AUTHOR INFORMATION

Section 1 of 10

Authored by Ninfa Mehta, MD, Staff Physician, Department of Emergency Medicine, State University of New York Downstate Medical Center, Kings County Hospital

Coauthored by Mark A Silverberg, MD, FACEP, MMB, Assistant Professor of Emergency Medicine, State University of New York Downstate College of Medicine, Assistant Residency Director, Department of Emergency Medicine, Kings County Hospital; A Antoine Kazzi, MD, Chief of Service, Department of Emergency Medicine, Medical Director of the Emergency Unit, American University of Beirut; Mazen El-Sayed, MD, Staff Physician, Department of Surgery, Washington Hospital Center

Edited by Michael Glick, DMD, Professor and Acting Chair, Department of Diagnostic Sciences, New Jersey Dental School, University of Medicine and Dentistry of New Jersey; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center, Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Pamela Dyne, MD, Program Director, Associate Professor, Department of Medicine, Division of Emergency Medicine, University of California at Los Angeles School of Medicine

Author's Email:	Ninfa Mehta, MD
Editor's Email:	Michael Glick, DMD

eMedicine Journal, March 14 2007, VOLUME 8, Number 3

INTRODUCTION

Section 2 of 10

Background: Peritonsillar abscess (PTA) is a common infection of the head and neck region. Combinations of aerobic and anaerobic bacteria colonize the peritonsillar space. This potential space is bounded by the tonsillar pillars anteroposteriorly, the piriform fossa inferiorly, and the hard palate superiorly.

Pathophysiology: Peritonsillar abscess is an infection that begins superficially and progresses into the deep soft tissues. The exact mechanism of the initial abscess formation is not known. Abscesses form between the palatine tonsil and its capsule, usually at the superior pole. It is believed that these abscesses most likely arise from an acute episode of tonsillitis which then progress to involve the soft tissues surrounding this area. Another proposed mechanism is necrosis and pus formation in the capsular area which then obstruct the weber glands, which then swell and the abscess forms.

Frequency:

• In the US: According to Herzon (1995) peritonsillar abscess is the most common infection of the peritonsillar space. In the U.S. the incidence is someplace around 30 cases per 100,000 persons per year which ends up causing approximately 45,000 cases annually.

• Internationally: A higher rate due to recurrence and antibiotic resistance is reported internationally.

Mortality/Morbidity:

• The death rate is unknown.

• Morbidity is due mostly to pain, cost, lost time, and complications.

Race: No predilection

Sex: males = female

Age: PTA can occur in anyone from 10-60 years old according to one source although they are most commonly seen between the ages of 20-40. The younger children who get PTA’s often are immunocompromised.

CLINICAL

Section 3 of 10

History: Symptoms begin 3-5 days prior to evaluation.
Unilateral sore throat
Dysphagia
Change in voice
Headache
Malaise
Fever
Neck pain
Otalgia
Odynophagia

Physical: Fever
Cervical lymphadenitis in the anterior chain
Asymmetric tonsillar hypertrophy
Trismus (inability or difficulty in opening the mouth)
Inferior and medial displacement of the tonsil
Contralateral deviation of the uvula
Erythema of the tonsil
Exudate on the tonsil
Drooling, salivation, trouble handling oral secretions
Hot potato/muffled voice
Tachycardia
Mild/moderate distress
Localized fluctuance
Dehydration

Causes: PTA’s are usually polymicrobial when the drained puss is cultured. Most common aerobic species found are Streptococcus sp. (especially Strep. Pyogenes) and the most common anaerobic species found are Prevotellar sp. and Peptostreptococcus sp. (Sakae, 2006)

DIFFERENTIALS

Section 4 of 10

Dental, Infections

Other Problems to be Considered:

Peritonsillar cellulitis
Retropharyngeal abscess
Mononucleosis
Pharyngitis
Tonsillitis
Carotid aneurysm
Epiglottitis
Parapharyngeal abscess
Leukemia
Lymphoma
Tracheitis
Ludwig’s angina

WORKUP

Section 5 of 10

Lab Studies:

• CBC with differential
  Chemistry panel if not taking PO or drooling
  Monospot test/ heterophile antibody
  Culture of fluid from needle aspiration

Imaging Studies:

• Xrays: lateral soft tissue neck xrays may help rule out other causes. The AP view of the neck may demonstrate distortion of soft tissue.

