Diagnosis of Acquired Uterine Arteriovenous Malformation by Doppler Ultrasound

BackgroundAcquired uterine arteriovenous malformation (AVM) is a rare cause of postpartum vaginal bleeding and can often be confused with retained products of conception (RPOC). Certain findings on ultrasound (US) increase the likelihood for AVM, such as hypoechoic areas in the myometrium and high velocity, multidirectional blood flow. Recognizing these changes on bedside US can cue the physician to send the patient for further studying and lead to the correct diagnosis.Case ReportA 31-year-old, multigravida, multiparous female presented 5 weeks post–cesarean section with heavy, intermittent vaginal bleeding. Patient had multiple previous visits for similar bleeding, including an evaluation for RPOC. Upon current presentation, the patient underwent an US in the emergency department with color and pulse wave Doppler. US revealed a hypoechoic area within the myometrium, with high velocity, bidirectional blood flow, raising the clinical suspicion for uterine AVM. Following confirmatory studies, the patient underwent successful embolization of the AVM.Why Should an Emergency Physician Be Aware of This?The proper diagnosis of AVM is crucial, because the primary treatment modality for the alternative diagnosis of RPOC (i.e., dilation and curettage) can worsen vaginal bleeding and lead to shock or death, and is therefore contraindicated for uterine AVM. US is a quick bedside tool that can be used for rapid diagnosis of uterine AVM.