Anesthesiology Clin 25 (2007) 699–708
The Diagnostic Workup of Patients with Neuropathic Pain
Steven H. Horowitz, MDa,b,
aUniversity of Vermont College of Medicine, Burlington, VT 05405, USA bDepartment of Neurology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
Current concepts of acute and chronic pain disorders distinguish ‘‘noci- ceptive,’’ ‘‘inflammatory,’’ ‘‘functional,’’ and ‘‘neuropathic’’ pains . Nocicep- tive pain is the common pain experienced from trauma, cancer, and so forth in which pain receptors (nociceptors) are activated. Transduction, conduction, and transmission of nociceptor activity to a conscious level involves peripheral and centralnervous systempain pathways, which,whenintact, function ina pro- tective and adaptive manner . However, damage to, or dysfunction of, these pain pathways, peripherally or centrally, can result in a different, much less fre- quent, but nevertheless important pain picturedthat of neuropathic pain.
Neuropathic pain is not a disease in and of itself, but rather a manifestation of multiple and varied disorders affecting the nervous system, particularly its somatosensory components. They include polyneuropathies such as those secondary to diabetes mellitus, alcoholism, and amyloidosis; idiopathic small-fiber neuropathy; hereditary neuropathies; mononeuropathies such as trigeminal, glossopharyngeal, and post-herpetic neuralgias; entrapment neu- ropathies; and traumatic nerve injuries producing complex regional pain syn- drome (CRPS) type II. CRPS type I is also considered a neuropathic pain disorder, although evidence for nerve damage as the underlying mechanism is more controversial. Neuropathic pain can occur in central nervous system disorders, especially spinal cord injury, multiple sclerosis, and cerebrovascu- lar lesions of the brainstem and thalamus. Neuropathic pain in these condi- tions confers no functional benefit and may be considered a ‘‘maladaptive’’ response of the nervous system to the primary pathology .
A version of this article originally appeared in the 91:1 issue of Medical Clinics of North America.
Department of Neurology, Massachusetts General Hospital, 55 Fruit Street, Boston,
MA 02114, USA. E-mail address: firstname.lastname@example.org
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