Overview 

Have you ever wondered why you automatically flinch when you touch something hot? This happens because receptors in your skin send messages to your brain to warn it of the pain. 

This is a normal response that allows you to react to pain, keeping you safe from danger. However, this process can sometimes go wrong. In the case of central pain syndrome (CPS), these pain receptors become hyperactive and send signals to the brain when we are not in pain or danger.¹ This hyperactivity may lead you to experience constant pain.²

CPS is a neurological condition in which your body’s pain receptors malfunction, causing you to feel pain when there is no actual danger.³ CPS occurs due to damage to the brain or spinal cord, or other conditions that cause chronic pain. CPS affects several million people across the globe.²

CPS can be a difficult condition to diagnose and treat, as its symptoms often vary between individuals.⁴ Unfortunately, unlike other types of pain, CPS usually can’t be treated using traditional painkillers, like ibuprofen. However, other medications, such as antidepressants and anticonvulsants (or anti-seizure drugs) have proven to be successful in relieving pain in some cases. In addition to these medications, physical therapy, mental health support and treating the neurological condition underlying CPS can help the treatment process.¹ 

Central pain syndrome can have a significant impact on the quality of your life and be a source of stress and pain.⁴ 

What is central pain syndrome? 

Central pain syndrome is a condition that occurs when there is an issue with your central nervous system (CNS), which consists of your brain and spinal cord.³

Normally, your CNS sends pain signals when your sensory receptors detect a pain stimulus. However, in CPS, the sensory receptors in your central nervous system become hypersensitive. This means the CNS will send pain signals even when there is no stimulus or will misinterpret non-harmful stimuli, such as touching soft fabric, as painful. This results in individuals suffering from CPS experiencing constant pain, which can vary from mild to moderate or even severe intensity. 

Causes of central pain syndrome

CPS has two main causes: damage to your CNS (brain or spinal cord) or as a result of an underlying disorder that causes chronic pain.⁵

Damage to the brain or spinal cord 

Damage to the CNS alters the way that pain signals are processed and transmitted. Multiple conditions can cause damage to your brain or spinal cord, including: 

• Stroke 
• Multiple sclerosis (MS) 
• Injuries to the spinal cord 
• Brain tumours
• Brain or spinal cord surgeries 
• Epilepsy 
• Parkinson’s disease 
• Infection ¹

Around 5-10% of patients with stroke, 30% of patients with multiple sclerosis, and 20-40% of patients with spinal cord injury develop CPS.¹

Disorders causing chronic pain 

Conditions that cause chronic pain have been linked to CPS. Over time, the way your nervous system responds to the constant pain signals caused by chronic pain conditions changes, causing the pain to be more intense and widespread across the body.¹ Some of the chronic pain conditions associated with CPS  include: 

• Rheumatoid arthritis 
• Osteoarthritis 
• Chronic back pain 
• Fibromyalgia (a condition causing widespread muscle pain) 
• Cancer
• Irritable bowel syndrome (IBS) 
• Migraines⁵

Risk factors of CPS

Multiple risk factors have been associated with CPS. One of these risk factors is genetics. Research shows that the risk of developing central pain syndrome has a 50% genetic component and a 50% environmental component.  First-degree relatives (e.g. siblings, offspring) of individuals with the condition are 8 times more likely to develop CPS than those who have no family history of CPS. This risk is even higher if there is a family history of mood disorders such as depression as well.¹ 

Other risk factors of CPS include: 

• Early life trauma 
• Chronic stress 
• Obesity 
• Depression¹ 

Signs and symptoms of central pain syndrome 

The main symptom of central pain syndrome is pain lasting more than 3 months that has no known cause and is triggered by things that wouldn’t usually cause pain.¹ The onset of CPS can occur days, weeks, months or even years after an injury, and in many cases is a life-long condition.³ The pain in CPS is often constant.  However, in some cases, it comes and goes. 

Central pain syndrome alters the way that individuals experience pain in many ways, including: 

• Allodynia: Pain caused by stimuli that are not normally painful, like a soft touch or a strong breeze.¹ 
• Hyperalgesia: Increased sensitivity to pain, when painful stimuli feel even more painful than normal.¹
• Environmental impact: In some cases, environmental factors can intensify the pain, for example, cold temperatures, stress or physical activity.³ 

Centralised pain can be widespread over the body or limited to certain parts. The intensity of the pain varies between individuals but is usually moderate or severe.³  

How is the pain described? 

