Dr Mark Miller FRCA
Consultant Anaesthetics and Pain Management
Royal Shrewsbury Hospital and Shropshire Nuffield Hospital.
Born 1965, Edinburgh. Qualified 1990 MBChB Manchester University. Acquired membership of the Royal College of Anaesthetists in 1997.

Complex Regional Pain Syndrome (CRPS)

This is a common condition and describes a group of symptoms occurring together in a painful part of the body. If there is NO associated nerve damage then the condition is called CRPS type1.
If there IS associated nerve damage then it is CRPS2.

Both conditions give the same symptoms and both conditions more often than not affect a foot or hand but any area of the body that has been injured in some way may give rise to the condition. The condition can occur spontaneously, especially in children. More often then not actual tissue damage e.g. surgery, is the cause.

The symptoms are:

• Pain arising from a stimulus which is not normally painful
• Excessive pain arising from a stimulus which is not normally that painful.
• Spontaneous, intermittent swelling
• Spontaneous, intermittent skin colour changes
• There may be excessive hair growth and changes in nail quality and bone X-rays may reveal some osteoporosis.

It is very important to remember that painful movement in this condition is not causing damage to the affected area. The earlier the condition is recognised the more likely it is to respond to treatment. Unfortunately not everyone responds and some people have life-long suffering.

The treatment in children is basically education that pain is not damage and maintenance of activity with graded physiotherapy. Psychotherapy may also help. Gabapentin is a drug which is licensed to treat this kind of pain. It is one of a range of such medications but is the best tolerated of all of them and may also be useful.

In adults the above is also true where both gabapentin and physiotherapy can help and indeed physiotherapy is the only proven method to beat CRPS1. In addition, however, a drug called Guanethidine can also be injected into the circulation in the affected area.

This area is first isolated with a tourniquet to prevent the initial spread of the Guanethidine. The drug may be diluted in local anaesthetic to reduce the pain of the technique. If there is a positive response then the technique can be repeated as many times as is necessary. Side-effects of Guanethidine include flushing, low blood pressure and headache but the tourniquet is kept inflated for at least 20 minutes so that the dose escaping from the treated area is minimal.

Guanethidine injections using the tourniquet technique are fine if the CRPS1 affects a hand or forearm or foot or leg below the knee. Higher problems in the upper arm and knee and thigh may need separate treatments. A treatment called lumbar chemical sympathectomy may be used for thigh and knee CRPS1. A stellate ganglion block may be used for upper arm and shoulder CRPS1. The details of such treatments with their associated chances of success and failure can be discussed in the clinic.

The take home message is that successful treatment of CRPS1 depends on early presentation and adequate pain relief to allow intensive physiotherapy.