Differential Diagnosis for Prolonged Bleeding, Late Period, and Left Iliac Fossa Pain on Progesterone-Only Contraception with Positive Pregnancy Test
- Single Most Likely Diagnosis
- Ectopic pregnancy: This is the most likely diagnosis given the combination of a positive pregnancy test, prolonged bleeding (which could be indicative of a failed or failing pregnancy), late period (suggesting a disruption in the normal menstrual cycle possibly due to an ectopic pregnancy), and left iliac fossa pain (which could be due to an ectopic pregnancy implanting in the left fallopian tube). The use of progesterone-only contraception does not completely rule out pregnancy, and ectopic pregnancies can still occur.
- Other Likely Diagnoses
- Ovarian cyst rupture or torsion: These conditions can cause acute pain in the lower abdomen, including the left iliac fossa, and can be associated with irregular bleeding. A positive pregnancy test could be due to an early intrauterine pregnancy or a very early ectopic pregnancy, but ovarian pathology should be considered, especially if there's significant pain.
- Threatened or incomplete abortion: Given the positive pregnancy test and prolonged bleeding, a threatened or incomplete abortion could be considered, especially if the pregnancy is intrauterine but not viable. The left iliac fossa pain could be due to uterine cramping.
- Do Not Miss Diagnoses
- Ruptured ectopic pregnancy: This is a medical emergency that requires immediate attention. The symptoms provided could be indicative of a ruptured ectopic pregnancy, which would present with severe abdominal pain, potentially life-threatening bleeding, and could lead to shock.
- Ovarian torsion: While less likely than ectopic pregnancy given the positive pregnancy test, ovarian torsion is a surgical emergency that can cause severe pain and requires prompt intervention to save the ovary.
- Rare Diagnoses
- Corpus luteum cyst rupture: This could cause acute abdominal pain and some bleeding, but it's less likely given the positive pregnancy test and the specific combination of symptoms.
- Molar pregnancy with ectopic component: Extremely rare, but could present with abnormal uterine bleeding, a positive pregnancy test, and potentially abdominal pain if there's an ectopic component or associated complications.