FAQs on CRPS and RSD

Complex regional pain syndrome (CRPS) is a chronic nerve-related condition that is not well-understood. With this disorder, there is usually pain in only one limb (arm or leg), and it is associated with motor, sensory, autonomic, bone, and skin abnormalities. The symptoms are quite debilitating.

What causes CRPS?

The exact cause of CRPS is not known, but experts believe it arises after an injury or traumatic event. However, this condition can occur in the absence of trauma. The two types of CRPS are:

  • CRPS I – Pain that develops in the absence of an identifiable nerve injury.
  • CRPS II – Pain that occurs along with damage to a major nerve.

How common is complex regional pain syndrome?

Also called reflex sympathetic dystrophy, the incidence rate is around 1-2%. CRPS can affect anyone at any age, but it is most common between ages 40 years and 60 years. According to statistics, CRPS occurs in 5% of injuries, 15% of peripheral nerve trauma patients, and around 20% of individuals with fractures.

What are the symptoms of CRPS?

The most common symptom is pain, which is burning in nature and worse than expected for the injury. Patients with chronic complex regional pain syndrome have:

  • Severe burning pain
  • Sensitivity to touch
  • Extremity swelling
  • Spontaneous temperature changes
  • Spontaneous sweating
  • Goosebumps that arise without reason

What are the risk factors for CRPS?

  • Reflex sympathetic dystrophy is associated with:
  • Stroke
  • Head injury
  • Polio
  • Prolonged bedrest
  • Brachial plexus injury
  • Polymyalgia rheumatic
  • Amyotrophic lateral sclerosis

How is CRPS diagnosed?

The diagnosis of complex regional pain syndrome is made based on symptoms. The patient must meet certain criteria for the diagnosis, such as presence of disproportionate pain, presence of two more serious symptoms, and no other explanation for the pain. Because nerves are involved, the doctor will usually order an electromyography (EMG) and nerve conduction study. In addition, diagnostic tests include a magnetic resonance imaging (MRI) and computed tomography (CT) scans.

How is complex regional pain syndrome treated?

  • Medications – These include tricyclic antidepressants, anticonvulsants, and pain medications. Topical agents (menthol, lidocaine, capsaicin) often provide pain relief.
  • Physical therapy – This involves use of heat/cold therapy, electrical stimulation, and ultrasound for pain relief. The therapist may teach certain exercises for improved movement.
  • Lumbar sympathetic nerve block – When the lower extremity is affected, this involves injecting a long-acting anesthetic, corticosteroid, and/or neurolytic agent onto the affected nerves. According to a recent study, the clinical success rate for this block was 80%, with the majority of participants having pain relief for up to two months.
  • Stellate ganglion block – For upper extremity pain, this block involves injecting a medication onto the stellate ganglion nerves, which are accessed through the neck region. Based on a recent research report, this block works around 80% of the time, and pain relief can last for as long as 24 weeks.
  • Radiofrequency ablation – If a nerve block works, the doctor may perform a radiofrequency ablation. This involves using heat to destroy a portion of the affected nerve roots, which offers long-lasting pain relief.
  • Intrathecal pain pump implant – To deliver pain medications right to the spinal cord region, and bypass the gastrointestinal tract, this treatment involves implanting a small pump in the lower abdomen or buttocks. A catheter runs from the device to the epidural space, which is around the spinal cord. Medications are delivered as necessary to alleviate pain.
  • Spinal cord stimulator (SCS) implant – This involves inserting a small device into the buttocks or lower abdomen. Small electrodes are surgically placed along the spinal cord area. Wires run from the device to the electrodes, and the device emits pleasant electrical current, which interferes with pain signal transmission.


Bottger E, Diehlmann K. Selected interventional methods for the treatment of chronic pain: Part 1: peripheral nerve block and sympathetic block. Deratology Anaesthesist. 2011;60(5):479-491;quiz 492.

Yucel I, Demiraran Y, Ozuran K, & Degrimenci E (2009). Complex regional pain syndrome type I: efficacy of stellate ganglion blockade. J Orthop Traumatol, 10(4): 179-183.