A 21-year-old woman who is 12 weeks pregnant according to the date of her last menstrual period comes to the emergency department with shortness of breath and chest pain.
One week ago she began experiencing pre-syncope and shortness of breath on minimal exertion and then even at rest on most days. The shortness of breath worsened throughout the week, eventually limiting her daily activities to such a degree that she restricted herself to bed rest.
Her chest pain started today while she was sitting in church, without any apparent provocation. It is right-sided, sharp, and focal, and it does not radiate. At the same time, her shortness of breath was more severe than before, so she immediately came to the emergency department.
This is her third pregnancy; she has had one live birth and one abortion. Her last pregnancy was full-term, with routine prenatal care and no complications. However, so far during this pregnancy, she has had no prenatal care, she has not taken prenatal vitamins, and she has been unable to maintain adequate nutrition because of persistent emesis, which began early in her pregnancy and continues to occur as often as two or three times daily. She has lost 20 pounds over the past 12 weeks.
She says she has no close contacts who are sick, and she has had no fever, diarrhea, dysuria, urinary frequency or urgency, palpitations, swelling of the legs or feet, blurry vision, or increase in neck girth. She says she does not smoke or use alcohol or illicit substances. Her only previous surgery was laser-assisted in situ keratoplasty (LASIK) eye surgery in 1998. She is allergic to seafood only. She has not eaten at any new places recently. She is up to date with her childhood vaccinations. She has no family history of hypercoagulability or venous thrombotic events.
She is breathing rapidly—as fast as 45 breaths per minute. Her temperature is 37.2°C (98.9°F), blood pressure 95/60 mm Hg, oxygen saturation 100% while on 10 L of oxygen using a nonrebreather mask, pulse 102 beats per minute, and weight 55.9 kg (123.2 pounds). She appears alert, oriented, and comfortable, with a thin body habitus. She has no jugular venous distention, neck mass, or thyromegaly. Her lungs are clear to auscultation, with no wheezes or rales. The cardiovascular examination is normal. She has a regular heart rate and rhythm, normal S1 and S2 sounds, and no rubs, clicks, or murmurs. Pulses in the extremities are normal, and she has no peripheral edema. The neurologic examination is normal.
Electrocardiography shows sinus tachycardia with first-degree atrioventricular block.
1. At this point, which is the most probable cause of her symptoms?
- Pulmonary embolism
- Peripartum cardiomyopathy
- Acute coronary syndrome
- Aortic dissection
- Expected physiologic changes of pregnancy
Pulmonary embolism would be the most probable diagnosis, given the patient’s pregnancy, shortness of breath, and tachycardia and the pleuritic quality of her chest pain.
Peripartum cardiomyopathy is also a possible cause, as it may present with profound shortness of breath and markedly decreased cardiac function. But it is much less likely in this patient because she is early in her pregnancy, and peripartum cardiomyopathy usually is seen during the last month of gestation or the first months after delivery.
Acute coronary syndrome is unlikely, given her young age and the lack of significant risk factors or a supporting history.
Aortic dissection is unlikely in view of her medical history.
Physiologic changes of pregnancy. Many pregnant women experience a sensation of not being able to catch their breath or expand their lungs fully, as the diaphragm is limited by the gravid abdomen. They also present with dyspnea, fatigue, reduced exercise capacity, peripheral edema, or volume overload.1 However, these changes tend to occur gradually and worsen over time. This patient’s degree of shortness of breath and its sudden onset do not seem like normal physiologic changes of pregnancy.
Other possible causes of dyspnea in a pregnant woman include asthma, pleural empyema, pneumonia, and severe anemia. Asthma should be considered in anyone with a history of wheezing, cough, and dyspnea. Fever and sputum production would support a diagnosis of pneumonia or empyema. In addition, maternal heart disease (eg, endocarditis, pulmonary hypertension) complicates 0.2% to 3% of pregnancies.1
The emergency department staff decide to evaluate the patient for heart failure and pulmonary embolism.
Bedside echocardiography reveals an ejection fraction of 55% (normal range 50%–75%), normal heart function and size, and no valvular abnormalities.
Chest radiography is normal.
Lower-extremity duplex ultrasonography is negative for deep-vein thrombosis.
The D-dimer level is 380 ng/mL (normal range < 500 ng/mL).
The medical intensive care unit is consulted about the patient’s continued tachypnea and the possible need for intubation. A ventilation-perfusion scan is performed to screen for pulmonary embolism, and it is negative.
An obstetric team performs Doppler ultrasonography at the bedside; a fetal heartbeat can be heard, thus confirming a viable pregnancy.
The patient has normal serum levels of the cardiac enzymes troponin T and creatine kinase-MB fraction, thus all but ruling out myocardial ischemia.
The patient is admitted to the hospital the next day, and a cardiology consult is obtained.