The Case

A 35-year-old woman, 38 weeks pregnant, presented to the emergency department (ED) in the middle of the night complaining of left leg pain. She also had some mild lower back pain, but no other symptoms. Hospital policy stated that all patients greater than 20 weeks’ gestation should go directly to labor and delivery unless their problem was clearly unrelated to the pregnancy. At ED triage, the pain was deemed to be non-obstetrical in nature, and so she was evaluated in the ED rather than being sent to labor and delivery.

Physical examination revealed her left leg was slightly cooler than the right leg but was otherwise unremarkable. A Doppler venous ultrasound revealed no evidence of deep venous thrombosis, but there appeared to be decreased blood flow to the leg in the left-lying position with normal blood flow in other positions. After many hours of evaluation and observation in the ED, the pain was diagnosed as musculoskeletal. To facilitate evaluation by her obstetrician, she was transferred briefly to labor and delivery. Fetal monitoring was normal and the patient was discharged home.

The following morning, the patient’s husband found her dead at home. An emergency cesarean section was performed in the ED, but both the mother and the infant expired. Autopsy revealed a ruptured aortic dissection.

The Commentary

This case illustrates the frequent challenges that practitioners and institutions face in caring for pregnant women, who often present to EDs with complaints that may or may not be obstetrical in nature. Optimal evaluation of a pregnant woman with a non-obstetrical complaint requires an understanding of the physiology of pregnancy and possible pregnancy-related conditions. Just as essential, though, are a structured, systematic approach to caring for these patients, and open, clear lines of communication between obstetrical and emergency physicians.

Although aortic dissection is an uncommon disorder in a woman of childbearing age, it is a potentially lethal condition and so it should be kept in mind in patients with compatible presentations. In this case, the diagnostic challenges were made even greater by a relatively unusual presentation, even for a disease that often presents with non-specific symptoms and signs. Aortic dissection is thought to result from a tear in the intima of the aorta often associated with degeneration of the media from age or other predisposing conditions. Young women who do develop aortic dissection generally have a risk factor for the disease, such as Marfan’s syndrome, Ehlers-Danlos syndrome, hypertension, or bicuspid aortic valve. Pregnancy has been considered by many to be a risk factor, and some have estimated up to half of all dissections in women younger than 40 occur during pregnancy, typically in the third trimester.(1) A recent review suggests that pregnancy’s role as a risk factor may be overstated.(2,3)

The clinical presentation of aortic dissection varies and depends on the location and acuity of the dissection. Of more than 1,000 patients with aortic dissection included in a large registry, 76% of patients had chest pain as a presenting symptom, 55% had back pain, and 18% had migrating pain.(4) The mediastinum was widened on chest radiograph in 60%.(4) The pain is often described as ripping or tearing in nature. Ten percent of patients present with isolated leg ischemia as the initial symptom of an aortic dissection.(5) The location of the pain may help determine the location of the dissection (e.g., anterior chest pain is associated with dissection of the ascending aorta, neck and jaw pain with the aortic arch, pain in the interscapular area with the descending thoracic aorta, and pain in the lumbar area or abdomen with involvement below the diaphragm). When the integrity of one of the branches of the aorta is compromised, ischemic manifestations usually follow.(1) Dissection into the iliac or femoral artery probably caused this patient’s leg pain.

Little published data describe the clinical presentation of aortic dissection in pregnancy. The presentation of aortic dissection with initial symptoms of chest or back pain is similar between genders, though some suggest that dissection in women may be less likely to present with abrupt onset of pain.(6) Pregnancy-related dissection was rare in a group of more than 300 women with aortic dissection.(2) Degeneration of the collagen and elastin in the aortic media is considered a predisposing factor for dissection. This, together with increased wall stress from hypertension or valvular abnormalities (bicuspid aortic valve), is presumed to lead to intimal tear and dissection. Hypertension has been associated with 25% to 50% of cases of aortic dissection in pregnant women. The proximal aorta is the most common site of pregnancy-associated aortic dissection, with an intimal tear originating within 2 cm of the aortic valve in 75% of cases.(7) The aortic tear commonly occurs during the third trimester or during the first stage of labor.(8) It should be noted, though, that maternal and fetal mortality from aortic dissections in pregnancy have decreased substantially in the past two decades.(1)

Given its rarity and this atypical presentation, it is not entirely surprising that the diagnosis of dissection was missed in this patient. Nevertheless, some problems occurred in the triage and early management of this patient, and they help shine some light on more general safety issues regarding caring for pregnant patients with both obstetrical and non-obstetrical medical conditions. Five general principles should be addressed when developing a systematic approach to triage, evaluation, and management of urgent conditions that occur during pregnancy.

