Eleonora Galosi (Italy)
La sapienza, university of rome Human neuroscienceAuthor Of 1 Presentation
NEUROPATHIC PAIN AND SMALL-FIBER RELATED SYMPTOMS IN LATE-ONSET TRANSTHYRETIN FAMILIAL AMYLOID POLYNEUROPATHY (TTR-FAP): A CLINICAL, NEUROPHYSIOLOGICAL AND SKIN BIOPSY STUDY.
- Pietro Falco (Italy)
Abstract
Background and Aims:
Neuropathic pain and small-fibers related symptoms have been poorly studied in late-onset TTR-FAP patients, though small-fibre damage is traditionally considered a diagnostic disease clue. Our study aims at assessing neuropathic pain and small fiber-related symptoms in TTR-FAP, besides correlations with specific neurophysiological and skin biopsy findings.
Methods:
We enrolled 21 TTR-FAP patients and 11 asymptomatic TTR mutations carriers. Each individual underwent clinical examination, DN4, NPSI, SFN-SIQ questionnaires, nerve conduction study, Quantitative sensory testing (QST) and skin biopsy. PGP9.5 intraepidermal (IENFD) and piloerector muscle (PMNFD) nerve fiber density was assessed from distal skin samples, along with semi-quantitative evaluation of sweat gland innervation (GNFD). Skin biopsy variables were compared with those from 20 healthy subjects.
Results:
81% patients and 64% carriers showed IENFD, PMNFD and GNFD reduction (p=<0.01), respect to healthy subjects. 71% patients and no carrier presented neuropathic pain, being pins and needles and burning pain the most frequently reported. 50% of patients complained of orthostatic intolerance, palpitations, gastro-intestinal and urinary disturbances and xerostomia, whereas 40% of carriers complained of orthostatic intolerance. Neuropathic pain and small fiber-related symptoms questionnaires scores correlated with distal IENFD, PMNFD, GNFD, QST variables and sural SAP impairment. All neurophysiological and skin biopsy variables negatively correlated with disease stage and duration.
Conclusions:
TTR-FAP patients frequently report neuropathic pain, with higher ratings in advanced disease stages, whereas autonomic dysfunction is less frequently complained. However, since asymptomatic disease stages, a similar small sensory and autonomic fibers involvement is detected by skin biopsy.