emDOCs.net – Emergency Medicine EducationemDOCs Podcast: Episode 34 – Peritonsillar Abscess - emDOCs.net

Aug 2nd, 2021
Rachel Bridwell
categories:
Podcast

Today on the emDOCs cast with Brit Long, MD (@long_brit) and Rachel Bridwell, MD (@rebridwell), we cover peritonsillar abscess.

Peritonsillar Abscess

Epidemiology:

Most common deep neck infection in children and adolescents.
- Accounts for 50% of cases of deep neck infections in this population.¹
Rate of occurrence varies from 1-3/10,000 per year.²
Risk factors include recurrent tonsillitis, partially treated tonsillitis episodes following multiple antibiotics, and smoking.³
Primary age range is in adults 20-40 years old.²
Often polymicrobial, and predominant bacteria include:
- Streptococcus pyogenes (group A strep), Streptococcus anginosus, Staphylococcus aureus (including MRSA), Fusobacteria, Prevotella, and Veillonella^3,4

Clinical Presentation:

Classically, patient presents with severe sore throat, fever, odynophagia, and a muffled “hot potato” voice (dysphonia).
May also have neck swelling and pain and ipsilateral ear pain.⁵
Trismus occurs in only 2/3 of patients.⁶
- While trismus is a primary symptom classically associated with PTA, its absence should not exclude the diagnosis of PTA.⁶

Evaluation:

Assess ABCs and VS abnormalities.
- Assess airway for degree of potential upper airway obstruction. Patients exhibiting posturing, unable to handle secretions, or toxic-appearance should be monitored continuously while emergent airway interventions are prepared.
- Especially in the critically ill/toxic-appearing PTA patient with airway compromise, consider all adjuncts and difficult airway equipment (LMA, Video Laryngoscopy, bougie, ambuscope, awake intubation) as well as consultants (ENT/Anesthesia, surgery) nearby to call for help if needed.
- Difficult airway includes cricothyrotomy as well as mobilizing surgery for a bedside percutaneous tracheotomy.
Perform a complete physical examination, including HEENT, pulmonary, and CV.
- Perform a thorough examination and avoid anchoring on the obvious swollen peritonsillar region:
  - Oropharynx, sublingual tissue, nares, palpate neck, mouth floor, and throat.
  - Lung examination may reflect the degree of airway obstruction, based on work of breathing or use of accessory muscles.
- Often abscess collection at superior pole of tonsil is present with unilateral swelling, erythematous elevated soft palate, and edematous uvula deviated towards unaffected tonsil. Cervical lymphadenopathy may be present.⁷
- Abscess can still occur after tonsillectomy and adenoidectomy (T&A) as a parapharyngeal abscess, though this is less common than PTA. Thus, do not rule out abscess in same region where tonsils once were simply because a patient presents after T&A.
Imaging: CT vs. US.
- US can be performed at the bedside.
- Endocavitary probe for intraoral US may provide the best view of the PTA, but you can use the linear high frequency probe with a submandibular approach if the patient cannot tolerate the endocavitary ultrasound.
- Intraoral US: sensitivity 89-100%,specificity 100%.⁸
  - High frequency transducers specifically for intraoral use have been made, but can use endocavitary transducer if intraoral is not available.
- Intraoral US may be complicated by physical limitations and patient cooperation such as pain, gagging, or trismus.
- If intraoral US can not be tolerated, extraoral high-frequency linear probe may be used.
  - Sensitivity 80-91% and specificity of 80-93%.⁹
- CT requires supine position, which some patients may not tolerate.
- CT head & neck with contrast: sensitivity 100%, specificity 75%.
- While not necessary to make the clinical diagnosis of PTA, imaging can confirm diagnosis, better visualize location and complexity of abscess, and distinguish from other deep space infections (retro- or parapharyngeal abscess).
  - May identify rare but deadly extracranial ICA aneurysms; these mimic PTAs and are often catastrophically identified on attempted drainage.¹⁰
Laboratory Evaluation: adjunct to a clinical diagnosis of PTA, some evidence suggests lab work to include:
- CBC, serum electrolytes (if decreased PO intake), and gram stain/culture to help determine best choice of antibiotics if refractory to empiric antibiotics.¹¹
  - Gram stain/culture rarely changes initial management, but may help guide antimicrobial therapy in patients with complicated, extensive infection, those not improving on empiric oropharyngeal coverage, or in the immunocompromised.²

Treatment:

