Articles: hyperalgesia.
-
C fibre hyperexcitability is fundamental to chronic pain development in humans and rodents; therefore, peripheral sensory neuronal sensitization plays a role in the development of mechanical hyperalgesia. However, the axonal properties and underlying mechanisms that are associated to these chronic pain states still require investigation. ⋯ Nerve injury-induced enhanced neural responses to mechanical stimulation are associated to defined parameters setout by conduction velocity slowing, mediated via axonal processing. Application of galanin inhibits axonal excitability.
-
Review Case Reports
Intravenous Ketamine for Rapid Opioid Dose Reduction, Reversal of Opioid-Induced Neurotoxicity, and Pain Control in Terminal Care: Case Report and Literature Review.
We report a case of opioid-induced neurotoxicity (OIN) in an actively dying hospice patient, its reversal and improved analgesia that followed opioid dosage reduction made possible after addition of IV ketamine. We briefly review the diagnosis and treatment of OIN. ⋯ OIN should be considered as an etiology of CNS dysfunction occurring with prolonged, high-dose opioid therapy. This case highlights the opioid-sparing and analgesic properties of low-dose ketamine, allowing reversal of OIN in the home hospice setting.
-
Dry eye is a multi-factorial disorder that manifests with painful ocular symptoms and visual disturbances, which can only be partly attributed to tear dysfunction. This disorder may also involve neuroplasticity in response to neuronal injury. This review will emphasize the key characteristics of dry eye pain and its pathologic mechanisms, making the argument that a subset of dry eye represents a neuropathic pain disorder of the eye, more appropriately called "burning eye syndrome." ⋯ Dry eye is becoming a major health concern due to its increasing incidence, significant morbidity, and economic burden. Recent evidence suggests that a subset of dry eye may be better represented as a chronic neuropathic pain disorder due to its features of dysesthesia, spontaneous pain, allodynia, and hyperalgesia. Future therapies targeted at the underlying neuroplasticity may yield improved efficacy for patients with this subset of dry eye, which we term "burning eye syndrome."
-
Patients with functional pain disorders often complain of generalized sensory hypersensitivity, finding sounds, smells, or even everyday light aversive. The neural basis for this aversion is unknown, but it cannot be attributed to a general increase in cortical sensory processing. Here, we quantified the threshold for aversion to light in patients with fibromyalgia, a pain disorder thought to reflect dysregulation of pain-modulating systems in the brain. ⋯ Light exposure also resulted in a measurable but modest decrease in the threshold for heat-evoked paw withdrawal, as would be expected with engagement of this pain-modulating circuitry. These data demonstrate integration of information about light intensity with somatic input at the level of single pain-modulating neurons in the brain stem of the rat under basal conditions. Taken together, our findings in rodents and humans provide a novel mechanism for abnormal photosensitivity and suggest that light has the potential to engage pain-modulating systems such that normally innocuous inputs are perceived as aversive or even painful.
-
Anesthesia and analgesia · Apr 2016
A Comparison of the Effects of Burst and Tonic Spinal Cord Stimulation on Hyperalgesia and Physical Activity in an Animal Model of Neuropathic Pain.
Parameters of spinal cord stimulation (SCS) play a role in its effectiveness and may impact SCS mechanisms and outcomes. For example, SCS applied in a bursting pattern may result in better pain relief than that for tonic SCS for neuropathic pain. We tested the effectiveness of different SCS pulse frequencies given at 2 different burst frequencies in an animal model of neuropathic pain. ⋯ The current study shows that a variety of SCS pulse frequencies applied with a burst frequency result in greater improvement in hyperalgesia and activity levels than tonic SCS in a neuropathic pain model during stimulation.