Differential Diagnosis for 20-year-old Female with Severe Pelvic Pain, Palpitations, and High-grade Fever

• Single most likely diagnosis:

  • Toxic Shock Syndrome (TSS): This condition is highly suspected due to the patient's symptoms of severe pelvic pain, high-grade fever, palpitations, and the recent introduction of tampons. The presence of a retained tampon, which was subsequently removed, further supports this diagnosis, as TSS is known to be associated with tampon use, especially if a tampon is left in place for an extended period.

• Other Likely diagnoses:

  • Pelvic Inflammatory Disease (PID): Although the patient reports not being sexually active, PID could still be considered, especially if there's a possibility of sexual activity that was not disclosed. However, the absence of sexual activity and the presence of a tampon make TSS more likely.
  • Septic Shock: The patient's high fever, tachycardia, and severe pain could also suggest septic shock, possibly due to an infection. The removal of the tampon and the context of the symptoms, however, point more directly to TSS.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed):

  • Ectopic Pregnancy: Although the patient denies sexual activity, it's crucial to consider ectopic pregnancy due to its potentially fatal outcome if missed. A pregnancy test should be performed to rule out this possibility.
  • Ovarian Torsion: This is a surgical emergency that can present with severe pelvic pain. Although less likely given the context of tampon use and fever, it's essential to consider due to its urgency.
  • Appendicitis: While the pain is pelvic, appendicitis can sometimes present with pain that might be confused with pelvic pathology, especially if the appendix is located in a retrocecal position.

• Rare diagnoses:

  • Endometriosis: Although endometriosis can cause severe pelvic pain, it is less likely to cause the acute onset of symptoms described, especially in conjunction with fever and palpitations.
  • Hematometra or Hematocolpos: These conditions involve the accumulation of blood in the uterus or vagina, respectively, and can cause severe pain. However, they are less likely given the acute presentation and the presence of systemic symptoms like fever and tachycardia.