Managing sore throats N 11, 1999 V

Transcription

Managing sore throats N 11, 1999 V
NATIONAL PRESCRIBING CENTRE
VOLUME 10
Contents:
NUMBER 11, 1999
Managing sore throats
Managing sore throats
Sore throat is a common
complaint, which occurs
predominantly in children and
young adults, and more often
in winter than summer. A GP
with 2,000 patients can expect
to see around 120 cases of
acute throat infection every
year.1 Throat infections are
usually self-limiting and resolve
within a week.1 Complications
are rare, but can include quinsy
and rheumatic fever.
This Bulletin discusses the
management of sore throats,
and the evidence for and against
treatment with antibiotics.
Causes of sore throats
Sore throats may be caused by
either bacterial or viral infections;
viruses are the predominant
cause.2 Group A beta-haemolytic
streptococcus (GABHS) is the
most common causative bacteria1
and may be isolated in up to 30%
of patients.3 It should be borne in
mind that an acute sore throat
occurring in a young adult may
also be caused by infectious
mononucleosis.
It is not possible to distinguish
reliably between bacterial and
viral causes of sore throat on
clinical grounds. Pain on swallowing is usually a predominant
feature, regardless of aetiology.
Fever, headache, tonsillar exudate, nausea, vomiting and
abdominal pain may also be
present. Cough, rhinorrhoea and
hoarseness are uncommon with
bacterial infection, and may be
suggestive of a viral aetiology.2
Acute throat infections occur
most commonly in children
SUMMARY
* Sore throat occurs predominantly in children and
young adults, and is a common complaint in the
winter months. It is usually self-limiting, and most
patients recover within one week.
* Most sore throats are viral in origin. The most common
bacterial cause is group A beta-haemolytic
streptococcus (GABHS). It is not possible to distinguish
clinically between viral and bacterial infections.
* Throat swabs have been used to try to identify GABHS
infection. However, they are not able to distinguish
carriage from clinical infection. It takes time for
results to be available, which limits their usefulness
in general practice. Rapid antigen tests produce
results quickly, but are insufficiently sensitive for
routine use.
* Symptomatic relief of sore throat can be achieved
using simple analgesics and antipyretics. Non-medical
measures such as increasing fluid intake and gargling
with salt water may also be helpful. Antibiotics have
a small effect on the duration of symptoms of sore
throat. However, no studies have demonstrated any
reduction in time to return to school or work.
* Sore throat caused by GABHS may rarely lead to
complications such as quinsy, nephritis or rheumatic
fever. Antibiotics reduce the incidence of complications
but, as these events are rare, large numbers of
patients need to receive antibiotics in order to prevent
one episode of a complication.
* High prescribing of antibiotics is associated with the
developing problem of antibiotic resistance. Reducing
prescribing for minor, self-limiting illnesses such as
sore throat may help to contain this problem.
The MeReC Bulletin is produced
by the NHS for the NHS
MeReC Bulletin Volume 10, Number 11, 1999
41
between 5 and 10 years, and in
young adults in the 15-25 age
group.1 The majority of patients
with GABHS do not have the
‘classic’ symptoms; only 15% of
cases present with the triad of
fever, pharyngeal exudate and
anterior cervical adenopathy.4
Even in patients suffering from
pharyngeal exudate and fever,
GABHS accounts for only a
minority of infections.2
Complications
The complications of acute sore
throat caused by GABHS may
be classified as suppurative or
non-suppurative. Suppurative
complications include sinusitis,
otitis media, quinsy and cervical
adenitis. Non-suppurative
complications include acute
nephritis and rheumatic fever.
Diagnostic tests
Two different types of test have
been used to try to identify sore
throats of bacterial origin - throat
swabs and rapid antigen tests.
Each is associated with different
advantages and disadvantages.
Throat culture results can take
24 to 48 hours to be reported.
This limits their usefulness to
prescribers, who prefer to decide
during the consultation whether
or not to prescribe antibiotics.
