Do you want to learn about peritonsillar abscesses?
This post provides information for what peritonsillar abscesses are and how they are treated.
This post was written by an Ear, Nose, and Throat (ENT) Surgeon.
There are several illustrations that help explain the infection and how it spreads.
Summary for peritonsillar abscess:
Peritonsillar abscesses occur when a severe infection occurs in the throat.
Classically, a patient has an infection of the tonsils and the infection spreads to the tissue beside the tonsils (known as the peritonsillar area).
Initially, the peritonsillar infection causes swelling (cellulitis) and over time it can become a more significant infection known as an abscess (pus and debris inside).
Peritonsillar abscesses can be drained at the beside in the clinic or at the bedside in the emergency room.
In some cases, the surgeon may recommend going to the operating room.
Two main ways for draining an abscess include needle aspiration and incision and drainage. Rarely, a tonsillectomy may be recommended.
After draining the abscess, the surgeon will typically prescribe antibiotics with or without oral steroids.
What is a peritonsillar abscess?
A peritonsillar abscess is an infection from the tonsils that spreads to the surrounding tissue and the infection is so significant that the body forms a capsule around the infection (an abscess).
An abscess is a collection of pus and debris that is walled off.
Peritonsillar abscesses tend to form in a potential space that is located between the tonsil capsule and the surrounding muscle (superior pharyngeal constrictor). 
What factors predispose someone to develop a peritonsillar abscess?
A throat infection precedes a peritonsillar abscess and risk factors for the infection to become an abscess include:
- Poor oral hygiene,
- Tobacco product use, and
- Recent antibiotic use. 
What is the classic presentation of a patient with a peritonsillar abscess?
Patients with a peritonsillar abscess typically have had a sore throat for a few to several days.
The sore throat gets dramatically worse.
Then usually one side of the throat will become more infected and swollen.
Patients develop significant pain with swallowing and difficulty with swallowing, especially when the infection spreads beyond the tonsils to the area around it (peritonsillar area).
Typical signs and symptoms include [2, 3]:
- Swelling of one or both of the tonsils and/or tissue around the tonsil (peritonsillar area),
- Hot potato voice (voice sounds muffled),
- Fever (usually above 101.5 F),
- Shifting of the uvula away from the middle of the throat (the tissue in the back of the throat may deviate away from the middle of the throat),
- Difficulty in opening the mouth (trismus, which happens because the muscle around the area [ptyerygoid muscles specifically] that help to open the mouth are affected),
- Difficulty swallowing (dysphagia),
- Pain with swallowing (odynophagia), and
- Drooling in children.
Note: if there is shortness of breath, then this could lead to an emergency situation.
What are complications from a peritonsillar abscess?
Because a peritonsillar abscess is a severe infection, it can also cause significant problems.
Potential complications include :
- Difficulty with breathing due to swelling of the tissue of the throat,
- Severe dehydration when patients refuse to drink,
- Bleeding from the infection after it damages major blood vessels (such as the internal carotid artery),
- Spread of the infection into the bloodstream (sepsis) which can lead to toxic shock syndrome,
- Spread of the infection to the brain,
- Spread of the infection into other spaces of the neck (such as the parapharyngeal space) and then spreading down the neck and even into the chest (mediastinitis),
- Lung infection (pneumonia) from the infectious material making it down the airway (aspiration), and
- Death is very rare but possible from these complications.
What types of organisms are found in a peritonsillar abscess?
Bacteria such as Group A streptococcus, Streptococcus viridans, Klebsiella pneumoniae, Prevotella, and Fusobacterium necrophorum. [1, 4]
Will peritonsillar cellulitis go away on its own?
If the infection is cellulitis (phlegmon) and not an abscess, then it is possible that the antibiotics could help treat the infection without a procedure.
It depends on factors such as whether the patient is on antibiotics, is immunocompromised (i.e. has Human Immunodeficiency Virus (HIV), diabetes, or is on chronic steroids), how long the infection has been present, and the size and location of the infection.