Needle Aspiration: Please see this emDocs Unlocking Common ED Procedures Post.
- Can be less painful and with a lower need to hospitalize in comparison to I&D.
- Set up for drainage:
  - Hurricane spray and/or 4% viscous lidocaine to topically anesthetize (1% lidocaine with 1:100,000 epinephrine to inject locally).
    - Hurricane spray used as topical anesthetic has a low risk of methemoglobinemia, around 0.035%.^12,13
  - 3cc syringe with 18g needle (for drawing lido) and 27g needle (for injection)
  - Control top syringe with 18g needle, or consider using a spinal needle with an IV catheter extension tubing OR:
  - #11 blade (With guard retracted 1.5 cm)
  - Hemostats (if I&D)
  - Suction with Yankauer tip
- Headlamp, bottom half of speculum, or laryngoscope blade, held by patient can displace the tongue and free up the operator.
- Usually performed with patient sitting.
- Initial aspiration site should be superior pole of peritonsillar tissues, proceeding inferiorly if not successful.
- Needle advanced in sagittal plane to avoid aspirating internal carotid artery.
  - ICA lies approximately 2.0-2.5cm posterior and lateral to the palatine tonsils.
  - Can also use a needle guard by cutting 1 cm off the plastic sheath that comes with a spinal needle to aspirate, helping safeguard against aspirating too laterally.^12-14
Incision and Drainage
- Generally, less preferred than needle aspiration, as I&D is more painful with more bleeding.¹⁵
  - If abscess pocket identified, make an approximately 1cm long incision, following the orientation of the arch of the swollen tonsil tissue (from medial to lateral in a hockey stick shape).
  - Spread the pocket with hemostats and break up septations, or use Yankauer tip to gently apply pressure around incision site.
  - Leave the hole open for drainage.
- Patients must be observed after I&D to ensure tolerance of PO antibiotics, pain medications, and liquids (hospitalization vs. 24-hour follow-up).⁵
- If discharging the patient, give cotton tipped applicators and instruct the patient to run the applicators inside incision site to prevent premature closure. This serves in lieu of packing or vascular loop which is not tolerated in this anatomic region.
Antibiotics
- While often polymicrobial infections, antibiotics should cover GAS and Fusobacterium.¹⁶
- Amoxicillin/clavulanic acid 875mg BID x 10 days OR Penicillin VK 500mg QID + Metronidazole 500mg QID x 10 days
- If PCN allergy: Clindamycin 150mg QID x 10 days
- If PO intolerant: Amoxicillin/Sulbactam (Unasyn) IV, 3g q6hrs
- Other considerations:
  - Ibuprofen provides better pain relief than acetaminophen in pain and fever in pharyngitis, though both are better than placebo and reduce symptoms at 48 hours.¹⁷
  - Steroids can reduce odynophagia, with one study showing methylprednisolone or dexamethasone reducing pain and odynophagia at 24 hours.¹⁸
Complications:^5,7
- Airway obstruction
  - Immediate life threat in complicated patients
- Aspiration pneumonia following rupture of abscess into airway
- Septicemia
- Injury to the internal carotid artery from I&D or needle aspiration is a feared complication.
- Quinsy Tonsillectomy is the simultaneous urgent incision and drainage of abscess followed immediately by tonsillectomy by ENT.
  - This urgent operative procedure incurs a higher risk complications such as bleeding (0 to 7% rate of occurrence) or aspiration of abscess contents.¹⁶
  - Performed due to of significant upper airway obstruction, severe recurrent pharyngitis or PTA, or failure of abscess to resolve after needle aspiration and/or I&D.¹⁴

Disposition:

Patients discharged from the ED should be seen for follow-up within 24 to 36 hours.
Patients admitted to hospital (either for risk of complications or Quinsy tonsillectomy) require follow-up within several days following discharge.
- ICU admission may be warranted in immunocompromised patients, high risk of airway compromise, or those with sepsis.
Treat with antibiotics for 10 days if discharged from ED, with strict return precautions for continued or worsening dyspnea, fever, worsening neck or throat pain, trismus, bleeding, or enlarging peritonsillar mass.
Lack of improvement in symptoms within 24 hours following drainage and antibiotics should prompt reevaluation or further surgical intervention, along with broadening antibiotic therapy or redrainage.²⁰

Pearls:

PTA is primarily a clinical diagnosis, but imaging may assist, with US and CT as options.
To improve access and your dexterity, use a spinal needle with or without an IV extension tubing set with dynamic ultrasound guidance.
Cut the needle cap off 1.5 cm to prevent accidental ICA puncture. Similarly, use an 11 blade that has an incrementally retractable cover for the same purpose.