Neuropathic Pain Disorder
Neuropathic pain is common, and in some individuals becomes a chronic problem. It is unclear if some individuals are predisposed to chronic pain; whereas others given the same initial painful stimuli will not ever develop chronic pain, e.g. following a mastectomy or hernia a predictable number of patients develop chronic pain despite no obvious secondary surgical/treatment cause.
Others have conditions where pain is common – but not all affected get pain, e.g. diabetics treated with insulin and those oncology patients treated with chemotherapy, such as Danarubicin and Cisplatin, who do and who don’t get a painful neuropathy. Chronic pain may have an underlying peripheral, spinal cord or central nervous system basis.
There are also a number of specific chronic neuropathic pain phenotypes, e.g. burning mouth syndrome, erythromelalgia, complex regional pain syndrome, and “all over pain”. Our approach will be to choose those individuals with the most extreme phenotypes from all pain presentations, and within this to ensure representative cohorts of >50 with each definable pain phenotype. Our analysis of genotype to phenotype will reflect this diversity of possible pain types, and hence be by type of pain, location of pain, pain syndrome, and to also analyse all individuals. Results will hopefully allow us to sub-categorise pain by underlying mechanism, and thence be able to assess treatments and natural history on a more scientific basis.
There are a small number of medications, less than a dozen, that significantly alleviate the suffering caused by the pain up. These are effective in about half of individuals, but at present we cannot predict who the half are. Neither can we predict who will respond to which medications, nor who is at risk of unbearable side effects, e.g. to Gabapentin, and who is not a risk. Therefore, a second form of analysis of our phenotype data will be to seek underlying genomic changes that may explain this pharmacological variability; if found, such changes would be of considerable clinical utility.
Inclusion and exclusion criteria
Patients with a proven history of life-style altering pain for greater than 6 months, for which treatments offered, have not lead to significant improvement.
Pain can be generalised or restricted to one part of the body; the pain can be of any type.
Patients with a known underlying genetic cause of chronic pain, e.g. Fabry’s disease and SCN9A congenital erythromelalgia.
Patients with learning disorder or/and autistic features sufficient that they could not give either consent or partake in possible additional pain phenotyping.
Centres at which NPD is currently recruiting:
Cambridge University Hospitals NHS Foundation Trust
Chelsea & Westminster Hospitals NHS Trust
Great Ormond Street Hospital for Childrent NHS Foundation Trust, London
Kings College Hospital NHS Foundation Trust, London
Oxford University NHS Trust
Salford Royal NHS Foundation Trust
University College London Hospital