1. Presenting Complaint Pregnant women can present with a myriad of complaints, making appropriate triage challenging. Complaints that clearly are obstetrical (e.g., episodic lower abdominal pain consistent with uterine contractions) should be triaged directly to the labor and delivery unit. However, presenting complaints that are non-obstetrical in nature or not clearly obstetrically related (e.g., chest pain, acute shortness of breath, leg pain) should be triaged depending upon the individual institution’s resources, consultant availability, and access to diagnostic testing. For example, a pregnant patient with acute chest pain or sudden shortness of breath may be more appropriately evaluated in the ED where there is often better access to diagnostic imaging than in labor and delivery. In contrast, pregnant patients in the second or third trimester with pregnancy-related complaints would be better served with an evaluation in labor and delivery. In either situation, clear communication between the emergency physician and obstetrician is important. Some examples of presenting complaints in pregnant women are included in Table 1 and may help guide an institution in developing a triage policy.
2. Availability of Consultant/Clinical Expertise For obstetrically related issues, the availability of consultants and clinical expertise typically resides within labor and delivery. However, in other circumstances, such as presentation with leg pain, the expertise of the emergency physician and the rapid availability of consultants may make the ED a more appropriate setting for evaluation. Depending upon the health system’s structure, these resources may be equally available in the labor and delivery setting. Local administrators and clinical leaders should carefully evaluate their own consultant availability to determine how best to develop the system for triage depending upon availability of consultant and clinical expertise.
3. Timeliness of Testing Access to advanced imaging and testing should also help guide the development of institutional policies. In many settings, diagnostic testing such as computed tomography (CT) scanning or ultrasound is most expeditiously performed through the ED, whereas in others, an inpatient unit such as labor and delivery may be most effective. Exposure to radiation has always been a special concern during pregnancy. Fetal exposure is generally not a concern until 5 Rads (5000 mRad) of exposure has occurred. A CT scan of the abdomen typically results in 150-200 mRad fetal exposure, whereas a CT of the abdomen and pelvis delivers approximately 2000 mRad to the fetus.(9) In other words, concern about fetal radiation should not stand in the way of appropriate diagnostic evaluation.
4. Need for Fetal Evaluation Most pregnant women with urgent or emergent complaints, unless clearly of no threat to the fetus, will undergo formal fetal monitoring. In most circumstances, fetal evaluation is done most expeditiously and thoroughly in a labor and delivery setting. However, maternal circumstances sometimes require prolonged stay in an ED (e.g., evaluation of multiple system trauma). In those circumstances, depending upon the viability of the fetus and the capabilities of the individual health system, arrangements for fetal evaluation should be made in the ED. Policies should be developed to assure the availability of appropriate clinical skills and equipment for continuous fetal monitoring in the ED when needed. Every ED should have the capacity to assess fetal heart rate, at a minimum by handheld Doppler. In an ED where a pregnant woman may require a prolonged stay, a protocol to provide fetal monitoring with appropriately trained personnel interpreting the monitor tracings should be developed. This can be accomplished by having a fetal monitor and labor and delivery nurse come to the ED, or, as in our institution, fetal monitoring initiated in the ED with remote interpretation of the monitor in labor and delivery.
5. Gestational Age at Presentation Some diagnoses are limited to certain timeframes in pregnancy and must be considered in the initial evaluation. For example, ectopic pregnancies most commonly occur between 5 and 10 weeks’ gestational age. However, they may occur as late as 14 to 15 weeks in interstitial (cornual) pregnancy. Women who present at or near the point of fetal viability (approximately 23 to 24 weeks) require special consideration, because they could require immediate fetal evaluation and potential delivery. Building a policy for triage and transfer between the ED and labor and delivery requires consideration of gestational age. For example, if a pregnant woman at 22 weeks’ gestational age presents to the ED with vaginal bleeding and has stable vital signs, she would be transferred to labor and delivery (see Table 2, scenario III). Nursing-to-nursing communication should take place at the time of transfer to assure transmission of information (presenting complaint, vital signs, etc.).

