Author: Jason M Kendall / Editor: Jason Kendall / Codes: CAP7, HAP8 / Published: 03/09/2010 / Review Date: 03/09/2013
Acute chest pain is a common presenting complaint: it accounts for approximately 700 000 presentations to the emergency department (ED) per year in England and Wales and for 25% of emergency medical admissions .
Chest pain is caused by a spectrum of pathology ranging from the innocent to the extremely serious (see Table 1); amongst the latter are a number of conditions which are potentially catastrophic and can cause death within minutes or hours. The large volume of patients presenting with a potentially serious condition places chest pain at the very core of emergency medicine work.
Emergency physicians are responsible for robustly identifying and treating a significant minority of patients with serious pathologies whilst also avoiding unnecessary investigation and admission for the majority of patients who can be safely discharged. This is a difficult challenge: it has been reported that 6% of patients discharged from a UK ED have subsequently been proven to have prognostically significant myocardial damage .
|Cardiovascular|| || || |
|Pulmonary|| || || |
|Gastrointestinal|| || || |
|Other|| || |
The diagnostic approach to chest pain in the emergency department
Patients attending the ED with chest pain present a classic diagnostic challenge.
A minority will have an imminently or potentially life-threatening condition and need to be quickly and robustly identified and treated.
A significant minority will have benign pathology or no significant cause identifiable for their pain and these also need to be identified, reassured and discharged.
The rest will have a specific identifiable cause for their pain that will require a diagnosis and treatment plan during their ED attendance.
A logical and systematic approach to patients will achieve a diagnosis in the vast majority of cases whilst they are in the ED (see algorithm in the chart click the image to see a larger version).
A focused history and physical examination supported by an ECG and chest x-ray in most, with some specific ancillary investigations in a few, will allow a firm diagnosis to be made or confident reassurance to be given.
All of the assessments and investigations discussed in this session are within the remit of the emergency physician and should be available within the ED.
This module is about achieving a diagnosis in a patient presenting with chest pain, not about the treatment of a condition once a diagnosis has been made.
When a diagnosis has been reached with the required degree of certainty, management of that condition is covered in the relevant learning session and the patient drops out of the algorithm.
Figure 1: The diagnostic approach to patients with chest pain
One of the main purposes of early and rapid assessment of a patient with chest pain is to identify life-threatening conditions and, in particular, to rule in or rule out an acute coronary syndrome (ACS). There are various features in the history that are traditionally associated with cardiac ischaemic chest pain and various features that make it less likely.
So what would be the first step in the diagnostic process?
A thorough description of the pain is the first step in the diagnostic process and will help to make the initial differentiation between cardiac and non-cardiac pain and ischaemic and non-ischaemic pain (see links to flowchart and table below).
Symptom evaluation will include a description of the character of the pain, the location, severity and radiation of the pain, onset and duration of the pain, relieving and aggravating factors, and associated symptoms. Other important features of the history will include risk factor determination, previous episodes and relevant past medical history.
Cardiac and non-cardiac causes of chest pain
Characteristic description of symptoms associated with major causes of chest pain
|Condition||Description of symptoms|
|Ischaemic cardiac pain||Retrosternal pressure, tightness, constrictingRadiation to shoulders/arms/neck/jawCrescendo in nature, related to exertion |
Associated with diaphoresis, sweating, nausea, pallor
|Pericarditis||Atypical, retrosternal, sometimes pleuriticPositional relieved on sitting forward|
|Gastro-oesophageal||Retrosternal, burningAssociated with ingestion|
|Aortic dissection||Tearing pain, sudden in onset, radiation to back|
|Pulmonary embolism||Atypical, may be pleuriticAssociated with breathlessness; occasional haemoptysis|
|Pneumothorax||Atypical, may be pleuriticAssociated with cough, sputum, fever|
|Musculoskeletal||Sharp, positional, pleuriticAggravated by movement, deep inspiration and coughing|
* In heterogenous studies likelihood ratios expressed as a range
Therefore, based on these analyses, the chest pain history is a helpful, but not diagnostic, first step in the assessment of these patients. Specifically, no single factor in the history carries with it a consistently powerful enough likelihood ratio to allow the emergency physician to safely discharge a patient without further diagnostic testing.
