Differential Diagnosis for Vaginal Bleeding in a 17-year-old Primigravida
- Single most likely diagnosis
- Incomplete miscarriage: This diagnosis is the most likely due to the presence of an open cervical os with the gestational sac protruding through the cervix, indicating that the miscarriage process has begun but is not yet complete. The transvaginal ultrasound showing a viable intrauterine pregnancy with a crown-rump length corresponding to 9 weeks' gestation and a positive heartbeat supports the notion that the pregnancy was initially viable, but the clinical presentation suggests an incomplete miscarriage.
- Other Likely diagnoses
- Threatened miscarriage: Although less likely given the open cervical os and protruding gestational sac, a threatened miscarriage could still be considered if the bleeding were minimal and the cervar was closed. However, the clinical findings in this case are more suggestive of an incomplete miscarriage.
- Septic miscarriage: This could be a consideration if there were signs of infection such as fever, abdominal pain, or foul odor, which are not mentioned in the scenario provided. The presence of infection would significantly alter the management approach.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Ectopic pregnancy: Although the ultrasound shows an intrauterine gestational sac, an ectopic pregnancy cannot be entirely ruled out without considering the possibility of a heterotopic pregnancy (especially in the context of known risk factors or in the future with assisted reproductive technologies). This diagnosis is critical to consider due to its potential for severe morbidity and mortality.
- Molar pregnancy: While less common, a molar pregnancy could present with vaginal bleeding and should be considered, especially if there were unusual ultrasound findings or significantly elevated beta-hCG levels.
- Rare diagnoses
- Anembryonic pregnancy (bladder pregnancy): Given the ultrasound findings of a viable intrauterine pregnancy, this diagnosis is less likely. Anembryonic pregnancy refers to a condition where the gestational sac develops without an embryo, which does not align with the provided ultrasound results showing a positive heartbeat.
- Placenta previa or placental abruption: These conditions could cause vaginal bleeding but are less likely given the early gestational age and the specific findings of an open cervical os with a protruding gestational sac. They are more commonly associated with later gestational ages and different clinical presentations.