Complex Regional Pain Syndrome (CRPS) - Causes, Symptoms, and Treatment

Although most cases of CRPS recover over time on their own, some people might suffer a prolonged period of excess pain. However, this condition is treatable, and early diagnosis can improve the chances of faster recovery. To learn more about its causes, symptoms and treatment, read on.

Complex regional pain syndrome (CRPS) is a neurological disorder characterised by prolonged pain in the arms or legs due to a dysfunction in the peripheral nervous system, often induced by an injury, fracture, or surgery.

Based on the causes, there are mainly two types of complex regional pain syndrome, namely, Type I and Type II.

1. Type I

Type I CRPS can take place due to an injury or illness that does not directly affect the nerve. This type was previously known as reflex sympathetic dystrophy.

However, this condition can also develop due to injuries or trauma, such as surgeries, triggering nerve damage.

2. Type II

In this category, direct and distinct nerve damage results in the CRPS condition. Previously, it was known as causalgia. The damage can occur from external injuries such as fractures or major and minor trauma like surgeries, heart attacks, etc.

Other than these, CRPS can also be acute, i.e. short-term or chronic, i.e. prolonged periods longer than six months.

The signs and symptoms and their extent in CRPS vary from person to person.

In most cases, the symptoms start showing after 3-6 weeks post-injury or surgery. However, it can also develop without an identified cause.

The following are the most common CRPS symptoms:

• Experiencing more pain than usual to external pain stimuli such as pinching
• Continuous unprovoked pain, especially in arms, hands, legs, or feet, with burning or throbbing sensation.
• Inflammation of the painful region
• The temperature of the skin may change – it may feel colder or warmer
• Increased sensitivity to touch or cold
• Changes in the colour of the skin in the affected region, ranging from white, red or blue, and often blotchy.
• The affected area of the skin may change its texture and become tender, shiny or thin.
• Abnormal sweating, including profuse or no sweating
• Growth of hair and nails may be increasing rapidly or be stunted
• Stiffness, swelling or damage in the affected joints
• Reduced capacity to move the affected body part or numbness
• Muscle spasms and reduced muscle strength and movement (atrophy)
• In some severe cases, psychological issues like depression, post-traumatic stress disorder and situational anxiety may also develop.

The underlying cause behind CRPS disease is damage to the nerve fibres. This can occur due to direct damage to the nerves or from conditions or injuries triggering it.

In most cases, CRPS is caused by nerve trauma from an affected limb which causes damage to the thinnest sensory and autonomic fibres. As a result, they transmit pain or heat signals to the brain.

The most common injury that causes nerve damage triggering CRPS is bone fractures (mainly in the wrist). Therefore, damage can either occur from a displaced bone or from the pressure of the tight cast.

In addition, several other injuries can also lead to this condition, such as:

• Sprains or strains damaging the connective tissues and over-stretching of nerves
• Burns and bruises
• Medical surgery, stitches, or incision damage

The significant risk factors of complex regional pain syndrome are as follows:

1. Demographic Factors

Gender: CRPS can affect people of any gender but are more frequent in females than males.

Age: Elders, around the peak age of 40 years, are more likely to be affected by CRPS than younger populations or children.

2. Other Factors

Other factors that may increase the risk of CRPS are:

Factors affecting nerve health: People who have health conditions such as diabetes or neuropathy are more susceptible to CRPS. This is because their nerves have low resilience and have difficulty repairing damaged cells. In addition, the effects of chemotherapy may also reduce the capacity for nerve regeneration.

Poor immune system: Immune system plays a significant role in inflammation. Therefore, if your body produces more inflammatory chemicals, such as cytokines, it can trigger CRPS symptoms. In addition, people with inflammatory conditions such as asthma or autoimmune diseases may also be at a higher risk.

Genetics: According to various studies, genetics play a huge role in developing CRPS, as well as recovering from it.