No single factor in the history alone can confidently rule in or rule out AMI
The history does, however, form a start point in the diagnostic process, broadly establishing whether pain is likely to be cardiac ischaemic (or not) in origin; it provides information to add to baseline risk factors (see Table 4) which makes the diagnosis of ACS significantly more or less likely. Specifically, radiation of the pain to the arms or shoulders, and its association with exertion or diaphoresis will make the diagnosis more likely. Chest pain that is pleuritic, sharp, positional and reproducible on palpation makes an alternative diagnosis much more likely. This information, in addition to other rapidly available clinical features (e.g. examination findings and the ECG) will determine the continued direction of investigation and initial management (see Figure 1).
Characteristics of the pain with the highest likelihood for AMI are radiation of the pain to the right arm/shoulder or to both arms/shoulders
Various studies have used a chest pain score (based upon ascribing positive or negative points to typical or atypical aspects of chest pain location, character, radiation, onset, and associated symptoms ) and then combined this with historical risk factors to generate positive predictive values for ruling in or ruling out ACS [11,12].
However, this approach has not led to sufficiently robust positive likelihood ratios to definitively rule in ACS (i.e. commit to specific therapies) or rule out ACS (i.e. allow safe discharge).
Other life-threatening conditions present with chest pain, apart from ACS. The above discussion of likelihood applies specifically to AMI; the clinician will have to consider the presenting features in the history that are typical of other conditions (e.g. a tearing feeling and radiation to the back in aortic dissection, or haemoptysis and shortness of breath in pulmonary embolism) alongside the risk factors (previously highlighted) specific to these conditions in order to narrow the differential diagnosis and guide subsequent investigation and management.
Table 3 Risk factors associated with major life-threatening causes of chest pain [7-9]
|Acute coronary syndromes|| |
|Aortic dissection|| |
|Pulmonary embolism|| |
The physical examination
The history will have established whether a patients chest pain is ischaemic in nature and likely to be related to an ACS, or whether it is pleuritic or atypical in nature, and unlikely to be related to an ACS. Examination findings will further refine the differential diagnosis generated from the history.
How would you describe the physical findings associated with ACS?
Physical findings associated with ACS are generally non-specific and include pallor, anxiety, sweating, tachycardia and tachypnoea.
Generally, specific physical findings are associated with other (non-ischaemic) causes for chest pain or are associated with the complications of AMI: for example, a third heart sound occurring in heart failure, a pan-systolic murmur from mitral valve regurgitation, hypotension related to cardiogenic shock, or pulmonary crepitations secondary to left ventricular failure. These physical findings make AMI more likely [4,5].
|Examination finding||Likelihood ratio|
|Increased likelihood of AMI:Third heart soundHypotension (systolic BP <80 mmHg) |
|Decreased likelihood of AMI:Chest pain reproducible by palpation||0.3||0.2-0.4*|
|*In heterogenous studies, likelihood ratios expressed as a range.|
The finding of a third heart sound, hypotension or pulmonary crepitations makes AMI more likely.
Table 5: Value of specific components of the physical examination for the diagnosis of acute myocardial infarction(7,8)
|Examination finding||Likelihood ratio|
|Ref 7||Ref 8|
|Increased likelihood of AMI:|
|Third heart sound||3.2||3.2|
|Hypotension (systolic BP <80 mmHg)||3.1||3.1|
|Decreased likelihood of AMI:|
|Chest pain reproducible by palpation||0.3||0.2 0.4*|
* In heterogenous studies likelihood ratios expressed as a range
The key physical findings associated with conditions presenting with chest pain in the emergency department are described below. Pivotal physical signs, or combinations of signs, which are highly suggestive of the relevant diagnoses, are shown in bold.
|Acute coronary syndrome||Diaphoresis, tachycardia, tachypnoea, pallor|
|Complications of acute MI||Hypotension, third heart sound, pulmonary crepitations, elevated JVP, bradycardia, new murmur|
|Aortic dissection||Diaphoresis, hypotension, hypertension, tachycardia, differential blood pressures and/or pulses, new murmur (aortic regurgitation), focal neurological findings|
|Pulmonary embolism||Acute respiratory distress, diaphoresis, hypotension, tachycardia, hypoxaemia, elevated JVP, pleural rub|
|Pneumonia||Fever, signs of pulmonary collapse/consolidation, tachycardia, tachypnoea|
|Oesophageal rupture||Diaphoresis, hypotension, tachycardia, fever, Hammans sign*, subcutaneous emphysema, epigastric tenderness|
|Simple pneumothorax||Tachypnoea, tachycardia, unilateral diminished air entry and breath sounds, subcutaneous emphysema|
|Tension pneumothorax||Tachypnoea, hypotension, tachycardia, hypoxaemia, elevated JVP, unilateral diminished air entry and breath sounds, subcutaneous emphysema, tracheal deviation|
|Pericarditis||Tachycardia, fever, pericardial rub|
|Myocarditis||Hypotension, tachycardia, fever, third heart sound, pulmonary crepitations, displaced apex beat|
|Mediastinitis||Tachycardia, fever, Hammans sign*, subcutaneous emphysema, hypotension|
|Cholecystitis||Diaphoresis, fever, tachycardia, right upper quadrant tenderness|
|*Hammans sign: audible systolic noise on cardiac auscultation|
Certain physical signs, or combinations of signs, are highly suggestive of certain diagnoses and are highlighted in bold.
