Chronic neuropathic pain management – a review article

Abstract

Chronic neuropathic pain (NEP) is commonly seen in clinical practice and represents a challenge to patients as well as clinicians. Pain is a complex sensory modality, resulting from the physiological activation of nociceptors that trigger a behavioural process to protect the individual from any existing, or further, tissue damage. Conditions that are frequently associated with NEP can be classified into two main groups: first, conditions that cause damage to the central nervous system (CNS), such as cortical and subcortical strokes; and, secondly, conditions that cause damage to the peripheral nervous system (PNS) such as ischaemic neuropathy, nerve root compression and phantom pain. There are multiple theories and pathophysiological processes underlying NEP; both basic and human research indicates that a lesion of afferent pathways is necessary for development of NEP. Furthermore, data clearly indicate that several mechanisms can lead to NEP and many of these mechanisms do not depend on the cause of the disease. The main mechanisms for the development NEP are ectopic nerve activity, upregulation of receptor proteins, central sensitization, inflammatory mechanism and disinhibition. The management of chronic NEP is challenging and the primary goal is to treat the pain and associated comorbidities, such as anxiety and depression. The secondary goals of treatment are to improve sleep, the ability to function normally and the overall quality of life. Tricyclic antidepressants (TCAs) are the most effective treatment in the management of NEP; however, serotonin–noradrenaline reuptake inhibitors (SNRIs), gabapentin and pregabalin, or lidocaine patches are also effective. Randomized controlled trials have reported the efficacy of opioids for different peripheral and central neuropathic disorders; however, using opioids for the treatment of NEP is not necessarily associated with a significant improvement in quality of life, psychological comorbidities or sleep disorders. In summary, management of NEP should be tailored to the individual patient on the basis of pain type(s), the causative disease, the relevant psychological factors and the interactions between the biological and psychosocial processes.