Central pain syndrome symptoms vary between individuals. Some of the common ways that people describe the pain include: 

• Burning
• Aching 
• Cutting or tearing
• Deep tissue or muscle pain 
• Severe itchiness 
• Painful “pins and needles” sensation
• Tingling or numbness
• Sudden episodes of excruciating pain^3,5

Other impacts of CPS on the body

Over time, dealing with chronic pain can become debilitating, significantly impacting an individual’s mental health, well-being and quality of life.^3,5 Therefore, individuals suffering from CPS may also experience: 

• Depression 
• Anxiety 
• Fatigue 
• Mood changes
• Disturbed sleep
• Impaired memory ¹ 

Diagnosis of central pain syndrome

CPS can be difficult to diagnose because the symptoms often vary between individuals. The symptoms of CPS overlap with other conditions that cause chronic pain such as fibromyalgia, rheumatoid arthritis or multiple sclerosis¹. Therefore, before making a diagnosis of CPS, it is important to make sure other conditions are not causing the symptoms.³

A diagnosis of CPS is made by: 

• Detailed medical history 
• Physical examination 
• Imaging tests 
• Laboratory tests 

A detailed medical history should include information about features of the pain, such as when it started, what it feels like, where the pain is or how much it hurts. You may also be asked if you are experiencing any other symptoms or if you (or members of your family) have any other medical conditions.⁵

A physical examination is usually done on the areas of your body that experience pain. A neurological exam may also be done, which tests your vision, hearing, coordination, balance and reflexes. Your muscles and bones may also be examined.⁵

Imaging tests can help confirm CPS by identifying a brain or spinal cord injury. An example of a commonly used imaging test in CPS is an MRI (magnetic resonance imaging) scan.¹ Other imaging scans that may be used include a positron emission tomography (PET) scan or electroencephalography (EEG).⁵

Laboratory tests are sometimes done to help determine the underlying cause of the pain.^1,6 For example, these tests can help detect if you have an underlying immune or inflammatory disorder, like rheumatoid arthritis. 

Usually, CPS can be diagnosed based on injury to the CNS or another condition before the presence of centralised pain symptoms.¹

Management and treatment of CPS

Unfortunately, there is currently no cure for central pain syndrome. However, there are many treatment options available to manage your symptoms and pain. Often, CPS management focuses on treating the underlying disorder causing it. However CPS is a complex condition and it is important to manage the physical, psychological and emotional aspects of this disorder as well. This means treatment of CPS requires using various strategies, as well as collaboration between different types of doctors such as neurologists, physical therapists and psychologists.^1,5

Medications 

Traditional painkillers such as NSAIDs (like ibuprofen or aspirin) typically do not relieve CPS pain. Even stronger painkillers, such as opioid medications, are not usually successful in treating CPS.³ 

First-line treatment for CPS usually involves one or more of the following medications: 

• Antiepileptic (antiseizure) drugs, like pregabalin or gabapentin
• Tricyclic antidepressants (TCAs), like amitriptyline 
• Serotonin-norepinephrine reuptake inhibitors (NRIs), which are a type of antidepressant, like venlafaxine and duloxetine^1,6

Non-medication methods 

Alongside medications, many non-medication methods could help treat CPS. The utility of these methods varies, as it is specific to the individual patient’s needs and the opinion of the doctors. Whilst they have proved effective for some individuals, more research needs to be done to optimise patient outcomes. Some examples include: 

• Transcutaneous electrical nerve stimulation (TENS): sending electrical pulses to the skin to relieve pain  
• Motor cortex stimulation (MCS): sending electrical pulses to the brain’s surface to relieve pain
• Deep brain stimulation (DBS): sending electrical pulses to the deep into the brain to relieve pain 

Lifestyle and mental health 

Physical therapy includes techniques that help patients with chronic pain to be more active and feel more at ease when doing daily activities. Better mobility can help reduce anxiety and depression and improve quality of life. Some methods of physical therapy include massage, acupuncture, manipulation or traction, and stretching exercises.^1,6

Cognitive behavioural therapy (CBT) can help you cope with the effects chronic pain can have on your mental health. Addressing the emotional and psychological aspects of a CP scan reduces your emotional distress and improves both your ability to manage pain and your overall quality of life.⁶

Discussing how to reduce stress and improve the quality of your sleep with your healthcare provider can help improve your overall health and well-being, as well as improve your condition. If you have an underlying chronic pain condition that is causing your CPS, you should also discuss how best to manage your condition with your doctor, as this can improve your quality of life.⁶

