Central pain syndrome: Do you know you have it?

Posted by Sukant Khurana
February 7, 2018

By Priyanka Nehete and Sukant Khurana

http://www.bbc.com/future/story/20170110-why-pain-is-so-hard-to-measure—and-treat

Central Pain Syndrome is a neurological condition related to the central nervous system which includes the brain, brain stem and spinal cord. It is caused by damage or dysfunction of the central nervous system. It is commonly observed in patients with spinal cord injury. This condition can be caused by several conditions like a stroke, brain trauma, tumors, epilepsy, brain hemorrhage, multiple sclerosis, aneurysm, spinal cord injury, Parkinson’s disease and surgical procedures that involve the brain or spine. There are subdivisions of CPS namely thalamic pain syndrome or Dejerine–Roussy syndrome which is caused after a thalamic stroke, central post stroke pain which is caused by damage to neurons in the brain. The central pain is associated with the lesions of the central nervous system that lead to damage of somatosensory pathways.

This syndrome could affect large portion of body or could affect even a specific part of body. The Extent of pain is usually related to the cause or extent of damage to central nervous system. The pain is described as agonizing, intolerable by those who experience it and is considered to be one of the most distressing forms of chronic pain. [1] Knowing the patient’s history would be highly beneficial in identifying central pain syndrome and knowing what exactly is the cause of the condition. Since many times the syndrome goes undetected and the patient is administered altogether different medication.

What are the symptoms of central pain syndrome that we should look for?

People with central pain syndrome often experience severe burning, sharp pains, aching, stabbing, freezing, shocking, prickling often feeling like pins and needles. In severe cases people complained experiencing all pain at once and may have pain even by mere touch of clothing. The severe pain can result in unremitting nausea, causing vomiting in some cases. It can also lead to hyperventilation and increase in blood pressure. [2] Central pain can be constant, intermittent and range from moderate to severe fluctuating during the day. Some people may experience bursts of excruciating pain and symptoms may become worse by factors like stress,anxiety,anger, temperature changes especially cold temperature , wind, altitude changes, involuntary movements like sneezing and even by touch. Due to extreme sensitization, pain sensations are often spontaneous and occur despite no reason or trigger. Many at times these symptoms are taken lightly and undergo undiagnosed or are attended in an entirely wrong manner. It is extremely important to know the patient history and to get cleared of other associated disorders.

What is the cause of this syndrome?

The central pain syndrome is caused by damage to central nervous system. It could be due to accidents or major surgery dealing with spinal cord. Most common cause is spinal cord injury and trauma with an incidence rate of 6.4 % to 94% [1]. The conditions associated with this syndrome which are most likely the cause are stroke, multiple sclerosis, spinal cord injury or brain tumors. Pain after spinal cord injury can be immediate or may take some time, sometimes even up to 5 years to occur. If the onset is delayed beyond one year the person may suffer from lesions leading to a condition named as syringomyelia. In 2000 a classification system was developed by (IASP) International Association for the study of Pain for patients with spinal cord–related pain that identifies the pain type, system involved, and structures or pathology. [3] Brain -related central pain are due to strokes in majority of the cases and are said to be comparatively rare, occurring in only 1% to 2% of all stroke patients where 90% of it is arising due to vascular etiology.[1]

What are the Means of diagnosis and problems in diagnosis, is there anything like false diagnosis?

A diagnosis of central pain syndrome is based on patients detailed history, thorough clinical evaluation consisting of various specialized tests like MRI scans, CT/CAT scans. Neurological examination can assess nonneuropathic contributions to the patient’s pain and also commonly musculoskeletal, inflammatory, myofascial, and psychological processes. The physical examination is suggested to be done so as to elicit all of the positive sensory phenomena such as allodynia, hyperalgesia, hyperpathia, summation, and after-sensation. [4] If the doctor is well aware of the syndrome and the patient’s medical history is available, this syndrome can be identified correctly and treated. Though this syndrome is not fatal but it leaves the sufferer distressed.

What are the Known Treatment that work for this rare syndrome?

Central Pain Syndrome is often treated with Tricyclic antidepressants such as nortriptyline or anticonvulsants such as neurontin (gabapentin).Central pain syndrome treatment varies from person to person where every patients medical history, symptoms and cause of this syndrome plays a crucial role. Treatment includes pain medications but are only responsible for reducing the pain and does not cure the disease completely. some of the drugs like Lamotrigine, an anti-seizure drug (anticonvulsant) and Amitriptyline an antidepressant has been found to be effective in central brain related pain. These medications are also considered as first line of defense. Patients with spinal cord related pain when used lamotrigine showed reduction in pain evoked by an innocuous brush and wind-up-like pain. [5] Tricyclic antidepressants are advised to be used with extreme caution in elderly patient’s due to toxic adverse effects to heart and anticholinergic effects. Medications like gabapentin, opioid analgesics, tramadol also should be used with caution because of cognitive impairment. Carbamazine is used in treatment of trigeminal neuralgia and common side effects include nausia, vomiting, drowsiness, ataxia, photosensitivity. When medications fail patients are directed towards surgical procedures like motor cortex stimulation, deep brain stimulation but this is mostly considered as last resort.

Any Case studies which can help us understand?

The very own Central Pain syndrome foundation founder Louise Mowder developed the syndrome after a stroke that lead to damage in the spinal cord. During an interview to Huff post live Mowder shared her experience with disease. She said “CPS didn’t cause a loss of feeling, but instead caused her to feel every sort of pain sensation known to man all at once, all day.” According to Mowder it’s been since last 10yrs the symptoms are categorized into Central Pain Syndrome. “Often people go on complaining to the doctor about symptoms like burning, freezing, electrical stab and are told that there is nothing clinically wrong with them.” [6] The central pain foundation website hosts a number of wonderful stories shared by the sufferers and are constantly working towards spreading awareness about this rare disease, its identification and treatments.

