Compartment syndrome
Formal Definition
An orthopedic and surgical emergency caused by elevated pressure within a closed fascial compartment (muscles and nerves encased in a rigid fascial sheath), compromising microcirculation and leading to ischemic injury to muscles and nerves; most commonly occurs in the anterior compartment of the leg after tibial fracture; characterized by the five P s (pain out of proportion to injury, pain with passive stretch, paresthesia, pallor, pulselessness) and diagnosed by measuring compartment pressure >30 mmHg or within 30 mmHg of diastolic pressure (delta pressure); requires emergent fasciotomy to prevent irreversible muscle necrosis and limb loss.
How It's Used on the Ward
"Compartment syndrome" — the swelling inside a muscle compartment is so bad it is cutting off blood flow; the telltale sign is pain with passive stretch (you can t stretch the muscle without causing agony); the only fix is cutting open the fascia to release the pressure (fasciotomy); if you wait, the muscle dies and the limb is lost.
Example
""25-year-old male with right leg tibial plateau fracture, placed in posterior splint. 4 hours post-op: complaining of severe right lower leg pain — says it feels like his leg is "about to burst." Exam: compartment tense and exquisitely tender to palpation, pain with passive dorsiflexion of toes (stretches anterior compartment muscles) — he screams. Sensation over first web space slightly diminished. Motor function of toe extensors 2/5 (was 5/5 pre-op). Pulses present and capillary refill <2s. Compartment pressure measured at 55 mmHg (normal <10). Diagnosis: acute compartment syndrome of the right leg. Emergency fasciotomy performed — two longitudinal incisions through skin and fascia of all 4 compartments of the leg. Wound left open, dressed with wet-to-dry.""
Clinical Context
Etiology: tibial fractures (most common), forearm fractures, prolonged compression, burns, vascular injuries. The 6 P s: Pain out of proportion (most sensitive early sign), Pain with passive stretch of compartment muscles (most reliable early finding), Paresthesia, Pallor, Paralysis (late), Pulselessness (late — absent pulse is a VERY late finding). Diagnosis: clinical + compartment pressure measurement (cutoff >30 mmHg or delta pressure [diastolic - compartment pressure] <30 mmHg). Serial compartment checks if suspicious. Treatment: emergent fasciotomy (two-incision four-compartment fasciotomy for leg). Missed diagnosis → muscle necrosis → rhabdomyolysis → renal failure → amputation. Timing: fasciotomy within 4-6 hours of onset for optimal outcome. Post-fasciotomy: wound management (vacuum dressing), delayed closure or skin graft, monitor for reperfusion injury and hyperkalemia.