Chapter 22: GI Dysfunction & Fluid/Electrolyte Disorders

GI Dysfunction & Fluid/Electrolyte Disorders details the pathophysiology, clinical manifestations, and management of dehydration, classifying it into isotonic, hypotonic, and hypertonic types, and outlines critical interventions like Oral Rehydration Therapy (ORT) and parenteral fluid resuscitation for shock. Disorders of motility are thoroughly explored, including acute and chronic diarrhea caused by pathogens like Rotavirus, and constipation, with a specific focus on Hirschsprung disease (congenital aganglionic megacolon) and its surgical correction via pull-through procedures. The text analyzes inflammatory conditions, differentiating between the two major forms of Inflammatory Bowel Disease (IBD)—Crohn disease and ulcerative colitis—and covers the diagnosis and management of acute appendicitis, Meckel diverticulum, and Peptic Ulcer Disease associated with H. pylori. Obstructive disorders are detailed, specifically Hypertrophic Pyloric Stenosis, characterized by projectile vomiting and a palpable olive-shaped mass; Intussusception, noted for currant jelly-like stools and treatment via gas or hydrostatic enema; and the surgical emergency of Malrotation with Volvulus. Malabsorption syndromes such as Celiac disease (gluten-sensitive enteropathy) and Short Bowel Syndrome (SBS) are discussed in the context of life-long dietary restrictions, nutritional support (TPN and enteral), and intestinal adaptation. Hepatic disorders are covered, including the transmission, prevention, and management of viral Hepatitis (A, B, and C), the surgical management of Biliary Atresia via the Kasai portoenterostomy or liver transplantation, and the complex nursing care required for children with Cirrhosis and portal hypertension. Finally, the chapter addresses congenital structural defects, including Esophageal Atresia (EA) and Tracheoesophageal Fistula (TEF), abdominal wall defects like umbilical and inguinal hernias, and various Anorectal Malformations requiring surgical reconstruction and long-term bowel management.