CLINICAL RISK REDUCTION
Adult chest infections
Professor Duncan Empey addresses the sometimes difficult question – when to refer in an adult patient presenting with chest infection?
C
HEST infections are one of the commonest reasons for consultations in primary care, and for most patients with viral acute bronchitis,
symptomatic treatment and reassurance are all that is needed. However, at the opposite extreme, for a small number of others, the outcome can be a severe pneumonia with a high risk of death. Community acquired pneumonia (CAP) affects
between five and 11 per 1,000 of the population each year with an overall mortality of around one per cent. Most patients are successfully diagnosed and managed in primary care. However, each year MDDUS receives complaints and claims of clinical negligence related to delayed referral to hospital of patients in whom the diagnosis of CAP has been missed or not adequately treated. Hospital mortality is between 13 and 15 per cent and rises from 22 to 49 per cent for patients admitted to ICU, with worse outcomes for those whose admission is delayed. As with many conditions, good decision-making for
patients with pneumonia depends on careful assessment and clinical acumen rather than severity scores, algorithms or other guidelines.
Diagnosis Te presenting symptoms of pneumonia may be cough, with or without sputum production, fever or pleuritic pain. Examination of the chest may not reveal any abnormality, or there may be localised signs such as crepitations heard on auscultation. Oſten patients with pneumonia produce little or no sputum, and chest examination may reveal no abnormality, so cough, fever and feeling very unwell may be the only clues. Particularly in older patients, a fever and tachycardia may be the main or even the only abnormal observations with little to point directly to a chest problem. In the absence of a completely reliable combination
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of symptoms and signs by which to define and diagnose pneumonia it is oſten necessary to perform a chest X-ray to confirm or exclude the diagnosis, particularly in older patients or smokers. Atypical pneumonia nowadays accounts for 20 per
cent of CAP in some localities, particularly caused by Mycoplasma pneumoniae or Chlamydophila pneumoniae, the latter being common in student groups living together in halls of residence. Legionella pneumophila is fortunately much rarer. Physical signs in the chest in atypical pneumonia may be absent, and even on X-ray there may only be a small area of consolidation (hence the name “atypical”). Remember that patients who have contact with birds risk psittacosis (caused by Chlamydophila psittaci), a very severe form of atypical pneumonia, or the type of hypersensitivity pneumonitis caused by allergy to bird antigens which can sometimes present with cough and fever, imitating infection. Patients with pre-existing conditions such as
diabetes, significant heart, liver, kidney or lung disease, or neuromuscular problems or taking immune suppression (including oral steroids) must be assessed as much for the effect of an infection on their overall condition as for the severity of pneumonia itself.
The CRB65 Score Te CRB65 system has been devised as a guide to the severity of pneumonia, but this type of severity score must not be relied upon alone – decisions must be based on overall assessment and clinical judgement. In the CRB65 system one point is given for: • Confusion (assessed by an abbreviated mental test, or the appearance of new disorientation)
• Respiratory rate > 30/min • Blood pressure (SBP< 90 or DBP< 60 mmHg) • Age > 65 years. A score of 0 for a patient less than 50 years with no
SUMMONS
Top: X-ray showing pneumonia affecting the right lung. Above: False-colour SEM of Streptococcus pneumoniae
(pneumonococcus)
PHOTOGRAPHS: SCIENCE PHOTO LIBRARY
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