Sonographic Diagnosis of Chronic Abruption

CASE REPORT CASE REPORT

Sonographic Diagnosis of Chronic Abruption Melissa Walker, MSc,1 Wendy Whittle, MD, PhD,1 Sarah Keating, MD,2 John Kingdom, MD1 1

Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto ON

2

Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, University of Toronto, Toronto ON

Abstract Background: Placental abruption is usually an acute event in which clinical decision-making overrides the need for ultrasound imaging. By contrast, chronic abruption may present with vague or even confusing clinical findings. We describe a case in which the diagnosis of chronic abruption was established by ultrasound and the findings directly influenced clinical care. Case: A 30-year-old woman with asymptomatic preeclampsia was evaluated in our fetal medicine unit at 30 weeks’ gestation. Despite normal fetal monitoring, a large, retroplacental sonolucent area was noted on ultrasound. A planned Caesarean section was performed two days later, despite normal daily fetal monitoring, because the mass had increased in size. Placental pathology confirmed the diagnosis of chronic abruption. Conclusion: Ultrasound may establish the diagnosis of a large chronic placental abruption that is relevant for clinical management.

Résumé Contexte : Le décollement placentaire constitue habituellement un événement aigu dans le cadre duquel la prise de décision clinique l’emporte sur la nécessité de procéder à une imagerie échographique. En revanche, le décollement chronique peut présenter des constatations cliniques vagues ou même déroutantes. Nous décrivons un cas dans le cadre duquel le diagnostic de décollement chronique a été établi par échographie et les soins cliniques ont été directement influencés par les constatations cliniques. Cas : Une femme de 30 ans présentant une prééclampsie asymptomatique a été évaluée au sein de notre unité de médecine e fœtale à la 30 semaine de gestation. Malgré un monitorage fœtal normal, la présence d’une large région anéchogène rétroplacentaire a été constatée à l’échographie. Une césarienne planifiée a été menée deux jours plus tard, malgré un monitorage fœtal quotidien normal, parce que les dimensions de la masse s’étaient accrues. La pathologie placentaire a confirmé le diagnostic de décollement chronique. Conclusion : L’échographie peut permettre de diagnostiquer la présence d’un important décollement placentaire chronique s’avérant pertinent pour ce qui est de la prise en charge clinique. Obstet Gynaecol Can 2010;32(11):1056–1058

Key Words: Placental abruption, abruption placentae, ultrasound, chronic Competing Interests: None declared. Received on June 23, 2010 Accepted on June 24, 2010

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INTRODUCTION

remature separation of the placenta before birth has a wide spectrum of clinical presentation and occurs in about 1% of pregnancies.1 Minor degrees of placental abruption cause slight vaginal bleeding, vague abdominal pain, or false preterm labour. More extensive placental separation leads to acute fetal distress associated with maternal shock due to substantial revealed and/or concealed blood loss. Ultrasonography is commonly employed at the bedside in a labour and delivery setting to exclude placenta previa in stable non-acute patients, but is rarely performed in unstable patients because the acute diagnosis is obvious.

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Many of the previously published case reports on placental abruption either did not include images2 or included images of poor quality3 or images obtained using B-scan ultrasonography,4–6 which is no longer used in clinical practice. In addition, images were often obtained prior to fetal viability (< 24 weeks).7,8 We present here the ultrasound findings in a confirmed case of chronic abruption. The sonographic images of the placenta led to admission and planned delivery by Caesarean section. THE CASE

A 30-year-old primigravid woman with no significant prior medical history was referred to our fetal medicine unit at 30+0 weeks’ gestation because of preeclampsia (blood pressure 148/99 with 4+ proteinuria on dipstick testing). Ultrasound examination revealed asymmetrical intrauterine growth restriction with an estimated fetal weight of 1218 g (10th percentile). Umbilical artery Doppler velocimetry was normal (pulsatility index [PI] = 1.05), but middle cerebral artery Doppler demonstrated blood flow redistribution (PI = 1.29). The biophysical profile was normal, but uterine artery Doppler was elevated (mean PI = 1.76). The placenta was anterior and thick (maximum depth 4.5 cm), and a central sonolucent area was noted measuring 4.7 cm × 1.6 cm (Figure 1A).This appeared to be located at the base of the placenta, and thus a chronic abruption was suspected. A non-stress test was reactive.

Sonographic Diagnosis of Chronic Abruption

Figure 1. Ultrasound images of chronic abruption obtained at admission (A) and immediately prior to delivery (B)

Figure 2. Pathology microscopy image of placenta stained with hematoxylin and eosin; scale bar represents 1 mm; H = hemorrhage

Placental pathology confirmed chronic retroplacental hemorrhage with a single focus of intraparenchymal blood clot measuring 4.5 cm × 3.2 cm × 3.7 cm. Microscopic evaluation revealed hemorrhage adjacent to the maternal surface with a zone of infarction of the adjacent villi (Figure 2). DISCUSSION

The patient was therefore admitted for daily monitoring, and received corticosteroids for fetal lung maturation (intramuscular betamethasone, 12 mg given twice 24 hours apart). Daily non-stress tests were reactive. A repeat ultrasound two days later showed a normal biophysical profile, but the umbilical artery Doppler was elevated (PI = 1.98). Placental ultrasound revealed extension in the dimensions of the suspected retroplacental clot to 6.3 cm × 2.2 cm (Figure 1B). The patient was transferred to the labour and delivery unit for a planned Caesarean section. On opening the uterus, a central, organized, dark retroplacental clot was found. A female infant weighing 1210 g (> 20th centile) and with normal Apgar scores was delivered. Umbilical cord arterial blood gases revealed pH = 7.26, pO2 = 3 mmHg, pCO2 = 53 mmHg, and base excess = –4.8 mmol/L. The infant was discharged from our neonatal intensive care unit to regional Level II care on day 14.

The diagnosis of placental abruption is important to establish, since prompt Caesarean section will avoid unnecessary maternal and/or perinatal morbidity or mortality. The most readily available imaging modality in a labour and delivery setting is a portable ultrasound machine, but if this is used several factors including image resolution, background lighting, and user skills may compromise the interpretation of findings.9 Normal placental variants, such as the marginal sinus draining blood back to the uterine veins or large lakes, may be mistaken for abruption.10 In view of these limitations with bedside ultrasound, coupled with the often acute presentation, it is understandable that ultrasound evaluation plays little role in the management of acute placental abruption. By contrast, chronic abruption may present in an ambulatory or subacute setting, where clinical findings (such as early-onset preeclampsia, intrauterine growth restriction, minor antepartum hemorrhage, or threatened preterm labour) would often lead to elective high-quality ultrasound. We suspected the diagnosis of a central, old abruption due to the position of this mass and its sonolucent NOVEMBER JOGC NOVEMBRE 2010 l 1057

CASE REPORT

characteristics, suggesting liquefied consolidated hemorrhage. The finding prompted admission and intensive fetal monitoring pending administration of a course of corticosteroids to promote fetal lung maturation at 30 weeks’ gestation. In the absence of this placental finding, we would likely have administered corticosteroids on an inpatient basis due to the preeclampsia, but would probably have discontinued daily clinical and non-stress test monitoring. This would have placed the fetus at risk of either subsequent asphyxia from an acute extension of the abruption or intrauterine fetal death from a more gradual extension of the lesion. CONCLUSION

Recognition and diagnosis of a significant central old abruption led to hospital admission, intensive daily fetal monitoring, corticosteroid administration, and a favourable outcome following planned delivery by Caesarean section. ACKNOWLEDGMENTS

The woman whose story is told in this case report has provided written consent for its publication.

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