Patients who experience chronic, severe burning pain in a limb due to an injury to a peripheral nerve may have once been told that they suffer from causalgia. Today, the condition is more often referred to as Type 2 Complex Regional Pain Syndrome (CRPS II).

Peripheral nerves run from the brain and spine to the body’s extremities. In cases of Type 1 CRPS (CRPS I), pain develops even though there has been no direct damage to the nerves in the extremity. But CRPS II is caused by an identifiable injury or trauma to the nerves in the affected extremity. CRPS II affects a small minority of patients (1 out of 100,000) who are diagnosed with CRPS.[i]

Examples of the kind of injury or trauma that can trigger CRPS II include:

  •       soft-tissue damage, such as a sprained ligament or tendon
  •       injuries in which an extremity is crushed (e.g. workplace injuries involving heavy equipment)
  •       complex bone fractures
  •       surgery
  •       amputation

CRPS II produces pain around the injured nerve. A person who severely sprains their ankle may have lasting pain in that area, even after the injured tissues have healed. That is because the surrounding nerves have been damaged as well.

Pain from CRPS II is often searing and patients report extreme sensitivity around the injured area. The mere touch of clothing can exacerbate the pain. Some patients experience the sensation of pins and needles, while others report a burning, aching sensation. There may be skin color and/or temperature changes to the skin near the injured area. 

New Options for CPRS II Pain Relief

Although researchers have yet to determine why only some people develop CRPS II, it is possible that these patients have nerve fibers that are simply hypersensitive. This can trigger abnormal inflammatory responses that contribute to their pain.

Following a thorough diagnostic exam, which may include x-rays or MRIs to assess for injury and to rule out other issues (such as fibromyalgia), patients with CRPS II have a number of treatment options, including:

  •       Over-the-counter pain relievers such as non-steroidal anti-inflammatories or acetaminophen
  •       Prescription antidepressants and anticonvulsants that can help relieve pain
  •       Corticosteroid injections to the affected area to reduce inflammation
  •       Nerve blocks that inject an anesthetic that interferes with the activity of the sympathetic nerves that control pain in the extremities
  •       Spinal cord stimulation and peripheral nerve stimulation. These minimally invasive procedures implant a small device under the skin. It delivers precise electrical pulses to interrupt pain signals before they reach the brain and replaces those pain signals with a tingling sensation.  

These treatments may be prescribed in conjunction with physical therapy to help the patient reclaim their range of movement and flexibility in the injured area. Some patients also benefit from cognitive behavioral therapy to gain coping strategies for dealing with chronic pain.  

CRPS II is a challenging diagnosis, which is why patients should consult with a qualified pain medicine expert who understands the source of their pain as well as the latest interventions available to treat it.

[i] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5244710/

https://www.mayoclinic.org/diseases-conditions/crps-complex-regional-pain-syndrome/diagnosis-treatment/drc-20371156

https://www.healthline.com/health/causalgia