Article, Radiology

Saddle pulmonary emboli mimicking pulmonary artery dissection

Case Report

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American Journal of Emergency Medicine

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American Journal of Emergency Medicine 33 (2015) 127.e1-127.e3

Saddle pulmonary emboli mimicking pulmonary artery dissection

Abstract

Pulmonary embolism (PE) can be a potentially fatal condition and requires early diagnosis. It is a frequently underdiagnosed, under- estimated, and undertreated disease because of various features and nonspecific clinical presentation. Laboratory D-dimer test, lung scan, and echocardiography can help in making the diagnosis. Recently, computed tomography has been most common used for the diagnosis. We report a case of pulmonary embolism mimicking pulmonary artery dissection by initially using images from computed tomography. Further evaluation of the computed tomographic images using coronal plane confirmed the diagnosis of pulmonary embolism. Because the treatment modalities are completely differ- ent between the 2 diseases, we emphasize that 2 different orthogonal planes are necessary for diagnosis using computed tomographic image examination.

In the case study presented, a 75-year-old man was presented with blood-tinged sputum and increasing shortness of breath after minimal exertion for nearly 1 week. He denied having any coughing, wheezing, fever, nausea, or vomiting and had neither a habit of smoking nor drinking. However, he had a medical history of hypertension requiring regular medication and 10 years ago had undergone a surgical management procedure for gastric cancer treatment. Chest x-ray showed normal heart size, mildly enlarged bilateral hilar shadows, and slight blurring of right costophrenic (CP) angle (Fig. 1). He received chest ultrasonography, as a small pleural effusion was suspected. The results revealed negative findings except pure pleural effusion. Thoracentesis was not performed because of the little amount of pleural effusion that has been detected. A week later, the patient was presented to our emergency department with a worsening shortness of breath. On examination, he was afebrile, his blood pressure was 168/88 mm Hg, pulse rate was 130 beats per minute, and oxygen saturation was 99% as measured using the Pulse oximeter. Physical examination did not reveal any abnormalities. His electrocardiogram revealed sinus tachycardia with a rate approximately 120 beats per minute. The laboratory Blood results showed a hemoglobin level of 13.1 g/dL and white cell count of 8500 cells/uL. Liver function tests, urea and electrolytes, inflammatory markers, and coagulation profile were normal, whereas the D-dimer test was 10.46 mg/L (reference range, N 0.55). A chest computer tomography (CT) was arranged. The results revealed a contrast filling defect extending left pulmonary trunk to Right pulmonary artery mimicking intimal flap formation and associated with thrombi formation (Fig. 2). However, further evaluation by coronal plane CT images clearly demonstrates a saddle embolus completely occluding the right pulmonary artery, extending through the main pulmonary artery segment to involve the left pulmonary artery (Fig. 3).

Pulmonary embolism has a wide spectrum of clinical presentations

and is a frequently underestimated and underdiagnosed disease. In

acute pulmonary embolism, clinical presentation is variable and includes shortness of breath, chest pain, and even hemodynamic instablility. It can be a potential fatal condition and requires early assessment and management, especially in those who are hemody- namically unstable. However, misdiagnosis is frequent because of various features and nonspecific clinical presentation. In our case, the patient’s initial chest x-ray showed mildly enlarged bilateral hilar shadows, and slight blurring of right CP angle raised the initial suspicion of pulmonary embolism. In a retrospective study of 230 consecutive patients with PE, approximately one-third patients presented with small Pleural effusions, mostly unsuitable for diagnostic thoracentesis [1]. Examination of the serum D-dimer test, echocardiography, and venous Doppler ultrasonography of the legs

Fig. 1. Chest radiography shows mild enlarged bilateral hilar shadows and blunt right costophrenic angle.

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127.e2 H.Y. Chen / American Journal of Emergency Medicine 33 (2015) 127.e1127.e3

Fig. 2. Chest CT with contrast demonstrates dilated pulmonary trunk (2.4 cm in diameter) and a large Filling defects extending to bilateral pulmonary artery (arrow) associated with multiple scattered thrombi formation (white arrow) mimicking intimal flap formation. There is also small amount of pleural effusion at right lower lobe posterior basal segment.

