What are the signs of compartment syndrome in a patient with a hand in a cast?

Signs of Compartment Syndrome in a Hand with Cast

The most critical signs of compartment syndrome in a patient with a hand in a cast are severe pain out of proportion to the injury, pain on passive stretch of the affected muscles, and increasing tightness or firmness of the compartment. These early warning signs must be recognized promptly to prevent irreversible tissue damage.

Primary Clinical Signs

Compartment syndrome occurs when increased pressure within a closed fascial space compromises circulation to the tissues within that compartment. In a hand with a cast, the following signs should be monitored:

Early Signs (Most Important)

• Pain:

  • Severe pain disproportionate to the injury
  • Pain that is unresponsive to appropriate analgesics
  • Pain worsened by passive stretching of the muscles in the affected compartment

• Paresthesia:

  • Numbness or tingling in the affected area
  • Decreased sensation in the distribution of nerves passing through the compartment

• Pressure:

  • Tense, firm swelling of the compartment
  • Increasing tightness under the cast

Late Signs (Indicate Severe Damage Already Occurring)

• Paresis/Paralysis: Weakness or inability to move fingers
• Pallor: Pale appearance of fingers
• Pulselessness: Diminished or absent pulse
• Poikilothermia: Cool temperature of the affected digits

Diagnostic Approach

The sensitivity and positive predictive value of individual clinical signs are low, while specificity and negative predictive value are high 1. This means the absence of signs is more reliable in excluding compartment syndrome than their presence is in confirming it.

When multiple clinical signs are present together, the likelihood of compartment syndrome increases significantly:

• Severe pain + pain on passive stretch = 68% positive predictive value
• Severe pain + pain on passive stretch + paralysis = 93% positive predictive value 1

Special Considerations for Hands in Casts

1. Cast-Related Factors:

   • A tight or constrictive cast can directly cause compartment syndrome
   • Swelling within a non-yielding cast increases compartment pressure
   • Cast should be immediately removed if compartment syndrome is suspected

2. Monitoring Through Cast:

   • Regular neurovascular checks including capillary refill
   • Ability to wiggle fingers
   • Sensation in fingertips
   • Temperature comparison with unaffected hand

High-Risk Situations

Certain scenarios increase the risk of compartment syndrome in a casted hand:

• Crush injuries
• Fractures (especially comminuted)
• Circumferential burns
• Reperfusion after ischemia
• Prolonged compression
• Post-surgical swelling

Management Algorithm

1. If compartment syndrome is suspected:

   • Immediately remove or split the cast
   • Elevate the extremity is contraindicated as it may reduce perfusion pressure 2
   • Measure compartment pressures if diagnosis remains in doubt
   • Fasciotomy is indicated when tissue pressure increases to within 10-30 mmHg of diastolic pressure 1

2. Compartment Pressure Measurement:

   • Direct measurement is indicated when clinical diagnosis is uncertain
   • Traditional threshold for fasciotomy: ≥30 mmHg absolute pressure or differential pressure (diastolic BP - compartment pressure) <30 mmHg 1

Common Pitfalls

1. Delayed Recognition: Paralysis and pulselessness are late signs indicating irreversible damage has likely occurred 1, 3.

2. Reliance on Single Clinical Sign: No single sign is sufficiently sensitive; multiple signs should be evaluated together 1.

3. Inadequate Assessment in High-Risk Patients: Diagnosis is particularly challenging in:

   • Obtunded or unconscious patients
   • Young children
   • Patients with communication barriers

4. Mistaking Pain Control for Improvement: Effective analgesia may mask worsening compartment syndrome.

5. Failure to Recognize Complications: Monitor for rhabdomyolysis and potential kidney injury if compartment syndrome is established 1.

Early recognition and prompt treatment of compartment syndrome are essential to prevent permanent disability, tissue necrosis, and potential systemic complications including renal failure from myoglobinuria 2.