Differential Diagnosis for Sudden Gush of Clear Vaginal Fluid in a Pregnant Woman
- Single Most Likely Diagnosis
- Premature Rupture of Membranes (PROM): This is the most likely diagnosis given the sudden gush of clear vaginal fluid, which is nitrazine-positive, indicating the presence of amniotic fluid. The patient's symptoms and the ultrasound finding of decreased amniotic fluid support this diagnosis.
- Other Likely Diagnoses
- Incompetent Cervix: Although the cervix is currently closed, a history of intermittent vaginal bleeding in the first trimester could suggest an incompetent cervix, which may lead to premature rupture of membranes or other complications.
- Vaginal Fistula: A possible, though less likely, cause of continuous leakage of clear fluid, which could be amniotic fluid if it communicates with the uterus.
- Do Not Miss Diagnoses
- Placenta Previa: Although the patient does not have vaginal bleeding at the moment, the history of intermittent vaginal bleeding in the first trimester necessitates considering placenta previa, especially since any vaginal bleeding in pregnancy can be a sign of this condition. Missing this diagnosis could lead to severe maternal and fetal complications.
- Uterine Rupture: Although the patient does not have abdominal pain, uterine rupture is a catastrophic event that must be considered, especially in a patient with a history of a previous vaginal delivery, as it can occur without significant warning signs.
- Rare Diagnoses
- Amniotic Fluid Embolism: This is a rare but potentially fatal condition where amniotic fluid enters the maternal circulation. The current presentation does not strongly suggest this, but it's a differential to keep in mind given the context of amniotic fluid leakage.
- Cervical or Uterine Anomalies: Certain congenital or acquired anomalies of the cervix or uterus could potentially lead to premature rupture of membranes or other complications. These would be rare causes but should be considered if other diagnoses are ruled out.