Differential Diagnosis for Right Lower Abdominal Pain

The patient presents with intermittent right lower abdominal pain that is noticeable when taking tirzepatide, a medication used for the treatment of type 2 diabetes. Given this context, the differential diagnoses can be categorized as follows:

• Single Most Likely Diagnosis

  • Gastrointestinal side effects of tirzepatide: Tirzepatide is known to cause gastrointestinal side effects such as nausea, vomiting, and abdominal pain due to its mechanism of action as a dual GIP/GLP-1 receptor agonist. The fact that the pain is intermittent and associated with the use of tirzepatide makes this a likely explanation.

• Other Likely Diagnoses

  • Appendicitis: Although the pain is intermittent, appendicitis can present with varying degrees of severity and intermittency, especially in its early stages. The location in the right lower abdomen is consistent with appendicitis.
  • Gastroesophageal reflux disease (GERD) or peptic ulcer disease: These conditions can cause abdominal pain and may be exacerbated or become more noticeable due to the gastrointestinal effects of tirzepatide.
  • Intestinal obstruction: Partial obstruction could cause intermittent pain, especially if related to the timing of meals or medication intake.

• Do Not Miss Diagnoses

  • Mesenteric ischemia: This is a serious condition that could present with abdominal pain, especially if the patient has risk factors such as cardiovascular disease. It's crucial to consider this diagnosis due to its high mortality rate if not promptly treated.
  • Pancreatitis: Although less common, pancreatitis can be a side effect of certain medications and can present with abdominal pain, often radiating to the back.
  • Diverticulitis: Inflammation of a diverticulum in the intestine can cause severe abdominal pain, usually in the left lower quadrant but can occur on the right side, especially if the sigmoid colon is involved.

• Rare Diagnoses

  • Inflammatory bowel disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic or intermittent abdominal pain and may be exacerbated by certain medications.
  • Carcinoid syndrome: Rare tumors in the intestines can produce substances that cause a variety of symptoms, including abdominal pain, although this would be an uncommon presentation.
  • Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause intermittent abdominal pain, more common in children but can occur in adults, often with a lead point such as a tumor.