3248 SIBO and Gastroparesis: Downstream Effects of Diabetes

Abstract

INTRODUCTION: Homeostasis of the GI mucosal environment depends on gut motility and normal gastric acid secretion. The autonomic nervous system plays an important role in these processes. Diabetes has been shown to injure the enteric nervous system, resulting in slowed motility. Gastroparesis and small intestinal bacterial overgrowth are two consequences of the enteric injury associated with diabetes. CASE DESCRIPTION/METHODS: A 23-year-old male with type 1 diabetes presented with 6 months of diffuse abdominal pain and diarrhea, which had recently worsened. He noted 4-6 loose bowel movements daily and vomiting after food. He had previously been seen by gastroenterology and had an unremarkable colonoscopy, EGD, and celiac testing. He had been trialed on rifaximin and neomycin, which improved his symptoms for a short period. He tried eluxadoline with little effect. On presentation, he was hemodynamically stable with labs significant only for mildly elevated AST (58 units/L). WBC, ESR, CRP, feces ova and parasites, and C. difficile Ag were all unremarkable. A gastric emptying study revealed moderate (24%) gastroparesis. A right upper quadrant ultrasound was unremarkable. Small intestinal bacterial overgrowth related to gastroparesis was suspected. A trial of rifaximin and metoclopramide improved his symptoms leading to empiric diagnosis of SIBO. DISCUSSION: Small intestinal bacterial overgrowth occurs when the normal homeostatic mechanisms that control bacterial populations are in some way disrupted. Frequently, this occurs with decreased gastric acid secretion or dysmotility of the small intestine. The most common symptoms of SIBO include bloating, abdominal discomfort and distention, chronic diarrhea, weight loss, and malabsorption. One proposed theory for SIBO in gastroparesis is the idea that phase 3 migratory motor complexes may be diminished in frequency or altogether absent. While the gold standard for diagnosis requires jejunal aspirate, lactulose and glucose breath testing have been used as indirect measures of SIBO. Multiple studies have been done to analyze the relationship between gastroparesis and SIBO with results showing up to 60-70% of study participants with gastroparesis test positive for SIBO via lactulose breath testing. Once the diagnosis of SIBO has been established, the goal of therapy is to correct the underlying cause, provide nutritional support, and treat overgrowth with a course of antibiotics.