Differential Diagnosis for Lifelong Bowel Pain and Associated Symptoms

The patient's presentation of lifelong bowel pain, escalating symptoms, fatty liver, small gallstones, and fatigue suggests a complex underlying condition. The following differential diagnosis is organized into categories to guide further evaluation and management.

• Single Most Likely Diagnosis

  • Irritable Bowel Syndrome (IBS) with possible progression to Inflammatory Bowel Disease (IBD): The patient's long history of bowel pain, worsening symptoms over time, and normal colonoscopy could initially suggest IBS. However, the development of fatty liver, gallstones, and increasing fatigue may indicate a progression towards an inflammatory process, potentially IBD, which includes conditions like Crohn's disease and ulcerative colitis.

• Other Likely Diagnoses

  • Chronic Pancreatitis: Episodes of extreme bowel pain followed by periods of low-level pain and inflammation could be indicative of chronic pancreatitis, especially with the presence of small gallstones which might be causing pancreatic duct obstruction.
  • Small Intestine Bacterial Overgrowth (SIBO): This condition can cause chronic abdominal pain, bloating, and changes in bowel habits, and might be considered given the patient's long-standing symptoms and recent worsening.
  • Celiac Disease: Although the patient has a normal diet, celiac disease can sometimes present with non-classical symptoms, including chronic abdominal pain and fatigue, and should be considered, especially if there's any malabsorption or deficiency.

• Do Not Miss Diagnoses

  • Cancer (e.g., Pancreatic, Colorectal): Although less likely given the patient's age and normal colonoscopy, cancer must always be considered, especially with worsening symptoms and the development of new signs like fatty liver and gallstones.
  • Infiltrative Diseases (e.g., Sarcoidosis, Amyloidosis): These rare conditions can affect multiple organ systems, including the gastrointestinal tract, and present with non-specific symptoms like chronic pain and fatigue.
  • Vasculitis (e.g., Systemic Lupus Erythematosus): Systemic vasculitis can cause a wide range of symptoms, including abdominal pain, and is important not to miss due to its potential for serious complications.

• Rare Diagnoses

  • Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, leading to chronic abdominal pain, among other symptoms.
  • Mastocytic Disorders (e.g., Mastocytosis): These conditions involve the accumulation of mast cells in various tissues, including the gastrointestinal tract, and can cause chronic abdominal pain, diarrhea, and other symptoms.
  • Intestinal Lymphangiectasia: A rare disorder characterized by dilation of the lymphatic vessels in the small intestine, leading to malabsorption, chronic diarrhea, and abdominal pain.