Fibromyalgia and neuropathic pain - differences and similarities. A comparison of 3057 patients with diabetic painful neuropathy and fibromyalgia

Abstract

BackgroundPatients with diabetic neuropathy (DPN) and fibromyalgia differ substantially in pathogenetic factors and the spatial distribution of the perceived pain. We questioned whether, despite these obvious differences, similar abnormal sensory complaints and pain qualities exist in both entities. We hypothesized that similar sensory symptoms might be associated with similar mechanisms of pain generation. The aims were (1) to compare epidemiological features and co-morbidities and (2) to identify similarities and differences of sensory symptoms in both entities.MethodsThe present multi-center study compares epidemiological data and sensory symptoms of a large cohort of 1434 fibromyalgia patients and 1623 patients with painful diabetic neuropathy. Data acquisition included standard demographic questions and self-report questionnaires (MOS sleep scale, PHQ-9, PainDETECT). To identify subgroups of patients with characteristic combinations of symptoms (sensory profiles) a cluster analysis was performed using all patients in both cohorts.ResultsSignificant differences in co-morbidities (depression, sleep disturbance) were found between both disorders. Patients of both aetiologies chose very similar descriptors to characterize their sensory perceptions. Burning pain, prickling and touch-evoked allodynia were present in the same frequency. Five subgroups with distinct symptom profiles could be detected. Two of the subgroups were characteristic for fibromyalgia whereas one profile occurred predominantly in DPN patients. Two profiles were found frequently in patients of both entities (20-35%).ConclusionsDPN and fibromyalgia patients experience very similar sensory phenomena. The combination of sensory symptoms - the sensory profile - is in most cases distinct and almost unique for each one of the two entities indicating aetiology-specific mechanisms of symptom generation. Beside the unique aetiology-specific sensory profiles an overlap of sensory profiles can be found in 20-35% of patients of both aetiologies.

Pain Severity and Neuropathic Pain Symptoms in Primary Sjögren's Syndrome: A Comparison Study of Seropositive and Seronegative Sjögren's Syndrome Patients

“…Neuropathic pain assessment tools such as the Neuropathic Pain Questionnaire used in this study are increasingly employed as the first step in the diagnostic work-up of persons with chronic pain. Classification of patients into neuropathic and non neuropathic pain syndromes based on verbal descriptors alone, however, is not sufficient for diagnosis in individual patients, since chronic disorders such as painful neuropathy and fibromyalgia may in fact share very similar sensory phenomena (35). …”

Reappraising neuropathic pain in humans—how symptoms help disclose mechanisms

“…74 The most common type of provoked pain by far is dynamic mechanical allodynia, which corresponds clinically to allodynia evoked by gentle brush, and has a prevalence of 18-54% in patients with neuropathic pain. 34,95 Typical examples of dynamic mechanical allodynia include patients with thoracic postherpetic neuralgia who report pain due to contact between skin and shirt; and patients with peripheral neuro pathy who experience pain owing to contact between feet and bed sheets.…”

Neuropathic sensory symptoms: association with pain and psychological factors

“…Neuropathic sensory symptoms, however, did not distinguish TNP from FM. Although in the majority of FM patients no nerve lesion can be detected,37 numerous studies have demonstrated similarities between neuropathic pain patients and FM patients with regard to the experience of sensory symptoms 3. Vierck37 suggested that changes in the milieu of muscles and other deep somatic structures in FM might lead to a similar state of hyperactivity in nociceptive neurons as is observed after nerve damage.…”