Differential Diagnosis for Right Lower Quadrant Abdominal Pain

Single Most Likely Diagnosis

• Appendicitis: This is the most common cause of right lower quadrant abdominal pain, especially in younger individuals. The pain often starts around the navel and then moves to the right lower quadrant. Appendicitis is an emergency that requires prompt surgical intervention.

Other Likely Diagnoses

• Ovarian Cyst or Torsion: In females, ovarian cysts or torsion can cause severe right lower quadrant pain. The pain can be sudden and may be accompanied by nausea and vomiting.
• Ectopic Pregnancy: Another condition in females, ectopic pregnancy can cause right lower quadrant pain, especially if the ectopic pregnancy is located in the right fallopian tube.
• Diverticulitis: Although more common on the left side, diverticulitis can occur on the right side and cause lower quadrant pain, especially in individuals with a redundant sigmoid colon that extends to the right.
• Kidney Stone: A stone in the right ureter can cause severe pain that radiates from the flank to the groin, including the right lower quadrant.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease can cause chronic inflammation of the bowel, leading to right lower quadrant pain, especially if the terminal ileum is involved.

Do Not Miss Diagnoses

• Ruptured Ectopic Pregnancy: A life-threatening condition that requires immediate surgical intervention. The pain can be severe and sudden, accompanied by signs of shock.
• Ruptured Appendix: If appendicitis is not treated promptly, the appendix can rupture, leading to peritonitis, which is a life-threatening condition.
• Ovarian Torsion: This condition can cut off blood supply to the ovary, leading to necrosis if not promptly treated.
• Intestinal Obstruction: Although not exclusive to the right lower quadrant, an obstruction can cause severe pain and is a medical emergency if not relieved.

Rare Diagnoses

• Meckel's Diverticulitis: A congenital anomaly of the small intestine that can cause inflammation and mimic appendicitis.
• Right Lower Quadrant Hematoma: A collection of blood in the right lower quadrant, which could be due to trauma or a bleeding disorder.
• Yersinia Ileitis: A rare cause of right lower quadrant pain due to infection with Yersinia enterocolitica, which can mimic appendicitis.
• Carcinoid Tumor: A rare tumor of the small intestine that can cause right lower quadrant pain, often accompanied by other systemic symptoms like flushing and diarrhea.