Literature Marathon

Neuropathic pain PMC Luana Colloca, ら　 2017   Mechanisms/pathophysiology       Research in the pain field has focused on understanding the plastic changes in the nervous system after nerve injury, identifying novel therapeutic targets and in facilitating the transfer of knowledge from animal models to clinical practice. We describe briefly the multiple causes of neuropathic pain and present an overview of animal and human findings that have provided insights on the pathophysiology of neuropathic pain     Causes and distributions Central neuropathic pain is due to a lesion or disease of the spinal cord and/or brain. Cerebrovascular disease affecting the central somatosensory pathways (poststroke pain) and neurodegenerative diseases (notably Parkinson disease) are brain disorders that often cause central neuropathic pain26. Spinal cord lesions or diseases that cause neuropathic pain include spinal cord injury, syring...

Neuropathic pain PMC Luana Colloca, ら　 2017 Chronic neuropathic pain is more frequent in women (8% versus 5.7% in men) and in patients >50 years of age (8.9% versus 5.6% in those <49 years of age), and most commonly affects the lower back and lower limbs, neck and upper limbs24. Lumbar and cervical painful radiculopathies are probably the most frequent cause of chronic neuropathic pain. Consistent with these data, a survey of >12,000 patients with chronic pain with both nociceptive and neuropathic pain types, referred to pain specialists in Germany, revealed that 40% of all patients experience at least some characteristics of neuropathic pain (such as burning sensations, numbness and tingling); patients with chronic back pain and radiculopathy were particularly affected   ・慢性神経障害性疼痛は、女性（男性で 8 ％対 5.7 ％）および 50 歳以上の患者（ 49 歳未満では 8.9 ％対 5.6 ％）でより頻繁に見られ、最も一般的には腰と下肢、そして頸部と上肢に影響を与えます ・慢性神経障害性疼痛の最も頻度の高い原因は、腰椎及び頸椎部で生じる神経根症です。 ・これらのデータと一致し、ドイツの疼...

Neuropathic pain PMC Luana Colloca, ら　 2017     Box 2 Validated screening tools for neuropathic pain   Symptom and clinical examination items can be assessed using distinct validated screening tools. The most common tools are listed below.   Leeds Assessment of Neuropathic Symptoms and Signs • Four symptom items (pricking, tingling, pins and needles; electric shocks; hot or burning sensations; and pain evoked by light touching) • One item related to skin appearance (mottled or red) • Two clinical examination items (touch-evoked allodynia and altered pinprick sensation)   Douleur Neuropathique 4 questions • Seven symptom items (burning, painful cold, electric shocks, tingling, pins and needles, numbness and itching) • Three clinical examination items (touch hypoaesthesia (reduced sense), pinprick hypoaesthesia and brush-evoked allodynia)   Neuropathic Pain Questionnaire •...

Neuropathic pain PMC Luana Colloca, ら　 2017   Epidemiology   The estimation of the incidence and prevalence of neuropathic pain has been difficult because of the lack of simple diagnostic criteria for large epidemiological surveys in the general population. Thus, the prevalence of neuropathic pain in the chronic pain population has mainly been estimated on the basis of studies8 conducted by specialized centres with a focus on specific conditions, such as postherpetic neuralgia9, 10, painful diabetic polyneuropathy1,11 – 13, postsurgery neuropathic pain14, multiple sclerosis15, 16, spinal cord injury17, stroke18 and cancer19, 20.   The recent development of simple screening tools in the form of questionnaires21 has helped conduct several large epidemiological surveys in different countries (the United Kingdom, the United States, France and Brazil) and provided valuable new information on the general prevalence of neuropathic pain4. In us...

