury leads to a buildup of blood and fluid that causes swelling and “compresses” the area. This often happens in different parts of the limbs (i.e. forearm, foot, hand, legs). Patients will present with a recent history of a severe injury and will complain of intense pain. Patients may also have had a recent viral infection that induced inflammation and swelling -anything that causes a muscle group to swell within its confining compartment. Other contributing factors to acute compartment syndrome may include use of constrictive casts, splints, or wound dressings.

Chronic Compartment Syndrome

Chronic compartment syndrome is also known as exertional compartment syndrome. This form of compartment syndrome is induced by exercise, although the mechanisms are not fully understood. Chronic compartment syndrome commonly affects runners because of the repetitive impact involved in running. Patients will present with a history of gradually developing pain, that improves after the activity (i.e. running) is stopped. Patients will also have swelling associated with the activity. Since this swelling compresses the nerves in the area, patients may also present with signs and symptoms of neuropathy. These include weakness, tingling, numbness, and burning of the affected limb.

Physical Exam

The hallmarks of acute compartment syndrome, particularly in the lower limbs, include the following “six Ps” :

Pain: Patients will have pain associated with the affected muscle(s) and nerve(s).
Poikilothermia: In acute compartment syndrome, the affected limb may be colder than the surrounding areas.
Pallor: This refers to pale, shiny skin that is more commonly seen in the late stages of acute compression syndrome. The compression of the capillaries (tiny blood vessels) in the affected area can cause the vessels to refill more slowly.
Pulselessness: Like pallor, this is a late stage finding of acute compartment syndrome. During physical examination, patients will have very dull pulses in the limbs due to compression of the blood vessels.
Paresthesia: This refers to a tingling, prickling, or burning sensation on the skin. Paresthesia is a symptom of neuropathy and occurs due to compression of the nerves in the affected area.
Paralysis: This is a late stage finding of compression syndrome and is due to both decreased blood circulation and compression of nerves in the area.

General physical exam findings of both acute and chronic compression syndrome include swelling or a bulge in the area, marked pain (especially when the involved muscle is moved), paresthesia (burning or prickling sensation), and numbness. These two forms of compression syndrome can be differentiated using patient history.

Treatment

The diagnosis or suspicion of compartment syndrome requires urgent surgical treatment. Pressure testing of the muscles using a compartment pressure monitor can be helpful. However, if a physician suspects compartment syndrome based on the patient’s history and clinical examination an urgent surgical release (fasciotomy) of the constrictive compartments is usually required. A fasciotomy will be performed to decompress the compartment by opening the fascia (tissue layer) that binds the compartment.

Edited March 29, 2021