  CT scan: head and neck scan with IV contrast is useful if I&D is failed, patient can not open the mouth or patient is young ( <7 years old). You may see a hypodense fluid collection in the affected tonsil with rim enhancement. Foreign bodies such as fish or chicken bones may also be found as an inciting factor.

  Ultrasound: Intraoral ultrasound has a sensitivity of 95.2% and specificity of 78.5%. Transcutaneous ultrasound has a sensitivity of 80% and specificity of 92.8%. This method is cost-effective and fast.

Procedures:

• Needle Aspiration: Used for symptom relief and is the gold standard for diagnosis. Lidocaine with epinephrine should be used to anesthetize the area. A 16-18 gauge needle with a 10 cc. syringe should be used to aspirate from the area which is most fluctuant. Since the superior pole is the most common place for the abscess to develop, that is usually the first place aspirated if the entire tonsil looks boggy. The middle 1/3 and then the lower 1/3 aspiration should then be attempted if not pus is returned from the superior pole.

  Tonsillectomy: For recurrent peritonsillar abscesses.

TREATMENT

Section 6 of 10

Prehospital Care:

• Transport with supplemental oxygen.

Emergency Department Care: ABC’s, paying attention to the patient’s airway. If the patient’s airway is compromised they need immediate intubation. If intubation can not be completed then a cricothyroidotomy or a tracheotomy may need to be performed. These patients are often dehydrated due to their avoidance of food and liquid and will need fluid resuscitation. Antipyretics should be administered for elevated temperature, and adequate analgesia should be provided for pain. Needle aspiration should be done to drain the abscess and provide pain relief. If aspiration can not be completed the abscess may need an incision and drainage. If this is the case, otolaryngology should be consulted to perform the procedure. After drainage antibiotics should be administered. Steroids have been shown in one study to decrease the number of in-hospital days . Patients can be managed on an outpatient basis unless they show signs of toxicity, sepsis, airway compromise, or complications.

Consultations: Otolaryngology, Anesthesia for difficult airway management.

MEDICATION

Section 7 of 10

Antibiotics are the main component of therapy. Along with drainage of the abscess, antibiotics usually suffice to resolve PTA. Begin antibiotic therapy prior to needle aspiration and report of culture results. Because of streptococcal resistance of more than 30% and infection with mixed bacterial flora, many practitioners recommend combination therapy of a penicillin and metronidazole (98% sensitivity). Some physicians still use only penicillin initially. Penicillin resistance is reported in 11-65% of patients. Analgesics and throat washes are recommended. Some physicians report using adjunctive steroids to decrease edema and pain.

Drug Category: Antibiotics -- Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Drug Name	Penicillin G benzathine (Bicillin L-A) -- DOC in combination with metronidazole. Effective in approximately 98% of patients. Interferes with synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.
Adult Dose	600 mg (~1 million U) IV q6h for 12-24 h
Pediatric Dose	12,500-25,000 U/kg q6h
Contraindications	Documented hypersensitivity
Interactions	Probenecid can increase effects; coadministration of tetracyclines can decrease effects
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in impaired renal function

Drug Name	Metronidazole (Flagyl) -- DOC in combination with penicillin. Effective in approximately 98% of treated patients. Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Appears to be absorbed into the cells of microorganisms that contain nitroreductase. Unstable intermediate compounds are formed that bind DNA and inhibit synthesis, causing cell death.
Adult Dose	Loading dose: 15 mg/kg or 1 g for 70-kg adult IV over 1 h Maintenance dose: 6 h following loading dose, infuse 7.5 mg/kg or 500 mg for 70-kg adult over 1 h q6-8h; not to exceed 4 g/d
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	May increase toxicity of anticoagulants, lithium, and phenytoin; cimetidine may increase toxicity disulfiram reaction may occur with orally ingested ethanol
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Adjust dose in hepatic disease; monitor for seizures and development of peripheral neuropathy; known or previously unrecognized vaginal candidiasis may present more prominent symptoms during metronidazole vaginal-gel therapy; >6% of patients have developed symptomatic candidal vaginitis during or immediately following therapy

