Chronic pain, somatic unexplained complaints and multimorbidity: A mutimorbidity painful syndrome?

INTRODUCTION: Chronic illnesses are a major research challenge due to its implications in aging and quality of life of adults and elders, and it can be associated with chronic illnesses and other complaints. The objective of this study was to investigate the role of morbidities (chronic diseases with or without somatic unexplained symptoms) and somatic unexplained complaints in a hypothetical model of a multimorbidity painful syndrome. Our hypothesis is that chronic pain should be considered part of a syndrome that includes other chronic diseases and pathological states, especially conditions with somatic unexplained symptoms, and fibromyalgia is one of the evidence on that. METHODS: A pilot sample of 306 subjects was investigated in this study (254; 83.0% with chronic pain). The following features were investigated: demographic data, chronic diseases (classified as with or without somatic unexplained symptoms), medications in use, pain characteristics, fulfillment of diagnostic criteria of fibromyalgia, and somatic unexplained complaints (gastric complaints, sleep disturbances, numbness, and the dry mucosa score). Statistical analysis included descriptive data, tested with chi-square, Fisher's exact, nonparametric Kolmogorov-Smirnoff, Student's t test; data normalization with Z-score; Pearson's coefficient for correlation, two-steps cluster classification, multivariate linear regression, LASSO and logistic regression. RESULTS: Both groups of chronic diseases were more prevalent in the group of patients (p < 0.001 and p = 0.013, respectively), which had higher frequency of somatic unexplained complaints (gastrointestinal, dry mucosa and numbness) than controls. There was a high positive correlation between number of pain areas and somatic unexplained symptoms score (R2 = 0.626; p < 0.001), and diseases with these symptoms were a risk factor for chronic pain (R2 = 0.5748) and fibromyalgia (AIC = 5.8952). CONCLUSIONS: Diseases with somatic unexplained symptoms and somatic unexplained complaints were associated with chronic pain, including fibromyalgia. They may be risks factors for pain spread. The findings support that chronic pain could be further investigated as part of a multimorbid syndrome, which should be better assessed to improve aging and quality of life of patients.

Quantitative sensory testing in trigeminal traumatic neuropathic pain and persistent idiopathic facial pain.

The objective of this article was to investigate, with a systematic protocol of quantitative sensory testing, patients with persistent idiopathic facial pain (PIFP) and others with trigeminal traumatic neuropathic pain (TTN) compared to controls. Thirty patients with PIFP, 19 with TTN, and 30 controls were evaluated on subjective numbness and dysesthesia and with a systematic protocol of quantitative sensory testing for thermal evaluation (cold and warm), mechanical detection (touch and pinpricks for mechanical pain), superficial pain thresholds, and corneal reflex. We found that PIFP and TTN had numbness and dysesthesia higher than controls (p<0.001 and p=0.003), and that in both of them mechanical pain by pinpricks detection was abnormal intra and extra orally at the mandibular branch (p<0.001). Cold, warm, and tactile detections and pain thresholds were similar among the groups. Corneal reflex was abnormal in TTN (p=0.005). This study supports neuropathic mechanisms involving pain processing in PIFP and that the criterion on absence of sensorial variations in PIFP should be revised.

Quantitative sensory testing in trigeminal traumatic neuropathic pain and persistent idiopathic facial pain / Teste sensitivo quantitativo em dor neuropática trigeminal pós-traumática e dor facial idiopática persistente

The objective of this article was to investigate, with a systematic protocol of quantitative sensory testing, patients with persistent idiopathic facial pain (PIFP) and others with trigeminal traumatic neuropathic pain (TTN) compared to controls. Thirty patients with PIFP, 19 with TTN, and 30 controls were evaluated on subjective numbness and dysesthesia and with a systematic protocol of quantitative sensory testing for thermal evaluation (cold and warm), mechanical detection (touch and pinpricks for mechanical pain), superficial pain thresholds, and corneal reflex. We found that PIFP and TTN had numbness and dysesthesia higher than controls (p<0.001 and p=0.003), and that in both of them mechanical pain by pinpricks detection was abnormal intra and extra orally at the mandibular branch (p<0.001). Cold, warm, and tactile detections and pain thresholds were similar among the groups. Corneal reflex was abnormal in TTN (p=0.005). This study supports neuropathic mechanisms involving pain processing in PIFP and that the criterion on absence of sensorial variations in PIFP should be revised.

O objetivo deste artigo foi investigar, com um protocolo sistemático de testes sensitivos quantitativos, pacientes com dor facial idiopática persistente (DFIP) e outros com dor neuropática trigeminal traumática (DNTT) comparado aos controles. Trinta pacientes com DFIP, 19 com DNTT e 30 controles foram avaliados quanto à dormência e à disestesia subjetiva e por meio de um protocolo sistemático de testes sensitivos quantitativos, que incluiu avaliação térmica (frio e quente), detecção mecânica (táctil e alfinetes), limites de dor superficial e reflexo córneo-palpebral. Foi observado que os pacientes apresentaram mais dormência e disestesia do que os controles (p<0,001 e p=0,003), além de mais anormalidades intra e extraorais no ramo mandibular (p<0,001). As alterações de calor, frio, dor e tato foram semelhantes entre os grupos. O reflexo córneo-palpebral foi anormal somente no grupo com DNTT (p=0,005). Este estudo suporta mecanismos de dor neuropática envolvidos no processamento da DFIP, e o critério de ausência de variações sensoriais nesta deve ser revisto.