Joining support groups with other individuals with CPS or other chronic pain conditions can help you cope with the emotional aspect of the condition, and help you build a support network. You can speak to your healthcare provider about the available support groups.⁷ 

Treatments being researched

There is currently ongoing research on alternative methods to managing CPS, as well as continued research on some current methods. These include: 

• Hypnosis: inducing a relaxed state and diverting attention away from pain to alter pain perception and reduce stress  
• Transcranial magnetic stimulation (TMS): using magnetic fields to stimulate areas of the brain
• Direct current stimulation (DCS): sending a continuous electrical current to the brain^3,6

Outcome

CPS is usually a life-long condition that can have a major impact on the quality of your life, making it difficult to work, socialise, and do the things you enjoy.  In some cases, the condition can be treated, depending on the underlying cause, severity and treatments used.^1,5

If your central pain syndrome is the result of an underlying condition has a better outcome, as treating the underlying cause can treat or reverse some of the symptoms of CPS. If you do not have an underlying condition, CPS is managed by treating the symptoms.^1,5

Early diagnosis and treatment are key contributors to improved patient outcomes.⁵ It is also important to treat CPS holistically, treating both the physical and mental health aspects of the condition as both of these can have a significant impact on the patient’s quality of life.^1,2 Many new treatment options are currently being researched, which have the potential to improve the lives of those affected.²

FAQs

What is the difference between CPS and fibromyalgia? 

CPS and fibromyalgia both involve widespread, chronic pain. Fibromyalgia causes widespread pain in your muscles and joints.⁵ CPS usually occurs due to an injury to the brain or spinal cord, or an underlying chronic pain condition, whereas fibromyalgia often arises without an identifiable cause. Fibromyalgia also has some symptoms that CPS usually doesn’t, such as digestion issues.^1,5

Despite these differences, the two conditions are often connected. Individuals with fibromyalgia are more likely to develop central pain syndrome than unaffected individuals, as chronic pain can make the central nervous system hypersensitive. 

When should I call my healthcare provider?

If you have experienced an injury or undergone treatment in your brain or spinal cord, and are dealing with persistent pain, you should speak to your doctor.⁷ CPS can develop days or years after an injury.  

If you have been diagnosed with CPS, your doctor will arrange regular appointments with you to monitor your condition and adjust your treatment plan as required. If you notice a sudden change in your symptoms, or they become very severe, you should contact your doctor immediately - especially if you experience stroke symptoms.^5,7

How common is CPS? 

Central pain syndrome affects millions of people around the world.¹ It is relatively rare compared to other pain conditions, but it has a higher prevalence among individuals with certain underlying conditions.⁷

Around 5-10% of stroke patients, 30% of multiple sclerosis patients, and 20-40% of patients with spinal cord injuries develop CPS.¹ 

Centralised pain is seen in approximately 13-40% of rheumatoid arthritis patients and 10-15% of osteoarthritis patients.¹ CPS is also seen as associated with other chronic pain conditions such as migraines or fibromyalgia, but its prevalence varies significantly. 

Summary 

Central pain syndrome (CPS) is a neurological condition in which you experience pain even when there is no actual danger or pain stimulus. Normally, our central nervous system only sends pain signals when there is a pain stimulus, but in central pain syndrome, it becomes hypersensitive and interprets non-painful stimuli as painful ones. This hypersensitivity often leads individuals with CPS to experience constant pain. 

CPS usually occurs due to an injury to the brain or spinal cord like stroke or multiple sclerosis,  or due to an underlying condition that causes chronic pain, like rheumatoid arthritis or fibromyalgia. Certain risk factors like genetics, early life trauma, chronic stress, obesity, and depression can increase your likelihood of developing CPS. 

As the symptoms in CPS overlap with other pain conditions, it can be difficult to diagnose CPS. Although there is no cure for CPS, there are many treatment options available that can help manage your symptoms. Whilst traditional painkillers are usually ineffective for treating the pain, antidepressants and anti-seizure medications have proven to be effective treatments. Other methods that can help individuals manage their symptoms include physical therapy, cognitive behavioural therapy (CBT) and lifestyle modifications. 

Central pain syndrome is often a life-long condition, and can significantly impact an individual’s quality of life. However, early diagnosis and treatment, managing the underlying cause of CPS, and holistically treating CPS can help manage your symptoms and improve your quality of life.