However, once an abscess has formed, it means that the body has walled off the infection and it should be treated.
It can be very difficult to determine if the patient has peritonsillar cellulitis (phlegmon) or a peritonsillar abscess. Therefore, a patient should see a professional healthcare provider, so they can evaluate and appropriately treat the patient.
Can a peritonsillar abscess spread?
Yes, a peritonsillar abscess can start off small and can grow and spread.
Initially, during the formation of a peritonsillar infection, the tissue is swollen and infected and this is known as cellulitis.
As the infection worsens, it spreads outside the tonsils themselves into the peritonsillar area.
As the infection worsens yet again, the cellulitis can become a phlegmon (almost like an early abscess), but not quite an abscess.
Then once the body has walled off the infection, it becomes an abscess.
The abscesses themselves can become larger and can continue to spread.
What is the treatment for a peritonsillar abscess?
Treatment depends on the size and location of the infection.
If the infection is caught early and the abscess is very small, then it is possible to place the patient on oral antibiotics with close observation to ensure they are getting better.
If the patient is dehydrated, then sometimes intramuscular (IM) or intravenous (IV) antibiotics are needed (sometimes with admission to the hospital, especially if the patient is significantly dehydrated).
If the infection has progressed, then a procedure may be needed.
The two most common procedures used are to place a needle into the abscess and then to remove the pus by suctioning (needle aspiration), or to make a cut on the surface of the peritonsillar abscess tissue and then drain it (incision and drainage). 
Rarely, a tonsillectomy may be performed because of the infection, known as a hot or quinsy tonsillectomy. 
Because it is infected, the tonsillectomy is much harder to perform than a regular tonsillectomy as the tissue tends to bleed more during the surgery.
Where are peritonsillar abscesses drained?
Peritonsillar abscesses are most often drained at the bedside (either in the emergency room or in the ENT clinic).
If there is a concern for problems with the airway, or if the abscess is difficult to drain, then the patient might be best served by having the procedure in the operating room.
In some cases, the ENT surgeon may recommend that the patient go to the operating room to have an incision and drainage of the peritonsillar abscess and additionally may recommend a tonsillectomy while there.
Because of the infection, bleeding during surgery is higher in patients who undergo a tonsillectomy, and the ENT surgeon and the patient have to weigh the risks, benefits, and alternatives prior to the surgery.
How is a peritonsillar abscess drained in the clinic?
The first step in draining a peritonsillar abscess is to spray the throat with a topical anesthetic (such as benzocaine spray).
The surgeon then waits a few minutes and then injects a local anesthetic (such as 1% lidocaine with 1:100,000 epinephrine) over the area where the incision is going to be made or where the needle will be used to aspirate.
Once the patient is sufficiently numb, the surgeon will then perform one of the two techniques.
The first technique is to perform a needle aspiration.
The second technique is to perform an incision and drainage.
What is a needle aspiration?
During aspiration, a needle is placed into the area that the surgeon has identified as the location where the peritonsillar abscess is or could be.
This decision is made on the clinical exam and sometimes is also based on imaging such as a computed tomography (CT) scan if one was performed.
If the surgeon identifies an area then he or she will aspirate with a needle.
At this point, the surgeon determines whether or not to perform the second technique, which is an incision and drainage of the peritonsillar abscess.
How is an incision and drainage performed for a peritonsillar abscess in the operating room?
When going to the operating room, an incision and drainage is the method of choice.
For draining a peritonsillar abscess, the surgeon determines the most likely location for the abscess pocket by using one of three techniques:
- Computed tomography (CT) scan,
- Physical exam, and/or
- Needle aspiration.
After determining the most likely location, the surgeon will use a surgical knife such as a 15-blade to make an incision over the mucosa (surface of the throat, similar to the skin).
Once the surgeon has gone through the mucosa the surgeon then selects a blunt instrument such as a Kelly forceps.