Additionally, there is a high
asymptomatic carrier rate of
GABHS, of up to 40% of the
population.5 Throat cultures
cannot distinguish between
carriage and infection with
GABHS. This means that some
patients who are not suffering
from a bacterial infection will
nevertheless produce a positive
throat culture result.
Rapid antigen tests use enzyme
immunoassay or agglutination to
detect the presence of group A
streptococcal antigen on a throat
swab. These tests produce a
result in a few minutes.
A study in general practice in the
Netherlands assessed the value of
a rapid streptococcal antigen
detection test, in addition to four
clinical features, in patients with
sore throat. Throat culture and
antibody titres were used as
42
reference tests.6 Clinical features
recorded were: fever ≥38.00C, lack
of cough, tonsillar exudate and
anterior cervical lymphadenopathy.
Compared with throat culture,
the sensitivity of the rapid test
was 65% and specificity 96%. In
those patients with three or four
clinical features, sensitivity
increased to 75%. The authors
concluded that the use of a rapid
test might have value in general
practice, although they felt that
tests with a higher sensitivity
would be needed (to minimise
false negative results) before
routine use could be considered.6
Neither throat cultures nor rapid
antigen tests seem sufficiently
accurate for routine use. Some
prescribers may wish to employ
them in specific patients, such
as those with recurrent infections. However, there is no
clinical trial evidence to support
such a strategy.
Treatment of sore throat
The aims of treatment for sore
throat are: to relieve symptoms,
shorten illness duration, and
prevent complications.
Symptomatic relief of sore throat
may be achieved using simple
analgesics such as paracetamol.
Adults may wish to take aspirin
as an alternative. Non-medical
measures, such as increasing
fluid intake, or gargling with salt
water, may also bring relief.
Do antibiotics relieve sore throat
symptoms?
Evidence for the effects of
antibiotics on the symptoms of
sore throat comes from a systematic review carried out by the
Cochrane collaboration, which
analysed the results of 22 trials
involving 10,484 cases.7 This
review concluded that antibiotic
treatment could shorten the
duration of symptoms, but only
by a mean of about eight hours
overall. About 90% of all patients
were symptom-free by one week,
regardless of therapy.
One open study included in this
review compared three strategies
for managing sore throat.8 These
were an immediate ten day
prescription for penicillin V or
erythromycin, no prescription,
or a delayed prescription, to be
collected if symptoms were not
beginning to settle after three
days. All patients were given
structured advice, which
included recommendations to
take analgesics or antipyretics.
The three groups did not differ in
symptom resolution at three
days, or in the median duration
of any symptom except fever. The
study also recorded the time
taken for patients to return to
work or school. This did not differ
significantly between the groups.
In another study involving 371
patients, penicillin V was
compared with placebo as initial
therapy for pharyngitis. All patients also received education and
standard symptomatic therapy.9
While there was a statistically significant increase in the number of
patients whose sore throat had
improved after 48 hours with
penicillin V, there was no difference in fever reduction or in rates
of return to school or work.
In summary, antibiotic treatment
of sore throat may have a small
effect on symptom resolution.
However, there is no evidence
that antibiotic treatment results
in an earlier return to school or
work, which may be important
to many patients.
Do antibiotics reduce the
complications of sore throat?
The Cochrane review estimated
that antibiotic treatment of sore
throat reduced the incidence of
acute otitis media to about one
quarter of that in the placebo
group, and that of acute sinusitis
to about one third of that in the
placebo group.7 Data from two
studies indicated that the incidence of quinsy was also reduced.
However, the relative benefits
described do not translate into
significant clinical benefits, as the
underlying incidence of these
complications is very low. The
Cochrane review estimated that,
in order to prevent one episode of
otitis media, about 30 children
and 145 adults with a sore throat
would have to receive antibiotics.7
MeReC Bulletin Volume 10, Number 11, 1999
One Scottish retrospective study
assessed the incidence of rheumatic fever in children as 0.6 per
100,000 per year (or 27 cases per
4.4 million child years).10 This
study also found that the risks of
developing rheumatic fever after
a sore throat were similar regardless of whether or not it had been
treated with antibiotics.
