Differential Diagnosis for Chronic Abdominal Pain

Given the symptoms of chronic abdominal pain, particularly in the lower abdomen and postprandial, the differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis

  • Irritable Bowel Syndrome (IBS): This condition is characterized by chronic abdominal pain, bloating, and alteration of bowel habits in the absence of any mechanical, inflammatory, or biochemical abnormalities. The postprandial exacerbation of symptoms fits with IBS, especially if the pain is relieved by bowel movements or is associated with changes in stool frequency or form.

• Other Likely Diagnoses

  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic abdominal pain, often in the lower abdomen, and can be exacerbated by eating. The presence of other symptoms such as diarrhea, weight loss, and blood in the stool would support this diagnosis.
  • Functional Dyspepsia: This condition involves chronic or recurrent upper abdominal pain or discomfort that is not exclusively relieved by defecation or associated with the onset of a bowel movement. While it primarily affects the upper abdomen, some patients may experience lower abdominal symptoms.
  • Diverticulitis: Inflammation of a diverticulum in the colon can cause lower abdominal pain, often on the left side, and can be exacerbated by eating. Fever, changes in bowel habits, and possible blood in the stool may accompany the pain.

• Do Not Miss Diagnoses

  • Appendicitis: Although typically presenting acutely, some cases of appendicitis can have a more chronic or smoldering course, especially if the appendix is not completely obstructed. Pain often starts around the navel and then moves to the lower right abdomen.
  • Ovarian Cysts or Torsion: In females, ovarian cysts can cause chronic or intermittent lower abdominal pain, and torsion of an ovarian cyst is a surgical emergency.
  • Intestinal Obstruction: Partial obstruction can cause chronic, intermittent abdominal pain, especially after eating, and can be associated with nausea, vomiting, and changes in bowel habits.
  • Colorectal Cancer: Though less common in younger populations, colorectal cancer can present with chronic abdominal pain, changes in bowel habits, weight loss, and blood in the stool.

• Rare Diagnoses

  • Chronic Intestinal Pseudo-obstruction: A rare condition characterized by impairment of the muscle contractions that move food, fluid, and air through the intestines, leading to symptoms similar to those of a true obstruction.
  • Eosinophilic Gastroenteritis: A rare condition involving eosinophilic infiltration of the gastrointestinal tract, which can cause chronic abdominal pain, nausea, vomiting, and diarrhea.
  • Abdominal Angina (Chronic Mesenteric Ischemia): A rare condition caused by reduced blood flow to the intestines, leading to chronic abdominal pain after eating, weight loss, and fear of food due to anticipated pain.