Clinical Scorecard: Aβ Low Threshold Mechanoreceptors Play a Role in Sensory Disturbances Associated with Fibromyalgia

At a Glance

Key Highlights

• FM is characterized by widespread pain, fatigue, tactile allodynia, paraesthesia, and dysaesthesia involving both small and large sensory fibres.
• Passive transfer of FM IgG to mice induces mechanical and cold hypersensitivity linked to sensitization of Aβ-LTMRs.
• In people with FM, Aβ-LTMRs show altered responses to cold and mechanical stimuli, supporting a role for autoreactive IgG in sensory symptoms.

Guideline-Based Recommendations

Diagnosis

• Consider clinical assessment of sensory abnormalities including tactile allodynia, paraesthesia, and dysaesthesia in FM patients.
• Evaluate small fibre neuropathy via skin biopsy and electrophysiological studies focusing on C-fibre sensitization.
• Assess presence of autoreactive IgG targeting large diameter sensory neurons as a potential biomarker.

Management

• Address sensory symptoms by targeting peripheral sensitization mechanisms involving both small and large sensory fibres.
• Consider immunological approaches given the role of autoreactive IgG in symptom development.
• Incorporate multidisciplinary care addressing pain, fatigue, and sensory disturbances.

Monitoring & Follow-up

• Monitor changes in sensory symptoms including mechanical and cold hypersensitivity over time.
• Use clinical questionnaires and microneurography to assess sensory fibre function and treatment response.
• Track immunological markers such as IgG reactivity to dorsal root ganglion neurons.

Risks

• Potential for persistent sensory disturbances due to ongoing peripheral sensitization.
• Risk of misattributing symptoms solely to small fibre neuropathy without considering large fibre involvement.
• Challenges in managing complex sensory symptoms that impact quality of life.

Patient & Prescribing Data

Individuals diagnosed with fibromyalgia exhibiting sensory abnormalities including tactile allodynia and paraesthesia

Therapies targeting IgG-mediated sensitization of Aβ-LTMRs may alleviate mechanical and cold hypersensitivity; current evidence supports a role for immunomodulatory strategies alongside symptomatic management.

Clinical Best Practices

• Incorporate comprehensive sensory phenotyping including assessment of both small and large fibre function.
• Utilize passive transfer models and immunological assays to understand patient-specific IgG effects.
• Engage patients in reporting detailed sensory experiences to guide personalized management.
• Consider sex as a biological variable given FM predominance in females and IgG effects in both sexes.

References

• Themistocleous et al. Scientific Commentary