Question

A 26-year-old G0 woman presents with severe right lower quadrant pain associated with nausea for the last six hours, which began shortly after she finished her aerobic exercises. She has a history of suspected endometriosis, which was diagnosed two years ago, based on her severe dysmenorrhea. She has been using NSAIDs during her menses to control the pain. She is not sexually active, and is otherwise in good health. Her menstrual cycles are regular and her last menstrual period was three weeks ago. She has no history of sexually transmitted infections. Her vital signs are: blood pressure 145/70; pulse 100; temperature 99.2°F (37.3°C). She appears uncomfortable. On abdominal examination, she has moderate tenderness to palpation in the right lower quadrant. On pelvic exam, she has no lesions or discharge. A thorough bimanual exam was difficult to perform due to her discomfort. Beta-hCG <5 mIU/ml and WBC is 8,500 /microliter. A pelvic ultrasound showed a 6 cm right ovarian mass. The uterus and left ovary appeared normal. There was a moderate amount of free fluid in the pelvis. What is the most likely diagnosis in this patient?

A. Appendicitis
B. Exacerbation of the endometriosis
C. Ovarian carcinoma
D. Ovarian torsion
E. Ectopic pregnancy

Answer 1

D. Ovarian torsion

The most likely diagnosis for a 26-year-old woman with severe right lower quadrant pain and a pelvic ultrasound showing a 6 cm right ovarian mass and free pelvic fluid is ovarian torsion, which is a medical emergency.

Step-by-step explanation:

Based on the case of a 26-year-old G0 woman presenting with severe right lower quadrant pain, nausea, and a history of suspected endometriosis, the most likely diagnosis is ovarian torsion.

Given the acute onset of symptoms post-exercise, an ovarian mass on ultrasound, and the presence of free fluid in the pelvis, these findings are suggestive of this condition. Ovarian torsion is a medical emergency caused by the rotation of the ovary on its ligamentous supports, which can lead to infarction.

The negative beta-hCG rules out ectopic pregnancy, while there are no signs of infection or systemic symptoms that would indicate appendicitis or pelvic inflammatory disease. The absence of sexual activity also decreases the likelihood of sexually transmitted diseases affecting the ovaries.

Although endometriosis could cause cysts and chronic pain, the acute presentation with a 6 cm mass is more indicative of torsion. Ovarian carcinoma is typically a diagnosis of exclusion and is less likely given the patient's age and acute symptom onset.