Angina module 4: diagnosis

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Presentation

Chest pain is a very common symptom with some 20-40% of the general population experiencing it during their lives. In the UK, chest pain accounts for up to 1% of visits to general practitioners (GPs), approximately 700,000 visits (5%) to emergency departments and up to 25% of emergency admissions to hospital.1 Importantly, in patients with chest pain due to an acute coronary syndrome (ACS) or angina, there are effective treatments to improve symptoms and prolong life. This module will focus on stable angina and will not review chest pain associated with ACS.

Table 1. Clinical assessment

Rapid access chest pain clinics (RACPC) have been developed to allow quick assessment of patients who do not have an acute coronary syndrome but with new onset angina, in suspected coronary artery disease.

Around 50% of patients admitted with chest pain to hospital have a non-cardiac cause of their symptoms.  Most of these patients can be better evaluated in the RACPC rather than in the emergency department for 10 to 12 hours after the beginning of symptoms.2

Whatever the setting the following protocol (see table 1) should be adopted when investigating chest pain, as research has shown that chest pain may have different aetiologies depending on where patients present.

The underlying cause of chest pain varies depending on whether a patient i) is seen by a GP, ii) calls the dispatch centre, iii) is treated by the ambulance crew or iv) is seen in the emergency department.  The distribution of aetiologies in relation to these four scenarios is shown in table 2. Not unexpectedly, chest pain of cardiac origin is less commonly seen by the GP (20%), whereas musculoskeletal disorders are common.2

Table 2. Aetiology to chest pain in various clinical settings

Causes of chest pain

As seen above, the most common causes of chest pain seen in the GP surgery are non-cardiac (table 3).4 They are usually differentiated by careful history taking. Differential diagnoses include oesophageal disorders.

Since there are many causes of chest pain, it is important to differentiate the different causes and confirm or eliminate cardiovascular causes.  Some of the cardiovascular and non-cardiovascular causes of chest pain are shown in table 3.

Common differentials for anginal pain

Table 3. Cardiovascular and non-cardiovascular causes of chest pain

Differentials for angina in the patient presenting with chest pain include the following conditions (table 4):

Musculoskeletal pain

This typically has an associated history which will suggest the cause, such as lifting a heavy object, undertaking exercise beyond usual habits, trauma or arthritic symptoms. The history will commonly not be readily apparent in these patients and a detailed exercise, sport and occupational history is very worthwhile in order to elucidate underlying provoking factors. Palpation of chest for provocation of costochondritic pain should be undertaken routinely in all chest pain patients who do not have a clear diagnosis.

Pulmonary embolism

The patient presenting with pulmonary embolism (PE) will commonly have a resting tachycardia, may or may not be hypoxic and may have underlying risk factors for thrombosis. Evidence of deep vein thrombosis (DVT) should be sought and risk scores such as Well’s score are very useful for predicting probability of PE. Patients may have clinical features of pulmonary infarction such as bronchial breathing and signs of pulmonary hypertension but most often have a normal exam. Electrocardiogram (ECG) should be inspected for sinus tachycardia, S1Q3T3 pattern and signs of right ventricular (RV) strain.

Pericarditis

This is characterised by a triad of friction rub, typical ECG changes and typical pleuritic pain. ECG changes include upwardly concave ST elevation which is usually diffuse and typically not associated with reciprocal changes apart from in AVR and V1. Low voltage ECG may be present in patients with an associated effusion. A history of a recent viral infection is common.