Central Pain Syndrome (CPS)
(AKA- Thalamic Pain Syndrome, Dejerine-Roussy Syndrome, Post Stroke Syndrome, Central Sensitization)
WHAT IS CPS? (CPSF Official Definition)
- Central pain syndrome (CPS) is a neurological disorder consisting of agonizing pain signals of many differing types at once: burning, freezing, shocking, aching, crushing, tearing, and spasticity.
- It has been characterized as the worst pain known to man.
- It is caused by damage to or injury of the Central Nervous System (CNS), which includes the brain, brainstem and spinal cord; its causes include but are not limited to, stroke, MS, epilepsy, head & spinal cord injuries, aneurysms, tumors and infections.
- It is estimated that millions of people in the U.S. suffer from CPS.
- It is aggressive, never ending and disabling, making normal life immensely painful and incredibly difficult.
- The medications and treatments used to fight it are very limited and highly ineffective.
- There is presently no cure.
- WHAT ARE SOME OF THE CAUSES OF CPS?
- WHAT ARE THE SYMPTOMS OF CPS?
- HOW INJURY OR DISEASE AFFECTS THE SPINOTHALAMIC TRACT IN CPS
- INJURED MOTOR NERVES VS. INJURED PAIN NERVES
- FINDING THE RIGHT MEDICAL CARE
- TREATMENTS AND MEDICATIONS
- WHAT IS THE PROGNOSIS?
Central Pain Syndrome (CPS) is known by many names, including thalamic pain syndrome, post-stroke syndrome, Dejerine-Roussy syndrome and Central Sensitization. CPS is not an ailment that develops in and of itself. Instead, it requires a precursory condition that first injures the Central Nervous System (CNS). This includes the brain, brain stem and spinal cord. Once thought an uncommon neurological curiosity, CPS is now said to be an important and underrecognized condition.
Central type pain has been documented since the early 1800’s. In 1891 it was formally described in a published paper by Dr. Edinger, a physician working in Frankfurt am Main Germany. After a stroke patient of his committed suicide from this pain, he hypothesized that central pain could be released independently of peripheral nociceptive stimulation. In 1906 Dejerine and Roussy described the so called “thalamic syndrome” that was said to be caused by and associated with a variety of thalamic infarctions and hemorrhages. Now, over 100 years later, CPS has been given numerous other titles and is known to be caused by CNS damage of varying types.
A lesion somewhere along the spinothalamic tract is the direct cause of CPS, but the cause of the lesion can come from many differing sources. In major infarcts and hemorrhages, such as strokes, and other medical conditions where damage is detectable, a diagnosis of CPS is sometimes easily obtained. However, lesions as small as the size of a pinprick, occurring anywhere along the spinothalamic tract can cause the very same excruciating pain as the larger, more easily detectable lesions. The smaller lesions are often entirely unseen via today’s scanning procedures. Therefore, many CPS sufferers are treated with inadequate medical care, due to a lack of clinical findings.
Some practitioners feel that patients are drug seeking or have emotional/mental issues that are the underlying cause of their pain. We hope to provide clinicians with the necessary knowledge to treat all CPS sufferers properly and in a timely manner. It is imperative to do so, since a delay in treatment can actually lead to worsening CPS pain.
Once the central nervous system is damaged, it can take days, weeks, months or even years for CPS to appear.
Some common causes are stroke, spinal cord or traumatic brain injury, cancer, Parkinson’s disease, multiple sclerosis and Epilepsy. Less common causes of CPS are:
- AIDS, especially end-stage
- Arteriovenous malformation
- Cauda equina syndrome
- Cervical myelopathy
- Charcot Marie Tooth
- Chemical toxicity
- Cluster headaches (some think this might be a form of central pain)
- Gunshot wounds
- Infection (bacterial or viral; such as Shingles and encephalitis)
- Lead neuropathy
- Meralgia paresthetica
- Mercury toxicity
- Posterior myelitis
- Post-polio syndrome
- Prion disorders
- Radiation exposure
- Reflex sympathetic dystrophy syndrome
- Spinal cord infarction
- Surgical accidents
- Tethered cord syndrome
- Transverse myelitis
- Vascular malformation
- Vitamin B-12 deficiency
- Any condition that causes nerve demyelination or other nerve or brain damage
CPS patients deal with PERSISTENT pain. It is characterized by a mix of pain sensations, the most common of which is constant burning, which may be unrelenting and occur over large areas of the body. CPS may also include other pain sensations such as freezing, aching, ballooning, stretching, crushing, spasticity, shocking/electrical type jolts & stabbing.
Depending on the location & amount of CNS damage, the pain can occur anywhere from head to toe or just in certain areas. It can be totally one sided or may cover the entire body. Often, as CPS progresses, it transforms, covering new areas and varying in pain intensity and character.
Other CPS symptoms include intolerance to temperature change, fatigue, a vague numb sensation (like coming out of dental anesthesia), hyperalgesia (abnormally excessive sensitivity to pain), allodynia (pain elicited by stimuli that normally doesn’t cause pain), allachesthesia ( a touch in one area resulting in pain in a neighboring area), visceral pain, bowel and bladder pain and emotional lability.