Another study found that there
was no clear evidence that antibiotic treatment of GABHS throat
infection prevents acute glomerulonephritis.3 In the Cochrane
review, a trend towards protection
against acute glomerulonephritis
was noted, but the numbers of
cases in the studies were too low
to be sure of this effect.7
It would seem from this evidence
that antibiotic treatment of sore
throat does have some small
protective effect against both
suppurative and non-suppurative
complications. However, the
absolute incidence of these
complications is very low. Therefore, large numbers of patients
would need to receive antibiotics
in order to prevent one episode
of a complication.
Do antibiotics reduce the rate of
recurrence of sore throat?
There is no evidence from clinical
trials as to whether antibiotic
treatment reduces the rate of
recurrence of sore throat. However, there is a theory that the
early use of antibiotic treatment
might increase recurrence; this is
thought to be a result of inhibition of formation of type-specific
antibodies to GABHS. Two studies
have investigated this theory by
comparing recurrence rates in
patients given immediate antibiotic therapy and those whose
treatment was delayed for 48
hours after presentation.11,12
In the first study, 113 patients
were followed up for four months
after completion of antibiotic
therapy, as well as during any
interim episodes of acute pharyngitis. No significant differences
were seen between the immediate
and delayed treatment groups in
the number of patients with
positive follow-up throat cultures,
recurrences, symptomatic
recurrences, or new infections.11
The second study followed up 229
children with culture-positive
GABHS infection for four
months.12 This study found that
both early (within seven weeks)
and late (within the same streptococcal season) recurrences were
more common in patients who
began treatment immediately.
These studies provide evidence
that delaying antibiotic treatment
will not be harmful, and may
have some benefits.
Choosing an antibiotic
In those patients for whom
antibiotic therapy is felt to be
necessary, the prescriber has to
decide which antibiotic to choose.
A study of samples of group A
streptococcal strains collected
over a period of 80 years showed
no development of resistance
to penicillin.13
Use of ampicillin, amoxicillin and
co-amoxiclav should be avoided
in patients with a sore throat.
This is because of the risk of
precipitating a maculopapular
rash if the patient is suffering
from infectious mononucleosis.
Most clinical trials in this area
used penicillin V 250mg, three
or four times daily, for ten days.
A review of studies of shorter
courses concluded that five to
seven days of penicillin V was less
effective than a ten day course at
achieving eradication of GABHS
from the pharynx.14 However,
there is no clear relationship
between ‘microbiological’ cure
and ‘clinical’ cure, in terms of
relief of symptoms. Furthermore,
patient compliance might be
expected to be better if shorter
courses are given. No studies of
shorter courses of penicillin V
have addressed these issues.
Erythromycin is an appropriate
choice for penicillin-allergic
patients. It may be given twice or
four times daily. Again, ten days
treatment effectively eradicates
GABHS from the pharynx.15
Antibiotic prescribing and
bacterial resistance
Increasing bacterial resistance
to antibiotics is becoming a
MeReC Bulletin Volume 10, Number 11, 1999
significant issue, both in primary
and secondary care. The Standing
Medical Advisory Committee
(SMAC) report ‘The path of least
resistance’ points out that some
50 million prescriptions for
antibiotics are dispensed each
year in England alone; 80% of
this activity occurs in primary
care.16 A twofold variation exists
in levels of antibiotic usage
between the areas of highest and
lowest prescribing, for which
there is no apparent explanation.
Although antibiotic resistance is
a worldwide problem, there is
evidence that local antibiotic
prescribing practices can affect
local resistance patterns. A study
in Wales investigated antibiotic
prescribing in general practitioners’ surgeries and resistance to
antibiotics over the period from
March 1996 to April 1998. Rates
of prescribing for urinary tract
infections and resistance rates in
coliform organisms were examined.17 A correlation between the
rate of prescribing of an antibiotic
and the rate of resistance to that
agent was demonstrated.
