Right lower quadrant (RLQ) abdominal pain accounts for nearly 50% of patients who go to the emergency department with abdominal pain. Appendicitis is the most common reason for RLQ pain in the United States requiring surgery.
Appendicitis is inflammation of the appendix, a finger-shaped pouch in the lower right side of the abdomen. The pain typically starts with a dull pain in the middle or right side of the abdomen and moves down to the lower right abdomen.
Other less frequent causes of RLQ pain include diverticulitis of the colon, kidney stone, colitis, and an intestinal blockage.
CT abdomen and pelvis with intravenous (IV) contrast is usually appropriate as the initial imaging test for RLQ pain. Ultrasound (US) abdomen, US pelvis, MRI abdomen and pelvis without and with contrast, MRI abdomen and pelvis without contrast, and CT abdomen and pelvis without contrast may also be appropriate.
For individuals with fever and high white blood cell count (leukocytosis), when appendicitis is thought to be the cause, CT scan abdomen and pelvis with contrast is usually appropriate. CT abdomen and pelvis without contrast, US abdomen, US pelvis, MRI abdomen and pelvis without and with IV contrast, and MRI abdomen and pelvis without contrast may also be appropriate.
For women who are pregnant with fever and leukocytosis with suspected appendicitis, US abdomen and MRI abdomen and pelvis without contrast are usually appropriate. US pelvis, CT of the abdomen and pelvis with IV contrast, and CT abdomen and pelvis without contrast may also be appropriate.
For more information, see the Appendicitis page.
— By Patti Brossard, RT® ARRT and Luke Ledbetter, MD. This information originally appeared in the Journal of the American College of Radiology.