Differential diagnoses of PTA include epiglottitis (inflammation of the epiglottis), infectious mononucleosis, lymphoma, peritonsillar cellulitis and retromolar or retropharyngeal abscess.1 On occasions when the diagnosis of PTA is in question, additional lab tests, needle aspiration (looking for pus), CT scan or x-ray may be required to rule out such other upper airway illnesses as epiglottitis, retropharyngeal abscess and peritonsillar cellulitis.

Epiglottitis is primarily a disease of young children caused by H. influenzae. The key clinical difference between epiglottitis and PTA is severe pain in the absence of erythema.5 A retropharyngeal abscess is a pocket of pus that forms beneath the soft tissue in the back of the throat rather than the tonsil. Retropharyngeal abscess is rare in adulthood because the lymph nodes that give rise to this infection are generally atrophied by then.5 Peritonsillar cellulitis is an infection of the soft tissue itself. 


Treatment 


Drainage, antibiotics and supportive therapy to maintain hydration and control pain are the foundation of treatment for PTA.1 The primary drainage procedures are needle aspiration, incision and drainage, and immediate tonsillectomy. Drainage using any of these methods combined with antibiotic therapy will result in resolution of the PTA in more than 90% of cases.7


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The gold standard for diagnosis of a PTA remains the collection of pus from the abscess through needle aspiration. The area should be anesthetized prior to aspiration with benzalkonium 0.5% spray followed by a gargle of lidocaine 2% (Xylocaine) with epinephrine. An 18-gauge spinal needle attached to a 10-mL syringe can be used to obtain material from the suspected abscess.3

Once collected, the fluid should be sent to the laboratory for gram stain and culture to determine the appropriate treatment regimen. Only properly trained health-care providers should perform a needle aspiration of a PTA. Potential complications include hemorrhage and aspiration of pus and blood. If the abscess is located in the distal part of the tonsil, puncture of the carotid artery can occur.3

Although not routinely performed for the treatment of PTA, immediate tonsillectomy should be considered for patients who have strong indications for the procedure, including those who have symptoms of sleep apnea, a history of recurrent tonsillitis (four or more infections per year despite adequate medical therapy), or a recurrent or nonresolving PTA.7

Antibiotic therapy should include antimicrobials effective against Group A streptococcus and oral anaerobes.8 Some studies have reported that more than 50% of culture results demonstrated the presence of beta-lactamase-producing anaerobes, leading many clinicians to use broader spectrum antibiotics as first-line therapy.9-11

Recommended antimicrobial regimens are listed in Table 4.1 It is important to remember that a PTA is very painful, and many patients have difficulty swallowing and are unable to tolerate pills. These individuals will require liquid (outpatient) or IV (inpatient) formulations of medicine. 


Table 4. Antimicrobial regimens

IV therapy
Ampicillin/sulbactam (Unasyn) 3 g every six hours
Penicillin G 10 million units every six hours plus metronidazole (Flagyl) 500 mg every six hours; if allergic to penicillin, clindamycin (Cleocin) 900 mg every eight hours
Oral therapy
Amoxicillin/clavulanic acid (Augmentin) 875 mg b.i.d.
Penicillin VK 500 mg four times daily plus metronidazole 500 mg four times daily
Clindamycin 600 mg b.i.d. or 300 mg four times daily
Source: Fairbanks DN, ed. Pocket Guide to Antimicrobial Therapy in Otolaryngology—Head and Neck Surgery. 12th ed. Alexandria, Va.: American Academy of Otolaryngology—Head and Neck Surgery Foundation, Inc.; 2005:40.

In addition to antimicrobial therapy, steroids have been used to decrease edema and inflammation associated with PTA. The use of steroids in the treatment of PTA has not been widely studied, but a recent investigation reported that 32 patients who received a single high dose of IV steroids (methylprednisolone [A-methaPred, Depo-Medrol, Solu-Medrol] 2 mg to 3 mg per kg up to 250 mg) plus antibiotics responded much more quickly to treatment than did the 28 patients who received antibiotics plus placebo.1 If steroids are needed for a longer period or required on an outpatient basis, liquid prednisone can be prescribed. 


Lastly, and the most important to the patient, is pain control. Adequate pain control plays an important role in compliance with treatment and in keeping the patient out of the hospital. There are multiple liquid forms of pain medication, ranging from OTC analgesics to prescription narcotics. Which one used is based upon a number of factors and is ultimately the provider’s preference. Topical anesthetic can also be beneficial and is available in liquid, gel, and spray forms. This medication provides temporary but very effective pain control. 


A clinician inexperienced in treating PTA should consult an otolaryngologist at the time of diagnosis to determine the appropriate surgical treatment.3 Most patients with a PTA can be treated in an outpatient setting, but a small percentage may require hospitalization.1

Hospital stays usually do not exceed two days and are required for pain control and hydration. It is important to educate patients that the overall risk of developing a second PTA is approximately 10% to 15% and may require a tonsillectomy.

David Areaux, MPAS, PA-C, is an assistant professor in the Physician Assistant Department at Western Michigan University in Kalamazoo.


References


  1. Galioto NJ. Peritonsillar abscess. Am Fam Physician. 2008;77:199-202. Available at www.aafp.org/afp/2008/0115/p199.html.

  2. Johnson RF, Stewart MG, Wright CC. An evidence-based review of the treatment of peritonsillar abscess. Otolaryngol Head Neck Surg. 2003;128:332-343.

  3. Steyer TE. Peritonsillar abscess: diagnosis and treatment. Am Fam Physician. 2002;65:93-96. Available at www.aafp.org/afp/2002/0101/p93.html.

  4. Clinical Key. Peritonsillar abscess. Available at www.clinicalkey.com/
topics/otolaryngology/peritonsillar-abscess.html.

  5. Andreoli TE, Benjamin IJ, Griggs RC, Wing EJ, eds. Cecil Essentials of Medicine. 8th edition. Philadelphia, Pa.: Saunders-Elsevier; 2010:949.

  6. Goldman L, Ausiello, D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Elsevier; 2008:2889.

  7. Herzon FS, Martin AD. Medical and surgical treatment of peritonsillar, 
retropharyngeal, and parapharyngeal abscesses. Curr Infect Dis Rep. 2006;8:196-202.

  8. Brook I. The role of beta-lactamase producing bacteria and bacterial 
interference in streptococcal tonsillitis. Int J Antimicrob Agents. 2001;17:439-442.

  9. Brook I. Microbiology and management of peritonsillar, retropharyngeal, and parapharyngeal abscesses. J Oral Maxillofac Surg. 2004;62:1545-1550.

  10. Kieff DA, Bhattacharyya N, Siegel NS, Salman SD. Selection of antibiotics after incision and drainage of peritonsillar abscesses. Otolaryngol Head Neck Surg. 1999;120:57-61.

  11. Ozbek C, Aygenc E, Unsal E, Ozdem C. Peritonsillar abscess: a comparison of outpatient i.m. clindamycin and inpatient i.v. ampicillin/sulbactam following needle aspiration. Ear Nose Throat J. 2005;84:366-368.

  12. All electronic documents accessed May 15, 2013.