Gastrointestinal manifestations seen in pediatric patients diagnosed with small fiber neuropathy.

OBJECTIVES: Small fiber neuropathy (SFN) affects the fibers involved in cutaneous and visceral pain and temperature sensation and are a crucial part of the autonomic nervous system. Autonomic dysfunction secondary to SFN and autoimmune receptor antibodies is being increasingly recognized, and gastrointestinal (GI) manifestations include constipation, early satiety, nausea, vomiting, and diarrhea. Enteric nervous system involvement may be a possible explanation of abnormal GI motility patterns seen in these patients. METHODS: Children suspected to have SFN based on symptoms underwent skin biopsy at the Child Neurology clinic at Arnold Palmer Hospital for Children, which was processed at Therapath™ Neuropathology. SFN was diagnosed using epidermal nerve fiber density values that were below 5th percentile from the left distal leg (calf) as reported per Therapath™ laboratory. RESULTS: Twenty-six patients were diagnosed with SFN. Retrospective chart review was performed, including demographic data, clinical characteristics, and evaluation. A majority of patients were white adolescent females. Autonomic dysfunction, including orthostasis and temperature dysregulation were seen in 61.5% of patients (p = 0.124). Somatosensory symptoms, including pain or numbness were seen in 85% of patients (p < 0.001). GI symptoms were present in 85% of patients (p < 0.001) with constipation being the most common symptom seen in 50% of patients. This correlated with the motility testing results. CONCLUSIONS: Pediatric patients with SFN commonly have GI symptoms, which may be the main presenting symptom. It is important to recognize and look for symptoms of small fiber neuropathy in children with refractory GI symptoms that may explain multisystemic complaints often seen in these patients.

Effect of Caffeine on Colonic Manometry in Children.

OBJECTIVES: Coffee and caffeinated products have been widely consumed for many centuries. Previous adult studies have suggested that both coffee and decaffeinated beverages induce colonic motility. However, no study has been conducted in pediatrics, and the role of caffeine alone in pediatric colonic motility needs to be explored. METHODS: A prospective study of pediatric patients undergoing standard colonic motility testing that were able to consume caffeinated coffee, decaffeinated coffee, and caffeine tablet during colonic manometry. Patients who had a gastrocolonic reflex and high amplitude propagated contractions (HAPCs) in response to intraluminal administration of bisacodyl in the colon were included in the final analyses. RESULTS: Thirty-eight patients were recruited, 22 of which were excluded, 11 due to abnormal studies (no HAPC seen in response to intraluminal response to bisacodyl), and 11 due to inability to consume all study agents or complete the study. Sixteen patients met criteria for final analyses. Intracolonic bisacodyl produced a larger area under the curve (AUC) compared to all other agents. Caffeinated coffee resulted in a higher AUC, motility index (MI), and time to HAPC compared with decaffeinated coffee ( P < 0.05). There was no significant difference between caffeinated coffee and caffeine tablet, or caffeine tablet and decaffeinated coffee. CONCLUSIONS: Caffeine is indeed a colonic stimulant; however, other components of caffeinated and non-caffeinated beverages likely induce colonic response and require further evaluation for possible use as a colonic stimulant.

Eosinophil-Derived Neurotoxin Predicts Response to Proton-Pump Inhibitor Treatment in Pediatric Eosinophilic Esophagitis.

OBJECTIVES: There are no tests or patient factors to help predict the best treatment approach for a patient with eosinophilic esophagitis (EoE). The prevalence of proton-pump inhibitor (PPI) responsive EoE in children ranges from 30% to 71% with multiple studies showing similar characteristics in responders and nonresponders. Eosinophil-derived neurotoxin (EDN), an eosinophilic granule protein, measured in esophageal brushing has been shown to be a viable measure of disease activity in EoE. Our aim is to determine if EDN can help predict response to PPI in pediatric patients with EoE. METHODS: We conducted a prospective cross-sectional study to compare EDN between PPI-responsive and PPI-nonresponsive EoE subjects from 2018 through 2020. Enrolled patients with active EoE were treated with high-dose PPI and underwent repeat endoscopy to determine PPI-responsiveness. EDN was measured at baseline endoscopy, before any treatment, and at follow up endoscopy, after PPI therapy. Subjects were divided into PPI-responsive and nonresponsive groups. EDN, endoscopic reference score (EREFS), and peak eosinophilic count (PEC) were compared. RESULTS: Fifteen out of the 36 enrolled subjects with EoE (age range 2-18 years, 73.3% male) were PPI-responsive and 21 (age range 2-19 years, 95.2% male) were PPI-nonresponsive. EDN concentration was significantly higher in the PPI-nonresponsive group than in the PPI-responsive group (219.1 ±â€Š229 mcg/mL vs 75.7 ±â€Š60 mcg/mL, respectively, P = 0.036). There was no difference between the two groups in EREFS (P = 0.55) or PEC (P = 0.15). CONCLUSIONS: EDN measured in esophageal epithelial samples obtained by brushing during endoscopy may predict PPI-responsiveness in children and young adults with EoE.