Acute chest pain: history, investigations and differential diagnosis

Overview

Acute chest pain is one of the commonest reasons for emergency attendance. Most patients turn out to have a benign cause, but a few have a life-threatening one that needs treatment within minutes.

The aim of the first assessment is simple: find or exclude the killers, then work out the rest. A careful history, a quick examination, a 12-lead ECG and a troponin answer most questions.

The dangerous causes to exclude first

History and presentation

Ask about the pain in a structured way: site, onset, character, radiation, associated features, timing, what makes it better or worse, and severity.

Character of pain by structure

Points that change the probability

• Cardiac risk factors: smoking, diabetes, hypertension, high cholesterol, family history of early heart disease, cocaine use.
• Dissection risk: long-standing hypertension, Marfan or Ehlers–Danlos syndrome, bicuspid aortic valve, pregnancy, recent aortic surgery.
• Clot risk: recent surgery, immobility, cancer, pregnancy, oestrogen use, previous DVT.
• Recent viral illness suggests pericarditis or myocarditis.
• Elderly and diabetic patients may have little or no pain with infarction; they may present with breathlessness, fatigue or collapse.

Examination

• Vital signs: pulse, BP in both arms, respiratory rate, oxygen saturation, temperature.
• Shock: pale, cold, clammy, low BP.
• Pulses: absent or unequal pulses suggest dissection.
• Heart: new murmur (early diastolic murmur of aortic regurgitation in dissection; pansystolic murmur in papillary muscle rupture), pericardial friction rub, quiet heart sounds (tamponade).
• Neck veins: raised JVP in tamponade, massive PE or right ventricular infarction.
• Chest: absent breath sounds and tracheal shift (pneumothorax); crackles (heart failure).
• Chest wall: tenderness over the costochondral junctions.
• Legs: swollen, tender calf (DVT).

Investigations

Differential diagnosis: the four TOS conditions

Myocardial infarction

• Central crushing pain lasting more than 20 minutes, not relieved by GTN.
• Sweating, nausea, pallor; may be hypotensive or have an arrhythmia.
• ECG: convex (dome-shaped) ST elevation in leads facing the infarct with reciprocal ST depression opposite; later Q waves and T inversion.
• Troponin rises.
• Full management is in the acute coronary syndrome chapter.

Aortic dissection

What happens: a tear in the inner lining (intima) lets blood split the media, creating a false channel.

Classification (Stanford):

Clinical features:

• Sudden, severe, tearing central chest pain going through to the back; may migrate.
• Unequal pulses or BP between the arms; absent pulses.
• New early diastolic murmur (aortic regurgitation) if the tear reaches the aortic root.
• Complications from branch blockage: stroke, paraplegia, inferior MI (right coronary ostium), renal failure, limb or gut ischaemia; tamponade if it ruptures into the pericardium.

Investigations:

• Chest X-ray: widened mediastinum (may be normal).
• CT aortogram is the usual confirming test; TOE is useful in an unstable patient; MRI is an alternative.
• ECG is often normal or shows LVH.

Management:

• Strong analgesia.
• Lower BP quickly with intravenous beta-blockers (labetalol, metoprolol), adding a vasodilator if needed. Kumar and Clark gives a systolic target of below 120 mmHg.
• Type A: urgent surgery. Managed with drugs alone, about half die within 2 weeks.
• Type B: medical first; stenting for complications (malperfusion, expansion, uncontrolled pain).

Acute pericarditis

Causes: most are idiopathic or viral (Coxsackie, echovirus). Others: bacterial, tuberculosis (important in Pakistan), early after MI, Dressler syndrome (weeks after MI), uraemia, hypothyroidism, autoimmune disease (SLE, rheumatoid arthritis, rheumatic fever), cancer, radiation and drugs (hydralazine, procainamide, isoniazid).

Diagnosis needs two of four features:

1. Sharp, pleuritic chest pain, worse lying flat and eased by sitting forward.
2. Pericardial friction rub (scratchy, best heard with the patient leaning forward).
3. ECG: widespread concave (saddle-shaped) ST elevation with PR depression; reciprocal changes only in aVR and V1.
4. Pericardial effusion on echo.

Raised CRP, ESR and white cell count; troponin rises if the myocardium is involved (myopericarditis).

Management: an NSAID (ibuprofen) or high-dose aspirin for 1–2 weeks plus colchicine (0.5 mg twice a day, continued for three months) to cut recurrence. Keep steroids for specific immune causes. Admit high-risk patients (fever above 38°C, large effusion, tamponade, poor response).

Gastro-oesophageal reflux disease (GERD)

• Burning retrosternal pain (heartburn), worse after meals, on bending, stooping or lying flat.
• Acid or bitter taste, regurgitation, water brash; may cause cough or wheeze.
• Pain eases with antacids or a proton pump inhibitor.
• ECG and troponin are normal.
• Endoscopy if there are alarm features: weight loss, dysphagia, vomiting, bleeding, anaemia, or new symptoms in an older patient.
• Long-standing reflux can lead to Barrett's oesophagus.

ECG comparison

Other causes to remember

• Pulmonary embolism: pleuritic pain, breathlessness, tachycardia, hypoxia; CTPA confirms.
• Pneumothorax: sudden one-sided pain in a tall young man or a patient with lung disease.
• Pneumonia: fever, cough, pleuritic pain.
• Oesophageal spasm: pain with swallowing; corkscrew oesophagus on barium swallow.
• Costochondritis (Tietze disease): tender costal cartilages.
• Herpes zoster: band-like pain, rash in one dermatome a few days later.
• Da Costa syndrome: sharp left submammary pain with anxiety.
• Peptic ulcer, biliary colic, pancreatitis: upper abdominal pain spreading up.

Quick revision

• Killers: ACS, dissection, PE, tension pneumothorax, tamponade, oesophageal rupture.
• ECG within 10 minutes; repeat ECG and troponin if the first are normal.
• MI: crushing pain >20 minutes, convex ST elevation in one territory.
• Dissection: tearing pain to back, arm BP difference, widened mediastinum, CT aortogram; BP down with IV beta-blocker.
• Type A surgery, type B medical.
• Pericarditis: pleuritic, eased sitting forward, rub, saddle ST elevation, PR depression; NSAID plus colchicine.
• GERD: burning, after meals and lying flat, antacid relief; endoscopy if alarm features.

Written by The House Job from standard references (Kumar and Clark's Clinical Medicine).

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