Drug Name	Nafcillin (Unipen) -- Initial therapy for suspected penicillin G-resistant streptococcal or staphylococcal infections. Use parenteral therapy initially in severe infections. Change to PO therapy as condition warrants. Due to thrombophlebitis, particularly in the elderly, administer parenterally only for short term (1-2 d); change to PO route as clinically indicated.
Adult Dose	1-2g IV q4h
Pediatric Dose	50 mg/kg/d divided q4-6h
Contraindications	Documented hypersensitivity
Interactions	Associated with warfarin resistance when administered concurrently; effects may decrease with bacteriostatic action of tetracycline derivatives
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	To optimize therapy, determine causative organisms and susceptibility; administer more than 10 d of treatment to eliminate infection and prevent sequelae (eg, endocarditis, rheumatic fever); take cultures after treatment to confirm that infection is eradicated

Drug Name	Erythromycin (E.E.S, Ery-Tab, Erythrocin) -- Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes causing RNA-dependent protein synthesis to arrest. For treatment of staphylococcal (including S aureus) and streptococcal infections. Indicated if patient is allergic to penicillin.
Adult Dose	15-20 mg/kg/d IV divided q6h; not to exceed 4 g/d
Pediatric Dose	30-50 mg/kg/d (15-25 mg/lb/d) PO divided q6-8h; double dose for severe infection
Contraindications	Documented hypersensitivity; hepatic impairment
Interactions	Coadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin; coadministration with lovastatin and simvastatin, increases risk of rhabdomyolysis
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in liver disease; estolate formulation may cause cholestatic jaundice; GI adverse effects are common (administer doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur

Drug Name	Clindamycin
Adult Dose	25-40 mg./kg./d. IV Q6 hours

Drug Name	Augmentin
Adult Dose	200 mg./kg./d. IV Q6 hours

FOLLOW-UP

Section 8 of 10

Further Inpatient Care:

• Observation, imaging studies, airway management, and IV hydration may be required.

• Other methods of operative management strategy may be indicated and should be performed by an otolaryngologist.

• Incision and drainage formerly was the treatment of choice; however, great care must be taken in suctioning the purulent material to avoid aspiration, which may lead to pneumonitis and/or pneumonia.

• Emergent tonsillectomy came under criticism because studies of the procedure demonstrated that desired outcomes did not occur as rapidly as supporters had predicted.
  • Costs were increased considerably.

  • Bleeding complications (1-7%) were higher.

  • Less invasive and equally effective alternatives are now available in uncomplicated cases.

  • Emergent tonsillectomy is used to treat patients with a history of 3 or more PTAs.

  • Recurrence obviates the need for a second hospitalization for interval tonsillectomy after incision and drainage. Whether recurrence is an indication for tonsillectomy remains unclear.

• To prevent recurrence, interval tonsillectomy may be considered 3-4 weeks after disappearance of edema and symptoms. The value of such a strategy is somewhat controversial. Tonsillectomy reduces the need for admission for recurrences of PTA; however, that need is rare since most PTAs now are treated percutaneously and on an outpatient basis.

Further Outpatient Care:

• If outpatient care is used, the patient can be discharged (after needle aspiration treatment) on an appropriate regimen of antibiotics and pain medications.

• Relative indications for elective tonsillectomy can be identified in almost a third of all patients who present with PTA (eg, recurrent tonsillitis).

Complications:

• Necrotizing soft tissue infection of the neck and chest wall (Losanoff, 2005)
  Recurrence
  Aspiration which may lead to pneumonia or pneumonitis
  Cervical abscess
  Mediastinitis
  Meningitis
  Sepsis
  Cerebral abscess
  Jugular vein thrombosis
  Carotid artery rupture

Prognosis:

• Uncomplicated, treated peritonsillar abscess have a resolution rate of 94%. In the U.S. there is 10% recurrence rate although, this jumps to 15% internationally.

Patient Education:

• For excellent patient education resources, visit eMedicine's Ear, Nose, and Throat Center. Also, see eMedicine's patient education articles Peritonsillar Abscess, Tonsillitis, and Antibiotics.

TEST QUESTIONS

Section 9 of 10

CME Question 1: Which of the following antibiotic treatments provides the widest coverage for patients with peritonsillar abscess (PTA)?

A: Penicillin and erythromycin
B: Penicillin and metronidazole
C: Penicillin alone
D: Nafcillin and erythromycin
E: Erythromycin alone

The correct answer is B: The combination of penicillin and metronidazole is effective in approximately 98% of patients with PTA.

