Adult chest infections

CHEST 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

The 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. Often 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 of symptoms and signs by which to define and diagnose pneumonia it is often 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

The 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 co-existing disease usually indicates a good prognosis with home treatment. A score of 1 or 2 indicates an increased risk of death, particularly with a score of 2, and hospital referral should be considered. A score of 3 or 4 indicates the need for urgent hospital admission.

The CRB65 score is useful for highlighting the need for referral for those with a higher score, but a low score is not completely reassuring. A young breathless patient with a CRB65 score of 1 but feeling very unwell with a respiratory rate of 40/min definitely warrants hospital treatment. Or a patient in his late fifties with bilateral basal crepitations could score 0, but clearly has extensive infection, would be at high risk of developing severe pneumonia and should be referred.

Beyond the CRB65 Score

More information can be obtained by using a pulse oximeter, which are widely available these days. Cyanosis is an unreliable clinical sign, but the pulse oximeter can give useful information – for a patient with pneumonia an oxygen saturation (SaO2) level reduced below 94 per cent is an adverse feature indicating the need for oxygen treatment in hospital.

An otherwise fit patient with suspected pneumonia, a low CRB65 score and who is not too unwell can usually be treated at home, but a chest X-ray is still advisable and a review within 24 to 48 hours is essential, as well as advising the patient to go to A&E if there is any deterioration.

Breathlessness with wheeze may be seen in patients with a history of asthma, and increased treatment for their asthma will be needed as well as antibiotics for the pneumonia. Any patient with known asthma or COPD must have their spirometry, or at least peak expiratory flow rate, measured and the results compared with their usual values. Worsening asthma or an exacerbation of COPD may be an indication for hospital referral even if the pneumonia is not thought to be severe.

Breathlessness in any patient at any age with no past history of chest disease who has symptoms suggesting pneumonia is a very worrying combination. There may be few signs in the chest but for the patient to be breathless the pneumonia must be extensive and urgent referral is needed.

Social factors may also influence the decision to refer, as will the patient’s own preferences. It goes without saying, of course, that if a sick patient declines referral to hospital this must be fully documented and the patient followed up at home to ensure a good response to treatment, or to suggest again that they should go to hospital (see case study on page 20).

Bear in mind that sometimes other diseases such as pulmonary embolism, pulmonary oedema, pneumothorax, fibrosing alveolitis and lung cancer might be confused in their early stages with chest infections.

Giving antibiotics

A review of when to prescribe or not prescribe antibiotics is beyond the scope of this article but fit younger patients with a viral acute bronchitis do not usually need them. Older patients and those with a history of lung disease such as asthma, COPD, emphysema or bronchiectasis, or a history of previous pneumonia should have the benefit of a lower threshold for prescribing as they are at increased risk of developing pneumonia. The clinical assessment should include consideration of the effects of the pneumonia on these conditions and also the effects of an infection on any other chronic conditions which may be present. Again, a relatively low threshold for prescribing antibiotics or referring to hospital may avoid later problems in vulnerable patients.

Conclusion

Recognising pneumonia and then deciding whether the patient is suitable for home treatment or should be referred for hospital review is a common but complex scenario. Severity scores such as CRB65 may help, but clinical judgement is much more important. History taking and examination must be thorough, record keeping accurate and existing medical conditions must be taken in to account. If suitable for home treatment, follow-up review in 24 to 48 hours is important. Any cause for concern – significant malaise, fever, tachycardia, breathlessness or confusion – must result in referral for hospital assessment.

Professor Duncan Empey is a consultant respiratory physician and Professor Emeritus in the School of Postgraduate Medicine at the University of Hertfordshire

REFERENCES

BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax 2009;64 (Suppl III):iii1–iii55. doi:10.1136/thx.2009.121434

Recent changes in the management of community acquired pneumonia in adults. Hannah J Durrington, Charlotte Summers. BMJ 2008; 336:1429-33 doi: 10.1136/bmj.a285