A 65 year old man presents to the emergency department with crushing central chest pain radiating down his left arm, which started 45 minutes ago. His past medical history includes peripheral vascular disease and hypertension. On examination, his heart rate is 90 beats/min and regular, he is tachypnoeic and apyrexial. Initial troponins are raised, however his ECG is normal.

What is the most likely diagnosis?

Options:
explanation: Pulmonary embolism classically presents with pleuritic chest pain, breathlessness, tachycardia, haemoptysis and the presence of a deep vein thrombosis (although their presentation can often be very non-specific in reality). This patient presented only with tachypnoea and had none of the classical risk factors for pulmonary embolism (for example long haul flights, history of cancer, surgery, prolonged immobility). Although pulmonary embolism can present with raised troponins, given the whole clinical picture, myocardial infarction is more likely
name: Pulmonary embolism
label: b
answer: no
explanation: This is the typical presentation of a myocardial infarction. This is a 65 year old man with significant cardiovascular risk factors. Central, crushing chest pain is the characteristic description of a myocardial infarction and this classically radiates down the left arm. Although myocardial infarctions often present with ECG changes, the absence of ECG changes does not rule out a myocardial infarction. Raised troponins are very suggestive of myocardial infarction in this clinical history, as this confirms myocardial cell lysis. In this case, the specific diagnosis would be classified as a non-ST elevation myocardial infarction (NSTEMI)
name: Myocardial infarction
label: a
answer: yes
explanation: Pneumonia typically presents with pyrexia, a productive cough, tachypnoea and pleuritic chest pain. This patient only presented with tachypnoea out of these features and this chest pain fits the classical description of cardiac chest pain. Pneumonia does not tend to cause a rise in troponin levels unless the patient is septic and very unwell
name: Pneumonia
label: e
answer: no
explanation: Unstable angina and myocardial infarction are both subtypes of acute coronary syndrome (ACS). This is used to generally describe an episode of myocardial chest pain and as such, unstable angina and myocardial infarction present very similarly. To differentiate these, it is best to look at troponins. A raised troponin means the myocardial tissue is infarcted, as the myocardiocytes die and release troponins into the blood. In unstable angina, there is no myocardial death, so there is no associated troponin rise. Therefore, in the presence of raised troponins, it is more likely to be a myocardial infarction
name: Unstable angina
label: d
answer: no
explanation: Stable angina is defined by the presence of at least 2 of the following criteria:

- constricting chest/jaw/arm pain
- pain triggered by exercise
- pain relieved by rest for 5 minutes or glyceryl trinitrate

Although this patient has chest pain typical in nature, they have not had a clear history of their pain being exercise induced and more importantly, this pain is still present after 45 minutes. In addition, stable angina does not cause raised troponins as there is no associated myocardial death as this tissue is ischaemic, not infarcted. Overall, this makes a diagnosis of myocardial infarction more likely
name: Stable angina
label: c
answer: no

Correct answer: a