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Compartment Syndrome

 

Definition of compartment syndrome

  • The condition where elevated pressure within a confined space can lead to damage of its contents
  • This can occur in other areas of the body (e.g. abdominal compartment syndrome, raised intracranial pressure) but in this situation it refers to the elevation of pressure within a discrete myofascial compartment leading to irreversible injury to its contents (particularly muscles and nerves)

 

Epidemiology of compartment syndrome

  • Compartment syndrome is most common in patients under 35 years of age, with a gender preponderance towards men, often following fractures of the tibial diaphysis
  • It is most often seen in the leg, followed by the forearm
  • It can also affect the hand and foot and rarely the upper arm or thigh

 

Causes of compartment syndrome

  • Extraneous forces that constrict the size of the compartment
    • Closure of fasical defects
    • Tight plaster casts
    • compression bandages
    • Pneumatic anti-shock garments or burns
  • Intrinsic changes that alter the compartment’s contents
    • Haemorrhage following soft tissue injury/fracture
    • Post-operative swelling and oedema
    • Post-ischaemic swelling
      • e.g. after tourniquet use intraoperatively or in pre-hospital care

 

Presentation of compartment syndrome

  • The ‘six Ps’ are often stated as the diagnostic criteria for compartment syndrome
    • Pain, pallor, pressure, paraesthesiae, paralysis and pulselessness
      • Although they are often present, if one waits for these to develop (particularly paralysis and pulselessness) it is most likely too late
  • The first sign, in an alert responsive patient without distracting injury, is pain out of proportion to the injury
  • On examination, the most reliable sign is severe pain on passive stretch of the involved muscles within the affected compartment.
    • One can also see that the compartment in question is also swollen to a high intensity.

 

Video on diagnosis and treatment of compartment syndrome

 

Differential diagnosis of compartment syndrome

  • Deep vein thrombosis
    • Due to the similar presentation with pain and swelling in the lower leg
  • Cellulitis
    • Presenting with pain and often lower-limb swelling. Check for temperature and inflammatory markers.
    • There should not be pain on passive stretch of muscles.
  • Peripheral vascular disease/ischaemic limb
    • These are included together as they are part of a spectrum of disease. They often present with the 4 Ps due to inhibition of blood supply, but the compartment is often soft and there is often coexisting vascular disease.
  • Septic Arthritis
    • This can often present with excruciating lower limb pain with swelling
    • Look for raised inflammatory markers, pyrexia or a joint effusion to differentiate between this and compartment syndrome.
  • Rhabdomyolysis
    • This also often follows trauma. It also presents with muscle pain but also a picture of more generalised malaise
    • Look for dark urine, deteriorating renal function and raised creatinine kinase
    • Consultant a renal physician if acute renal failure in this context

 

Diagnosis of compartment syndrome

  • Compartment syndrome is a clinical diagnosis on the basis of the above clinical picture together with an evaluation of the clinical likelihood.
    • It is often difficult to ascertain in those who have a reduced conscious state (e.g. intubated poly-trauma patients on ITU)
    • For this reason there are other diagnostic criteria that can be used:
  • Measurement of intra-compartmental pressure
    • If the pressure exceeds 30mmHg then compartment syndrome is likely

If this exceeds 40mmHg or rises to within 20mmHg of the patient’s diastolic blood pressure (i.e. above 50 for a patient with a diastolic pressure of 70), urgent fasciotomy should be carried out as a limb/life saving measure.

 

Initial management of compartment syndrome

  • Initial management centres around early appreciation of risk of compartment syndrome, together with close monitoring. Monitoring includes:
    • Pain out of proportion to injury
    • Checking compartment pressures in those unable to respond to pain
      • e.g. patients who have blocks, patients with a reduced Glasgow Coma Score
  • Remove any constrictive dressings or split them down to the skin
  • Hold the limb at the level of the heart (not above) to promote arterial inflow
  • If there is any suspicion of compartment syndrome there should be a low threshold for urgent referral and assessment by an orthopaedic specialist
    •  They may wish to perform formal compartment pressure monitoring using specialist equipment

 

Further management of compartment syndrome

  • Urgent fasciotomy
    • The release of the restrictive fascial compartment with both the skin and fascia left open to decompress the structures within
    • The skin can be grafted at a later date by a centre with a plastic surgery department

 

Complications of compartment syndrome

  • If left untreated, the end result is necrosis of the muscles
  • This leads to an ischaemic contracture depending on the compartment involved and loss of the movements generated by the muscle group in question
    • This is known as Volkmann’s contracture in the forearm, wherein the muscles of the flexor compartment contract resulting in a claw like deformity of the hand

 

Prognosis following compartment syndrome

  • Prognosis is highly dependent on time to intervention
  • If dealt with within 6 hours, with an urgent fasciotomy the outcomes are excellent
  • If delayed up to 12 hours only 68% of patients have a normal limb function
  • Beyond this the rates of normal limb function are just 8%

 

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