The University of Michigan (a tertiary referral center) has developed a triage protocol for obstetrical patients presenting to the ED (Table 2). In the present case, the patient would fall into Category V (medical complaint not related to pregnancy, greater than 20 weeks' gestation) and would be evaluated in the ED. Careful attention to the differential diagnosis, appropriate consultation and the judicious use of diagnostic testing (e.g., CT scan) might have detected the aortic dissection before the discharge and subsequent tragic outcome. When resources and consultants are available, this system works well, but it would not work as well for a hospital without available obstetrical consultants. Nevertheless, even in such hospitals, it can be used as a general guide in developing institutional policies.

The mother and fetus in this case suffered a tragic outcome at a hospital that appeared to lack a structured protocol for triaging obstetric patients. It is unclear whether the outcome would have been different elsewhere. This case highlights the need to create clear guidelines for urgent management of pregnant patients and to maintain clear lines of communication between providers.

Take-Home Points

• Aortic dissection is a rare complication of pregnancy but carries substantial risk of morbidity and mortality.
• Institutions should establish structured protocols for the triage of obstetrical patients presenting with emergency complaints.
• In developing protocols, hospitals must consider many factors, including the nature of the complaints, consultant and testing availability, the need for fetal monitoring, and the fetal age.

Mark D. Pearlman, MD Professor and Vice Chair, Department of Obstetrics and Gynecology Professor of Surgery University of Michigan Medical Center

Jeffrey S. Desmond, MD Clinical Assistant Professor and Service Chief Department of Emergency Medicine University of Michigan Medical Center

References

1. Lewis S, Ryder I, Lovell AT. Peripartum presentation of an acute aortic dissection. Br J Anaesth. 2005;94:496-499. [ go to PubMed ]

2. Nienaber CA, Fattori R, Mehta RH, et al. Gender-related differences in acute aortic dissection. Circulation. 2004;109:3014-3021. [ go to PubMed ]

3. Oskoui R, Lindsay J Jr. Aortic dissection in women go to PubMed ]

4. Januzzi JL, Marayati F, Mehta RH, et al. Comparison of aortic dissection in patients with and without Marfan's syndrome (results from the International Registry of Aortic Dissection). Am J Cardiol. 2004;94:400-402. [ go to PubMed ]

5. Pacifico L, Spodick D. ILEAD--ischemia of the lower extremities due to aortic dissection: the isolated presentation. Clin Cardiol. 1999;22:353-356. [ go to PubMed ]

6. Konishi Y, Tatsuta N, Kumada K, et al. Dissecting aneurysm during pregnancy and the puerperium. Jpn Circ J. 1980;44:726-33. [ go to PubMed ]

7. Immer FF, Bansi AG, Immer-Bansi AS, et al. Aortic dissection in pregnancy: analysis of risk factors and outcome. Ann Thorac Surg. 2003;76:309-314. [ go to PubMed ]

8. Khan IA, Nair CK. Clinical, diagnostic, and management perspectives of aortic dissection. Chest. 2002;122:311-328. [ go to PubMed ]

9. Goodsitt MM, Christodoulou EG. Diagnostic imaging during pregnancy: risks to the fetus. In: Pearlman MD, Tintinalli JE, Dyne PL, eds. Obstetric and Gynecologic Emergencies: Diagnosis and Management. New York, NY: McGraw-Hill; 2004:535-548.

Tables

Table 1. Case Examples

Table 2. Triage Guidelines for Obstetrical Patients Presenting to the Emergency Department (Adapted from University of Michigan Hospitals and Health Centers Emergency Department Guidelines)

All patients who present to emergency department triage will have a triage assessment completed and documented prior to labor and delivery (L&D) transfer