Peritonsillitis and Peritonsillar Abscess

Essentials

• Tonsillitis may proceed to cause first cellulitis of the tissue surrounding the palatine tonsils, i.e. peritonsillitis, and further a peritonsillar abscess.
• The symptoms include fever, severe, often unilateral, throat pain and difficulty swallowing, sometimes trismus and difficulty speaking.
• Laboratory tests and imaging are usually unnecessary.
• Untreated, the disease may progress to cause a deep neck infection.
• The disease always requires emergency treatment.
• Adult patients feeling relatively well can often be treated also in primary health care.

Symptoms and findings

• The diagnosis is based on clinical findings.
• The disease is most common in young adults but may occur in patients of any age.
• There is fever and throat pain that is more severe on the side of the abscess and may radiate to the ear.
• Swallowing is affected.
• There may be trismus or opening of the mouth may be restricted.
• Speech may be slurred due to a swollen upper respiratory tract.
• The palatine tonsils are usually symmetric on inspection. In the soft palate, however, there is more bulging and erythema on one side.
• The inflammation (abscess) is situated above or laterally to the palatine tonsil. The inflammation pushes the palatine tonsil in the medial direction and often also pushes the uvula over the midline.
• Once an abscess has developed, the peritonsillar space (above and laterally to the palatine tonsil) is taut on palpation (with a cotton swab, for instance). Compare the finding to the opposite side that usually gives way and is not tender. Bilateral abscesses are rare but possible.
• In patients with peritonsillitis, symptoms and findings are similar but there is no pus accumulation yet.
• Epiglottitis Epiglottitis and Supraglottitis in an Adult, supraglottitis and laryngitis Hoarseness and Dysphonia should be considered as differential diagnosis. If there are no symptoms of infection, the possibility of a tumour should be considered.
• Throat culture need not be done if an abscess is suspected. It is negative in more than half of the patients. There is often a mixed infection.
• A peritonsillar abscess may occur in association with infectious mononucleosis. Consider doing a rapid test for infectious mononucleosis if the patient is young, both palatine tonsils are greatly swollen and the cervical lymph nodes are also swollen.
• Inflammatory markers (CRP and leukocytes) may help to assess the patient's general status. Nevertheless, the diagnosis of peritonsillar abscess and peritonsillitis is based on clinical findings.

Treatment in outpatient care

• The cellulitis preceding the development of peritonsillar abscess, i.e. peritonsillitis, causes similar symptoms as an abscess. Therefore, the final diagnosis can often only be made after finding out whether pus can be obtained by aspiration, for example.
• In an adult patient who is in good clinical condition, with patent airway and no indication of complications, starting antimicrobial treatment can be considered even without aspiration. If the symptoms are not alleviated within 24 hours, the patient probably has a peritonsillar abscess. Alleviation of symptoms suggests peritonsillitis. On the other hand, if the clinical picture is suggestive of a peritonsillar abscess, aspiration will confirm the diagnosis and symptoms will usually begin to subside immediately after draining the abscess cavity.
• If an adult patient is in a good general clinical condition, the peritonsillar abscess can usually be opened and treated in outpatient care. This can be done either by incision and drainage or by needle aspiration (see below).
• Antimicrobial therapy
  • Ten days of antimicrobial therapy is recommended.
  • If the abscess is easy to drain and the patient is in good clinical condition, the first-choice antimicrobial drug is phenoxymethylpenicillin, for adults 1 million units (IU) 3 times daily. There is no evidence of any benefit of using broader-spectrum antimicrobial drugs.
  • Secondary antimicrobial drugs are cephalexin or amoxicillin. The adult dose is 500 mg 3 times daily.
  • For patients with severe penicillin or cephalosporin allergy, clindamycin should be started. The adult dose is 300-450 mg 3 times daily.
  • If the abscess cannot be drained, anaerobic pathogens causing peritonsillitis can be covered by using a broader-spectrum antimicrobial drug. In addition to penicillin, adults should be prescribed metronidazole, 400 mg 3 times daily. Alternatively, monotherapy with clindamycin can be used, 300-450 mg 3 times daily.
• Give sufficient analgesics (paracetamol and NSAID).
• Advise the patient to get in touch if symptoms are not clearly alleviated in 1 to 2 days or if they recur. In patients with peritonsillitis, an abscess may develop even if antimicrobial treatment has been started. About 10% of drained peritonsillar abscesses recur within the next few days. If so, tampon forceps can be used to reopen the abscess cavity slightly under local anaesthesia or aspiration can be repeated.
• Advise the patient to eat and drink normally once the throat no longer feels numb. Intravenous fluids can be administered, as necessary.
• Depending on the patient's work, sick leave should usually be prescribed for a few days or a week.

To examine the pharynx and treat a peritonsillar abscess, you will need:

• An ENT examination chair, a headlight
• A nurse positioned behind the patient to support the patient's head and to assist with the instruments
• Equipment for local anaesthesia (10% lidocaine, i.e. Xylocaine, spray and 2 ml syringe, 1% lidocaine-adrenaline and a long 25 gauge needle)
• Tongue blade, long 18 gauge needle and 10 ml or 20 ml syringe, No. 11 scalpel blade, tampon forceps or haemostatic forceps
• Suction equipment
• I.v. rehydration kit if the patient is dehydrated

Examination of the pharynx and incision of peritonsillar abscess

1. Before the procedure, make the patient feel more comfortable, if necessary, by administering i.v. fluids and analgesic medication.
2. With the patient sitting upright and keeping his/her mouth as wide open as possible, depress the tongue with a tongue depressor. Perform indirect laryngoscopy with a mirror to make sure that the abscess does not reach the hypopharynx and cause airway obstruction.
3. Spray the most prominent area of the mucous membrane overlying the abscess with Xylocaine anaesthetic.
4. Infiltrate 1-2 ml of local anaesthetic under the palatoglossal arch at the location of the abscess, first immediately under the mucous membrane and then deeper. After administering the anaesthetic, try to localize the abscess cavity by using the same needle to aspirate from three locations (picture 1).
5. The abscess cavity can primarily be emptied by draining the pus carefully with the anaesthetic needle or with a larger needle.
6. If the abscess is not sufficiently emptied by needle aspiration, a larger incision is needed. Incision can also be used primarily. Under local anaesthesia make a 1-1.5 cm incision in the mucous membrane parallel to the palatal arch at the site with the largest bulge.
7. Dissect bluntly along the capsule of the tonsil with haemostatic or tampon forceps until the abscess cavity is found. Open the forceps only when in the abscess cavity. You should find your way to the back of the tonsil around its edge and not proceed to the tonsillar tissue. Work in the sagittal plane.
8. Remove all pus with a rigid catheter for oral suction (metal or plastic) and take a sample for bacterial culture if needed.
9. The patient should sit leaning forward and rinse the mouth with cool water until bleeding stops.

Indications for ENT consultation