What clinical features suggest that a pain is neuropathic?
The following clinical features are most helpful in supporting a suspicion that a given pain state is neuropathic:
- • Perhaps most notably, neuropathic pain is usually associated with signs and symptoms of sensory loss, although that sensory loss may be modest or restricted to small fiber (thermal and sharp perception) modalities. A diagnosis of neuropathic pain should be questioned if there are neither signs nor symptoms of sensory loss.
- • The presence of spontaneous paresthesias, spontaneous cutaneous burning pain, allodynia, or hyperalgesia strongly supports the conclusion that pain is neuropathic.
- • The aforementioned are often referred to as negative (sensory loss) and positive (spontaneous or stimulus-evoked abnormal sensations) sensory symptoms and signs.
- • Neuropathic pain is often worst at night and at rest. Pain that is worst with weight bearing (e.g., foot pain when walking that is relieved with rest) is less likely to be neuropathic, although neuropathic pain at rest may be worse after being on one’s feet a great deal than after a sedentary day.
- • Most neuropathic pain states present in an anatomic distribution that is consistent with their etiology. Thus, for example, PHN pain should be dermatomal, posttraumatic neuropathy pain should be in the cutaneous territory of the affected nerve, and central poststroke pain should be in a hemibody distribution. A notable exception to this rule is a sensory ganglionopathy, which is non-length-dependent, often asymmetric, and does not necessarily present in a definable dermatomal pattern.
Several discriminative tools have been designed and validated to identify symptoms of neuropathic pain. The presence of paresthesias, sharp, shooting pain, a spontaneous cutaneous burning sensation, allodynia, or hyperalgesia with symptoms of sensory loss correlates with a high likelihood that pain is neuropathic.