Neuropathic pain PMC Luana Colloca, ら　 2017   Neuropathic pain is associated with increased drug prescriptions and visits to health care providers3,4. Patients typically experience a distinct set of symptoms, such as burning and electrical-like sensations, and pain resulting from non-painful stimulations (such as light touching); the symptoms persist and have a tendency to become chronic and respond less to pain medications. Sleep disturbances, anxiety and depression are frequent and severe in patients with neuropathic pain, and quality of life is more impaired in patients with chronic neuropathic pain than in those with chronic non-neuropathic pain that does not come from damaged or irritated nerves3,5.   Despite the increases of placebo responses6,7 that result in the failure of multiple new drugs in clinical trials, recent progress in our understanding of the pathophysiology of neuropathic pain provides optimism for the development of new diagno...

Neuropsthic pain   PMC Luana Colloca, ら　 2017     The peripheral and central changes induced by nerve injury or peripheral neuropathy   Preclinical animal studies have shown that damage to all sensory peripheral fibres (namely, A β , A δ and C fibres; BOX 1) alters transduction and transmission due to altered ion channel function. These alterations affect spinal cord activity, leading to an excess of excitation coupled with a loss of inhibition. In the ascending afferent pathways, the sensory components of pain are via the spinothalamic pathway to the ventrobasal medial and lateral areas (1), which then project to the somatosensory cortex allowing for the location and intensity of pain to be perceived (2). The spinal cord also has spinoreticular projections and the dorsal column pathway to the cuneate nucleus and nucleus gracilis (3). Other limbic projections relay in the parabrachial nucleus (4) before contacting the hypothalamus and...

Neuropathic pain PMC Luana Colloca, ら　 2017     Although distinct definitions of neuropathic pain have been used over the years, its most recent (2011) and widely accepted definition is pain caused by a lesion or disease of the somatosensory system. The somatosensory system allows for the perception of touch, pressure, pain, temperature, position, movement and vibration. The somatosensory nerves arise in the skin, muscles, joints and fascia and include thermoreceptors, mechanoreceptors, chemoreceptors, pruriceptors and nociceptors that send signals to the spinal cord and eventually to the brain for further processing ( BOX 1 ); most sensory processes involve a thalamic nucleus receiving a sensory signal that is then directed to the cerebral cortex. Lesions or diseases of the somatosensory nervous system can lead to altered and disordered transmission of sensory signals into the spinal cord and the brain; common conditions associated with neuropathic ...

Neuropathic pain PMC Luana Colloca, ら　 2017   Abstract Neuropathic pain is caused by a lesion or disease of the somatosensory system, including peripheral fibres (A β , A δ and C fibres) and central neurons, and affects 7 – 10% of the general population. Multiple causes of neuropathic pain have been described and its incidence is likely to increase owing to the ageing global population, increased incidence of diabetes mellitus and improved survival from cancer after chemotherapy. Indeed, imbalances between excitatory and inhibitory somatosensory signalling, alterations in ion channels and variability in the way that pain messages are modulated in the central nervous system all have been implicated in neuropathic pain. The burden of chronic neuropathic pain seems to be related to the complexity of neuropathic symptoms, poor outcomes and difficult treatment decisions. Importantly, quality of life is impaired in patients with neuropathic pain owing to...

Neurogenic pain syndromes and their management D Bosher British Medical Bulletin , Volume 47, Issue 3, July 1991, Pages 644–666,   Neurogenic pain is defined as pain due to dysfunction of the peripheral or central nervous system, in the absence of nociceptor (nerve terminal) stimulation by trauma or disease. Other terms used to describe some (but not all) forms of neurogenic pain include neuropathic pain, deafferentation pain, and central pain; all these terms are subsumed into the wider expression ‘neurogenic pain’. The clinical syndromes representing this type of disorder make up at least 25% of the patients attending most pain clinics. This is undoubtedly proportionately greater than its incidence in chronic pain as a whole, and is a measure of its intractability and of the therapeutic dilemma which it presents. However, neurogenic pain syndromes are much commoner than is perhaps generally recognized: when all categories are taken into account, there are ...