Differential diagnosis
The differential diagnosis of abdominal pain in a gravid patient includes placental abruption, cholecystitis, pancreatitis, appendicitis, intussusception, pyelonephritis, round ligament syndrome, hydronephrosis, ovarian torsion, uterine fibroid degeneration, ovarian cysts or tumors, intra-abdominal and rectus muscle abscesses, and Crohn’s disease with diffuse peritoneal inflammation. Given the location of the pain and the lack of vaginal bleeding, the most likely diagnoses are cholecystitis and appendicitis.
Making the diagnosis
We performed several laboratory analyses, including a complete blood count, chemistry panel (including electrolytes and liver function studies), amylase, lipase, and a urinalysis. The test results were all normal. She had a white blood cell count of 15,000/μL, which can be normal in pregnancy. The initial evaluating physician had obtained a right upper quadrant ultrasound, which showed no gallstones or bilateral hydronephrosis; unfortunately, no attempt was made to visualize the right lower quadrant or appendix at that time.
In light of the physical exam findings and the absence of gallstones, the patient was admitted to rule out appendicitis. The surgery team at the university hospital was consulted. They requested a computed tomography (CT) scan of the abdomen with and without contrast. To avoid the risk of radiation to the fetus, the family medicine team spoke with Radiology to obtain another ultrasound.
The ultrasound showed an enlarged and inflamed appendix with a transverse diameter of 13 mm (normal is <6 mm) (FIGURES 3 AND 4).1 A graded compression technique was used to assess the appendix. This involves using pressure of the ultrasound probe starting above the area of tenderness and working toward the tender area while scanning for the appendix. This showed obvious peristalsis in the cecum and no movement within the appendix, indicating obstruction or inflammation.
FIGURE 3
Appendix: Longitudinal view
FIGURE 4
Appendix: Transverse view
