درد در بیماری پارکینسون: شیوع و خصوصیات

Parkinson’s disease is a chronic, progressive, incurable neurodegenerative disease. As the disease progresses, motor disturbances and non-motor symptoms represent considerable illness burdens. Symptom relief is the goal for the treatment. Pain is frequently observed in patients with Parkinson’s disease, but its prevalence, characteristics and associations with Parkinson’s disease are poorly documented. These were investigated in 176 home-living PD patients. They underwent a neurological examination and a structured interview for registration of pain characteristics in addition to responding to standardised questionnaires. Pain was reported by 146 (83%) patients. Compared to the general population, the Parkinson’s disease patients experienced significantly more pain as measured by SF-36 Bodily Pain Scale. The average pain during the last 24 h measured by the Brief Pain Inventory was 2.85. Fifty-three percent of the patients reported one, 24% reported two and 5% reported three pain types. Musculoskeletal pain was reported by 70%, dystonic pain by 40%, radicular-neuropathic pain by 20% and central neuropathic pain by 10%. Thirty-four percent were on analgesic medication. Pain was not associated with age, disease duration or severity of the disease; female gender was the only significant predictor of pain. Pain is frequent and disabling, independent of demographic and clinical variables except for female gender, and is significantly more common in Parkinson’s patients compared to the general population. A minority of the Parkinson’s disease patients with pain received analgesic medication. The findings call for improved attention to assessment and treatment of pain in the follow-up of Parkinson’s disease patients.

In addition to the motor disturbances experienced by the patients suffering from Parkinson’s disease (PD), several non-motor symptoms including pain also affect the PD patients [5]. Five different types of pain have been described in PD patients: musculoskeletal pain (due to parkinsonian rigidity, rheumatological disease or skeletal deformity), radicular-neuropathic pain (due to a root lesion, focal or peripheral neuropathy), dystonic pain (related to antiparkinsonian medication), central neuropathic pain (related to antiparkinsonian medication) and akathisia (under off-period or drug induced) [12]. Neuropathic central pain (NCP) is a disease-specific symptom in PD and also a symptom of stroke [29] and multiple sclerosis [24] as well. NCP can be very intense and difficult to treat [11]. To our knowledge, only two studies have assessed all types of pain in patients with PD, and the prevalence of pain was as high as 68% and 85%, respectively [18] and [25]. One study assessing pain perceived by the patients as directly related to their PD found that 46% experienced pain attributed to PD [14]. Some studies have examined specific types of pain in PD patients or pain localized to specific regions. For example, the prevalence of back pain was reported to be 60–74% [4] and [7]. A recent review of non-motor symptoms in PD patients emphasized the need for large community-based studies on the prevalence of pain and other non-motor symptoms [5]. Except for the studies on back pain, the intensity and prevalence of pain in the PD patients have, to our knowledge, never been compared to the general population [4] and [7]. Pain is a prevalent symptom in the general population, thus important to adjust for. For example, 19% of the European population and 30% of the Norwegian population are reported to suffer from chronic pain [3]. The prevalence of pain increases by age [20], which is also of relevance, since PD primarily affects the elderly. Pain treatment can also be an indicator of the magnitude of pain as a clinical problem in PD patients. Treatment of pain in PD patients has to our knowledge only been assessed in two studies, who reported that 58% [18] and 34%, only for back pain [4], were taking some form of analgesic medication. The aim of the present study is to examine the prevalence of pain in PD patients, including pain types, the intensity and the duration of pain. The prevalence of pain in PD patients will be compared to the general population. Clinical and demographic predictors of pain in the PD patients will also be investigated as well as the usage of different analgesic treatments.