Poster, Podium & Video Sessions
Presentation Authors: Annie Chen*, Charles E. Argoff, Elise De, Albany, NY
Introduction: We report prevalence of small fiber polyneuropathy (SFPN) in patients with refractory CPP and concurrent pain diagnoses. Studies show that patients with CPP have an average 2.4 pain comorbidities such as irritable bowel syndrome (IBS), interstitial cystitis (IC), and fibromyalgia (FM) [5, 8, 12]. The lack of a common etiology complicates treatment options. SFPN is emerging as a major contributor to unexplained multi-symptom syndromes involving chronic widespread pain and is often present in patients with IBS and FM [1, 7]. SFPN diagnosis can be confirmed via skin biopsy: decreased epidermal nerve fiber density is demonstrated on immunofluorescence. The reported "minimum prevalence" of SFPN is 53/100,000 . In our practice a significant proportion of refractory CPP patients had biopsies consistent with SFPN, a finding that has not been reported in the literature. We propose that SFPN is a unifying underlying treatable mechanism for pain in the refractory CPP patient.
Objective: To demonstrate the prevalence of SFPN in patients with refractory CPP and/multiple pain syndromes by diagnostic skin biopsy.
Methods: We evaluated refractory CPP patients for SFPN: epidermal nerve fiber density in 3mm punch biopsies of the lower extremity was evaluated by immunofluorescence. The sensitivity and specificity of the test are 78-92% and 65-90%, respectively.
Results: 17 (61%) of 28 patients were positive for SFPN. Comorbid conditions were high in our population including migraine (39%), IBS (36%), endometriosis (21%), FM (32%), IC (14%), GERD (50%), vulvodynia (7%), lower back pain (32%), and other types of chronic pain syndrome (35%). Duration of pain was not different between the SFPN (+) and (-) groups (8.36 years SD=9.92 versus 6.03 years SD=3.14); p=0.42 based on sample t-test for unequal variances. Number of prior visits for pain and age also did not differ (16.4 prior visits versus 15.2 and average age 43 versus 47 for SFPN (+) versus (-)).
Conclusions: The prevalence of SFPN in specialty referral patients with refractory CPP is remarkably high versus published population data. Consideration of SFPN shifts the focus from a syndrome complex to a unifying treatable disorder. Making the diagnosis of SFPN may result in treatments not usually offered to CPP patients such IVIG or other immunomodulatory therapies . Identifying SFPN should be a priority in this population.
Source Of Funding: None
Saturday, May 13
9:30 AM – 11:30 AM