A case report in 2014 was published which reported a 75-year-old Indian female from AP India suffering with thalamic pain syndrome. She was admitted with complaints of weakness of right upper and lower limb with sudden onset in speech disturbances. After 8 days of admission she developed right half of body pain. She showed symptoms of constant burning with allodynia. During hospitalization patient was treated with tricyclic antidepressants and antihypertensive. [7] There are many such cases but only some are reported with systematic medical history.

Another case report was published in 2008 in the nature international spinal cord society where a new treatment option was presented. They presented a case of 54-year-old male patient suffering from metastatic pancreatic cancer. The patient was said to develop a severe at-level neuropathic pain syndrome after surgical decompression of spinal cord. “After all pharmacological approaches failed, lidocaine 5% patches were initiated. Within 4 hrs. after the first patch, neuropathic symptoms started to disappear and after 12 hrs. the patient was reported to be completely pain free with lasting analgesics effect”. [8]

Now not only researchers but people who suffer from this deadly disease are sharing their experiences so as to help others. Social media websites like YouTube has numerous number of such videos where people have posted their so called “messages from hell”!

How many people are affected by this disease?

Central Pain Syndrome is estimated to affect millions of people worldwide. 8–10 % of people who suffer stroke develop CPS, while one third or more people with spinal cord injury are bound to develop CPS, 20 % people suffering from multiple sclerosis are expected to get CPS and over 30,000 in USA alone are said to suffer from thalamic pain syndrome. [9] [10]

So what are the Known medicines prescribed for this syndrome and what is their cost?

1. Amitriptyline Hcl (25 mg) 100Tablet Price is Rupee100 in India and in US for 25mg -90 tablets cost around in the range of 21.64–25$.

2.Gabapentin (Neurontin) ranges from around $13.38, 82% off the average retail price of $75.54.

In India GABAPIN 100MG TABLET 10’S is Rs.56.00.

3.Carbamazepine (Tegretol, epitol) in US.is around $32.00, 58% off the average retail price of $77.08.

In India cost of TEGRITAL CR (400MG) TABLET 10’S is Rs.29.70

4.Pregabalin in USA is around $394.63, 17% off the average retail price of $475.78.

In INDIA known by name MAXGALIN 75MG CAPSULE 10’S, (PREGABALIN 75MG) is Rs.120.00.and LYRICA 75MG CAPSULE 14’S (PREGABALIN 75MG) Rs.842.00

5.Topiramate (Topamax) is around $9.21, 88% off the average retail price of $82.39.

In India TOPAMAC 25MG TABLET 10’S (TOPIRAMATE 25MG) Rs.79.00 and 149 for 50 mg.

What are the Challenges surrounding this disease, in form of stigma, family support, and what kind of educational mediums are available for people to understand better?

The key challenge surrounding this disease is the way it goes undiagnosed. Since doctors often relate the symptoms to some other condition, the main cause goes unnoticed. Also, patient needs to have a systematic medical history which makes it easy for the doctor to identify the symptoms and clear off other suspected diseases. People who suffer from CPS often suffer from excruciating pain, electrical stabs, freezing and family or their loved should try to understand and provide support to fight this crippling disease in such situation.

In order to identify and ensure correct education, proper medical treatments and understanding the disease there are some foundations like

1. https://centralpainsyndromefoundation.com/

2.https://www.theacpa.org/condition/central-pain-syndrome

3. https://rarediseases.org/

4. https://www.americanbrainfoundation.org/

These organizations not only spread awareness about the disease but also help understand the disease and improve the lives of people suffering from CPS and their family too.

References:

1.Loeser JD, ed. Bonica’s Management of Pain. 3rd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2001:434–457

2. Bowsher, David (1996), “Central pain: clinical and physiological characteristics”, Journal of Neurology, Neurosurgery, and Psychiatry, 61 (1), pp. 62–69

3.Nicholson BD. Evaluation and treatment of pain syndromes. Neurology. 2004;62(suppl 2):S30-S36

4. Backonja MMGaler BS Pain assessment and evaluation of patients who have neuropathic pain. Neurol Clin.1998;16:775–789.PubMed

5. Finnerup NB, Sindrup SH, Bach FW. et al. Lamotri­ gine in spinal cord injury pain: a randomized controlled trial. Pain. 2002;96:375–383

6. http://www.huffingtonpost.in/entry/central-pain-syndrome-undiagnosed_n_2792799

7. N.S.Sampath, Kumar, Anil Kumar t, Ravi,kiranpadal,Govindraju,Venugopal,Neerja DEJERINE ROUSSY SYNDROME. Narayana Medical Journal.2014 Issue1–20.

8. GH Hans, DN Robert and KN Van Maldeghem Treatment of an acute severe central neuropathic pain syndrome by topical application of lidocaine 5% patch: a case report. Spinal Cord (2008) 46, 311–313

9. Ramachandran, V. S., McGeoch, P. D., & Williams, L.; McGeoch; Williams (2007). “Can vestibular caloric stimulation be used to treat Dejerine-Roussy Syndrome?”. Medical Hypotheses. 69 (3): 486–488.

10. Klit, H., Finnerup, N. B., Jensen, T. S.; Finnerup; Jensen (2009). “Central post-stroke pain: clinical characteristics, pathophysiology, and management”. The Lancet Neurology. 8 (9): 857–868.