Chapter 3 Chest pain
Introduction
Chest pain is the commonest reason for 999 calls and accounts for 2.5% of out-of-hours calls. Of patients taken to hospital, about 10% will have an acute myocardial infarction (AMI). Evidence suggests that up to 7.5% of these will be missed on first presentation. There are a number of other life threatening conditions which can present as chest pain and must not be overlooked. The objectives of this article are therefore to provide a safe and comprehensive system of dealing with this presenting complaint (Box 3.1).
Box 3.1 Objectives of assessment of patients with chest pain
To identify any patients who have a normal primary survey but have an obvious need for hospital admission
To undertake a secondary survey considering other systems of the body where dysfunction could present as chest pain
Discuss treatment based on the probable diagnosis(es) and whether home management or hospital admission is appropriate
Primary survey
Follow the ABC principles (Box 3.2).
Patients with normal primary survey with obvious need for hospital admission
There are three immediately life threatening medical conditions that can present with chest pain:
The history and a brief examination may lead you to suspect that one of these is the probable diagnosis. Patients may often have normal physical signs. Urgent hospital admission must be arranged if you suspect any of the above or any other life threatening diagnosis.
Fifty percent of sudden cardiac deaths occur within 1 hour of the start of a myocardial infarction and 75% within 3 hours. The benefits of thrombolysis or percutaneous intervention (PCI) are directly related to the length of time between the onset of symptoms and its delivery. Therefore if you diagnose a myocardial infarction, ensure you have immediate access to a defibrillator and consider thrombolysis or arrange rapid transportation to a facility where thrombolysis or PCI can be delivered.
Secondary survey (including history taking)
Having dealt with the potential life threatening cases you will be left with a group of patients for whom a more thorough clinical examination will be required before considering whether they can be either treated and left at home, or referred elsewhere.
Take a history of the presenting complaint, gather relevant information, and perform an examination (see Chapter 2).
There is good evidence that history and examination cannot ‘rule out’ any specific diagnosis, especially acute myocardial infarction. Some types of pain are more commonly found in patients with ischaemia. However there is good evidence that history can help ‘risk stratify’ patients. In the context of acute chest pain, some other investigation will often be required.
The OPQRST of chest pain
Chest pain is often categorised into three main types (Table 3.1). It can be very difficult to place any particular patient into one of these categories, but there is evidence that the characteristics of pain can help in the diagnosis:
Somatic pain may arise from the chest wall (skin, ribs and intercostal muscles), pericardium (fibrous and parietal layer), and the parietal pleura. Pain from these structures is transmitted to the brain by the somatic nerve fibres that enable the brain to accurately locate the site of the problem. In the case of pleuritic chest pain, it will also be specifically related to movements of breathing.
Visceral pain in contrast originates from the deeper thoracic structures (heart, blood vessels and oesophagus) and is carried in the autonomic nerve fibres. These give a less precise location of the pain, and the pain is generally described as a discomfort, heaviness or ache. It is often referred to shoulders, arm or jaw.
Onset of pain
The pain of a myocardial infarction is classically described as rapidly increasing over a few minutes but it can develop gradually or even be intermittent. In an acute coronary syndrome the pain may well be intermittent. As the platelet thrombus breaks down, blood flow is restored and the pain is relieved. Beware of pain starting at rest, or that which wakes the patient up from sleep.
Precipitating factors/palliative factors
Gain a detailed impression of how the pain started. Establish if there is any relation to exercise, breathing or food. Pain that has been provoked by exercise or wakened the patient should be regarded as significant. GTN will improve angina pain but also will improve pain from oesophageal problems. Equally there is no evidence that improvement of pain after giving an antacid can help distinguish between cardiac and oesophageal pain.
Quality
Typical myocardial pain is easily recognised. It is often described as tight or squeezing. In a typical myocardial infarct it is very severe. Typical pleuritic pain is sharper and well localised. Atypical pain can take any form but is often described as ‘indigestion’ or retro-sternal burning. Such pain is also associated with inferior ischaemia and infarction.
Radiation and systemic symptoms
Typical ischaemic pain is often across the chest with radiation to the shoulders, arms or jaw. However it can be felt only in the jaw, arms, shoulder or back, or epigastrium. Pleuritic pain is well localised although it may be referred to the shoulder if the diaphragm is irritated.
Sweating, nausea, vomiting and shortness of breath are common in severe myocardial ischaemia. Ask about cough and sputum production. If the pain is pleuritic, ask about leg swelling or pain.
Timing
Typical cardiac pain that lasts less than 15 minutes is defined as angina; however, if the angina pain is of recent onset, occurring at rest, coming more often than the patient’s usual angina or if it lasts more than 15 minutes, this could indicate an acute coronary syndrome (unstable angina). It would be unusual for it to continue for over 24 hours. Chest pain lasting only a few seconds is unlikely to be cardiac.
Other factors
Previous similar symptoms
A previous history of ischemic heart disease makes it much more probable that the pain is cardiac. However, patients with heart disease do have other chest problems and the patient may say that the pain is different from the usual symptoms.
Risk factors
The presence of risk factors for cardiovascular disease should increase your suspicion as to a cardiac cause for the pain (Box 3.3).
Medical history/drugs allergies
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The system of assessment and care of the primary survey positive patient
Abdominal pain, abdominal pain in women, complications of pregnancy and labour
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