Compartment Syndrome

Question 1

What is compartment syndrome? [1]

Answer 1

elevated interstitial pressure within a closed fascial compartment resulting in microvascular compromise

Question 2

Where does compartment syndrome usually occur? [5]

Answer 2

1. Leg
2. Forearm
3. Thigh
4. Hand
5. Foot

Question 3

What are the causes of compartment syndrome? [13]

Answer 3

1. Increased internal pressure
   
   • e.g. Trauma - fractures, entrapment
     
     • Bleeding
   • Muscle oedema/myositis
   • Intracompartmental administration of fluids/drugs
   • Iatrogenic infiltration
   • Re-perfusion - vascular surgery
2. Increased external compression
   
   • e.g. Impaired consciousness/protective reflexes
     
     • associated with drug/alcohol misuse
   • Iatrogenic
   • Positioning in theatre (e.g. in a lithotomy surgery for removing a urinary stone)
   • Casts/bandages
   • Full thickness burns
3. Combination of both

Question 4

Describe the pathophysiology of compartment syndrome [9]

Answer 4

1. Pressure within the compartment exceeds pressure within the capillaries resulting in reduced blood flow
2. Muscles become ischemic and develop oedema through increased endothelial permeability
   
   • worsens the condition (causes ↑ internal pressure - essentially a vicious cycle)
3. Autoregulatory mechanisms overwhelmed
4. Necrosis begins in the ischaemic muscles after 4 hours and these damaged muscles release myoglobin
5. Ischaemic nerves become neuropraxic → transient blockage of nerve conduction
6. This may recover if relieved early, but permanent damage may result after as little as 4 hours
7. Irreversible damage — Loss of function, limb or life
8. Compromise of the arterial supply — late

Question 5

Describe the features of muscle ischaemia

1. after 1 hour? [2]
2. after 4 hours? [2]
3. after 8 hours? [2]

Answer 5

1. After 1 hour:
   
   • Nerve conduction normal,
   • Muscle viable
2. After 4 hours:
   
   • Neuropraxia in nerves, which is reversible
   • = Reversible muscle ischaemia
3. After 8 hours:
   
   • Nerve axonotmesis and irreversible change
   • Irreversible muscle ischaemia and necrosis

Question 6

What are the typical features of end stage limb changes? [4]

Answer 6

1. Stiff fibrotic muscle compartments
2. Impaired nerve function
3. Clawing of limbs
4. Loss of function

Question 7

What are the signs & symptoms of compartment syndrome? [11]

Answer 7

1. Out of proportion PAIN to that expected from the injury
2. PAIN on passive stretching of the compartment
3. Pallor
4. Paraesthesia
   
   • Usually occurs later on in the disease
5. Paralysis
   
   • Usually occurs later on in the disease
6. NO pulse
   
   • Pulses are usually present until the late stages unless there is an associated vascular injury
7. Swelling
8. Shiny skin
9. Autonomic responses
   
   • Sweating
   • Tachycardia
10. The deep nerves are affected 1st
    
    • 1st dorsal webspace

Question 8

Describe how urgent treatment is carried out for compartment syndrome [8]

Answer 8

1. Open any dressings/bandages
2. Reassess:
3. If symptoms settle → observation & reassess later
4. If no improvement/deterioration
   
   • surgical release
     
     • full length decompression of all compartment and excise any dead muscle
       
       • repeat debridement until pressure down and all dead muscle is excised
         
         • delayed wound closure (after >48hrs) +/- plastic surgery/skin grafting

Question 9

What factors must be monitored perioperatively (during surgery for compartment syndrome)? [6]

Answer 9

1. Adequate hydration
2. Manage fluid loss
3. Monitor and regulate electrolytes (K+)
4. Correct acidosis
5. Check for myoglobinuria
6. Ensure adequate renal function

Question 10

What happens if a patient with compartment syndrome presents or is diagnosed late? [4]

Answer 10

1. Irreversible damage already present
2. Fasciotomy will predispose to infection
3. Non-operative treatment is given (NB Renal failure)
4. Splint in position of function