n_rsd

reflex sympathetic dystrophy (RSD) / complex regional pain syndrome / causalgia

introduction

  • types of complex regional pain syndrome (CRPS):
    • type I: no evidence of nerve injury, formerly known as reflex sympathetic dystrophy (RSD) or Sudeck's atrophy
    • type II: associated with nerve injury, formerly known as causalgia
  • it is a painful disorder of a limb presumably mediated via sympathetic nervous system injury or irritation.
  • it is often precipitated by injury to a sympathetic nerve (which usually are located along peripheral arteries in limbs) &/or prolonged immobilisation and events which may initiate it include soft tissue injury (in 40%), fracture (in 25%), acute myocardial infarction (AMI/STEMI/NSTEMI) (in 12%), stroke (CVA) (in 3%), although no precipitating event was found in up to 35% of cases.
  • before early ambulation was advocated, RSD occurred in 5-20% of patients with acute myocardial infarction (AMI/STEMI/NSTEMI) and 12-20% of patients with hemiplegia.
  • accounts for 2-5% of adults, and up to 20% of paediatric patients at pain clinics
  • adults: females 3.5 x males, and mainly upper limb
  • paediatric: females 9.1 x males, and mainly lower limb
  • highest prevalence in Caucasians
  • emotional stress at the time may be an important factor.
  • in all phases, there is decreased sympathetic outflow to the limb.

3 clinical stages

1st stage

  • severe burning and sometimes throbbing limb pain, with diffuse uncomfortable aching, sensitivity to light touch or cold causing pain sensation (allodynia), increased sensitivity to pain (hyperalgesia), and localised oedema.
  • pain distribution does not relate to a nerve, nerve root or dermatome.
  • variable vasomotor disturbances including altered color, temperature, sweating.
  • most have a “hot, florid” initial phase although some start with the usual later “blue cold” phase - both of these phases are associated with swelling

2nd stage

  • progression of soft tissue oedema, thickening of skin and articular tissues, muscle wasting, osteoporosis and development of brawny skin.
  • may last 3-6 months

3rd stage

  • most severe stage
  • limitation of movement, shoulder-hand syndrome (capsular contraction of joints causing a frozen shoulder), contractures of fingers, waxy, trophic changes, brittle, ridged nails
  • severe osteoporosis

differential diagnoses

  • cervical nerve root impingement
  • Pancoast's syndrome
  • vasculitis
  • migratory osteolysis
  • venous thrombosis
  • arteriovenous fistulae
  • progressive systemic sclerosis
  • disuse atrophy
  • angioedema

diagnosis

  • essentially clinical
  • CT not recommended at any stage
  • bone scan findings are supportive and are useful in stage 1 and 2 - early scan (but AFTER 6 weeks from onset) is more sensitive (~97%) than late scans, and scanning after 6 months is generally not helpful.
  • plain Xrays may be useful in stage 3 when osteoporotic findings are more pronounced
  • MRI may be useful in stages 1 and 3

prevention

treatment

  • Rx is more effective if commenced in stage 1, BEFORE radiographic changes occur
  • early referral to a pain Mx specialist
  • early referral to physiotherapy for mobilisation rather than prolonged splinting, although little evidence that physio or OT improve outcomes in this condition.
  • stress the importance of working to regain use of the affected limb while recognizing the difficulty of doing so in the face of ongoing pain.
  • stress-management techniques
  • cease smoking as smoking appears to double the risk of CRPS.
  • pharmacologic Rx that appears to be better than placebo:
  • stage 1 Rx:
  • refractory to stage 1 Rx after 1-2 weeks Rx:
    • steroid injections if local tender muscle points
    • add an anticonvulsant such as gabapentin
    • if pain persists, add calcitonin or bisphosphonates and prednisolone 1mg/kg daily for 3 days and if effective, continue and taper over 3 weeks
  • stage 2 Rx:
    • as for stage 1
  • stage 3 Rx:
    • pain Mx specialist referral
n_rsd.txt · Last modified: 2015/06/06 07:38 by gary1