Acute chest pain: causes, red flags and when to call 999

The chest contains the heart, lungs, windpipe, food pipe, major blood vessels, ribs, muscles and nerves. Pain from any of them is felt in roughly the same area, and pain from organs below the chest, such as the stomach, can also be felt there. The description of the pain is therefore only a partial guide; timing, triggers and accompanying symptoms carry equal weight.

NICE CKS groups the causes into cardiac, respiratory, gastrointestinal, musculoskeletal and other. Cardiac causes include acute coronary syndrome, which covers unstable angina and heart attack, stable angina, pericarditis, myocarditis, and rhythm problems. Respiratory causes include pulmonary embolism, a collapsed lung, pneumonia and asthma. Gastrointestinal causes include reflux, ulcer and oesophageal spasm; musculoskeletal ones include rib injury and inflammation of the rib cartilage.

The NHS offers a simple symptom-to-cause table, with the warning not to self-diagnose. The patterns below combine that table with NHS pages on heart conditions.

The NHS lists three situations in its chest pain advice. First, sudden pain or discomfort in the chest that does not go away, which can feel like squeezing or pressure, burning or indigestion. Second, pain spreading to the left or right arm, or the neck, jaw, stomach or back. Third, chest pain with sweating, feeling sick, light-headedness or breathlessness. The NHS heart attack page adds pale, blue or grey skin, severe difficulty breathing and someone who has passed out and is not responding normally.

For someone with diagnosed angina, the NHS says to stop and rest, use the prescribed glyceryl trinitrate, repeat once after 5 minutes if it has not helped, and call 999 if symptoms continue 5 minutes after the second dose. While waiting for an ambulance the NHS suggests sitting and resting with knees bent and back supported, taking a 300mg aspirin if available and not allergic, and starting CPR if the person stops responding and breathing.

The NHS pericarditis page uses a time threshold: chest pain that lasts more than 15 minutes, spreads to arms, back, neck or jaw, makes the chest feel tight or heavy, or began with breathlessness, sweating and sickness should be treated as a possible heart attack.

• Pain, pressure or tightness that does not go away with rest.

• Pain moving to the arms, neck, jaw, stomach or back.

• Sweating, nausea, light-headedness or breathlessness with the pain.

• Grey, blue or pale skin or lips; collapse or a person who is not responding normally.

• Sudden severe breathlessness, a very fast heartbeat, or coughing up blood.

NICE CKS describes a clinical approach built on history, examination and tailored tests. The history covers the nature, site, trigger and duration of the pain, associated symptoms, risk factors and previous heart or lung disease. The NHS lists risk factors for heart problems: smoking, obesity, high blood pressure, diabetes, high cholesterol and relatives with heart attacks or angina before the age of 60.

CKS gives measurable markers of serious illness that call for emergency admission: a respiratory rate above 30 breaths a minute, a heart rate above 130, a systolic blood pressure below 90, oxygen saturation below 92 per cent, altered consciousness or a raised temperature, especially above 38.5 degrees. CKS also describes timing: current pain, or pain within the last 12 hours with an abnormal ECG, calls for emergency admission; pain-free patients are triaged to same-day or two-week assessment depending on how recent the episode was and what the ECG shows.

The NHS says suspected heart attack is diagnosed with an electrocardiogram and blood tests, and may be followed by an echocardiogram to look for damage and a coronary angiogram, which finds where blood flow is blocked and can allow treatment in the same procedure. For suspected angina, the NHS lists blood tests, an ECG, checking blood oxygen and scans such as an angiogram, MRI or CT, after referral to a cardiologist.

Pericarditis is investigated by listening to the heart, blood tests, and sometimes a chest X-ray, ECG or echocardiogram. A suspected pulmonary embolism leads to hospital for tests and treatment, typically starting with an anticoagulant injection before results are back, as the NHS describes. Chest infections may need a chest X-ray and blood tests.

There is little to self-treat when chest pain is new, and the NHS advice is to get medical help rather than wait to see whether it settles. Pain that is clearly linked to a pulled muscle, or to heartburn after a heavy meal, is a different matter, but even then the NHS says not to self-diagnose if you are worried.

If a heart attack is possible, the NHS advice is to call 999 straight away rather than wait to see whether the pain passes, to rest in a comfortable seated position while help comes, and not to drive. Anyone with a suspected heart attack who stops responding and stops breathing needs CPR.

The NHS recommends seeing a GP for chest pain that comes and goes, and also for chest pain that goes away quickly but still worries you, because the cause needs establishing. An urgent GP appointment or NHS 111 is the right route for sharp chest pain made worse by breathing, coughing or lying down.

Chest pain that is stable, with a known cause and a clear plan, is managed in primary care. Chest pain of uncertain cause with persisting symptoms is referred routinely, according to CKS, and anything suggesting a heart attack goes straight to the emergency services.