Complex regional pain syndrome (CRPS) is a poorly understood chronic pain condition (lasting more than six months) in which a person experiences persistent severe and debilitating pain. It is usually confined to one limb but can spread to other parts of the body.
Most cases of CRPS are triggered by an injury or trauma and the resulting pain is much more severe and long lasting than normal, and disproportionate to the initial event.
CRPS is believed to be caused by damage to, or malfunction of, the peripheral and central nervous systems. The central nervous system is composed of the brain and spinal cord; the peripheral nervous system involves nerve signalling from the brain and spinal cord to the rest of the body.
There are two types of CRPS:
Type 1 (RSD): Where the symptoms come on after a trauma/injury to the affected area but where there is no actual damage to the nerves. This is the most common form of CRPS and accounts for the majority of diagnosed cases
Type 2 (Causalgia): This comes on after a distinct injury to the nerves. This is a rarer form of CRPS, and the symptoms here tend to be more painful and difficult to control.
Who can get CRPS?
Studies have found that although it is more common in women, CRPS can occur in anyone at any age, with a peak at age 40. It is rare in the elderly. Very few children under age 10 and almost no children under five are affected.
Symptoms of CRPS
The key symptom is prolonged severe pain that may be constant. The severity of symptoms ranges from self-limiting and mild to severe and debilitating.
Symptoms may change over time (even numerous times a day) and they can vary from person to person. Sufferers can experience a range of symptoms such as:
- Burning, stabbing and stinging sensations;
- Tingling and numbness;
- The skin in the affected area may become very sensitive (allodynia);
- A feeling of the affected limb not belonging to the rest of the body, feeling bigger or smaller to the unaffected limb;
- Alternating changes in the skin – such as being hot, red and dry and other times cold, blue or sweaty;
- The skin may change colour, becoming blotchy, blue, purple, pale or red;
- The skin texture may appear shiny and thin;
- Hair and nail changes – hair and nails may grow unusually slowly or quickly, and nails may become brittle or grooved;
- Joint stiffness and swelling in the affected area;
- Abnormal movement in the affected limb, most often fixed abnormal posture (dystonia) but also tremors in or jerking of the limb;
- Problems co-ordinating muscle movement with decreased ability to move the affected body part;
- Difficulty sleeping;
- Smaller patches of fragile bones.
In very rare cases, CRPS can also lead to further physical complications, such as skin infections, ulcers, muscle atrophy and muscle contractures.
What causes CRPS?
CRPS is uncommon. It is unclear why some individuals develop CRPS, while others with similar trauma do not. In more than 90% of cases, the condition is triggered by a clear history of trauma or injury.
The most common triggers are:
- Fractures, sprains/strains;
- Soft tissue injury (such as burns, cuts or bruises);
- Limb immobilisation (such as being in a cast);
- Surgery; or
- Even minor medical procedures such as needle stick injury.
Diagnosis and prognosis
The diagnosis of CRPS is based on clinical findings which exclude other possible causes.
A number of diagnostic tests can help eliminate other causes and confirm a diagnosis such as:
- Blood tests can help exclude infection or inflammation in the joints as a possible cause of symptoms;
- Scans such as ultrasound may be used to rule out a blood clot;
- Thermography measures skin temperature of specific parts of the body. High or low skin temperature in the affected area could indicate CRPS;
- Electrodiagnostic testing or nerve conduction studies. Abnormal readings could indicate nerve damage and possible Type 2 CRPS;
- X-rays can detect mineral loss in the bones at later stages; and
- MRI scan can rule out any underlying problems with bones or tissue.
Currently there is no specific test which can confirm CRPS. It is a diagnosis based on a person’s medical history, and signs and symptoms that match the definition. Since other conditions can cause similar symptoms, careful examination is important.
The outcome of CRPS is highly variable. Younger persons, children and teenagers tend to have better outcomes. While older people can have good outcomes, there are some individuals who experience severe pain and disability despite treatment.
How is CRPS treated?
Treatment is most effective when started early and involves a multi-disciplinary approach. It is best for a specialty pain clinic to assess and determine a plan.
The following treatment therapies are often used:
- Rehabilitation and physical therapy: An exercise programme to keep the painful limb or body part moving can improve blood flow and lessen the circulatory symptoms. Additionally, exercise can help improve the affected limb’s flexibility, strength and function. Rehabilitating the affected limb can also help to prevent or reverse secondary brain changes which are associated with chronic pain;
- Occupational Therapy: This can help the individual learn new ways to work and perform new tasks. They can also prescribe assistive devices;
- Psychotherapy: CRPS is often associated with profound psychological symptoms. People with CRPS may develop depression and anxiety or post-traumatic stress disorder, all of which heighten the perception of pain. A psychologist can help the patient to cope with living with a chronic, painful condition;
- Medications: Several different classes of medication have been reported to be effective for CRPS, such as non-steroidal anti-inflammatory drugs (NSAIDS), like ibuprofen; anticonvulsants such as gabapentin to manage nerve pain; topical creams and patches; botox; opioids and corticosteroids for inflammation;
- Sympathetic nerve block: these involve injecting an anaesthetic next to the spine to directly block the activity of sympathetic nerves and improve blood flow; and
- Spinal cord stimulation: This involves placing stimulating electrodes through a needle into the spine near the spinal cord.
Who to instruct for a medico-legal report?
In order to be able to fully assess the extent of your client’s injuries, it is good practice to instruct a multi-disciplinary team of experts to arrive at an accurate diagnosis and prognosis of the injuries and to recommend a treatment plan.
Depending upon the nature of the symptoms, you should consider reports from a consultant in pain medicine, an orthopaedic consultant, a rheumatologist, a neurologist, a psychiatrist, and an occupational therapist.
Recent reported cases of interest
KM v Surya Hotels Ltd (2017)
The claimant, a woman aged 45, received £4m after slipping over a step and injuring her right ankle. She developed CRPS and fibromyalgia. The claimant experienced symptoms including depression, chronic fatigue and cognitive problems and her leg was later amputated.
Barnett v Leonard Cheshire Disability (2017)
The claimant, a 44-year-old woman, received £375,000 for her knee injury and subsequent diagnosis of CRPS after slipping on some spilt water at work. She suffered pain in different areas of her body, nightmares, flashbacks, panic attacks and limited mobility. The claimant was unable to work and required ongoing care and assistance