Differentials
Unstable angina
SIGNS / SYMPTOMS
Clinical presentation may not differentiate.
INVESTIGATIONS
ECG may show non-specific ST-segment and T-wave changes.
Cardiac biomarkers are normal.
Non-ST-elevation myocardial infarction
SIGNS / SYMPTOMS
Clinical presentation may not differentiate.
INVESTIGATIONS
ECG may show non-specific ST-segment and T-wave changes, but does not show ST-segment elevation.
Cardiac biomarkers are elevated in both non-ST-elevation MI and STEMI.
Aortic dissection
SIGNS / SYMPTOMS
Patients typically present with tearing chest pain, notably between the shoulder blades.
They can be in considerable distress and haemodynamically unstable.
Peripheral pulses may be unequal or absent distally.
INVESTIGATIONS
CXR may show a widened mediastinum.
ECG may be unremarkable, show sinus tachycardia, or show ST-segment changes if the dissection extends proximally and involves the coronary ostium.
A CT of chest and abdomen with intravenous contrast showing the presence of a dissection flap and a true lumen and false lumen is diagnostic for aortic dissection.
A trans-oesophageal echocardiogram may also show the dissection flap with the true and false lumens.
Pulmonary embolism (PE)
SIGNS / SYMPTOMS
Patients classically present with acute onset of sharp stabbing chest pain that is pleuritic in nature and associated with shortness of breath.
A background of increased clotting tendency, such as known hereditary thrombophilia or connective tissue disease; known deep venous thrombosis; or previous PE increases the likelihood of the diagnosis.
Other risk factors include recent prolonged immobilisation and limb trauma.
INVESTIGATIONS
Patients are hypoxic with an increased arterial-alveolar gradient on the arterial blood gas.
ECG may show sinus tachycardia or right ventricular strain with prominent S wave in lead I, prominent Q in lead III, and flipped T in lead III (S1Q3T3), or can be unremarkable.
D-dimer is useful for risk stratifications. In a patient with a low probability of PE on clinical scoring, with a non-elevated d-dimer, a PE can be excluded; if elevated, further work-up is required to confirm PE.
For patients with a high probability of PE on clinical scoring (i.e., PE is likely) or an abnormal D-dimer, imaging is required. The multiple-detector CT pulmonary angiography scanning of the chest is the imaging study of choice.
Pneumothorax
SIGNS / SYMPTOMS
Patients present with sudden onset of pleuritic chest discomfort and shortness of breath.
Tachycardia, hypotension, and cyanosis suggest a tension pneumothorax.
Known underlying medical conditions that predispose to pneumothorax, such as chronic obstructive pulmonary disease, connective tissue disease, or recent chest trauma, may support this diagnosis.
INVESTIGATIONS
CXR shows a visceral pleural line.
Pneumonia
SIGNS / SYMPTOMS
Patients usually have an insidious onset of fevers, cough (that may be productive of sputum), and shortness of breath.
Chest discomfort may be pleuritic in nature.
Examination will usually confirm pneumonic consolidation with decreased resonance, decreased air entry, and crackles over the affected lung.
INVESTIGATIONS
WBC count is usually elevated with neutrophilia.
CXR shows increased alveolar markings.
Blood and sputum cultures may be positive for an infective organism.
Pericarditis
SIGNS / SYMPTOMS
Patients can present with chest pain of varying quality that is typically better on sitting up and leaning forwards and worse with lying down.
There may be a history of recent viral syndrome and a pericardial friction rub on clinical examination.
INVESTIGATIONS
ECG may have diffuse ST-segment elevation that is concave up ('saddle-shaped') with PR segment depression.[141]
Cardiac biomarkers can be elevated if inflammation extends into the myocardium.
Inflammatory markers such as CRP and erythrocyte sedimentation rate may be elevated.
CXR demonstrating a globular cardiac shadow is suggestive.
Echocardiogram may show a pericardial effusion or may be unremarkable.
