Chapter 5: Gastroenterology

Beginning with esophageal conditions, the material covers gastroesophageal reflux disease and its management through lifestyle modifications and pharmacological interventions including proton pump inhibitors, as well as infectious esophagitis occurring primarily in immunocompromised populations and esophageal malignancies requiring multimodal treatment approaches. The chapter then addresses gastric pathology, including peptic ulcer disease pathogenesis related to Helicobacter pylori infection and nonsteroidal anti-inflammatory drug use, alongside gastritis and gastric neoplasms necessitating combined medical and surgical management. Intestinal disorders receive substantial coverage, distinguishing between inflammatory bowel disease subtypes such as Crohn's disease and ulcerative colitis with their distinct anatomical patterns and immunosuppressive treatment regimens, functional disorders like irritable bowel syndrome managed through dietary and behavioral interventions, malabsorption syndromes including celiac disease requiring nutritional rehabilitation, and colorectal malignancy with emphasis on screening and early detection strategies. The hepatobiliary section explores viral, autoimmune, and toxic hepatitis etiologies, the progressive complications of cirrhosis including portal hypertension and hepatic encephalopathy, and biliary tract disorders such as cholelithiasis and cholecystitis. Finally, pancreatic pathology encompasses acute and chronic pancreatitis with differentiation based on etiology and disease progression, along with pancreatic adenocarcinoma characterized by poor prognostic indicators and aggressive treatment protocols. Throughout the chapter, diagnostic methodologies, pharmacological management strategies, and surgical interventions are integrated to provide clinically relevant decision-making frameworks for patient care across the entire digestive system.