Congenital insensitivity to pain
|Congenital insensitivity to pain|
|Classification and external resources|
Congenital insensitivity to pain (CIP), also known as congenital analgesia, is one or more rare conditions where a person cannot feel (and has never felt) physical pain. The conditions described here are separate from the HSAN group of disorders, which have more specific signs and etiology.
For patients with this disorder, cognition and sensation are otherwise normal; for instance patients can still feel discriminative touch (though not always temperature), and there are no detectable physical abnormalities.
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.
There are some cases where the condition is caused by increased production of endorphins in the brain, in which case naloxone may be used as treatment. This treatment does not always work. In some cases, this disorder can be in the voltage-gated sodium channel SCN9A (NaV1.7). 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. NaV1.7 channels are expressed at high levels in nociceptive neurons of the dorsal root ganglia. As these channels are likely involved in the formation and propagation of action potentials in such neurons, it is expected that a loss of function mutation in SCN9A will lead to abolished nociceptive pain propagation.
Types of congenital pain indifference 
There are generally two types of non-response exhibited.
- Insensitivity to pain means that the painful stimulus is not even perceived: a patient cannot describe the intensity or type of pain.
- Indifference to pain means that the patient can perceive the stimulus, but lacks an appropriate response: they will not flinch or withdraw when exposed to pain.
Media depictions 
In Stieg Larsson's Millennium series, former boxer Paolo Roberto discovers that Ronald Niedermann was born with congenital analgesia and is therefore, as he describes "invulnerable" physically. ("He just keeps on going!") Even so, Roberto goes on to say that his inability to perceive pain is a severe danger because Niedermann has no way of understanding when his body is being put in mortal danger by way of punches, blows, burns, or even gunshots. It is suggested that human awareness of painful stimuli is an evolutionary necessity to avoid injury and death.
The movie Bereavement features a boy named Martin Bristol who suffers congenital analgesia who is kidnapped by a crazed man and taught the ways of murder.
One episode of N.C.I.S. featured a torturer who was "unable to feel pain himself" played by William Morgan Sheppard.
In the 2011 slasher film Wrong Turn 4: Bloody Beginnings, the characters Three Finger, One Eye and Saw Tooth are said to have the disorder by the head of the sanatorium they are in the portion of the film set in 1974, with it being theorized that the condition was caused by inbreeding. Due to their inability to properly register pain, the three were depicted as being prone to self-harm in their youth, mutilating, severing and eating some of their own body parts. The disorder is also referenced throughout the series, especially the first film, Wrong Turn. The opening credits depict a medical journal talking about "resistance to pain" among other birth defects, and the entire series shows the antagonists ignoring non-crippling injuries.
In the play "Almost, Maine" by John Cariani, the vignette "This Hurts" is about a man with Congenital Analgesia, or "Hereditary Sensory Neuropathy Type 4", who is clocked in the head with an ironing board, and in the end feels the pain of love.
In the mystery novel "The Freak Show Case" by Brian D. Eyre and Lezlie K. King, the detective's client and prime suspect has Congenital Analgesia and believes he cannot feel pain. He learns quickly that not all pain is physical, and that emotional pain can be extremely real and extremely motivating.
The video game Dark Sector's protagonist, as shown in previews has this disease, and as such while others infected went mad from the pain, he remains sane and rational.
In an episode of Grimm titled "Game Ogre" (season 1, episode 8), an escaped murderer is believed to have this condition, but in reality, he is an ogre, whose race naturally don't feel pain.
Episode 31 of series 14 of Holby City sees fictional doctor Elliot Hope perform an operation on a patient with this disease.
See also 
- Hereditary sensory and autonomic neuropathy
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- Cox JJ, Reimann F, Nicholas AK, Thornton G, Roberts E, Springell K, Karbani G, Jafri H, Mannan J, Raashid Y, Al-Gazali L, Hamamy H, Valente EM, Gorman S, Williams R, McHale DP, Wood JN, Gribble FM, Woods CG (2006). "An SCN9A channelopathy causes congenital inability to experience pain". Nature 444 (7121): 894–8. doi:10.1038/nature05413. PMID 17167479.
- Minde J (2006). "Norrbottnian congenital insensitivity to pain". Acta orthopaedica. Supplementum 77 (321): 2–32. PMID 16768023.
- Eyre, Brian D. and King, Lezlie K. The Freak Show Case: A Pegasus Investigations Mystery. Swinging Cats and Blinking Hats Press, 2011, ISBN 978-0-615-51554-0.
- The Hazards of Growing Up Painlessly By JUSTIN HECKERT, New York Times, November 15, 2012. Profile of Ashlyn Blocker, 13, who has congenital insensitivity to pain.