* Hammans sign: audible systolic noise on cardiac auscultation
The Electrocardiogram (ECG)
After taking a history and performing a physical examination, the most commonly and rapidly performed investigation for a patient with chest pain in the ED is an ECG (see Figure 1). An ECG should be performed as soon as possible in all patients presenting with chest pain, particularly if cardiac ischaemia is suspected from the history.
Table 7 presents the likelihood ratios for the association of various ECG changes and a final diagnosis of AMI(7,8). The presence of ST segment elevation, new Q wave formation, or a new conduction deficit (eg. left bundle branch block) in the context of acute ischaemic chest pain is associated with such significantly positive likelihood ratios for AMI that the diagnosis can be made with confidence and appropriate therapy commenced.
The presence of ST segment depression and/or T wave changes in the context of acute ischaemic chest pain normally indicates myocardial ischaemia (i.e. unstable angina) but is also associated with a positive likelihood ratio for AMI (i.e. non-ST elevation AMI see Table 7). Approximately 50% of patients with ST depression and 33% of patients with T wave inversion will subsequently be shown to have myocardial infarctionas defined by an elevated cardiac marker(13,14). This group of patients are presenting with an ACS (i.e. unstable angina or non-ST elevation myocardial infarction).
ST segment elevation is associated with the highest likelihood of AMI followed, in order, by new Q waves, new conduction deficit, ST depression and T wave changes
A normal ECG significantly reduces the probability of AMI(7,8). It does not, however, reduce this probability enough to allow confident safe discharge based upon the history and ECG alone(2). Therefore, patients who present with chest pain in whom cardiac ischaemia is suspected and who have a normal ECG should undergo further diagnostic testing (ie. delayed cardiac markers, exercise testing, etc.) before they can be confidently ascribed to a low risk group.
A normal ECG in a patient with chest pain does not allow safe discharge without further investigation
Table 7: ECG findings associated with non-ischaemic chest pain conditions
|Diffuse concave-upwardST segment elevation||Positional painPericardial rub||Pericarditis|
|Right ventricular strain |
|Pleuritic painHypoxiaPleural rub||Pulmonary embolus|
|Diffuse ST/T wave changes||Atypical painHeart failure||Myocarditis|
|Inferior ST elevation||Tearing chest painRadiation to backDifferential pulsesDifferential blood pressuresNew diastolic murmur||Aortic dissection|
The Chest X-Ray (CXR)
The CXR is the next investigation commonly performed in the ED for patients presenting with chest pain following initial clinical assessment and ECG (see Figure 1). Table 9 shows the radiographic findings in conditions presenting with chest pain. The CXR is particularly useful in patients presenting with non-cardiac chest pain and can definitively confirm a diagnosis suspected on clinical grounds (e.g. pneumothorax or pneumonia) or contribute significantly to the diagnostic process (e.g. widened mediastinum in aortic dissection or pneumomediastinum from oesophageal rupture). A normal CXR will also be helpful in making a diagnosis by excluding other potential causes for a certain clinical presentation: for example, a normal CXR in a patient with respiratory distress, pleuritic pain and hypoxia will exclude pneumothorax, make pneumonia unlikely, and increase the probability of pulmonary embolism.
There are no specific diagnostic findings on chest radiography associated with ACS; the usefulness of the CXR in this setting is to exclude other (non-cardiac) causes of chest pain or to evaluate complications of AMI (e.g. pulmonary oedema).
