Volume 65, Issue 4 (3 2007)                   Tehran Univ Med J 2007, 65(4): 87-91 | Back to browse issues page

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Abstract:   (4401 Views)
Background: People vary greatly in their response to painful stimuli, from those with a low pain threshold to those with indifference to pain. However, insensitivity to pain is a rare disorder, characterized by the lack of usual subjective and objective responses to noxious stimuli. Patients who have congenital indifference to pain sustain painless injuries beginning in infancy, but have sensory responses that are otherwise normal on examination. Perception of passive movement, joint position, and vibration is normal in these patients, as are tactile thresholds and light touch perception.
Case report: A twelve-year-old boy was admitted to the hospital for a painless deformity, degeneration in both knees and a neglected femoral neck fracture that was inappropriately painless. Further examination revealed normal sensory responses, perception of passive movement, joint position, vibration tactile thresholds and light touch perception. Spinal cord and brain MRI were normal as was the electromyography and nerve conduction velocity (EMG/NCV) examination. There was no positive family history for this disorder.
Conclusion: The deficits present in the different pain insensitivity syndromes provide insight into the complex anatomical and physiological nature of pain perception. Reports on pain asymbolia, in which pain is perceived but does not cause suffering, and related cortical conditions illustrate that there can be losses that independently involve either the sensory-discriminative component or the affective-motivational component of pain perception, thus highlighting their different anatomical localization. The paucity of experience with this entity and the resultant diagnostic problems, the severity of the associated disabling arthropathy and underscore the importance of this case report of indifference to pain.
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