Fig. 3. Chest CT (coronal plane) demonstrates a saddle embolus with a filling defect completely occluding right pulmonary artery with extending through the main pulmonary artery segment to involve the left pulmonary artery.

H.Y. Chen / American Journal of Emergency Medicine 33 (2015) 127.e1127.e3 127.e3

can help with diagnosis. More Advanced diagnostic imaging proce- dure such as lung scan, computed tomography, transesophageal echocardiography, and pulmonary angiography are more accurate and reliable techniques for diagnosis. Multidetector computed tomography (MDCT) is recently the most common, convenient, and faster technique used for examination of patients with PE. Not only is MDCT used for the diagnosis of PE, MDCT angiography has the potential for risk and prognostic stratification [2].

The outcome of pulmonary embolism varies and dependent on clinical manifestation, hemodynamic stability, and the location of emboli. Assessing different locations and saddle type had been reported in approximately 3% to 5% of patients diagnosed with PE using CT [3]. Wide application of CT allowed noninvasive early diagnosis and has provided the visualization of saddle thromboembolism lodged between the main right and left pulmonary arteries. This remains a controversial treatment for saddle PE. Prior study suggested aggressive surgical management to improve outcome [4]. Some recent studies revealed that saddle type PE was not associated with worse clinical outcome [5]. Other studies demonstrated that most patients with saddle pulmonary embolism were hemodynamically stable and did not require throm- bolytic therapy or other interventions [6]. However, the prognosis and management remain unclear by different patients’ characteristics and clinical manifestations.

The CT findings in this case represented a pitfall in diagnosis of PE. Our case indicated that the differentiation of chest pain associated with pulmonary dissection from that associated with pulmonary embolism is of critical importance. Because the treatment modalities between pulmonary dissection and pulmonary embolism are completely different because anticoagulant/thrombolytic therapy for one is contraindicated for the other. A correct diagnosis at the earliest stage

is of critical importance. Finally, we emphasize that 2 different orthogonal planes are necessary for diagnosis in CT image examination.

Hung Yi Chen, MD

Department of Cardiology Taipei City HospitalHeping Branch

Taipei, Taiwan Corresponding author. Department of Cardiology Taipei City Hospital-Heping Branch

No. 33, Sec. 2, Zhonghua Rd Taipei City 100, Taiwan

Tel.: +886-223889595X8408

E-mail addresses: [email protected],[email protected] http://dx.doi.org/10.1016/j.ajem.2014.06.010

References

  1. Porcel JM, Madronero AB, Pardina M, Vives M, Esquerda A, Light RW. Analysis of pleural effusions in acute pulmonary embolism: radiological and pleural fluid data from 230 patients. Respirology 2007;12(2):234-9.
  2. Becattini C, Agnelli G, Vedovati MC, Pruszczyk P, Casazza F, Grifoni S, et al. Multidetector computed tomography for acute pulmonary embolism: diagnosis and risk stratification in a single test. Eur Heart J 2011;32(13):1657-63.
  3. Ryu JH, Pellikka PA, Froehling DA, Peters SG, Aughenbaugh GL. Saddle pulmonary embolism diagnosed by CT angiography: frequency, clinical features, and outcome. Respir Med 2007;101:1537-42.
  4. McDonald IG, Hirsh J, Hale GS, Clarebrough JK, Richardson JP. Saddle pulmonary embolism: a surgical emergency? Lancet 1970;1:259-71.
  5. Pruszczyk P, Pacho R, Ciurzynski M, Kurzyna M, Burakowska B, Tomkowski W, et al. Short term clinical outcome of acute saddle pulmonary embolism. Heart 2003;89:335-6.
  6. Sardi A, Gluskin J, Guttentaq A, Kotler MN, Braitman LE, Lippmann M. Saddle pulmonary embolism: is it as bad as it looks? A community hospital experience. Crit Care Med 2011;39(11):2413-8.

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