Chapter 40: Gastric and Intestinal Disorders

Gastroesophageal reflux disease results from lower esophageal sphincter dysfunction allowing retrograde flow of gastric contents that erodes the esophageal mucosa and may progress to Barrett's epithelium, with management centered on proton pump inhibitor therapy and lifestyle modifications including head elevation and weight reduction. Peptic ulcer disease stems from an imbalance between mucosal protective mechanisms and aggressive gastric acid, predominantly caused by Helicobacter pylori infection or nonsteroidal anti-inflammatory drug use, requiring endoscopic confirmation and combination antibiotic therapy for bacterial eradication. Hemorrhoids represent dilated venous structures managed conservatively through dietary fiber supplementation and sitz baths, with procedural interventions such as rubber-band ligation reserved for refractory cases. Abdominal hernias involve fascial wall defects that necessitate surgical repair using synthetic mesh to prevent serious complications including bowel incarceration and strangulation. Irritable bowel syndrome functions as a gut-brain disorder characterized by altered intestinal motility and visceral hypersensitivity, diagnosed by Rome IV criteria and managed through dietary manipulation, particularly reduction of fermentable oligosaccharides and disaccharides, and adjunctive pharmacotherapy. Celiac disease represents an autoimmune condition triggered by gluten ingestion in genetically susceptible individuals, resulting in villous atrophy confirmed through tissue biopsy, with exclusive treatment being strict gluten elimination. Bowel obstruction presents with acute colicky pain and requires immediate nasogastric decompression and surgical intervention when indicated. Diverticular disease encompasses both asymptomatic diverticulosis and acute diverticulitis with potential perforation, managed through dietary fiber for prevention and antibiotics for acute inflammation. Inflammatory bowel disease encompasses ulcerative colitis and Crohn's disease as chronic autoimmune conditions with distinct anatomical patterns, treated with aminosalicylates, corticosteroids, immunomodulators, and biologic agents targeting tumor necrosis factor. Colorectal cancer predominantly arises from adenomatous polyps and requires surgical resection as primary treatment, with staging via the tumor-node-metastasis system and adjuvant chemotherapy determining prognosis and long-term surveillance protocols.