Table 9: Radiographic findings in conditions presenting with chest pain
|Acute coronary syndrome||No specific radiographic finding|
|Aortic dissection||Mediastinal wideningAbnormal aortic contourGlobular heart shadow (haemopericardium)Pleural effusion (haemothorax)||Suggestive in contextUnusual findingRare findingRare finding|
|Pneumothorax||Absence of pulmonary vascular markings||Diagnostic|
|Tension pneumothorax||Absence of pulmonary vascular markingsMediastinal displacement||DiagnosticDiagnostic|
|Pneumonia||Localised or diffuse pulmonary infiltrationLocalised pulmonary atelectasis / consolidation||Diagnostic in contextDiagnostic in context|
|Pulmonary embolism||Normal chest radiographLocalised pulmonary atelectasisSmall pleural effusion||Suggestive in contextRare findingRare finding|
|Oesophageal rupture||Pneumomediastinum||Diagnostic in context|
|Mediastinitis||Pneumomediastinum||Diagnostic in context|
|Pericarditis||Globular heart shadow||Pericardial effusion|
|Myocarditis||Enlarged cardiac shadow||Dilated cardiomyopathy|
The history, physical examination, ECG and CXR will normally allow the emergency physician to be fairly confident to achieve a diagnosis in a patient with chest pain presenting to the ED. There will still be a significant number of patients in whom the diagnosis is not clear or who require further investigations to allow safe discharge or definitive treatment.
Patients who present with a history of ischaemic chest pain who have a normal examination, ECG and CXR will require further risk stratification in order to allow safe discharge from the emergency department. Such a rule-out strategy will involve the use of cardiac markers (e.g. troponin) and possible exercise testing.
Pulmonary embolism is a relatively common condition that needs to be excluded with confidence due to its significant associated mortality if undiagnosed. Unfortunately, the history is variable, and there are no common diagnostic findings on examination, ECG or CXR. However, these findings, considered in association with historical risk factors for venous thromboembolic disorders, will allow the emergency physician to confidently ascribe the patient to a low, intermediate or high risk category(4). Without further investigation, however, patients at low risk cannot be confidently reassured and discharged, and those at high risk should not be committed to prolonged anticoagulation. For patients at low risk, the diagnosis can be confidently excluded with a negative D-dimer assay(15). For patients at intermediate or high risk the diagnosis can be confidently confirmed or excluded with a ventilation perfusion (V/Q) scan or CT pulmonary angiogram (CTPA)(15).
Pulmonary embolism will rarely be definitively diagnosed without ancillary investigations (D-Dimer, V/Q scan, or CTPA)
Aortic dissection is a diagnosis that should be strongly suspected if the appropriate features are present upon clinical assessment: the history (tearing pain), examination (new murmur of aortic regurgitation, differential blood pressures), ECG (inferior ischaemic changes) and CXR (widened mediastinum) will, when present in combination, be pathognomonic of aortic dissection. However, due to the potentially catastrophic nature of aortic dissection if undiagnosed, this condition will need to be definitively excluded even if the index of suspicion is low (e.g. if only one of the characteristic clinical features is present). In patients in whom the diagnosis is virtually certain from the clinical presentation, the anatomical extent of the dissection will need to be defined. In either case, a CT mediastinum will need to be performed and this will be diagnostic and define the anatomical extent.
CT mediastinum will be required to definitively exclude aortic dissection and/or to define its anatomical extent
Key learning points
- No single factor in the history is associated with a high enough likelihood ratio to confidently diagnose or exclude AMI (Grade of evidence 1b)
- The features of the chest pain history most likely to be associated with AMI are radiation to the right arm/shoulder or radiation to both arms/shoulders (Grade of evidence 1b)
- The features of the chest pain history least likely to be associated with AMI are sharp nature, positional, pleuritic and reproducible with palpation (Grade of evidence 1b)
- Examination findings which increase the likelihood of AMI in the context of chest pain are the presence of a third heart sound, hypotension and pulmonary crackles (Grade of evidence 1b)
- ECG findings diagnostic of AMI in the context of ischaemic chest pain are new ST segment elevation and new Q waves (Grade of evidence 1b)
- A normal ECG in the context of ischaemic chest pain does not rule out prognostically significant myocardial damage and further diagnostic testing will be required (Grade of evidence 1b)
- A logical diagnostic approach to patients presenting with chest pain will achieve a diagnosis in the majority based on taking a history, performing an examination, ECG and CXR in the ED
- Ancillary investigations will be required for the remainder and, specifically:
- A rule-out strategy for patients with ischaemic pain and a normal ECG (Grade of evidence 1b)
- D-dimer, V/Q scanning or CTPA for patients in whom pulmonary embolism is a possibility (Grade of evidence 1b)
- CT mediastinum for patients suspected of having an acute aortic dissection
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