Pain in patients with neuromyelitis optica spectrum disorders

Abstract

Neuromyelitis optica spectrum disorders (NMOSD) are a group of chronic autoimmune diseases of the central nervous system with a relapsing course. Unfortunately, the symptoms of exacerbation cannot always be completely stopped, and in addition to motor disorders, chronic pain and depression can worsen the patient's condition. Currently, one of the factors that significantly affects the quality of life of patients in this group is chronic, debilitating pain.Objective: to determine the prevalence of the pain syndrome in the population of NMOSD patients in Moscow region, to investigate its clinical characteristics and its impact on quality of life.Material and methods. The study included 33 patients with NMOSD (6 men and 27 women) aged 22 to 64 years. The following criteria were used to assess the neurological condition, presence and severity of the pain syndrome: Expanded Disability Status Scale (EDSS), Diagnostic Neuropathic Pain Questionnaire (DN4), Pain Detect Questionnaire (PDQ), McGill Pain Questionnaire (MPQ), SF-36 Quality of Life Questionnaire, Beck Depression Inventory and MRI data.Results. Among the patients analysed, the pain syndrome occurred in 19 patients (57.6%): 4 patients with NMOSD without antibodies against aquaporin-4 (AQP4-) and 15 with antibodies against AQP4 (AQP4+). In this group, neuropathic pain was observed in 14 patients (11 – AQP4+ and three – AQP4-), pain due to spasticity in 6 patients (5 – AQP4+ and 1 – AQP4-), painful tonic spasms in 2 patients with AQP4+ and neuropathic itching – in 1 patient with AQP4-. According to the questionnaires of the seropositive patients, the median DN4 was 3 [2; 3] (here and below the data are given in Me format [25th; 75th percentile]), PDQ – 6 [5; 12], on the MPQ scale: pain rank index – 11 [9; 15], index of the number of selected symptoms – 3 [3; 4], pain intensity – 2 [1; 3]. The results for the physical and psychological health domains of the SF36 questionnaire were 35.9 [6.5; 36] and 50.5 [5; 51.5] respectively. Among AQP4+ patients, 7 out of 15 patients were diagnosed with depression; in the AQPpatients, only one man was diagnosed with depression. There was a statistically significant correlation between the age of the patients and pain level: neuropathic pain according to DN4 was more pronounced in younger patients (p=0.009), and neuropathic pain was significantly more severe in patients with an early onset of the disease (p=0.04).Conclusion. There is currently no clear approach for the treatment of pain in NMOSD. In the present small study, different causes of pain were identified, depending on the location and severity of the lesion, the age of the patient and the duration of the disease. The most important factor in the prevention and treatment of pain syndrome in NMOSD is probably adequate immunotherapy of the disease.

Keywords

• neuromyelitis optica spectrum disorders
• aquaporin-4
• pain
• neuropathic pain