From the Guidelines
For a 66-year-old female patient with worsening right lower quadrant abdominal pain, I recommend starting with abdominal ultrasound as the initial imaging study, followed by CT abdomen and pelvis with contrast if ultrasound is inconclusive. This approach is supported by the American College of Radiology (ACR) Appropriateness Criteria for imaging of right lower quadrant pain, which suggests that ultrasonography of the abdomen is an appropriate initial imaging modality, with a rating of 6 1. The use of ultrasound as a first-line investigation is also recommended due to its non-invasive nature, lack of radiation, and ability to effectively evaluate gallbladder disease, kidney stones, and some intestinal pathologies that might cause right-sided pain.
Given the patient's history of hysterectomy and appendectomy, these organs are not contributing to her symptoms, but adhesions from previous surgeries could be a consideration. If ultrasound doesn't provide adequate information, CT with contrast would offer more comprehensive evaluation of the bowel, mesentery, and potential inflammatory or neoplastic processes. The ACR Appropriateness Criteria also suggest that CT of the abdomen and pelvis with contrast media is usually appropriate, with a rating of 8 1. The study by Rud et al 1 reported a summary sensitivity of 95% and summary specificity of 94% for CT in the diagnosis of appendicitis, highlighting its effectiveness in evaluating right lower quadrant pain.
The patient's age and duration of symptoms warrant thorough investigation despite the mild to moderate nature of the pain and unremarkable physical exam. The improvement with dietary modifications suggests a possible gastrointestinal etiology, but imaging is necessary to rule out more serious conditions given her age and persistent symptoms. The use of low-dose CT for evaluating suspected appendicitis is another strategy to decrease radiation exposure, and studies have shown significant decreases in CT use while maintaining acceptable diagnostic sensitivity and specificity 1.
Some key points to consider in this patient's evaluation include:
- The patient's symptoms have been worsening over time, which necessitates a thorough investigation to rule out serious conditions.
- The patient's history of previous surgeries may increase the risk of adhesions, which could be contributing to her symptoms.
- The use of ultrasound as a first-line investigation can help reduce radiation exposure and provide valuable information about potential causes of right lower quadrant pain.
- CT with contrast is a highly effective imaging modality for evaluating right lower quadrant pain, with high sensitivity and specificity for diagnosing appendicitis and other conditions.
From the Research
Imaging Recommendations
For a 66-year-old female patient with worsening right lower quadrant abdominal pain, the following imaging modalities are recommended:
- Computed Tomography (CT) scan, as it is the modality of choice for evaluation of patients with acute traumatic and nontraumatic conditions causing right lower quadrant pain 2
- CT scan can help diagnose not only common causes such as appendicitis but also less common conditions like epiploic appendagitis 3
- Ultrasound and Magnetic Resonance Imaging (MRI) can be used as alternative imaging modalities, especially in patients where radiation exposure is a concern, such as pediatric and pregnant patients 4
Differential Diagnoses
The patient's symptoms can be indicative of a vast list of differential diagnoses, including:
- Inflammatory and infectious conditions involving the ileocecal region
- Diverticulitis
- Malignancies
- Conditions affecting the epiploic appendages, omentum, and mesentery
- Miscellaneous conditions 2, 4, 5
Guidelines for Imaging
The American College of Radiology has appropriateness criteria for patients presenting with right lower quadrant pain, which can guide clinicians in ordering the most appropriate imaging study 6