Case Report: The Imperfect Association Between Craniofacial Lesion Burden and Pain in Fibrous Dysplasia

Identifying Pain Subtypes in Patients With Craniofacial Lesions of Fibrous Dysplasia/McCune-Albright Syndrome

BACKGROUND

Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a genetic disorder, marked by bone lesions, often affecting the craniofacial skeleton. Pain is a prevalent yet heterogeneous symptom reported by patients with craniofacial FD. Effective treatments are currently lacking, posing a significant clinical challenge to patient care.

PURPOSE

This preliminary study examined pain profiles in craniofacial FD and aimed to identify subtypes of patients based on pain phenotypes and emotional health.

STUDY DESIGN, SETTING, SAMPLE

A prospective, cross-sectional study involving 15 patients with FD/MAS, conducted at Boston Children's Hospital and Massachusetts General Brigham's Hospitals.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

Headache frequency, craniofacial pain severity, neuropathic pain quality, pain interference, allodynia, photophobia, depression, and anxiety were assessed using clinical questionnaires.

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was the symptom profile derived from standardized clinical questionnaires and analyzed using principal component analysis and K-means clustering.

COVARIATES

Covariates included demographic data, diagnosis, and lesion location(s).

ANALYSES

Principal component analysis and K-means clustering of patient-reported measures of pain and emotional health were performed. Analysis of variance was conducted to determine significant differences among patient subtypes. Statistical significance was set at (P < .05).

RESULTS

The study included 15 subjects with FD/MAS, with a mean age of 36.2 (13.9) years, including 1 male. Clustering analysis identified 3 subtypes of patients with distinct symptom profiles. Cluster 1 (n = 2) averaged 70 (28.3) headache days in a 90-day period, pain level of 7.5 (0.7) on a 0-10 scale, and severe anxiety, depression, allodynia, photophobia, and pain interference. Cluster 2 (n = 7) patients reported an average of 5.4 (7.5) headache days, an average pain level of 2.7 (2.6), mild or no anxiety, depression, allodynia, photophobia, and pain interference. Cluster 3 (n = 6) patients displayed a mixed symptom profile with an average of 47.3 (36.4) headache days and a pain level of 5.25 (1.4). Notably, patients with temporal and skull base lesions were predominantly found in Clusters 1 and 3, which exhibited the most severe symptomatology.

CONCLUSIONS AND RELEVANCE

This study establishes a basis for future longitudinal research aimed at understanding underlying pain mechanisms and evaluating the response to personalized pain management strategies in subtypes of patients with craniofacial FD.

Dissecting the heterogeneity of craniofacial lesions in patients with fibrous dysplasia/McCune-Albright Syndrome

Fibrous dysplasia/McCune-Albright Syndrome (FD/MAS) frequently involves the craniofacial skeleton. Craniofacial fibrous dysplasia lesions exhibit diverse imaging characteristics on multimodality evaluation, utilizing radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and 18F-sodium fluoride positron emission tomography (18F-NaF PET). A multimodal imaging classification of craniofacial fibrous dysplasia lesions may offer clinical insights into the types of lesions that are (1) prone to progression, (2) amenable to intervention (i.e., pharmacological or surgical), or (3) associated with symptoms such as pain. In this prospective, preliminary single site study of 15 patients with FD/MAS, the heterogeneity of craniofacial lesions (N = 35) was assessed using a combination of 18F-NaF PET, MRI, and CT. A k-means clustering algorithm was used to categorize lesions based on imaging characteristics. Clustering analysis revealed three types of lesion based on the magnitude of the regional 18F-NaF standardized uptake values (SUV), signal intensities on T1-weighted and fluid-sensitive sequences, and appearance on CT (lucent, sclerotic, and/or ground glass). This preliminary study provides a foundation for future longitudinal natural history or treatment studies, where the prognostic value of baseline craniofacial fibrous dysplasia imaging characteristics and clinical symptomatology can be further evaluated.

Phenotyping Pain in Patients With Fibrous Dysplasia/McCune-Albright Syndrome

CONTEXT

Pain is a poorly managed aspect in fibrous dysplasia/McCune-Albright syndrome (FD/MAS) because of uncertainties regarding the clinical, behavioral, and neurobiological underpinnings that contribute to pain in these patients.

OBJECTIVE

Identify neuropsychological and neurobiological factors associated with pain severity in FD/MAS.

DESIGN

Prospective, single-site study.

PATIENTS

Twenty patients with FD/MAS and 16 age-sex matched healthy controls.

