Differential Diagnosis for Abdominal Pain

Abdominal pain lasting for two months can have a wide range of causes. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Irritable Bowel Syndrome (IBS): This is a common condition characterized by chronic abdominal pain, bloating, and alteration of bowel habits in the absence of any mechanical, inflammatory, or biochemical abnormalities. The chronic nature of the pain and the lack of systemic symptoms (such as fever, weight loss) make IBS a plausible diagnosis.

• Other Likely Diagnoses

  • Gastroesophageal Reflux Disease (GERD): Chronic abdominal pain can be a symptom of GERD, especially if the pain is located in the upper abdomen and worsens with eating or lying down.
  • Peptic Ulcer Disease: Ulcers in the stomach or duodenum can cause chronic abdominal pain, often related to eating.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain, diarrhea, weight loss, and sometimes blood in the stool.
  • Chronic Pancreatitis: Inflammation of the pancreas can cause recurrent or chronic abdominal pain, often radiating to the back.

• Do Not Miss Diagnoses

  • Appendicitis: Although typically presenting acutely, some cases can have a more chronic presentation, especially if the appendix is not completely obstructed.
  • Ovarian Torsion or Cyst: These conditions can cause severe, chronic, or intermittent abdominal pain and are emergencies if not promptly treated.
  • Ectopic Pregnancy: Should be considered in women of childbearing age, presenting with abdominal pain and a missed period.
  • Abdominal Aortic Aneurysm: A potentially life-threatening condition that can cause chronic back or abdominal pain due to the expansion of the aorta.
  • Cancer (e.g., gastric, pancreatic, colon): Although less common, these conditions can present with chronic abdominal pain and should not be missed due to their significant impact on prognosis and treatment.

• Rare Diagnoses

  • Celiac Disease: An autoimmune reaction to gluten that can cause chronic abdominal pain, diarrhea, and malabsorption.
  • Whipple's Disease: A rare bacterial infection that can cause chronic abdominal pain, diarrhea, weight loss, and malabsorption.
  • Intestinal Lymphoma: A type of cancer that affects the immune cells in the intestines and can cause chronic abdominal pain, weight loss, and diarrhea.
  • Chronic Intestinal Pseudo-obstruction: A condition where there are symptoms of intestinal obstruction without any physical blockage, leading to chronic abdominal pain, nausea, vomiting, and constipation.

Each diagnosis should be considered based on the patient's specific symptoms, medical history, physical examination, and diagnostic tests. The key to narrowing down the differential diagnosis is a thorough clinical evaluation and the judicious use of diagnostic tests.