A 54 year old man presents to the emergency department with a 2 hour history of chest pain. The chest pain is a sudden onset, stabbing pain on the right side of his chest, that gets worse when he breathes in. On examination, he has a heart rate of 107/min, respiratory rate of 22/min and is apyrexial. No abnormalities are noted on examination, his chest x-ray is normal, and an ECG shows sinus tachycardia. He has recently been discharged after a bilateral hip replacement surgery 1 week ago and is currently on no medications.

What is the most likely diagnosis?

Options:
explanation: Myocardial infarction does present with chest pain, however it is characteristically a crushing chest pain radiating to the left arm and jaw. In this case the pain is more pleuritic, which is more in keeping with a pulmonary cause. There may or may not be signs on physical examination, ECG or chest x-ray in myocardial infarction however this patient has significant risk factors for pulmonary embolism rather than myocardial infarction, therefore in the context of the clinical history pulmonary embolism is more likely
name: Myocardial infarction
label: b
answer: no
explanation: Pericarditis typically presents with pleuritic chest pain as in this case. However, this typically has characteristic ECG signs (PR depression and widespread saddle shaped ST elevation), which were not present in this case. In the presence of sudden onset chest pain with significant risk factors for PE and an ECG showing tachycardia, a pulmonary embolism is the more likely diagnosis
name: Pericarditis
label: d
answer: no
explanation: Pneumonia can present with pleuritic chest pain, as described in this case. However, this is less likely to be of sudden onset and will probably be associated with other features including fever and a productive cough of green/rust coloured sputum. Most significantly, the chest x-ray is normal for this patient. In pneumonia, there are usually radiological features on the chest x-ray
name: Pneumonia
label: c
answer: no
explanation: Anxiety is a good differential in this case. It can present with chest pain and sinus tachycardia and should be considered if investigations are normal. However, pulmonary embolism can also present with the same physical examination and investigation results and the fact that this is sudden onset and in the presence of a significant risk factor increases the suspicion that this presentation is due to a pulmonary embolism. Therefore, pulmonary embolism should be considered above anxiety, until pulmonary embolism has either been confirmed or adequately ruled out
name: Anxiety
label: e
answer: no
explanation: There are several features in this case that suggest a diagnosis of pulmonary embolism. Pleuritic chest pain is a typical feature of pulmonary diseases, including pulmonary embolism. In addition, the symptoms of a pulmonary embolism are typically described as being sudden onset. Tachycardia is another typical feature. Pulmonary embolism often has no signs on physical examination or chest x-ray. This patient has a significant risk factor of recent surgery and as they are on no current medications they may not have been prescribed any thromboprophylaxis (e.g. low molecular weight heparin). Notably, there are several typical features absent from this presentation including no haemoptysis and no clinically obvious deep vein thrombosis (DVT). The absence of these features, does not rule out a pulmonary embolism
name: Pulmonary embolism
label: a
answer: yes

Correct answer: a