Complex Regional Pain Syndromes Clinical Presentation

Updated: Jun 20, 2018
  • Author: Gaurav Gupta, MD, FAANS, FACS; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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No specific diagnostic tests identify the presence of CRPS and no objective guidelines verify its existence. The current criteria for diagnosing CRPS are based mainly on physical examinations and a careful analysis of patient history.

Often, symptoms of CRPS type I begin immediately, days, or weeks after an injury, usually in a distal extremity. Rarely, the onset can be months after the injury. Usually, only one limb is involved, but in a few cases, the involvement is bilateral (4-5%), and even more rarely, 3 or 4 extremities are affected. CRPS type I can be acute (lasting < 2 months) or chronic (>2 months). Approximately half of patients with CRPS type I report it to be related to an on-the-job injury.

Clinical features of CRPS type I are influenced by the following:

  • Duration: As many as 80% of patients with the initial symptoms of CRPS type I are cured within 18 months from its onset, either spontaneously or with treatment. A longer duration of CRPS is related to a significantly greater likelihood of abnormalities of sensation and less of sweating abnormalities or edema.

  • Location: Pain and other symptoms can be located anywhere in the body. The extremities are involved most often, although other locations such as external genitalia or the nose may also be involved. Patients may have pain at the ulnar styloid process after a Colles fracture or at the lateral malleolus after a sprain. Frozen shoulder and/or tendinitis of the biceps often accompany CRPS type I in the hand.

Symptoms of CRPS type I include the following:

  • Spontaneous pain: Pain that is not limited to the territory of a single peripheral nerve is the cardinal feature of CRPS. The pain's character can be burning (occurring most often), aching, throbbing, or tingling. The pain is aggravated by activity of the affected extremity, and its severity is typically disproportionate to the inciting event.

  • Difficulty/inability in using the affected extremity

  • Neglect-like symptoms: These include cognitive neglect, in which the limb may feel foreign, and motor neglect, in which directed mental and visual attention are needed to move the limb.

  • Altered skin temperature: This is often noted as a difference in skin temperature between affected and unaffected limbs. At onset, the affected extremity is warmer in two thirds of cases and colder in one-third. Many patients report a history of warmer extremities at onset and colder extremities later in the evolution of the disease. Some authors distinguish between primarily cold reflex sympathetic dystrophy and primarily warm reflex sympathetic dystrophy.

  • Rapid fatigability: This is almost invariably present in the later stages.



Physical symptoms/characteristics of CRPS may include the following:

  • Some impairment of motor function is present in about 80-90% of patients at some point in the disease and consists of paresis, pseudoparalysis, or clumsiness.

  • Range of motion is often limited secondary to motor deficit and/or pain. Tremor of the affected limb is present in about half of patients in the later stages.

  • Dystonia of the affected foot or hand is described in 10% of patients in the later stages.

  • Muscle spasms are present in 25% of patients who have longer-duration CRPS type I.

  • Hypoesthesia is described in about 70% of patients and is most often present in a glovelike or stockinglike distribution. Hemihypoesthesia has also been described; hypothermesthesia and loss of proprioception are described in some cases.

  • Anesthesia dolorosa is sometimes present; this is when an area has lost its sensitivity to touch at the same time that severe pain is present.

  • Allodynia (ie, pain to touch) is described in 70-80% of patients.

  • Hyperpathia (ie, an exaggerated response to painful stimuli) is also present in 70-80% of patients.

  • Abnormal sweating is a sign of autonomic dysfunction. About half of the patients have hyperhidrosis.

  • Edema is secondary to autonomic dysfunction. Sometimes, persistent edema is caused by infection of the atrophied soft tissues.

  • Altered skin color is related to vasomotor changes. Skin discoloration and atrophy may occur later. Brown-gray, scaly pigmentation of the skin on the affected limb is described in some studies.

  • Atrophy of the soft tissues, muscles, and bones can also occur. These trophic changes are not included in the IASP diagnostic criteria because their pathophysiology is unknown thus far, so they might result from simple disuse of the affected extremity.

  • Altered skin temperature reflects vasomotor instability and leads to primarily cold CRPS, primarily warm CRPS, or secondarily cold CRPS. At the time of assessment by a physician, approximately 5-10% do not have a significant difference in skin temperature, about 40-45% have a warmer affected extremity, and 40-45% have a colder affected extremity.

  • Hypotrichosis is often noticed in the affected area. Other times, hypertrichosis is present, and it is considered a sign of sympathetic dysfunction. However, both are irrelevant for establishing the diagnosis.

  • Altered nail growth is also a sign of sympathetic dysfunction; however, it is not reliable for diagnostic purposes.



Most often, CRPS type I is initiated by trauma to an extremity. Such injuries account for more than 90% of patients with CRPS type I.

  • Injuries precipitating the development of CRPS, in order of decreasing frequency, are as follows: (1) sprain/strain, (2) surgical wounds, (3) fractures, (4) contusion/crush injury, and (5) rarely, other injuries such as venipuncture, lacerations, burns, inflammatory processes, electric shock, and spinal cord injuries.

  • Spontaneous cases/unknown causes account for approximately 5% of patients and may be explained by minor injuries that have been forgotten.

  • Unusual, disputed precipitating events include visceral lesions, CNS lesions (eg, strokes, tumors, brain injury, amyotrophic lateral sclerosis, meningitis, syringomyelia), peripheral vascular bypass procedures, arteriovenous grafts for hemodialysis, carpal tunnel surgery, and spinal cord injury.