Case # 20: Right Lower Quadrant Pain

A 40 year old male presented with a 4 day history of right lower quadrant pain. He reported that the pain was at its worse when it started but gradually improved. When in the ED he noted only minimal discomfort without the help of analgesics.  He denied ever having anorexia, fever, chills, nausea, vomiting, GU complaints. During examination, he had moderate tenderness to palpation in the right lower quadrant without rebound or guarding. 

Vitals:  T 97.7F    BP 130/77    HR 66    RR 16   SP02 100%

An abdominal ultrasound of the RLQ was performed and the following images were seen. What do you see and what is your most likely diagnosis? (4) (2)

Answer and Learning Points


In both the longitudinal and transverse views, you see a tubular structure in the right lower quadrant that is non- compressible, greater than 6mm (measures 15.6 mm), and lacks peristalsis. You can also appreciate some dependent free fluid around the appendix. These findings are consistent with the diagnosis of acute appendicitis.

CT abdomen/pelvis showed a retrocecal appendix with finding of acute uncomplicated appendicitis. No bowel obstruction or intra-abdominal/pelvic abscesses. Labs showed a slight leukocytosis to 14, otherwise were reassuring. Patient was given a dose of Zosyn in the emergency department and take to the OR for appendectomy by general surgery.

Learning Points

    • Appendicitis is the most common abdominal surgical emergency that presents to the ED in western countries [1]. 
    • The sensitivity and specificity of ultrasound for the diagnosis of appendicitis appears to be around 86% and 81%, respectively, based on results from older studies [2]. 
    • Ultrasound can be used to diagnosis acute appendicitis and may be the imaging modality of choice in certain patient populations such as pregnant women and children [3]. 
    • To obtain images you can use either the linear or curvilinear probe. Ask the patient to point where exactly they hurt and place the probe there. If you don’t see it you can use the landmark of the iliac crest (most lateral), psoas muscle (posterior), and iliac artery (most medial). Move superior and inferior along the iliac artery and the appendix should be just anterior to iliac artery. If you still haven’t found it, “lawnmower” along the right lower quadrant. Look for a tubular, blind ended pouch that has no peristalsis. It should be compressible and measure <6mm in AP diameter [4]. 


    1. Caterino, S., et al. Acute abdominal pain in emergency surgery. Clinical epidemiologic study study of 450 patients. Ann Ital Chir. 1997; 68: 807-817.
    2. Lim H, Bae S, Seo G: Diagnosis of acute appendicitis in pregnant women: value of sonography. AJR Am J Roentgenol 1992;159(3): 539–542.
    3. Excerpt From: Mike Mallin & Matthew Dawson. “Introduction to Bedside Ultrasound: Volume 2.” Emergency Ultrasound Solutions, 2013. Apple Books., M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. Accessed April 18th, 2020.


The following authors contributed to this post:

Amir Aminlari, MD; Danika Brodak, MD; Michael Macias, MD

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