Ultrasound Features of Uterine Arteriovenous Malformation with Concomitant Uterine Dehiscence Presenting as Secondary Postpartum Hemorrhage: A Case Report.

BACKGROUND

Uterine arteriovenous malformation (UAVM) is a rare cause of vaginal bleeding but potentially life-threatening condition. Defined as an abnormal vascular communication characterized by a direct connection between the uterine arterial and venous system without any capillary network contribution. The main clinical presentation of UAVM is recurrent, severe bleeding refractory to medical treatment, particularly after surgical procedures on the uterus, such as cesarean section (CS) or curettage. Although definitive diagnosis is ideally established by pelvic angiography, ultrasonography (US), particularly color Doppler US, serves as a valuable noninvasive tool for the diagnosis of UAVMs. The management of UAVM becomes increasingly difficult due to the concomitant presence of uterine dehiscence. The diagnosis of uterine dehiscence can be established using transvaginal US.

CASE REPORT: A 29-year-old woman, Para 1, Abortus 0 (P1A0), presented with recurrent, massive vaginal bleeding that began 12 days after a cesarean delivery. On admission, she was two months postpartum following her most recent CS. We performed an US examination and revealed a small hypoechoic area within the myometrium adjacent to the CS scar site with hypervascular appearance, turbulent multidirectional flow, high velocity and low resistance flow, raising the suspicion for UAVM. From transvaginal US we also found a triangular indentation at the CS scar site measuring 10.9 mm in length and 7.5 mm in depth with adjacent myometrial thickness (AMT) 9.9 mm and no residual myometrial thickness (RMT) indicating cesarean scar defect (uterine dehiscence). Given the presence of severe vaginal bleeding refractory to medical treatment, hysterorrhaphy was performed to achieve hemostasis, repair the uterine defect, and preserve fertility.

CONCLUSION

Color Doppler US can rapidly and accurately establish the diagnosis of UAVM and uterine dehiscence, allowing prompt management of patients who present with heavy vaginal bleeding, often accompanied by hemodynamic instability.