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

BTS guidelines
patients treated for CAP did not have radiographic abnormalities.
471 [III]
In patients with CAP, broad-spectrum intravenous antibiotics
should only be used following careful consideration, taking into
account severity of illness, likely pathogens involved and
patient-specific factors such as the ability to tolerate oral
medication. Whenever appropriate, narrow-spectrum oral antibiotics
should be used preferentially.
Recommendations
c The diagnosis of CAP and the decision to start
antibiotics should be reviewed by a senior clinician
at the earliest opportunity. There should be no barrier
to discontinuing antibiotics if they are not indicated.
[D]
c The indication for antibiotics should be clearly documented
in the medical notes. [D]
c The need for intravenous antibiotics should be
reviewed daily. [D]
c De-escalation of therapy, including the switch from
intravenous to oral antibiotics, should be considered as
soon as is appropriate, taking into account response to
treatment and changing illness severity. [D]
c Strong consideration should be given to narrowing the
spectrum of antibiotic therapy when specific pathogens
are identified or when the patient’s condition
improves. [D]
c Where appropriate, stop dates should be specified for
antibiotic prescriptions. [D]
(B) SPECIFIC PATHOGEN-DIRECTED ANTIBIOTIC
THERAPY
8.19 What are the optimum antibiotic choices when specific
pathogens have been identified?
In routine clinical practice, only about one-third to one-quarter
of patients with CAP admitted to hospital will be defined
microbiologically. Of these, some such as mycoplasma, chlamydophila
and C burnetii infection will be diagnosed late in the
illness on the basis of seroconversion, reducing the opportunity
for early targeted therapy. Among patients managed in the
community, very few will be microbiologically defined.
When a pathogen has been identified, specific therapy as
summarised in table 6 is proposed. In transferring patients from
empirical to pathogen-targeted therapy, the regimen and route
of administration will be determined by the continued need for
parenteral therapy and known drug intolerance. Hence, table 6
provides preferred and alternative regimens for intravenous or
oral administration. However, it should be remembered that
approximately 10% (see Section 3) of infections will be of mixed
aetiology, although many such co-pathogens will be viral and
hence not influenced by antibiotic choice. These recommendations
are again based on a synthesis of information which
includes in vitro activity of the drugs, appropriate pharmacokinetics
and clinical evidence of efficacy gleaned from a variety
of studies. The choice of agent may be modified following the
availability of sensitivity testing or following consultation with
a specialist in microbiology, infectious disease or respiratory
medicine.
Currently, S pneumoniae highly resistant to penicillin (MIC
>4 mg/l) is uncommon in the UK. S aureus is an uncommon
cause of CAP in the UK. Most community isolates are
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methicillin-sensitive, although the recent increase in MRSA in
hospitalised patients may result in subsequent readmission with
an MRSA infection which may include CAP. Options for
methicillin-sensitive and methicillin-resistant infections are
based on parenteral administration in view of the serious
nature of staphylococcal pneumonia.
Recommendations
c If a specific pathogen has been identified, the antibiotic
recommendations are summarised in table 6 [C].
8.20 Specific issues regarding the management of Legionnaires’
disease
Legionella infection is unique as a cause of CAP owing to the
mode of spread and the importance of trying to identify the
source to prevent further cases. The infection is acquired by
inhaling water mist containing legionella bacteria, which are
commonly found in natural and manmade water systems.
Common sources include drift from evaporative cooling towers
and aerosols generated from showers, aerated hot tubs,
humidifiers and potable water. In addition, the propensity to
cause severe illness including multiple organ failure and the lack
of response to b-lactam antibiotics suggests that specific
guidance will be helpful to clinicians managing a case.
Detection of legionella urinary antigen using a rapid
technique has revolutionised the early diagnosis of pneumonia
caused by L pneumophila serogroup 1 which is responsible for
over 90% of community cases in the UK and Europe. This is a
highly sensitive and specific test, particularly in patients who
are unwell enough or who have been ill long enough to require
hospital admission (see Section 6). Although urinary antigen
detection is now the most valuable and frequently used
diagnostic test, sputum culture still has a vital role in diagnosing
infection caused by other legionella serogroups and species. It is
also invaluable for matching legionella species and strains
identified from cases, with those positive water cultures from
a potential source. This can help prevent further cases of
infection. It is therefore important to send off sputum or
respiratory secretions specifically for legionella culture, even in
proven cases and after appropriate antibiotics have started (see
Section 5.11.5).
Legionnaires’ disease is not currently a notifiable disease in
the UK, but urgent action to investigate the source of infection
is essential. In proven cases of legionella pneumonia, the
clinician should liaise with the clinical microbiologist to confirm
that the local Health Protection Unit has been informed. The
Health Protection Unit should initiate immediate investigations
and this will include recording details of recent travel and
activities within the 2 weeks before illness onset (the usual
incubation period is 2–10 days) from the patient or their
relatives to assist epidemiological investigation. Clinicians
should help by explaining the need for this to patients and
relatives; this is important, especially at a time when the patient
may be very unwell and their relatives distressed. The Health
Protection Agency (HPA) will also request a clinical information
sheet to be completed which provides very valuable (anonymous)
clinical and outcome data to update the ongoing
national and European data sets which are available from the
HPA website (www.hpa.org.uk) or, for Scotland, from Health
Protection Scotland (www.hps.scot.nhs.uk) and the European
Working Group for Legionella Infections (www.ewgli.org).
Further details about the investigation of a potential source of
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