Differential Diagnosis
- Single most likely diagnosis + Abruptio placentae: This condition is characterized by the premature separation of the placenta from the uterus, which can cause severe abdominal pain, nausea, vomiting, and maternal hypotension. The patient's symptoms, including severe abdominal pain, nausea, vomiting, and hypotension, along with a rigid and tender uterus on examination, are consistent with this diagnosis. The fetal distress indicated by a heart rate of 100/min also supports this diagnosis.
- Other Likely diagnoses + Ruptured uterus: Although less likely given the patient's symptoms and the fact that her previous cesarean section was a lower segment transverse incision (which has a lower risk of rupture compared to a classical incision), it cannot be entirely ruled out without further investigation. The patient's history of a previous cesarean section and the current presentation of severe abdominal pain and uterine tenderness make this a consideration.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.) + Ruptured vasa previa: This is a condition where the fetal blood vessels, unsupported by the umbilical cord or placental tissue, are at risk of rupture. Although less common, it is critical to consider due to the high risk of fetal exsanguination. The patient's presentation of abdominal pain and fetal distress could potentially be related to this condition, especially if there were any issues with placental implantation or fetal vessel anatomy. + Umbilical cord prolapse: This condition, where the umbilical cord precedes the fetus in the birth canal, can cause fetal distress due to cord compression. While the patient is not in active labor, any condition causing significant uterine disturbance could potentially lead to cord prolapse, especially with the fetus at -1 station.
- Rare diagnoses + Chorioamnionitis: This condition, an infection of the fetal membranes, could present with maternal fever, uterine tenderness, and fetal distress. However, the patient's temperature is normal, making this diagnosis less likely. It remains a consideration in the differential due to the potential for rapid progression and severe consequences for both mother and fetus. + Placenta accreta spectrum (PAS) disorders: These conditions involve abnormal placental implantation and can cause severe antepartum hemorrhage or uterine rupture. While the patient's history and current presentation do not strongly suggest PAS, any condition causing significant uterine disturbance or maternal instability warrants consideration of these disorders, especially given the previous uterine surgery.