Sensory profiles and immune-related expression patterns of patients with and without neuropathic pain after peripheral nerve lesion.

In this multicenter cross-sectional study, we determined sensory profiles of patients with (NL-1) and without neuropathic pain (NL-0) after nerve lesion and assessed immune-related systemic gene expression. Patients and matched healthy controls filled in questionnaires and underwent neurological examination, neurophysiological studies, quantitative sensory testing, and blood withdrawal. Neuropathic pain was present in 67/95 (71%) patients (NL-1). Tactile hyperalgesia was the most prominent clinical sign in NL-1 patients (P < 0.05). Questionnaires showed an association between neuropathic pain and the presence of depression, anxiety, and catastrophizing (P < 0.05 to P < 0.01). Neuropathic pain was frequently accompanied by other chronic pain (P < 0.05). Quantitative sensory testing showed ipsilateral signs of small and large fiber impairment compared to the respective contralateral side, with elevated thermal and mechanical detection thresholds (P < 0.001 to P < 0.05) and lowered pressure pain threshold (P < 0.05). Also, more loss of function was found in patients with NL-1 compared to NL-0. Pain intensity was associated with mechanical hyperalgesia (P < 0.05 to P < 0.01). However, quantitative sensory testing did not detect or predict neuropathic pain. Gene expression of peptidylglycine α-amidating monooxygenase was higher in NL patients compared with healthy controls (NL-1, P < 0.01; NL-0, P < 0.001). Also, gene expression of tumor necrosis factor-α was higher in NL-1 patients compared with NL-0 (P < 0.05), and interleukin-1ß was higher, but IL-10 was lower in NL-1 patients compared with healthy controls (P < 0.05 each). Our study reveals that nerve lesion presents with small and large nerve fiber dysfunction, which may contribute to the presence and intensity of neuropathic pain and which is associated with a systemic proinflammatory pattern.

Pain in patients with transverse myelitis and its relationship to aquaporin 4 antibody status.

Pain in transverse myelitis has been poorly studied. The aim of the study was to investigate the relationship between transverse myelitis related pain and disability, quality of life, anxiety and depression, cognitive-affective states in neuromyelitis optica (NMO) patients and aquaporin4 antibody status (AQP4-Ab +ve as positive and AQP4-Ab -ve as negative). Transverse myelitis patients (44 in total; 29 AQP4-Ab +ve and 15 AQP4-Ab -ve) completed questionnaires including Pain Severity Index (PSI), Pain Catastrophising Scale (PCS), Hospital Anxiety and Depression Scale (HADS), Short Form-36 quality of life (SF-36 QOL). Clinical details such as disability, gender, age and spinal cord lesion type (short or long lesion) were noted. Correlation and multiple linear regression tests were performed using these clinical scores. Pain was found to be correlated strongly with quality of life in both groups but only correlated with disability in the AQP4-Ab +ve group. PCS, HADS and EDMUS were found to be highly correlated with pain severity using partial correlation, however, a stronger relationship between pain severity and PCS was found in the AQP4-Ab -ve group. Multiple regression analysis showed that pain severity was the most important factor for quality of life but not disability or anxiety and depression symptoms in the whole patient group. We confirm that pain is an important symptom of transverse myelitis and has more influence on quality of life than disability despite health services being predominantly focused on the latter. There may be different factors associated with pain between AQP4-Ab +ve and -ve patients.