Complex regional pain syndrome does not have a specific test. However, the most common CRPS diagnosis approaches include the following:

• Physical examination: A thorough examination by doctors (including neurologists or orthopaedists) to check for CRPS symptoms. The examination also includes reviewing medical history and physical examination of recent injuries or surgeries.
• Nerve conduction test: Some CRPS can be detected through nerve conduction studies. However, conditions that include damage to tiny nerves may not be detected this way.
• Imaging: Imaging tests such as ultrasound or magnetic resonance neurography (MRI) can be done to diagnose underlying nerve damage. MRI can also detect characteristic bone and bone marrow abnormalities to identify nerve damage.
• Bone scan: Physicians may also carry out triple-phase bone scans to identify excess bone resorption, which can help in localising and identifying CRPS.
• Others: Other tests may be performed in order to rule out CRPS. For example, electromyography (EMG) may help to determine the causes behind neuropathy that shows similar symptoms as CRPS.

CRPS for mild or early cases mostly recovers on its own. However, it is best to start early to get the maximum benefit from the treatment.

The primary complex regional pain syndrome treatment procedures include therapy, medication, and supportive care.

1. Therapy

• Physical therapy and rehabilitation: Physical therapy includes keeping the injured limbs or body parts moving to improve blood flow and reduce circulatory symptoms. Moreover, it improves flexibility and muscle function and helps regain strength. Rehabilitation helps to reverse or prevent the changes in the nervous system linked to chronic pain. It also helps people get back to their daily active life in new ways.
• Graded Motor Imagery (Mirror Therapy): This is a mental exercise where you will be asked to identify the painful body parts on the right and left sides while looking at the mirror. Moreover, this exercise requires you to visualise the body parts without actually moving them to send non-painful stimuli to the brain, reversing the changes caused by prolonged CRPS.
• Psychotherapy: This approach is used for people developing psychological symptoms like depression, PTSD, etc., which increases their perception of pain and reduces brain function. Therefore, psychotherapy can help you deal with CRPS and boost your recovery speed.

2. Medication

There are various classes of medications used in CRPS treatment. They include:

• Pain relievers: It includes medicines like aspirin, naproxen sodium (Aleve), and ibuprofen (Advil, Motrin IB, others) for mild pain and swelling. However, an opioid can be prescribed in low dosages in case of excessive pain.
• Corticosteroids: These include steroid medications, like prednisone, to reduce swelling and improve mobility of the affected limb.
• Antidepressants and anticonvulsants: These include amitriptyline and anticonvulsants to treat neuropathic pain.
• Sympathetic nerve-blocking medication: This helps block the pain fibres in the affected nerves through an injection to reduce pain sensation.
• Other medications: These may also be prescribed to improve blood pressure, prevent bone loss, etc.

3. Supportive Care

• Spinal cord stimulation: In this, tiny electrodes are inserted inside the spinal cord to send electrical impulses that help in relieving pain.
• Transcutaneous electrical nerve stimulation (TENS): By sending electrical impulses to nerve endings, chronic pain in CRPS can be reduced.
• Intrathecal drug pumps:  It is also known as pain pump. A small pump is used to deliver pain medication directly to the spinal cord.
• Acupuncture: This is an old traditional treatment method where long and thin needles are inserted at strategic points while stimulating nerves, muscles and connective tissue that are affected by the condition. It is also believed to increase blood flow and reduce pain.

Here are a few tips that can help you with better management of complex regional pain syndrome:

• Reach out to your friends and family and stay connected to people who can support you mentally through difficult times.
• Try to maintain an active lifestyle by doing typical activities before developing CRPS.
• Avoid taking the stress and get as much rest as possible.
• Distract yourself from focusing on the pain, and engage in day-to-day hobbies and activities.
• Share your feelings with a support group or a professional to relieve stress.
• Note down your queries before visiting the doctor.
• Inform your doctor about your health conditions without holding back

Complex regional pain syndrome affects the quality of life severely. Those suffering from prolonged pain are primarily affected mentally. It is characterised mainly by depression, denial, anger and frustration.

Furthermore, conditions of anxiety and depression can worsen the pain over time, creating a loop if not addressed or treated. Many people can also have prolonged disabilities leading to atrophy or contracture.

Now that you have a clearer idea about what a complex regional pain syndrome is, it will be easier for you to identify its symptoms and seek help accordingly. You must note that chronic pain conditions such as CRPS have the best chances of recovery if treated at the earliest. Therefore, if you notice any critical signs or symptoms, consult a professional immediately.