What is CRPS?  

CRPS is a condition which causes pain in  an arm or leg. It usually develops after  an injury, but the pain is more severe  and lasts much longer than would be  expected from the injury itself. 

What are the main symptoms  of CRPS?  

The main symptom of CRPS is a burning,  stabbing, stinging or throbbing pain in  the affected limb. It may also become  more sensitive to touch, change colour  or temperature, or sweat. The limb may  swell, leading to stiffness, and many  people say that the limb ‘feels strange’. 

Should I see a doctor?  

We would always recommend you see  your GP if you have pain that won’t go  away. CRPS is rare but it’s important to get  the right diagnosis so that appropriate  treatments can begin. Research shows  that treatment for CRPS is usually most  effective when it’s started early on. 

What causes it? 

The exact cause of CRPS isn’t yet known,  but it’s thought that abnormal pain  signals in the brain play an important  part. It’s often triggered by an injury, but  sometimes occurs after an operation or a  stroke. In about 1 case in every 10 there’s  no obvious trigger event.

What treatments are there? 

CRPS is best treated with a combination  of pain medications and rehabilitation  therapies. Rehabilitation therapies are  vital to normalise sensation in the limb  and to improve function and mobility.  There’s no single drug treatment that’s  effective for everyone with CRPS, but  medications may be helpful to allow you  to start the rehabilitation therapies. 

Treatments are likely to include the  following: 

• pain relief medications such  as paracetamol, codeine or  morphine-based drugs 

• drugs which alter pain signals  between the nerves and the brain –  e.g. gabapentin, pregabalin 

• low doses of antidepressants  (e.g. amitriptyline, duloxetine), which  can reduce pain signals and/or help  you sleep 

• drugs such as pamidronate which are mainly used to prevent thinning of bones but also have pain-relieving properties

How is CRPS diagnosed?

There’s no specific test that will confirm  you have CRPS. Doctors mainly base  diagnosis on your symptoms and a  physical examination, although tests may  be helpful – sometimes to rule out other  conditions: 

• An x-ray or bone scan of the affected  limb may show thinning of the bone  (osteoporosis) or other abnormalities.  

• Blood tests may help to rule out  infection or autoimmune conditions  such as rheumatoid arthritis. 

• Magnetic resonance imaging (MRI) scans may help to rule out problems  with the bones or other tissues. 

• Regional anaesthesia or blocking of  the sympathetic nervous system with a  local anaesthetic is occasionally used as  a diagnostic test. If this block eases the  pain, then it’s likely that you have CRPS. 

• Nerve conduction studies are  sometimes used to check for nerve  damage. 

The International Association for the  Study of Pain have set criteria, called  the Budapest criteria, to help with  diagnosis. These take into account signs  and symptoms in each of the following  categories: 

• unusual sensitivity to touch 

• differences in temperature or skin  colour between the affected and  unaffected limb 

• swelling and/or unusual sweating in the  affected limb 

• reduced range of motion or loss of  function in the affected limb and/or  changes in the skin, hair or nails of the  affected limb. 

If your GP is in any doubt about the  diagnosis you may be referred for a  specialist opinion. Once you’ve been  diagnosed with CRPS it’s likely that you’ll  be referred to a specialist pain clinic for  treatment – usually at a local hospital.