Rupture of Uterine Arteriovenous Malformation as a Cause of Severe Menorrhagia

Abstract

Menorrhagia is a common disorder during the reproductive age. It often results from myometrial or endometrial lesions. Menorrhagia caused by uterine arteriovenous malformations (AVMs) is a rare but life-threatening event. The major presentation of uterine AVMs is characterized by painless, intermittent, abrupt and profuse vaginal bleeding that is usually refractory to medical treatment [1]. The appropriate management of AVMs relies considerably on accurate diagnosis [2]. In order to achieve a prompt diagnosis, it is essential to raise a clinical suspicion of uterine AVMs in patients with unaccountably intractable vaginal hemorrhage with specific bleeding characteristics. The patient was a 38-year-old woman, gravida 2, para 2 (via cesarean section twice). Her last cesarean delivery was twelve years prior to this presentation, and her menstrual cycle had been regular without any experience of excessive menstrual flow after the delivery. She came to the emergency department complaining of sudden intermittent, painless and profuse vaginal bleeding with blood clots on the seventh day of her period. Vaginal spotting was the only unusual sign shortly before the event. She denied having any underlying hematologic disorders or drug exposure such as hormonal therapy. Pelvic sonography showed thin endometrium without definite uterine tumors (Figure 1). On pelvic examination, the appearances of the uterine cervix and vagina were grossly normal without traumatic lesions or tumor formations. However, there was intermittent flow of blood gushing out from the endocervical canal, and the amount of blood loss was approximately 500 mL within minutes. Results of coagulation studies were within normal limits, and urine β-hCG test was negative. Immediate hemodynamic resuscitation was done, with intravenous fluids supplement and blood component therapy. The hemorrhage was not responsive to intravenous medicines such as transamines (oxytocin) and uterotonics (methylergonovine). Subsequently, uterine tamponade with a Foley balloon was performed, and the bleeding gradually decreased. Eleven hours after the balloon tamponade, she experienced a gush of profuse vaginal bleeding again. As uterine AVMs were suspected, pelvic angiography was recommended for further diagnosis and treatment; however, the patient refused. Finally, the couple opted for surgical hysterectomy to avoid the possible failure of conservative treatment. Gross examination of the uterine cavity revealed one small vascular clump with laceration at the right isthmus (Figure 2A), and a well-defined hemorrhagic lesion was found at the isthmus of the formalin-fixed uterine wall (Figure 2B). Microscopic examination of the right isthmus showed dilated and tortuous vessels with mixed thick and thin vascular walls, which was consistent with uterine AVMs (Figure 3). The hospital course of the patient before the hysterectomy is summarized in the Table. The postoperative course was uneventful, and she was discharged on the fourth postoperative day. During her hospitalization, she was transfused with