Complex regional pain syndrome

Complex regional pain syndrome (CRPS), also known as Sudeck atrophy, is a condition which can affect the extremities in a wide clinical spectrum. CRPS is principally a clinical diagnosis seen more commonly in females than males with a mean age of presentation of 50 to 70 years 12. No one imaging study is sensitive or specific to rule in or rule out the syndrome. 

Two types of CRPS have been described 8:

  • type 1: no underlying single nerve lesion (formerly known as reflex sympathetic dystrophy)
  • type 2: underlying nerve lesion identified (formerly known as causalgia)

Patients present after an initiating event (see causes below) with symptoms of more than 6 months duration such as edema, changes in skin blood flow, abnormal motor activity, allodynia or hyperalgesia 11. Symptoms are often out of proportion to the initiating event and not limited to a single peripheral nerve 8.  

  • trauma: often minor
  • surgery 11
  • idiopathic: immobilization
  • unknown in many cases
  • CNS disorders
  • myocardial infarction

Occurs in hands and feet distal to the injury.

It is important to differentiate this from disuse osteopenia since the clinician could initiate aggressive physical therapy for the latter.

  • patchy bone marrow edema signal (particularly subcortical), although bone marrow signal may be normal in some cases
  • soft tissue edema and enhancement
  • skin thickening
  • joint effusion
  • synovial hypertrophy
  • muscle atrophy in later stages
  • presence of CRPS can be evaluated with a 3-phase bone scan
  • the classical presentation is increased biphosphonate tracer uptake in the affected limb on all three phases (seen less than 50% of the time, but has the highest diagnostic accuracy)
  • diffusely increased juxta-articular activity around all joints of the affected hand or foot on delayed images is the most sensitive indicator (infection and arthritis are potential false-positive findings)

In most cases, a multidisciplinary approach is required whereby a combination of various treatments may be employed, such as physical therapy, systemic or regional medications, sympathectomy or spinal cord stimulation, and psychotherapy. Interventional radiology can offer pain relief by peripheral nerve block procedures.

Article information

rID: 1154
Section: Syndromes
Synonyms or Alternate Spellings:
  • CRPS
  • Reflex sympathetic dystrophy
  • Sudeck atrophy
  • RSD
  • Reflex sympathetic dystrophy (RSD)
  • Sudeck's atrophy
  • Sudeck dystrophy
  • Sudeck osteodystrophy
  • Causalgia

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2
    Drag here to reorder.
  • Case 3
    Drag here to reorder.
  • Case 4: type 2
    Drag here to reorder.
  • Case 5
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Case 7: following Colles fracture
    Drag here to reorder.
  • Case 8: due to screw malposition
    Drag here to reorder.