Differential Diagnosis for Abdominal Pain in a 40-year-old Woman
- Single most likely diagnosis:
- Tubo-ovarian abscess (TOA): The patient's presentation of abdominal pain, fever, and an enlarged, tender right adnexal mass, along with the ultrasonography findings of a large, thick-walled, multiloculated mass filled with debris, is highly suggestive of a TOA. The patient's symptoms and the laboratory findings, including a high leukocyte count, further support this diagnosis.
- Other Likely diagnoses:
- Ovarian torsion: Although less likely given the presence of a mass, ovarian torsion could present with acute abdominal pain and a tender adnexal mass. However, the absence of severe, sudden onset pain and the specific ultrasonographic findings make this less likely.
- Ectopic pregnancy: Despite the negative urine pregnancy test, ectopic pregnancy should be considered in any woman of childbearing age presenting with abdominal pain and adnexal tenderness. However, the negative pregnancy test and the specific ultrasonographic findings make this less likely.
- Appendicitis: While appendicitis typically presents with right lower quadrant pain, the presence of an adnexal mass and the specific ultrasonographic findings point towards a gynecologic rather than a gastrointestinal cause.
- Do Not Miss diagnoses:
- Ruptured ectopic pregnancy: Although the urine pregnancy test is negative, a very early ectopic pregnancy could potentially not be detected by the test. The consequences of missing this diagnosis are severe, making it crucial to consider despite its lower likelihood.
- Ovarian cancer: While less common and not immediately suggested by the acute presentation, ovarian cancer can cause adnexal masses and should be considered, especially if the patient's condition does not improve with treatment for more likely causes.
- Septic abortion: Given the patient's sexual activity and the presence of abdominal pain and fever, septic abortion is a possibility, although the negative pregnancy test and regular menses make this less likely.
- Rare diagnoses:
- Adnexal tumor (e.g., dermoid cyst): While adnexal tumors can cause masses and pain, the acute presentation with fever and the specific ultrasonographic findings of a multiloculated mass filled with debris are more suggestive of an infectious process like TOA.
- Endometriosis: Although endometriosis can cause chronic pelvic pain and adnexal masses, the acute presentation with fever and the specific findings on ultrasonography are not typical for endometriosis.