Guidelines for the management of community ... - Brit Thoracic

BTS guidelines
c
c
Pneumonia caused by atypical pathogens clears more
quickly than pneumonia caused by bacterial infection. [III]
Radiological resolution is slower in elderly patients and
where there is multilobar involvement. [Ib]
5.6 When should the chest radiograph be repeated during
recovery and what action should be taken if the radiograph has
not returned to normal?
Repeat chest radiographs are probably often ordered unnecessarily
following CAP. 180 [IVa] Although it has become usual practice
to repeat the chest radiograph on hospital discharge and again at
‘‘routine’’ hospital clinic follow-up at around 6 weeks later,
there is no evidence on which to base a recommendation
regarding the value of this practice in patients who have
otherwise recovered satisfactorily.
The main concern is whether the CAP was a complication of
an underlying condition such as lung cancer. This concern will
depend on a variety of factors such as age, smoking status, preexisting
conditions such as COPD and the clinical condition of
the patient. In a study of 236 adults presenting to their general
practitioner with a clinical diagnosis of CAP, 10 were found to
have underlying lung cancer on investigation. There was a high
frequency of lung cancer in older smokers (6 of 36 (17%)
smokers aged .60 years), suggesting that a chest radiograph
was particularly indicated in this group of patients with CAP in
the community. 23 [II] Studies of CAP in hospital often exclude
patients found to have lung cancer, making it difficult to assess
how frequently lung cancer presents acutely with CAP. In one
study of 162 adults hospitalised with suspected CAP, the
diagnosis was accepted in only 127, 10 (6%) of the 162 being
found to have cancer. 36 [II] Another study found only 13 (1.3%)
of 1011 patients hospitalised with CAP to have an underlying
lung cancer on investigation. 181 [III] Eight of these were detected
on the admission chest radiograph and the others were detected
because of unsatisfactory clinical recovery. They concluded that
a convalescent radiograph was useful in detecting occult lung
cancer only if signs or symptoms persisted after a month or so.
The practice of performing bronchoscopy in patients
admitted to hospital with CAP prior to hospital discharge has
been investigated. 182 [III] In patients aged .50 years or who were
current or ex-smokers, 14% were found to have an abnormality
at bronchoscopy (11% had a bronchial carcinoma diagnosed).
Recommendations
c The chest radiograph need not be repeated prior to
hospital discharge in those who have made a satisfactory
clinical recovery from CAP. [D]
c A chest radiograph should be arranged after about
6 weeks for all those patients who have persistence of
symptoms or physical signs or who are at higher risk
of underlying malignancy (especially smokers and
those aged .50 years) whether or not they have been
admitted to hospital. [D]
c Further investigations which may include bronchoscopy
should be considered in patients with persisting
signs, symptoms and radiological abnormalities at
around 6 weeks after completing treatment. [D]
c It is the responsibility of the hospital team to arrange
the follow-up plan with the patient and the general
practitioner for those patients admitted to hospital
(see Section 7.5). [D]
5.7 What general investigations should be done in a patient with
suspected CAP in the community?
General investigations are performed to assess severity (see
Section 6), to assess the impact on or to detect the presence of
any comorbid disease, to provide some pointer to the particular
aetiological agent or group of pathogens, identify complications
and to monitor progress (see Section 9).
It may be appropriate to perform investigations in selected
patients, especially if there is delayed improvement on review.
However, no firm recommendations can be offered. It is a
matter of clinical judgement.
Recommendations
c General investigations are not necessary for the
majority of patients with CAP who are managed in
the community. [C] Pulse oximeters allow for simple
assessment of oxygenation. General practitioners,
particularly those working in out-of-hours and emergency
assessment centres, should consider their use
(see Section 7.1). [D]
c Pulse oximetry should be available in all locations
where emergency oxygen is used. [D]
5.8 What general investigations should be done in patients
admitted to hospital?
Apart from the chest radiograph essential for diagnosis, the only
other simple non-microbiological tests that influence immediate
management are the urea, which informs severity assessment,
and oxygen saturation, which affects supportive management
and track and trigger systems in accordance with the BTS
guideline for emergency oxygen use in adult patients. 183
In addition, it is normal practice to take blood for a full blood
count, urea and electrolytes, liver function tests and CRP. These
often help to identify important underlying or associated
pathologies including renal or hepatic disease and haematological
or metabolic abnormalities.
A white cell count of .15610 9 /l strongly implicates a
bacterial (particularly pneumococcal) aetiology, although lower
counts do not exclude a bacterial cause. 184 [III] A white cell count
of .20610 9 /l or ,4610 9 /l is an indicator of severity (see Section
6).
Considering the role of CRP in the diagnosis of CAP, a
prospective study performed in Spain reported a 96% specificity
for CAP using a threshold CRP level of .100 mg/l. 185 [II]
Criticisms of this study are the small number of patients in
one group and the fact that patients with infective exacerbations
of COPD were excluded. Another study showed that a
raised CRP level on admission is a relatively more sensitive
marker of pneumonia than an elevated temperature or raised
white cell count. All patients with CAP had CRP levels .50 mg/l
and 75% of patients had levels .100 mg/l. 186 [II] In the same paper
it was reported that a CRP level of .100 mg/l helped to
distinguish CAP from acute exacerbations of COPD. Another
group found that only 5% of patients admitted with CAP had
CRP levels ,50 mg/l. 187 [III] Although not yet widely available, a
bedside finger-prick CRP test has been used to predict CAP in 168
patients presenting with acute cough and, at a cut-off of 40 mg/l,
was found to have a sensitivity of 70% and a specificity of 90%
independent of any clinical characteristics. 188 [II] CRP levels are
generally higher in patients who have not received antibiotic
186 [II]
therapy before admission.
With regard to predicting the microbial aetiology of CAP,
higher CRP levels have been associated with pneumococcal
Thorax 2009;64(Suppl III):iii1–iii55. doi:10.1136/thx.2009.121434
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