CPS becomes worse with normal sensory input, such as light, sound, movement, vibrations, emotions, stress and even thinking. A light touch or hug, a breeze, sunshine or even clothing touching the skin may cause intense, burning pain. Touching an item that is hot or cold, such as a door handle, coffee mug, water faucet or steering wheel, can cause pain not only to the hand that touches it, but in a range of different areas in the body. The pain makes no sense. Barometric pressure changes, such as storms rolling in or out, and altitude can wreak havoc on a CPS sufferer. Preparing for and getting to a doctor’s appointment can be a major challenge with CPS. Showering, dressing, walking outside into the daylight, sitting on a hot or cold car seat, touching the warm or cool steering wheel and riding in a car that vibrates down the road can add to the pain a CPS patient feels.
For many with CPS, the most symptom free time of day is just after waking up, before the senses are bombarded with the input of normal everyday life. The sleep cycle can, in some, calm the pain and many CPS sufferers will attest to having their best hour(s) of the day shortly after waking. But, once sensory stimuli starts ( i.e. moving, getting dressed, walking to the bathroom, seeing daylight, talking, eating etc.) the pain begins to ramp up. Things that used to be easily accomplished are often avoided because of the extreme pain they evoke. Isolation and disability can occur due to the enormous amount of discomfort that normal ADL’s (activities of daily living) cause. CPS sufferers may have a lack of patience from tolerating constant neurological pain as well as emotional lability.
Central pain is by definition “bizarre” and is the result of a diseased pain pathway. Research reports the most severe central pain is found only in those with some remaining function, however miniscule, of the spinothalamic tract. Loss of motor function does not correlate with degree of central pain. In general, the most severe central pain can be expected where significant retention of spinothalamic tract is present. Such pain typically appears when the CNS injury is resolving and is revealed to be incomplete. In a healthy spinothalamic tract, radiostimulation causes no sensation. In patients with CPS it recreates the sensations of central pain and acts as if the entire pain system is like a nerve ending. When these ungated pain signals reach the cortex, they may cause unbearable suffering.
An injured motor nerve simply carries less current than an uninjured motor nerve. Injured pain nerves, however, do exactly the opposite, increasing their signal. But, it is not just a simple increase. They eventually gain power to influence uninjured neighbor neurons, which begin to autonomously fire. (Devor’s work in The Axon, ed. Waxman, Oxford Univ. Press, 1995).
The process can become so violent that the thalamus, the pain center of the brain, records “bursts” of impulses from these injured nerves. CPS apparently occurs at this point.
The longer that pain pathways relay pain messages, the more efficient those pathways become, causing greater pain to be transmitted, the way a stream carves a path through land, so that over time, it flows more quickly and turns into a river…..progressively deeper levels of pain cells in the spinal cord are activated with prolonged injury. Also it may be that descending pathways from higher brain centres which normally dampen ascending pain (as during the placebo effect) are weakened.
“Physical pain changes the body in the same way that emotional loss watermarks the soul. The body’s pain system is not hardwired, but soft-wired (what neuroscientists call ‘plastic’), and it can be maladaptively molded by pain to increase its pain sensitivity……But in the case of persistent pain, neuroplasticity is negative. The nerves in the spinal cord become hyperexcitable and begin spontaneously firing and recruiting other nerves in their service, and the whole system revs up to be increasingly responsive to pain, in a phenomenon discovered by the pain researcher Clifford Woolf and termed…..central sensitization (when hypersensitivity occurs within the central nervous system). ” from ‘The Pain Chronicles’ by Melanie Therstrom
It can be extremely difficult, time consuming and exhausting to find a doctor who is familiar with CPS. One of our main goals at CPSF is to educate the medical community about the causes of this menacing condition and how to effectively diagnose and treat patients who have it.
Because this type of pain can worsen with time, it is IMPERATIVE to diagnose and begin treatment of CPS as quickly as possible, before deeper damage is incurred. Although there is currently no cure for CPS, certain medications and treatments have been found to be more effective than others.
There are many medications used in the treatment of CPS, although none are completely effective in alleviating the symptoms. Through trial and error, patients and their doctors eventually find the medication(s) that work best for each specific case. It is essential to find the regime that allows for maximum quality of life for each patient. The most common medications for CPS are listed here:
Anticonvulsants, antidepressants, antispasmodics/anticholinergics, benzodiazipines, CNS stimulants, local anesthetics (transdermal cream and patches), medical marijuana (inhaled, ingested or topically applied), muscle relaxants, narcotic pain medications, neuroleptics and sedatives/sleep aids.
Medications will vary based on the precursory condition that led to CPS and any other medical issues a patient may be receiving treatment for.
Since chronic pain can worsen with vitamin D deficiency, ensure that vitamin D levels are within normal limits. Fatigue and depression, which are common in CPS may also be improved by adding a vitamin D supplement if needed.
Aside from medications, there are currently no treatments known to alleviate CPS symptoms. However, stress reduction, biofeedback and avoiding certain triggers help some patients keep their pain at more tolerable levels.
In past references, CPS is listed as a non-fatal condition. But, as pain spikes to unthinkable levels, so can blood pressure. In certain patients, such as those prone to stroke, an increase in blood pressure can deliver fatal consequences. Also, there is a high incidence of suicide in the CPS community because this insidious pain NEVER goes away, often gets worse over time and is incredibly difficult to effectively treat.
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