Bone Abstracts

Pain is common in patients with fibrous dysplasia (FD), however the mechanisms and presentation of pain is poorly understood. Retrospective studies have shown that pain in FD presents along a broad spectrum, responds variably to treatment, and does not correlate with FD disease burden. Pain may be generally conceptualized into two categories: nociceptive pain (associated with actual or potentially tissue damaging stimuli) and neuropathic pain (caused by dysfunction of the somatosensory nervous system). The contribution of nociceptive versus neuropathic pain in FD has not been determined, and it is unknown whether differences in pain type might explain variabilities in the presentation and response to treatment.

Methods: Data were analyzed from 2 FD patient registries: the FD Foundation (FDF) (US) and the RUDY study (UK). Subjects completed questionnaires for neuropathic pain (painDETECT), quality of life (SF-36), and mental health (Hospital Anxiety and Depression Scale) (HADS).

Results: 180 subjects in the FDF registry (mean age 38 y, range 8–77, 82% female) and 30 subjects in the RUDY study (mean age 47 y, range 18–71, 73% female) were assessed. Pain types were similar between cohorts: of FDF subjects 46% had nociceptive pain, 32% had neuropathic pain, with 22% unclear, and of RUDY study subjects 47% had nociceptive pain, 33% had neuropathic pain, with 20% unclear. In both cohorts, subjects with neuropathic pain scored significantly lower for general health and physical function on SF-36 (P<0.05), and significantly higher for anxiety and depression on HADS (P<0.05), in comparison to subjects with nociceptive pain.

Conclusions: Approximately 1/3 of subjects with FD met criteria for neuropathic pain, which was associated with lower quality of life and higher levels of anxiety and depression. These findings were consistent across 2 international cohorts. Evaluation of neuropathic pain should be considered in patients with FD and may inform the development of treatment and monitoring strategies.

Disclosure: The authors declared no competing interests.