Differential Diagnosis
- Single most likely diagnosis
- Pelvic Inflammatory Disease (PID): The patient's symptoms of lower abdominal pain, nausea, vomiting, fever, and purulent discharge from the cervical os, along with the physical examination findings of a tender uterus and adnexa, are highly suggestive of PID. The patient's history of being sexually active and having multiple partners also increases the risk of PID.
- Other Likely diagnoses
- Appendicitis: Although the patient's symptoms and physical examination findings are more suggestive of PID, appendicitis is still a possible diagnosis, especially given the diffuse tenderness over the lower quadrants of the abdomen.
- Ovarian torsion: The patient's severe abdominal pain and tenderness, along with the adnexal tenderness, could be indicative of ovarian torsion, although the lack of a palpable mass makes this less likely.
- Ectopic pregnancy: Although the urine pregnancy test is negative, it is still possible for the patient to have an early ectopic pregnancy, especially if the test was done too early.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Ruptured ovarian cyst: A ruptured ovarian cyst can cause severe abdominal pain and tenderness, and can be life-threatening if not promptly treated.
- Septic abortion: Although the patient's last menstrual period was 15 days ago and the urine pregnancy test is negative, it is still possible for the patient to have had a septic abortion, especially if she had a miscarriage or an incomplete abortion.
- Perforated viscus: A perforated viscus, such as a perforated appendix or intestine, can cause severe abdominal pain and tenderness, and can be life-threatening if not promptly treated.
- Rare diagnoses
- Endometriosis: Although endometriosis can cause abdominal pain and tenderness, it is less likely to cause the severe symptoms and physical examination findings seen in this patient.
- Tubo-ovarian abscess: A tubo-ovarian abscess is a possible complication of PID, but it is less likely to be the primary diagnosis in this patient, given the lack of a palpable mass.