A cross-sectional survey in
Iceland also found that carriage
of penicillin resistant pneumococci was strongly associated with
both individual and communitywide levels of antibiotic use.18
In Finland, the incidence of
erythromycin resistance in group
A streptococcus reduced by half
over three years following a
campaign to reduce the use of
macrolide antibiotics.19
Disadvantages of antibiotic
prescribing
Antibiotics are associated with
several well documented common
side-effects, including diarrhoea
and rashes, as well as rare, but
potentially life-threatening,
anaphylactic reactions. The risk
of side-effects should always be
considered before prescribing any
medication. Prescribing antibiotics can also have other, perhaps
unforeseen, consequences.
In the open study comparing
three approaches to the management of sore throat, patients who
received an immediate prescription for antibiotics were more
likely to believe that antibiotics
43
were effective in this condition.8
They were also more likely than
other patients to intend
consulting a GP in future
episodes. In a follow-up study,
a higher reconsultation rate in
those patients who had been
given immediate antibiotic
treatment was demonstrated.20
Other strategies for managing
sore throat
expectation of a prescription for
antibiotics for coughs, colds and
sore throats. They have produced
a patient information leaflet titled
‘Antibiotics. Don’t wear me out’,
featuring a character called Andy
Biotic. This is available on the
Department of Health website
(www.doh.gov.uk/
antibioticresistance/) or from the
Department of Health, PO Box
777, London SE1 6XH.
4
5
6
7
8
9
10
The open study mentioned earlier
compared immediate prescription, no treatment, or delayed
prescription for managing sore
throat, involving a total of 716
patients.8 Very ill patients were
excluded from the study.
Of the patients offered a delayed
prescription, 69% did not use it.
The proportion of patients who
were better by day three, and
the overall duration of illness,
did not differ between the groups.
Patients’ satisfaction with the consultation, and how their worries
were dealt with, also did not differ
between groups. Satisfaction was
closely associated with illness
duration, whereas antibiotic use
was not, suggesting that psychological issues are important in the
management of sore throat.
Information leaflets may be
helpful in explaining to patients
the reasons for not prescribing
antibiotics, and may provide a
useful substitute for a prescription in some consultations. The
PRODIGY decision-support
system includes an information
leaflet on sore throat, which can
be found on the PRODIGY web
site (www.schin.ncl.ac.uk/
prodigy/guidance/browser/pils/
pl154.htm).
The Scottish Intercollegiate
Guidelines Network have also
produced a guideline on the
management of sore throat and
indications for tonsillectomy,
which includes a patient information leaflet on tonsillitis and sore
throat. This guideline can also be
found on the internet
(www.show.scot.nhs.uk/sign/
html/htmtxt34.htm).
The Department of Health has
produced an advertising campaign aimed at reducing the
Conclusions
11
Evidence for the effectiveness of
antibiotic therapy in reducing
symptoms and preventing complications of sore throat is modest.
GPs should therefore aim to avoid
prescribing antibiotics for most
sore throats. Symptomatic
measures may be recommended.
Patients should be educated
about the very small benefits of
antibiotic therapy and its associated side effects. The possibility of
a delayed prescription, to be
collected if symptoms do not
improve in a few days, can also
be discussed. The prescriber and
patient can then make a joint
decision on the course of action.
Although this may require extra
time initially, it should reap
benefits in the long term, by
avoiding the increased
reconsultation rate associated
with prescribing antibiotics.
Several information leaflets
explaining why antibiotics are
unnecessary for simple sore
throats are available. Prescribers
may find these a useful substitute
for a prescription.
If antibiotics are considered
necessary (for example, in very ill
patients or those who have
previously suffered a complication), penicillin V remains the
agent of choice, as it is both
effective and inexpensive. Erythromycin may be useful in those
patients allergic to penicillin.
References
1 Fry J, Sandler G. Chapter 6, Acute throat
infections. In: Common diseases: their nature,
presentation and care, 5th ed. Kluwer
Academic Publishers, Lancaster 1993: 66-73
2 Dowell SF, Schwartz B, et al. Appropriate use
of antibiotics for URIs in children: Part II.
