Peritonsillar abscess is a complication of acute tonsillitis, where a collection of pus forms in the peritonsillar space. This pushes the affected tonsil inferomedially into the oropharyngeal space.
Red flags
Severe sore throat, hoarse/croaky voice, severe dysphagia and fever is epiglottitis until proven otherwise. Stridor may be a late sign and patients can decompensate rapidly.
Beware of severe sore throat with severe dysphagia - without any signs of tonsillitis/pharyngitis in the oropharynx. You should rule out epiglottitis first.
Rarely, patients with quinsy can present with profound sepsis.
Why is this important?
Although rare, epiglottitis can present with sore throat as the primary symptom so it is important to have a high index of suspicion.
It's important to recognise peritonsillar abscesses as they usually need aspiration.
If left untreated, peritonsillar abscesses may spread, resulting in deep neck space infections, which are airway emergencies.
When to involve the ENT Registrar
Immediately: If you suspect that you may be dealing with epiglottitis or a deep neck space infection, see stridorfor immediate management.
Soon: You should inform your senior if you think there may be any sort of pharyngeal airway compromise e.g. stertor from a large peritonsillar abscess.
Who to admit
A good principle: admit anyone unable to swallow enough fluid to stay hydrated
Patients with a peritonsillar abscess can be discharged after drainage, some intravenous antibiotics and a few hours' observation if they are well and able to swallow
Liverpool Peritonsillar abscess Score (LPS): This was originally developed through a prospective multicentre study (n= 100) and has just been externally validated through a second prospective multicentre study (n= 205)
The LPS Covid-19 Modification: we have modified the score to remove the need for mouth examination (see poster on this page); it reduces the accuracy of the score slightly
The LPS Covid-19 Modification is mainly helpful in its negative predictive value (NPV): patients scoring 0-3 are unlikely to have a peritonsillar abscess (NPV= 98%)
Positive predictive value for patients scoring 4-5 is approximately 60%
Positive predictive value for patients scoring 6+ is approximately 80%
The LPS does not replace clinical judgement and of course clinicians can choose to apply it or not. In addition, be wary of unwell patients with other signs such as hoarseness, torticollis etc. If indicated, you should still use appropriate PPE to perform a thorough examination.
Assessment and recognition
Typical symptoms for peritonsillar abscess include:Sore throat, often much worse on one side than the other (+/- otalgia)
'Thick' or 'hot potato' voice (not hoarse, croaky voice)
Stertor
Trismus
Inability to swallow more than saliva or a sip or water
The key signs that differentiate quinsy from tonsillitis are:
There is frequently a degree of trismus
On the affected side, the anterior arch will be pushed medially
On the affected side, the palate will bulge towards you ie the normally concave palate becomes convex
The uvula may be pushed away from the affected side
On the affected side, the mucosa of the arch and palate may look angrily erythematous
An asymmetrically swollen tonsil is NOT a peritonsillar abscess.
A peritonsillar abscess collects in the peritonsillar space, lateral to the tonsil - see photos.
When there is less pronounced swelling, it may be that there is peritonsillar cellulitis (an 'early quinsy'), as in photo B. On aspiration, no pus is forthcoming. These people would still be managed as per peritonsillar abscess and discharged if they improve clinically.
If photos B and C look similar, that is because the two conditions represent part of a spectrum from peritonsillar celllulitis through to formation of a peritonsillar abscess. It is more important to be able to distinguish tonsillitis from peritonsillar abscess/cellulitis
Immediate and overnight management
Abscesses need aspirationor and, if trismus is not too much of a problem, early intervention brings significant relief.
If you cannot be sure whether there is a peritonsillar abscess or just cellulitis, it would be prudent to get a second opinion and, if still unsure, to aspirate the possible abscess, given the potential benefits. Just be honest with the patient that there is a possibility of a "dry tap"- most are desperate to get better.
It may be difficult to examine the mouth if there is significant trismus. In this case,admit the patient, give them some IV treatment (see below)and re-examine later. The initial treatment can improve your view.
A good starting point when admitting patients:
IV access
FBC, U&Es, LFTs, glandular fever screen
Regular basic IV/PO analgesia e.g. paracetamol and ibuprofen, with stronger PRNs
Topical analgesic spray e.g. benzydamine spray
Fluid resuscitation - the vast majority of patients are young and dehydrated, and perk up after 1L of normal saline
Some surgeons prescribe a single dose of steroid (eg 6.6mg dexamethasone IV) to kick-start recovery, especially in those who have stertor
Advise those with increased snoring or stertor to sleep semi-upright
Further management
Arrange follow-up for patients with persistent unilateral symptoms of sore throat. These patients may have an underlying pathology and most units will follow-up patients over 40 if they have presented acutely with unilateral sore throat.
There may either be an obvious oropharyngeal mass on clinical examination, or symptoms may persist despite adequate antimicrobial therapy. Aspiration yields no pus. For more information, see Fort et al and Lau et al below.
Recurrent tonsillitis can disrupt school and working life significantly. In the UK, something like 35 million days are lost annually to sore throats.A history of multiple episodes of recurrent tonsillitis or two quinsies is felt to be a reasonable indication for elective tonsillectomy. See both guidelines below.
References
Fort et al, Am J Emerg Med 2013
Lau et al, Clin Otolaryngol 2021
ENT UK Commissioning Guide for Tonsillectomy (2021)
Scottish Intercollegiate Guidelines Network (SIGN) 117: Indications for Tonsillectomy (2010)
Page last reviewed: 1 December 2022
