In all patients with acute cardiopulmonary symptoms, vital signs like heart rate, blood pressure, arterial oxygen saturation, and respiratory frequency, should be recorded immediately, as these are fundamental during initial resuscitation and in risk stratification if PE is confirmed. However, no clinical important differences in vital signs are found between patients with or with-out PE (Goldhaber 2010).

Likewise, no physical findings are reported to either confirm or rule-out PE, although signs of deep vein thrombosis are found more frequently in patients with PE than patients without PE (Kline et al. 2004; Wells et al. 2000; Perrier et al. 2004; Le Gal et al. 2006). Clinical findings like wheezing and high fever are found more often in patients without PE, and suggest other diagnosis (Miniati et al. 2008; Stein et al. 2000; Kline et al. 2002; Kabrhel et al. 2006). Table 5 presents findings from 202 patients with and 298 patients without PE; differences in the frequency of leg swelling, high fever and wheezing between the two groups were statistically significant, but have limited clinical significance.

In general, patients presenting to the emergency room with respiratory impairment like tachypnea and hypoxemia most commonly suffers from one of the conditions seen in Table 6 (Ray et al. 2006). By nature, the distribution of these conditions will vary in different patient populations, e.g. children or very specialized centers.

Other, common and uncommon, diseases with symptoms and clinical findings mimicking PE by causing dyspnea are lung malignancies, cardiac or intrapulmonary shunt states, pneumothorax, interstitial lung diseases, pulmonary hypertension and tracheobronchial foreign bodies. In addition, non-cardiopulmonary conditions like severe anemia, obesity and certain neuromuscular diseases can result in dyspnea.

In the patient presenting with chest pain, syncope and hemodynamic instability, acute myocardial infarction, malignant cardiac arrhythmias, aortic dissection, ruptured aortic aneurism, and other forms of shock must be included as possible differential diagnosis (Finfer and Vincent 2013).

Even though Virchow’s Triad (consisting of abnormal blood composition, vessel wall abnormalities and stasis) has been used for more than a century to describe risk factors for VTE, the clinical value of this has recently been questioned and additional details and interactions between the three components have been suggested (Wolberg et al. 2012). In some patients, it is not possible to establish any obvious risk or disposing factors for PE (White 2003).

However, if one or more risk factors are demonstrated, it is important if these are temporary (like recovery from surgery) or permanent (like incurable cancer). In other words, it must be decided whether the patient has secondary/provoked or primary/unprovoked/idiopathic PE. The thrombophilias constitutes a separate entity, and are covered in details in another chapter.

Table 7 (modified from (Anderson and Spencer 2003)) shows important relative risk factors for PE.

In recent years more focus has been on VTE and arterial thrombosis sharing the same risk factors, and this has to be taken into account when assessing the patient with PE; both during diagnosis, treatment and prophylaxis of PE (Piazza 2015). The traditional risk factors for arterial thrombosis which are also recognized as risk factors for VTE and PE, are seen in Table 8 and are based on a metaanalysis of 63,552 patients (Ageno et al. 2008; Goldhaber 2010) (Table 9).

In 2011, almost 200,000 patients in the United States were admitted with PE (LaMori et al. 2015), and every year 300,000 and 600,000 patients with PE are diagnosed in Europe and United States, respectively (Cohen et al. 2007; Garcia et al. 2005).

However, these numbers are not of direct utility to the individual clinician, as the incidence varies widely across medical specialties. In some fields of practice, PE is very common. For example, some studies suggest that 20 % of patients admitted with exacerbation of chronic obstructive pulmonary disease in fact have PE (Rizkallah et al. 2009; Kim et al. 2014). Also patients with liver cirrhosis and different autoimmune diseases have increased risk of PE (Ng et al. 2015; Tamaki and Khasnis 2015). In the emergency department, up to 1/400 will be diagnosed with PE (Kline and Kabrhel 2015a). Even though PE in pregnancy, and especially in the postpartum period (Meng et al. 2015), is fairly uncommon with 0.1 % of pregnant woman developing PE (Neuberger and Wennike 2013; Simpson et al. 2001), the risk is increased (Heit et al. 2005), and PE is a leading cause of maternal mortality in developed countries (Khan et al. 2006). In addition, the impact of PE in this patient category is often more complex with ethical and legal aspects in addition to the tragic nature of the situation. In surgery, increased risk of PE has to be taken into account in many specialties – e.g., 5 % of patients undergoing urooncological surgery will develop PE (Kukreja et al. 2015), in orthopedic surgery, 1 % of patients undergoing lower extremity surgery developed PE (Park et al. 2015; Wahlsten et al. 2015; Dixon et al. 2015) and the same is the case in patients with severe trauma and spine surgery (Lichte et al. 2015; Hamidi and Riazi 2015). Even in psychiatry, increased risk of PE is found in schizophrenic patients with a twofold risk of PE (Hsu et al. 2015). The examples above are by no means exhaustive, but meant as illustrations that clinicians in every field of medicine must have some knowledge of PE.

When assessing patients with acute cardiopulmonary symptoms, a range of investigations is indicated. In most patients, arterial gas analysis, chest x-ray, electrocardiogram (ECG) and venous blood samples are performed. In the following, the usefulness of these examinations in suspected PE will be reviewed.

Recently, focused point-of-care ultrasonography of the lungs, heart and deep vein have gained popularity in some centers, and seems utterly applicable in patients with respiratory symptoms and hypoxemia, increasing the number of patients with correct diagnosis at 4 h from admission from 64 to 88 % (Laursen et al. 2014). Ultrasonography of the lungs, heart and deep veins in the primary evaluation of these patients have several advantages in addition to establishing differential diagnoses to PE. Firstly, lung ultrasound has, in a recent meta-analysis, been found to have sensitivity of 87 % and specificity of 82 % for the diagnosis of PE (Squizzato et al. 2013). In addition, ultrasonography of the heart (echocardiography) will aid in risk stratification (as described later) and ultrasound of the deep vein can reveal deep venous thrombosis which will increase the possibility of PE in patients with relevant symptoms. However, while lung ultrasound has obvious benefits, is radiation free and can be used bedside, important limitations, primarily concerning training issues and interobserver variability exists (Touw et al. 2015).