Differential Diagnosis for Abdominal Pain

The differential diagnosis for abdominal pain, considering the possibilities of appendicitis or iliac valve pain (more commonly referred to as ilioinguinal or iliopsoas-related pain), can be categorized as follows:

• Single Most Likely Diagnosis
  • Appendicitis: This is a common cause of acute abdominal pain, especially if the pain starts near the navel and then moves to the lower right abdomen. The symptoms can include nausea, vomiting, and loss of appetite.
• Other Likely Diagnoses
  • Iliopsoas or ilioinguinal pain: This can be due to various reasons such as muscle strain, hernias, or even referred pain from the spine. The pain is typically in the lower abdomen and may radiate to the groin.
  • Gastroenteritis: Inflammation of the stomach and intestines, usually due to infection, can cause abdominal pain, diarrhea, and vomiting.
  • Urinary tract infection (UTI): Especially in women, UTIs can cause lower abdominal pain, frequent urination, and burning sensation while urinating.
• Do Not Miss Diagnoses
  • Ectopic pregnancy: Although less common, an ectopic pregnancy can present with severe abdominal pain and is a medical emergency.
  • Ovarian torsion: This is a condition where the ovary twists around its ligaments, cutting off blood supply. It's extremely painful and requires immediate medical attention.
  • Intestinal obstruction: This can cause severe abdominal pain, vomiting, and constipation. It's a serious condition that may require surgery.
  • Kidney stones: While often presenting with flank pain, kidney stones can sometimes cause lower abdominal pain, especially if they are moving down the ureter.
• Rare Diagnoses
  • Mesenteric lymphadenitis: Inflammation of the lymph nodes in the mesentery (the tissue that attaches the intestines to the back of the abdominal wall) can mimic appendicitis.
  • Meckel's diverticulum: A congenital anomaly of the small intestine that can cause abdominal pain, nausea, and vomiting, especially if it becomes inflamed or obstructed.
  • Endometriosis: Although chronic, endometriosis can cause acute exacerbations of pain, especially during menstruation, and might be considered in the differential for recurrent or cyclic abdominal pain.

Each of these diagnoses has distinct characteristics and symptoms, but some can present similarly, making a thorough medical evaluation crucial for an accurate diagnosis.