Compulsive targeted self-injurious behaviour in humans with neuropathic pain: a counterpart of animal autotomy? Four case reports and literature review.

Four cases of compulsive self-injurious behaviour (SIB) with variable degrees of tissue damage targeted to the painful body part are reported in humans with neuropathic pain. Review of human literature revealed several cases, primarily after central nervous system (CNS) lesions, during which non-psychotic verbally communicating humans (mostly with intact mental status) target specifically the painful part which is usually analgesic or hypoalgesic. In few instances, however, the involved part is not only sentient but also hyperalgesic in part or as a whole. The act is characterized by uncontrollable urge and compulsion, aggravated under conditions of stress, isolation, confusion or depression, and occasionally occurring in patients with personality disorders, ongoing drug abuse and pre-existing compulsive habits (i.e., habitual nail biting or picking). It fails to be deterred by the appearance of the injured part, social mores or even the experience of pain. Successful treatment of underlying painful dysesthesiae with specific medications, neurostimulation or surgery has resulted in marked improvement of dysesthesiae accompanied by wound healing in several cases. The four presented cases and the human literature experience provide evidence that compulsive targeted SIB in humans with neuropathic pain and painful dysesthesiae is consistent with the concept that animal autotomy may result from chronic neuropathic pain after experimental peripheral or CNS lesions.