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No pain, no gain: A beginner’s guide to congenital analgesia

Arguably one of the most extreme of human conditions is having congenital insensitivity to pain (CIP). One of the most high profile portrayals of CIP (which is where I first became aware of the condition) was in The Girl Who Played With Fire (the sequel of The Girl With The Dragon Tattoo), where one of the peripheral characters (Ronald Niedermann – ‘The Giant’) had CIP and was seen as physically invulnerable by those around him.

CIP was first reported by Dr. G. Dearborn in 1932 (in the Journal of Nervous and Mental Diseases) and is also known as congenital analgesia. Those with CIP have no capacity to feel physical pain, usually because of a hereditary genetic mutation associated with the body’s pain receptors. However, there are also cases where the causes are non-genetic. For instance, there are a few cases of CIP that appear to be due to an increase in endorphins (the body’s own morphine-like chemicals) in the brain.

Although CIP might sound like a great (almost superhuman) condition to have, individuals with CIP are much more susceptible to death via trauma as they are completely unaware of what damage has been done to their body following accidents (so they can’t feel cuts, know if they have bitten their tongue, or know if they have broken bones). Furthermore, one of the behaviours associated with CIP is self-mutilation (as highlighted in a 2010 case study of a young boy in the Online Journal of Health and Allied Sciences by Dr. Praveen Kumar and his colleagues). Evolutionary psychologists would therefore argue that pain perception is an evolutionary necessity to avoid injury and/or death.

The condition is very rare (for instance, in the US, it is estimated that only around 100 people have the condition). However, there is a higher incidence of the disorder in societies where there is less biodiversity (so-called ‘homogenous societies’). For instance, an interesting 2006 paper by Dr. Jan Minde in the journal Acta Orthopaedica Supplementum reported that in the village of Vittangi (in the north Swedish Municipality of Kiruna) had documented 43 cases. Given the hereditary nature of CIP, many papers tend to report case studies within families. For instance, Dr. D.C. Thrush reported across two papers in a 1973 issue of the journal Brain, the case of four siblings with CIP that all reported numerous painless injuries, bone fractures, and autonomic dysfunction. Similarly, Dr. Karmani and colleagues reported on a family where three out of four children all had CIP in the Journal of the Royal Society for Medicine in 2001. They reported that in relation to the condition:

Presentation in childhood is commonly at the time of tooth eruption, with biting and self-mutilation of lips, tongue and digits. Pyrexia of unknown origin is another way the condition can show itself in early infancy. Cuts, abrasions and burns of the limbs are common”.

CIP is different from the group hereditary sensory and autonomic neuropathy (HSAN) disorders that inhibit specific sensations (which I’ll hopefully cover in a future blog). A 2002 paper in the Journal of Bone and Joint Surgery by Dr. E. Bar-On and colleagues reported that among those with CIP musculoskeletal manifestations are very common although the pathology, inheritance, and pathophysiology of these, as well as their relationship to the different subtypes, have only been partially clarified, mainly in case reports”. Other than the incapacity to feel pain, those with CIP are physically normal (although some individuals have difficulty in experiencing different temperatures). The Wikipedia entry on CIP also notes that:

“Children with this condition often suffer oral cavity damage both in and around the oral cavity (such as having bitten off the tip of their tongue) or fractures to bones. Unnoticed infections and corneal damage due to foreign objects in the eye are also seen. Because the child cannot feel pain they may not respond to problems, thus being at a higher risk of more severe diseases or otherwise. In some people with this disorder, there may be a mild intellectual disability”.

Another minority may have CIP in the ‘voltage-gates sodium channel SCN9A’ (and in the words of Vienna by Ultravox, “this means nothing to me”). There is a series of papers published by Dr. James Cox and his colleagues in journals like Nature and Human Mutation examining the hard-core genetics of CIP. I had hoped that the Wikipedia entry on the genetics of CIP might dumb things down a little but after reading the following, I am still generally none-the-wiser:

“Patients with such mutations are congenitally insensitive to pain and lack other neuropathies. There are three mutations in SCN9A: W897X, located in the P-loop of domain 2; I767X, located in the S2 segment of domain 2; and S459X, located in the linker region between domains 1 and 2. This results in a truncated non-functional protein…it is expected that a loss of function mutation in SCN9A will lead to abolished nociceptive pain propagation”.

Some people working in the field distinguish between pain insensitivity and pain indifference. Pain insensitivity refers to individuals who have absolutely no perception of the stimulus to pain (i.e., they are unable to describe the type or intensity of pain). Pain indifference refers to individuals that have perception of the stimulus to pain have inappropriate responses to the pain stimulus (e.g., they wouldn’t flinch if something very hot or on fire touched their flesh).

Finally, Dr. Praveen Kumar and colleagues report in the Online Journal of Health and Allied Sciences that there is “no single gold standard treatment available” for CIP and that there are some studies suggesting (the opioid antagonists) naloxone and naltrexone (most often used in the treatment of drug addictions) can be used to reverse the analgesic effects of CIP. However, they also note that treatment with opioid antagonists “lacks evidence and further support” and that most treatments are concerned with other associated conditions.

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Bar-On, E., Weigl, D., Parvari, R., Katz, K., Weitz, R. & Steinberg, T. (2002). Congenital insensitivity to pain. Journal of Bone and Joint Surgery, 84, 252-257.

Cox, J.J., Reimann, F. & Nicholas, A.K. (2006). An SCN9A channelopathy causes congenital inability to experience pain. Nature, 444, 894–8.

Cox, J.J., Sheynin, J., Shorer, Z., et al (2010). Congenital insensitivity to pain: Novel SCN9A missense and in-frame deletion mutations. Human Mutation, 31, E1670-E1686.

Dearborn, G. (1932). A case of congenital general pure analgesia. Journal of Nervous and Mental Diseases, 75, 612–615.

Karmani, S., Shedden, R. & De Sousa, C. Orthopaedic manifestations of congenital insensitivity to pain. Journal of the Royal Society of Medicine, 94, 139-140

Kumar, P.B, Sudhakar S. & Prabhat, M.P.V. (2010). Case report: Congenital insensitivity to pain. Online Journal of Health and Allied Sciences, 9(4).

Manfredi, M., Bini, G., Cruccu, G., Accornero, N., Berardelli, A. & Medolago, L. (1981). Congenital absence of pain”. Archives of Neurology, 38, 507-511.

Minde J (2006). Norrbottnian congenital insensitivity to pain. Supplementum 77, 2-32.

Nagasakoa, E.M., Oaklanderb, A.L., Dworkin, R.H. (2003). Congenital insensitivity to pain: an update. Pain, 101, 213–219.

Thrush, D.C. (1973). Congenital insensitivity to pain: A clinical, genetic and neurophysiological study of four children from the same family. Brain, 96, 369-86.

Thrush, D.C. (1973). Autonomic dysfunction in four patients with congenital insensitivity to pain. Brain, 96, 591-600.

Wikipedia (2012). Congenital insensitivity to pain. Located at: http://en.wikipedia.org/wiki/Congenital_insensitivity_to_pain

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