• Home
  • Neuropathic Pain – Complex Regional Pain Syndrome

What is complex regional pain syndrome?

Complex regional pain syndrome (CRPS) is a chronic pain condition that usually affects one limb after an injury or trauma. It is characterised by severe, persistent pain that is disproportionate to the initial injury. CRPS is often divided into two types:

  • CRPS-I (previously known as reflex sympathetic dystrophy, RSD): this occurs without a confirmed nerve injury and mostly follows an illness or injury that didn’t directly damage the nerves in the affected limb.
  • CRPS-II (previously known as causalgia): this is a type of complex regional pain syndrome that develops after a specific and identifiable injury to a nerve. In this condition, nerve damage is the cause of chronic pain and other symptoms affecting the related limb.
CRPS Singapore
Complex Regional Pain Syndrome (CRPS) is a chronic pain condition which often affects a limb following injury or surgery.

What causes complex regional pain syndrome?

The exact cause of complex regional pain syndrome (CRPS) is not fully understood. Still, it is believed to result from a combination of factors, leading to abnormal nervous and immune responses. Here are the key factors that contribute to the development of CRPS:

  • Nerve injury: in CRPS-II, the condition is directly linked to a known nerve injury. However, CRPS-I does not require a confirmed nerve injury, suggesting that more subtle nerve function changes may be involved.
  • Inflammation: after an injury, inflammation can result in redness, warmth, and swelling in the affected area. In CRPS, this inflammatory response is exaggerated or prolonged, leading to severe pain and tissue damage.
  • Abnormal nervous system responses: CRPS is characterised by changes in the central and peripheral nervous systems. This includes increased sensitivity to pain and the abnormal firing of nerve signals, which can result in intense pain sensations from stimuli that are usually not painful (allodynia) and an increased pain response to painful stimuli (hyperalgesia).
  • Immune system response: some research suggests that CRPS may involve an abnormal immune response, with specific immune system factors playing a role in the inflammation and pain associated with the condition.

The complexity of CRPS arises from the interaction of these factors, which makes it a multifaceted condition that can be challenging to diagnose and treat.

What are the symptoms of complex regional pain syndrome?

Complex regional pain syndrome (CRPS) presents with a range of symptoms, which can vary in severity and duration. The most common symptoms of CRPS include:

  • Chronic pain: often described as a burning, stabbing, or throbbing sensation, the pain is usually disproportionate to the initial injury and may spread beyond the original site.
  • Changes in skin colour, temperature, and texture: the affected area may become red, blue, pale, or blotchy and feel warmer or cooler than surrounding areas. Skin texture may change, becoming thin, shiny, or sweaty.
  • Swelling and stiffness: the affected limb may swell and experience stiffness in the joints, reducing the range of motion.
  • Sensitivity: some people are more sensitive to touch, pressure, or temperature changes, and light contact or slight temperature shifts can cause discomfort.
  • Motor dysfunction: motor dysfunction in CRPS includes weakness, tremors, spasms, or difficulty coordinating muscle movements, resulting in reduced ability to move the affected limb.
  • Altered hair and nail growth: research suggests hair may grow faster or slower, and nails might grow abnormally fast or become brittle and grooved.
  • Osteoporosis: decreased bone density can occur in the affected limb, increasing the risk of fractures.

These symptoms can evolve, with early stages marked by severe pain, redness, and swelling and later stages possibly involving more significant changes in skin and bone, as well as muscle atrophy. Early diagnosis and treatment can help manage the symptoms and improve the prognosis.

joint pain singapore
Complex regional pain syndrome can cause joint pain, reducing range of motion.

Who is at risk of complex regional pain syndrome in Singapore?

The risk factors for complex regional pain syndrome (CRPS) include:

  • Gender and age: CRPS is more commonly seen in women than in men and can occur at any age, but the peak incidence is around 40 to 60 years old.
  • Injury or trauma: individuals who have experienced a significant injury, such as a fracture, surgery, stroke, or heart attack, are at higher risk. Even minor injuries, like sprains or soft tissue trauma, can lead to CRPS in some cases.
  • Nerve damage: those who have sustained nerve injuries are particularly susceptible to developing CRPS-II.
  • Genetic factors: there may be a genetic predisposition to CRPS, which suggests that individuals with family members who have had CRPS might be at a higher risk.

