12.3 Musculoskeletal Critical Care

Compartment Syndrome in Children

Acute compartment syndrome occurs when pressure within a closed fascial compartment rises enough to impair capillary perfusion, causing muscle and nerve ischemia. In the PICU it follows fractures (especially tibial and forearm), crush injury, reperfusion after arterial repair, tight casts/dressings, burns, extravasation, and occasionally extreme overuse or infection. Children may not describe symptoms clearly, so serial exams and a high index of suspicion matter.

The traditional "6 Ps" are pain, pressure, paresthesia, pallor, paralysis, and pulselessness. For exam and bedside practice, remember the chronology: pain out of proportion and pain on passive stretch are the earliest and most useful findings. Paresthesias follow as nerves ischemic. Paralysis and pulselessness are late — waiting for a lost pulse risks irreversible damage. A tense, swollen compartment that feels rock-hard supports the diagnosis even when verbal reports are limited.

Measurement and action

When clinical concern is high, surgeons may measure intracompartmental pressure. Values near ≥30 mm Hg, or a diastolic blood pressure minus compartment pressure ≤30 mm Hg, commonly trigger fasciotomy decisions. Nursing actions while mobilizing surgical care include removing constrictive dressings/casts (bivalve as ordered), keeping the limb at heart level (not elevated high above the heart, which can worsen ischemia), providing analgesia, maintaining systemic perfusion, and preparing for operative decompression. After fasciotomy, expect open wounds, fluid shifts, infection surveillance, and rehab planning.

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Musculoskeletal Trauma: Pediatric Patterns

Children’s bones are more porous and the physis (growth plate) is relatively weak, so Salter-Harris fractures can threaten future growth. Greenstick and torus fractures are common; however, high-energy trauma still produces unstable pelvic, femoral, and spinal injuries requiring hemorrhage control and damage-control orthopedics. Pelvic fractures may hide substantial blood loss. Traction, external fixation, and spica casts create unique nursing challenges: skin integrity, neurovascular checks distal to devices, and positioning for pulmonary hygiene.

Neurovascular assessment distal to any fracture or operative fixation is non-negotiable: color, temperature, capillary refill, pulses, sensation, and motor function. Increasing analgesic needs, tense swelling, or loss of sensation should trigger compartment evaluation. Fat embolism syndrome is less common in young children than in adolescents with long-bone fractures but remains possible — watch for respiratory distress, petechiae, and neurologic change after instrumentation or injury.

Maltreatment red flags during MSK care

Any fracture evaluation in a non-ambulatory infant, metaphyseal corner fractures, posterior rib fractures, multiple fractures at different healing stages, or an injury story that changes or does not match developmental ability requires a structured child protection response. Patterned bruises, bilateral black eyes without appropriate mechanism, and delayed care seeking are additional concerns. Your duty is to stabilize the child, document objectively, and activate the institutional reporting pathway — not to conduct a forensic interrogation alone.

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Rhabdomyolysis

Rhabdomyolysis is skeletal muscle necrosis with release of myoglobin, potassium, phosphate, and creatine kinase (CK) into the circulation. Pediatric triggers include crush injury, prolonged immobilization, status epilepticus, malignant hyperthermia, viral myositis, extreme exertion, toxins, and reperfusion injury. Dark tea-colored urine, myalgia, weakness, and oliguria are classic, but young children may only show irritability and reduced urine output.

Why the PICU cares

Myoglobin is directly nephrotoxic in the setting of hypovolemia and acidosis, producing acute kidney injury. Released potassium can cause life-threatening arrhythmias. Hypocalcemia (calcium enters damaged muscle) and later hypercalcemia during recovery complicate management. Compartment syndrome and rhabdomyolysis frequently coexist — swelling raises pressure, and ischemia worsens muscle necrosis.

Management priorities:

1. Aggressive IV fluid resuscitation to restore renal perfusion and promote myoglobin clearance, titrated to urine output goals set by the team (often roughly 1–2 mL/kg/hr or higher early).
2. Continuous cardiac monitoring for peaked T waves, widened QRS, or arrhythmias from hyperkalemia; treat hyperkalemia emergently.
3. Serial CK, electrolytes, BUN/creatinine, and urine output trending.
4. Avoid nephrotoxins; consider alkalinization only if ordered and safe for the child’s physiology.
5. Surgical collaboration for fasciotomy or debridement when compartments or necrotic muscle drive ongoing injury.
6. Dialysis readiness if refractory hyperkalemia, fluid overload, or uremia develops.

Family teaching should explain that CK may remain elevated for days and that early mobility will be balanced against renal and wound healing needs. Coordinate PT/OT once the child is metabolically safe.

Integrated trauma tip

In the crushed or multi-trauma child, think of the limb, the kidney, and the heart as one system: ischemic muscle threatens compartments, released potassium threatens rhythm, and myoglobin threatens the kidney. Frequent neurovascular checks, ECG monitoring, and urine surveillance together catch deterioration earlier than any single parameter.