COMPLEX REGIONAL PAIN SYNDROME- TYPE 1
(CRPS 1)

Complex Regional Pain Syndromes type 1 and 2 represent regional pain disorders not limited to the site of injury, with the following features:

1. Pain greater than might be expected from the original injury
2. Altered blood flow, localized edema, skin and hair changes
3. The pain itself may be burning or electrical in nature and is usually non-dermatomal due to hyperalgesia. Allodynia is often present.

The distinction between CRPS 1 and CRPS 2 is made by the specific neural mechanism of injury. CRPS 1 patients have the involvement of the Sympathetic Nervous System, while CRPS 2 patients have involvement of a specific injured Nerve. Both syndromes exhibit pain beyond the distribution of the original injury.

CRPS 1 patients were formerly diagnosed with Reflex Sympathetic Dystrophy. This was a misnomer as the condition did not involve reflexes or dystrophy. The current terminology was developed in 1994 by the International Association for the Study of Pain (IASP). Typically CRPS 1 patients go for years without a proper diagnosis. Although the classic case shows immobilization and guarding of an extremity, with mottling of the skin, change in temperature, edema, allodynia and dysesthesia, many cases present with variations of this theme and can involve any or all of the extremities and even trunk or neck pain. People with these conditions are aften misdiagnosed with psychogenic pain disorders because of the non-dermatomal nature of their pain and the severe psychological distress it engenders.

On an anatomical and physiological basis it appears that there are several processes occurring. One involves central sympathetic coupling with Wide Dynamic Range (WDR) Neurons in the Dorsal Horn serving to link the Dorsal Horn Nuclei with Sympathetic Nuclei. Increased activity of Sympathetic Efferents only tells part of the story. There is also an increase in Catecholamine sensitivity at the site of the injury. Additionally the sustained pain from the sensitization of Dorsal Root Ganglion Cells may trigger increased release of epinephrine systemically and in the local area of injury.

The best treatment for CRPS 1 is mobilization to the affected extremity(ies). Pain control with anticonvulsants (Gabapentin, Carbemazepine, Lamotrigine, Topramax), Tricyclic Analgesics (Nortriptyline, Desipramine, Amitriptyline), Long Acting Opioids (MS Contin, Oramorph, Kadian, OxyContin, Duragesic, Methadone), Alpha 1 Blockers (Phenoxybenzamine, Terazocin), Alpha 2 agonists (Clonidine), Sodium Channel Blockers (LIdocaine, Mexilletine, Amantadine, Ketamine) and Calcium Channel Blockers (Verapamil, Ditelizem, Niphedipine) may help individually or in combination. Local Sympathetic Blocks of specific regional ganglia may be very helpful, especially if the condition is caught in the acute phase. These may be done without steriods and are often tried as a series of blocks every day or every other day. At times a constant infusion with a catheter may be necessary. Spinal Cord Stimulators can be highly effective. Intrathecal pumps are useful in delivering opioids in combination with Sodium Channel Blockers (Bupivacaine), Antispasmodics (Baclofen), or Alpha 2 agonists (Clonidine).