Awareness and early intervention are crucial, so individuals with a history of trauma or injury, especially if they experience persistent and disproportionate pain, should seek medical advice promptly to mitigate the risk of developing CRPS.

How is complex regional pain syndrome diagnosed?

Diagnosing complex regional pain syndrome (CRPS) involves a thorough evaluation, as no single test can definitively diagnose the condition. The diagnosis is primarily clinical, based on the patient’s medical history and symptoms, and the following steps are usually taken:

  • Medical history and symptom assessment: your pain specialist will review your medical history, including any injuries or surgeries, and assess symptoms like chronic pain, changes in skin colour, temperature, and swelling.
  • Physical examination: a physical exam will be conducted to identify signs of CRPS, such as skin changes, swelling, temperature differences, and sensitivity to touch.
  • Diagnostic criteria: the Budapest Criteria are often used to diagnose CRPS. These criteria include continuing pain disproportionate to any inciting event, evidence of oedema at some point, changes in skin blood flow, abnormal sudomotor activity in the region of pain, and the absence of another diagnosis that would explain the symptoms.
  • Imaging tests: while no imaging test can confirm CRPS definitively, some tests like X-rays, magnetic resonance imaging (MRI), or bone scans can help rule out other conditions and may show changes in bone metabolism or soft tissues that are consistent with CRPS.
  • Thermography: this diagnostic tool measures skin temperature and blood flow to the affected area. Differences in temperature between the affected and unaffected limbs can support a diagnosis of CRPS.
  • Response to treatment: sometimes, the diagnosis is supported by observing how the condition responds to certain medications or therapies, such as sympathetic nerve blocks.

Since CRPS can mimic other conditions, part of the diagnostic process involves excluding other possible causes for the symptoms. It is important to start this process early, as early diagnosis and treatment can lead to better outcomes.

thermography singapore
Thermography measures skin temperature and blood flow to the affected area.

What are the treatment options for complex regional pain syndrome in Singapore?

The treatment of complex regional pain syndrome (CRPS) is multidisciplinary and aims to relieve pain, improve function, and enhance the quality of life. Here are the primary treatment options for CRPS:

  • Pain management: medications such as over-the-counter pain relievers (e.g., ibuprofen, acetaminophen), prescription painkillers, antidepressants, anticonvulsants, and topical analgesics may be used to manage pain.
  • Physical therapy: a key component of CRPS treatment, physical therapy helps to maintain or improve the range of motion, strength, and function of the affected limb. Desensitisation techniques may also be used to reduce sensitivity.
  • Occupational therapy: helps patients regain the ability to perform daily activities and improve their quality of life through adaptive techniques and equipment.
  • Nerve blocks: sympathetic nerve blocks can temporarily relieve pain by interrupting the pain signals sent to the brain. These blocks can sometimes lead to long-term pain relief.
  • Corticosteroids: steroids can reduce inflammation and improve mobility in the affected limb, especially in the early stages of CRPS.
  • Neuromodulation techniques: methods like spinal cord stimulation (SCS) or peripheral nerve stimulation can help manage pain by sending electrical pulses to the nerves to interrupt pain signals.
  • Intravenous infusions: for some patients, intravenous infusions of ketamine or bisphosphonates can help alleviate pain and improve function.
Physical therapy CRPS
Physical therapy can help improve the affected limb's mobility, strength, and function among CRPS patients.

Treatment plans are highly individualised and often require adjustments over time. Early diagnosis and treatment initiation are crucial for reducing the progression of CRPS. Collaboration among healthcare providers, including pain specialists, physiotherapists, occupational therapists, and psychologists, is essential for effectively managing CRPS. If you are suffering from complex regional pain syndrome, please schedule an appointment with us for a thorough diagnosis and an appropriate treatment plan.

Frequently asked questions

Yes, CRPS can spread from its original site to other body parts, although this is relatively rare. The spread can occur in a mirror image area, an adjacent area, or a distant area in the body.

CRPS is not curable, but with early and comprehensive treatment, many patients can achieve remission or significantly reduce symptoms. The focus is on managing symptoms and improving quality of life.

CRPS can contribute to additional health issues such as mobility problems, muscle atrophy, and psychological conditions like depression and anxiety due to chronic pain and disability.

Many patients report that weather changes, particularly cold and damp conditions, can exacerbate CRPS symptoms, increasing pain and sensitivity in the affected area.