Thursday, April 12, 2012

Congenital insensitivity to pain

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.

Presentation

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 cornealdamage 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, as well as an impaired corneal reflex.[citation needed]

Causes

In some cases, this disorder can be due to mutations in the voltage-gated sodium channel SCN9A (NaV1.7). Patients with such mutations are congenitally insensitive to pain. 
Leprosy, an infectious illness, can result in the progressive destruction of the nerves; the disease can be passed on to offspring, sometimes remaining dormant except for nerve damage. This scenario can mimic the truly hereditary diseases described above.

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.[citation needed]

    Incidence

    The disorder is primarily found in homogeneous societies[citation needed].
    For example, it is found in Vittangi, a village in Kiruna Municipality in northern Sweden, where nearly 40 cases have been reported.
    Also, Ashkenazi Jews have been found to have a higher risk, though it is still unusual.[citation needed]

    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 continues 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 Grey's Anatomy episode Sometimes a Fantasy features a young girl named Megan Clover that suffers from congenital analgesia believing herself to be a superhero.
    The episode of House, M.D. entitled Insensitive also features a young girl named Hannah Morganthal who suffers from congenital analgesia, making her sickness extremely difficult to diagnose.
    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 in the portion of the film set in 1974, with it being theorized that the condition was the result of 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.
    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 has this condition.


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