The Kelly forceps are then used to bluntly spread into the abscess so that it can be drained.
Once the abscess is drained, the surgeon then decides whether or not the patient needs to be admitted. There are many factors involved in determining whether a patient is admitted to the hospital or not.
Surgeons may choose to send the patient home on oral antibiotics and pain medications. Strict follow-up precautions are given for the patient to return to the emergency room or the clinic if there is any worsening.
Sometimes because of airway concerns, and depending on how much of the abscess was able to be drained, the surgeon may recommend admission to the hospital for intravenous (IV) antibiotics.
When a child has a peritonsillar abscess, are they drained in the operating room or in the emergency room?
Drainage of a peritonsillar abscess in children is more difficult because they don’t generally keep their mouths open for the procedure.
It does depend on their age.
The older the child, the more likely they will follow instructions.
For younger children, if the surgeon and emergency room provider agree that it is safe to drain the abscess under sedation, then the child can be given sedating medications that are generally considered safe when the airway is involved (such as ketamine).
The authors of the study point out that appropriate personnel and equipment (monitors, intubating equipment) should be present because the medications could result in deep sedation.
If there is any concern for the patient’s airway, then the procedure should be performed in the operating room with a breathing tube (endotracheal tube) being placed into the airway to ensure that the airway is protected during surgery.
When are tonsillectomies performed in addition to an incision and drainage?
In extreme cases, the surgeon might recommend that the patient also have a tonsillectomy at the time of incision and drainage of the peritonsillar abscess while they are in the operating room.
Factors include the location of the infection (inferior were below the tip of the uvula and were more likely to have a tonsillectomy at the same time) and whether the infection has spread beyond the peritonsillar region into other areas such as the parapharyngeal space or the retropharyngeal space.
This is more often the case if the infection is large and/or also have the involvement of an intra-tonsillar abscess that could not adequately be drained.
A major challenge when performing a tonsillectomy in a patient who has an active infection is that there is more bleeding.
The tonsillar tissue becomes friable and the surgery is more challenging.
Sometimes the surgeon may recommend that the patient have a few months to recover before determining whether a tonsillectomy is a good option.
There are guidelines that are used by otolaryngologists, known as the Paradise criteria in which the number of regular tonsil infections (not per-tonsillar abscesses) would need to be met (i.e. 3 infections a year for 3 years, 5 infections a year for 2 years or 7 infections in one year). 
Are steroids recommended for patients who have had a peritonsillar abscess?
A review article found that difficulty swallowing (dysphagia), fevers, and pain scores were improved in patients who had steroids compared with those who were given a placebo (a test pill with no substance, used to test how well medications work).
Another review article found that the use of short-term, high-dose corticosteroids may be safe and effective.
Are patients who have a needle aspiration more likely to have a recurrence of the peritonsillar abscess when compared to an incision and drainage?
A systematic review found that there is no high-quality evidence that an incision and drainage is more effective than a needle aspiration of a peritonsillar abscess.
However, the same study states that very low-quality evidence suggests that incision and drainage may be less likely to present with a recurrence when it is compared to a needle aspiration.
One group of surgeons found that patients who had incision and drainage initially ended up spending less time in the hospital when they were admitted. 
Additionally, patients who underwent incision and drainage were less likely to need a repeat procedure (10%) when compared to needle aspiration (46%). 
It is also possible that in patients who have a very large peritonsillar abscess that the surgeons might favor incision and drainage, while in patients with a small peritonsillar abscess that the surgeons might favor a needle aspiration.
What is the International Classification of Diseases-10 (ICD-10) Code for peritonsillar abscess?
The ICD-10 Code is J36.
What is the Current Procedural Terminology (CPT) code for incision and drainage of a peritonsillar abscess?
The CPT codes are:
- 42700 for a standard incision and drainage,
- 42720 for an intraoral approach with retropharyngeal or parapharyngeal surgery, and
- 42725 for an external approach (neck approach).
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