INTERVENTION

Assessments of pain severity, neuropathic pain, pain catastrophizing (pain rumination, magnification, and helplessness), emotional health, and pain sensitivity with thermal quantitative sensory testing. Central nervous system (CNS) properties were measured with diffusion tensor imaging, structural magnetic resonance imaging, and functional magnetic resonance imaging.

MAIN OUTCOME MEASURES

Questionnaire responses, detection thresholds and tolerances to thermal stimuli, and structural and functional CNS properties.

RESULTS

Pain severity in patients with FD/MAS was associated with more neuropathic pain quality, higher levels of pain catastrophizing, and depression. Quantitative sensory testing revealed normal detection of nonnoxious stimuli in patients. Individuals with FD/MAS had higher pain tolerances relative to healthy controls. From neuroimaging studies, greater pain severity, neuropathic pain quality, and psychological status of the patient were associated with reduced structural integrity of white matter pathways (superior thalamic radiation and uncinate fasciculus), reduced gray matter thickness (pre-/paracentral gyri), and heightened responses to pain (precentral, temporal, and frontal gyri). Thus, properties of CNS circuits involved in processing sensorimotor and emotional aspects of pain were altered in FD/MAS.

CONCLUSION

These results offer insights into pain mechanisms in FD/MAS, while providing a basis for implementation of comprehensive pain management treatment approaches that addresses neuropsychological aspects of pain.

The experience of living with Niemann-Pick type C: a patient and caregiver perspective

BACKGROUND

Niemann-Pick disease type C (NPC) is a rare inherited lysosomal storage disease typified by accumulation of cholesterol and other lipids in late endosomes/lysosomes, thereby resulting in a spectrum of neurological, psychiatric, and systemic symptoms (notably liver disease). Though it is well-known that NPC exacts a physical and emotional toll on both patients and caregivers, the burden of NPC can vary between patients, while the challenges of living with NPC can evolve over time (i.e., from time of diagnosis to the present day). To further grasp patient and caregiver perceptions and experiences with NPC, we carried out focus group discussions with pediatric and adult individuals with NPC (N = 19), with partial or full representation of the patient by their caregiver. Furthermore, we utilized our NPC focus group discussion to provide guidance on study design parameters and feasibility of prospective investigations aiming to characterize the central manifestations of NPC using neuroimaging, specifically, magnetic resonance imaging (MRI) methodology.

RESULTS

Focus group discussions revealed that neurological signs, including declining cognition, memory loss, and psychiatric symptoms, as well as increasingly impaired mobility and motor function, are among the most pressing past and current concerns for patients and caregivers. Moreover, several participants also expressed concern over a loss of independence, social exclusion, and uncertainty for what the future holds. Caregivers described the challenges that participation in research poses, which included logistical difficulties mainly due to traveling with medical equipment and the need for sedation in a minority of patients when undergoing MRI.

CONCLUSIONS

The findings derived from focus group discussions highlight the outstanding challenges that NPC patients and their caregivers face daily, while also providing direction on the potential scope and feasibility of future studies focusing on the central phenotypes of NPC.

Pharmacological Interventions Targeting Pain in Fibrous Dysplasia/McCune-Albright Syndrome

Fibrous dysplasia (FD) is a rare, non-inherited bone disease occurring following a somatic gain-of-function R201 missense mutation of the guanine-nucleotide binding protein alpha subunit stimulating activity polypeptide 1 (GNAS) gene. The spectrum of the disease ranges from a single FD lesion to a combination with extraskeletal features; an amalgamation with café-au-lait skin hyperpigmentation, precocious puberty, and other endocrinopathies defines McCune-Albright Syndrome (MAS). Pain in FD/MAS represents one of the most prominent aspects of the disease and one of the most challenging to treat-an outcome driven by (i) the heterogeneous nature of FD/MAS, (ii) the variable presentation of pain phenotypes (i.e., craniofacial vs. musculoskeletal pain), (iii) a lack of studies probing pain mechanisms, and (iv) a lack of rigorously validated analgesic strategies in FD/MAS. At present, a range of pharmacotherapies are prescribed to patients with FD/MAS to mitigate skeletal disease activity, as well as pain. We analyze evidence guiding the current use of bisphosphonates, denosumab, and other therapies in FD/MAS, and also discuss the potential underlying pharmacological mechanisms by which pain relief may be achieved. Furthermore, we highlight the range of presentation of pain in individual cases of FD/MAS to further describe the difficulties associated with employing effective pain treatment in FD/MAS. Potential next steps toward identifying and validating effective pain treatments in FD/MAS are discussed, such as employing randomized control trials and probing new pain pathways in this rare bone disease.