Discussion
In the review of the literature to date, no significant clinical harm
has been reported using oral formulations of phenoxymethyl penicillin
alone as part of peritonsillar abscess incision and drainage
interventions in the treatment of peritonsillar abscess.
Specifically, here, the studies focussed on the clinical outcomes rather
than the microbiology findings. We have not focussed the polymicrobial
nature of pus samples from quinsy and antibiotic administration. This
is because ultimately resolution of symptoms and clinical cure is
the priority in these patients.
All studies advocated the use of either needle aspiration or incision
and drainage as the source control measure in addition to the
appropriate administration of antibiotics, and this is a well-documented
treatment in the literature.25 It is the general
consensus that antibiotics alone are not appropriate for the treatment
of peritonsillar abscess, and the literature has shown no difference in
effectiveness between needle aspiration vs incision.4What differed between the studies reviewed, was the use of aspiration
or incision and drainage. Turner et al 1986 performed daily aspiration
or incision and drainage for up to 10 days or until no more pus was
drained. At the end of the 10 days, patients in both groups were deemed
completely treated, and no recurrence was demonstrated. In contrast
Wiksten et al 2016 performed needle aspiration on day one and then
monitored for signs of recurrence within a 56-day window. One could
argue daily drainage is eliminating the risk of any potential recurrence
from sub-therapeutic antibiotic therapy, and therefore it is hard to
assess accurately the effect of the antibiotic.
This systematic review is a useful addition to the literature in the
context of rationalising antimicrobial choice that provides effective
clinical cure without unnecessarily broadening the antimicrobial
spectrum of activity. In the context of increasing burden of
antimicrobial resistance26, the current evidence (such
as it is) suggests that addition of a second agent specifically
targeting anaerobes (Metronidazole) and other pathogens
(Sulbactam-Ampicillin) does not provide additional clinical benefit.
Further optimisation of therapy to improve clinical efficacy and lessen
impact on resident flora from single agent oral phenoxymethyl penicillin
may be considered in context of optimising dose, frequency and duration.
Furthermore all three studies used a 10 day treatment duration for which
evidence is lacking. In line with other specialties reviewing the use of
shorter duration of antimicrobials whilst maintain clinical efficacy, it
would be appropriate to consider shorter courses in the light of
improvements in clinical signs and symptoms and effective surgical
drainage.
When analysing potential benefit of the addition of metronidazole to
penicillin for the treatment of peritonsillar abscess, another important
factor to consider is cost. A typical
course of oral metronidazole is 400mg three times a day for seven
days, with a cost of around £2.17 in the NHS.28 The
current evidence does not support the routine use of metronidazole (or
second agent) in the routine management of quinsy, therefore there is
the potential for cost saving if only single therapy penicillin is
prescribed.