Cough, pharyngitis and the common cold. Am
Fam Physician 1998; 58: 1335-1345
3 Taylor JL, Howie JG. Antibiotics, sore throats
and acute nephritis. J R Coll Gen Pract 1983;
33: 783-786
12
13
14
15
16
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18
19
20
Kiselica D. Group A beta-hemolytic streptococcal pharyngitis: current clinical concepts. Am
Fam Physician 1994; 49: 1147-1154
Del Mar C. Managing sore throat: a literature
review. I. Making the diagnosis. Med J Aust
1992; 156: 572-575
Dagnelie CF, Bartelink ML, et al. Towards a
better diagnosis of throat infections (with group
A β-haemolytic streptococcus) in general
practice. Br J Gen Pract 1998; 48: 959-962
Del Mar CB, Glasziou PP. Antibiotics for sore
throat (Cochrane review). In: The Cochrane
Library Issue 3, 1999. Oxford: Update Software
Little P, Williamson I, et al. Open randomised
trial of prescribing strategies in managing sore
throat. BMJ 1997; 314: 722-727
Middleton DB, D’Amico F, Merenstein JH.
Standardized symptomatic treatment versus
penicillin as initial therapy for streptococcal
pharyngitis. J Pediatr 1988; 113: 1089-1094
Howie JGR, Foggo BA. Antibiotics, sore throats
and rheumatic fever. J R Coll Gen Pract 1985:
35: 223-224
Gerber MA, Randolph MF, et al. Lack of impact
of early antitbiotic therapy for streptococcal
pharyngitis on recurrence rates. J Pediatr
1990; 117: 853-858
El-Daher NT, Hijazi SS, et al. Immediate vs.
delayed treatment of group A beta-hemolytic
streptococcal pharyngitis with penicillin V.
Pediatr Infect Dis J 1991; 10: 126-130
Macris MH, Hartman MD, et al. Studies of the
continuing susceptibility of group A streptococcal strains to penicillin during eight decades.
Pediatr Infect Dis J 1998; 17: 377-381
Pichichero ME, Cohen R. Shortened course of
antibiotic therapy for acute otitis media,
sinusitis and tonsillopharyngitis. Pediatr Infect
Dis J 1997; 16: 680-695
Ginsburg CM, McCracken GH, et al. Erythromycin therapy for group A streptococcal pharyngitis. Am J Dis Child 1984; 138: 536-539
Standing Medical Advisory Committee Subgroup on Antimicrobial Resistance. The path of
least resistance. September 1998
Magee JT, Pritchard EL, et al. Antibiotic
prescribing and antibiotic resistance in
community practice: retrospective study,
1996-8. BMJ 1999; 319: 1239-1240
Arason VA, Kristinsson KG, et al. Do
antimicrobials increase the carriage rate of
penicillin resistant pneumococci in children?
Cross sectional prevalence study. BMJ 1996;
313: 387-391
Seppala H, Klaukka T, et al. The effect of
changes in the consumption of macrolide
antibiotics on erythromycin resistance in group
A streptococci in Finland. N Engl J Med 1997;
337: 441-446
Little P, Gould C, et al. Reattendance and
complications in a randomised trial of
prescribing strategies for sore throat: the
medicalising effect of prescribing antibiotics.
BMJ 1997; 315: 350-352
Corrections
Prices of two calcium and vitamin
D products were omitted from the
cost information in MeReC Bulletin Vol. 10 No. 7. Calcichew D3
Forte costs £69.35 per year, at a
dose of two tablets daily. Adcal-D3
costs £54.75 per year, at a dose
of one tablet twice daily.
The licensed dose of Erymax for
the treatment of acne (MeReC
Bulletin Vol. 10 No. 8) is different
from the BNF recommendations
for erythromycin in acne. Erymax
is licensed at a dose of 250mg
twice daily for the first month,
and 250mg daily thereafter. Costs
for these doses are £10.82 and
£5.41 per month, respectively.
Date of preparation: January 2000
 The National Prescribing Centre, The Infirmary, 70 Pembroke Place, Liverpool, L69 3GF.
Telephone: 0151-794 8146/8140/8143/8145 Fax: 0151-794-8139/44
44
MeReC Bulletin Volume 10, Number 11, 1999