The muscles in the body, together with blood vessels and nerves that supply them,
are organized into compartments, each of which is encased in a thin but tough membrane called
a fascia. For example, the lower leg has 4 muscle compartments: anterior, lateral, superficial
posterior, and deep posterior. The function of the fascia is to keep the muscles in place;
its ability to expand is limited. Compartment syndrome develops when excessive
swelling or bleeding increases the muscle volume beyond the ability of the fascia to stretch. As
a result, pressure within the closed compartment rises, impairing blood flow. Without oxygen and
nutrients from the blood, muscle and nerve cells cannot function properly and eventually die.
Compartment syndrome occurs most often in the lower leg, especially in the anterior compartment,
but it may also happen in the thighs, feet, arms, hands, abdomen and buttocks.
The earliest, and also most prominent symptom is pain,
which intensifies when muscles are stretched. The muscles can feel tight and swollen. When nerves
are affected, patients can feel tingling, burning sensations, as well as numbness
and muscle weakness. These are signs that permanent tissue damage has occurred.
There are 2 types of compartment syndrome: acute and chronic.
Acute compartment syndrome is typically due to a serious injury that results in internal
bleeding or swelling, causing compartment pressure to rise rapidly to a dangerous level.
Other possible causes include having casts or large bandages that are too tight,
use of anabolic steroids that increase muscle size too quickly, and sudden return of blood
flow after it was blocked for a long time, such as during a surgery or loss of consciousness.
The pain associated with acute compartment syndrome is typically severe, much more than it
is expected from the injury alone. Diagnosis is by physical exam, X-ray imaging to detect fractures,
and compartment pressure measurement tests. Acute compartment syndrome requires emergency surgery
to cut open the fascia to relieve pressure. Chronic compartment syndrome, also known as
exertional compartment syndrome, is most commonly caused by muscle exertion, such as
overtraining in athletes. Sports that involve repetitive movements such as running, biking,
and swimming, pose a higher risk. People with less flexible fascia are more susceptible than others.
The pain typically comes during exercise, intensifies as it continues, but usually resolves
within half an hour of rest. Over time, however, symptoms can get worse and take longer to subside.
Unlike the acute condition, chronic compartment syndrome is usually not dangerous,
simply because the pain typically stops people from continuing the causative activities before
their nerves and muscles are permanently damaged. Diagnosis is by ruling out other causes,
and involves physical exam, imaging studies, and compartment pressure measurement tests.
X-ray imaging is used to rule out fractures. MRI scans can help evaluate muscle structure
and assess fluid volume. Another technique, near-infrared spectroscopy,
measures the oxygen saturation level. These tests are non-invasive and are therefore preferred over
the invasive compartment pressure testing. The tests are done before and after exercise.
Chronic compartment syndrome can be prevented by doing low-impact exercise;
alternating different types of exercise to avoid repeating the same movements for too long;
building endurance slowly, not abruptly; working out on a softer surface; and wearing proper shoes.
Anti-inflammatory medications and physical therapy may help some patients. However,
people who want to return to the offending sport usually need surgery to release the fascia.
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