CME Question 2: What is the best way to diagnose a patient with suspected peritonsillar abscess (PTA) who presents with severe trismus?

A: History and physical and needle aspiration with culture and sensitivity
B: History and physical and CBC with differential
C: History and physical and intraoral ultrasound
D: History and physical and CT scan
E: History and physical and needle aspiration

The correct answer is D: Patients presenting with trismus often have difficulty opening their mouth due to the involvement of the internal pterygoid muscle, preventing the use of intraoral ultrasound and needle aspiration as diagnostic modalities. Although more costly, a CT scan can be very useful in diagnosing PTA.

Pearl Question 1 (T/F): Intraoral ultrasound is a cost-effective diagnostic modality that may be ordered to exclude peritonsillar cellulitis and retropharyngeal abscess.

The correct answer is True: Ultrasound (with a high degree of accuracy) confirms the presence of an abscess as well as the volume, location, and relationship of the abscess to the carotid artery.

Pearl Question 2 (T/F): Peritonsillar abscess (PTA) most commonly is observed in individuals aged 45-60 years.

The correct answer is False: PTA most commonly is observed in individuals aged 20-40 years.

Pearl Question 3 (T/F): Classic symptoms of odynophagia begin 3-5 days prior to evaluation and diagnosis.

The correct answer is True: Classic symptoms begin 3-5 days prior to evaluation and diagnosis; time from onset of symptoms to abscess formation is about 2-8 days.

Pearl Question 4 (T/F): Oropharyngeal examination typically reveals only edema of tissues lateral and superior to the involved tonsil.

The correct answer is False: Oropharyngeal examination also reveals medial and/or anterior displacement of that tonsil and displacement of the uvula to the contralateral side of the pharynx. The tonsil may or may not be erythematous, enlarged, or covered with exudate.

BIBLIOGRAPHY

Section 10 of 10

• Ahmed K et al.: Radiology in focus: The role of ultrasound in the management of peritonsillar abscess. J Laryngol Otol 1994; 108: 610-612.
• Aldakhail AA, Khan MI: A retrospective study of peritonsillar abscess in Riyadh Medical Complex. Saudi Med J 2006 Aug 27; 8: 1217-21.
• Araujo Filho BC, Sakae FA, et al.: Intraoral and transcutaneous cervical ultraound in the differential diagnosis of peritonsillar cellulitis and abscesses. rev Bras Otorrinolaringol (Engl Ed) 2006; 3: 377-81.
• Blokmanis A: Ultrasound in the diagnosis and management of peritonsillar abscesses. J Otolaryngol 1994; 23: 260-262.
• Fauci AS et al: Harrison's Principles of Internal Medicine, 14th ed. New York, McGraw-Hill. 1998; 183.
• Garcia Callejo FJ, Nunez Gomez f, et al.: Management of peritonsillar infections. An Pediastr. 2006 jul; 65: 37-43.
• Hanna BC, McMullan R, Hall SJ: Corticosteroids and peritonsillar abscess formation in infectious mononucleosis. J Laryngol Otol 2004 Jun; 118(6): 459-61.
• Herzon FS, Martin AD: Medical and surgical treatment of peritonsillar,retropharyngeal, and parapharyngeal abscesses. . Curr infect dis rep 2006 May; 8(3): 196-202.
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• Ozbek C, Aygenc E, Tuna EU, et al: Use of steroids in the treatment of peritonsillar abscess. J Laryngol Otol 2004 Jun; 118(6): 439-42.
• Passy V: Pathogenesis of peritonsillar abscess. Laryngoscope 104; 1994: 185-190.
• Roberts J: Emergency department considerations in the diagnosis and treatment of peritonsillar abscess. Emerg Med News 1996; 2: 4-7.
• Sakae FA, Imamura R., et al: Microbiology of peritonsiallar abscesses. . Rev Bras Otorrinolaringol (Engl Ed) 2006 Mar-Apr; 72 (2): 247-51.
• Sakaguchi M et al: Radiology in focus: Computed tomographic findings in peritonsillar abscess and cellulitis. J Laryngol Otol 1995; 109(59): 449-451.
• Strong E et al: Intraoral ultrasound evaluation of peritonsillar abscess. Laryngoscope 1995; 105: 779-782.
• Tintinalli J et al (eds): Emergency Medicine: A Comprehensive Study Guide. New York, McGraw-Hill. 1996; 1077-1078.

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