Myocarditis
SIGNS / SYMPTOMS
Patients often have a recent history of influenza-like illness or underlying autoimmune condition such as systemic lupus erythematosus.
They are likely to be young and often do not have risk factors for coronary artery disease.
Myocarditis is more likely to present with symptoms of cardiac failure than with chest pain.
INVESTIGATIONS
ECG changes and cardiac biomarkers can mimic MI.
Inflammatory markers (erythrocyte sedimentation rate and CRP) and autoimmune assays may be elevated.
Test of choice is cardiac magnetic resonance imaging, with delayed enhancement imaging showing an epicardial or mid-myocardial involvement.
Gastro-oesophageal reflux disease
SIGNS / SYMPTOMS
Patients present with burning retrosternal discomfort that is relieved by antacids.
Discomfort/pain is usually non-exertional.
INVESTIGATIONS
Diagnosis is usually clinical.
Cardiac biomarkers, ECG, and CXR are normal.
Oesophagogastroduodenoscopy is indicated for patients with persistent or atypical symptoms and may show oesophagitis (erosions, ulcerations, strictures) or Barrett's oesophagus.
Peptic ulcer disease
SIGNS / SYMPTOMS
Pain is described as burning epigastric pain that occurs hours after meals or with hunger. It often wakes the patient at night and is relieved by food and antacids.
There may be a previous history of reflux or medications that can cause peptic ulcer (i.e., recent use of steroid or non-steroidal anti-inflammatory drugs).
INVESTIGATIONS
Endoscopy may show ulcers, erosion, or gastropathy.
Oesophageal spasm
SIGNS / SYMPTOMS
Patients present with squeezing retrosternal discomfort that may be relieved by glyceryl trinitrate (due to relaxation of the spasm).
Discomfort/pain is usually non-exertional.
INVESTIGATIONS
Cardiac biomarkers, ECG, and CXR are normal.
Oesophageal manometry or barium swallow may show evidence of dysmotility.
Costochondritis
SIGNS / SYMPTOMS
Musculoskeletal chest wall discomfort that is worse with certain movement and deep breaths.
Focal tenderness over the costochondral joints may be present.
INVESTIGATIONS
Cardiac biomarkers, ECG, and CXR are normal.
Anxiety or panic attack
SIGNS / SYMPTOMS
Normal examination; however, evidence of hyperventilation is sometimes present.
INVESTIGATIONS
Cardiac biomarkers, ECG, and CXR are all normal.
Oesophageal rupture (Boerhaave syndrome)
Acute cholecystitis
SIGNS / SYMPTOMS
On physical examination there is constant right upper quadrant pain with or without Murphy's sign (inhibition of inspiration due to pain on palpation). There may be a history of gallstones or previous episodes of biliary colic.
INVESTIGATIONS
Ultrasound may show a distended gallbladder and gallstones.[144] If ECG changes accompany cholecystitis, these would most likely include ST elevation.
Brugada syndrome
SIGNS / SYMPTOMS
More common in Asian people and men aged 30-50 years. Patients typically present after an episode of polymorphic ventricular tachycardia or a cardiac arrest.
INVESTIGATIONS
ECG shows saddle-shaped ST elevation in leads V1-V3. These changes are associated with complete or incomplete right bundle-branch block and T-wave inversions.
Acute stress cardiomyopathy
SIGNS / SYMPTOMS
Clinical features are similar to non-STEMI (NSTEMI) and may include chest pain, shortness of breath, and left ventricular wall motion abnormalities. A characteristic feature is that often the clinical state is triggered by a severe extracardiac stressor (e.g., intracranial haemorrhage, pheochromocytoma, exogenous catecholamine administration, severe emotional stress, postoperative stress, sepsis).
INVESTIGATIONS
Often these patients present with ECG changes, cardiac biomarker elevations, and left ventricular dysfunction on cardiac imaging that are indistinguishable from NSTEMI but on coronary angiography will have no obstructive lesion. Coronary angiography remains the definitive test for diagnosis of this condition.
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