Special Senses & Otolaryngology

Peritonsillar abscess: diagnosis and management

Clinical Overview and When to Suspect Peritonsillar Abscess

— Peak incidence ages 15–40, slight male predominance

— Annual US incidence ~30 per 100,000 in young adults

— Often a complication of acute tonsillopharyngitis, but up to one-third arise without preceding sore throat (Weber gland obstruction theory)

— Group A Streptococcus (most common single isolate)

— Fusobacterium necrophorum (especially adolescents; risk of Lemierre syndrome)

— Staphylococcus aureus (including MRSA), Streptococcus anginosus group, Prevotella, Porphyromonas, Bacteroides

— Severe unilateral sore throat + trismus + "hot potato" muffled voice

— Worsening pharyngitis despite 48–72 h of outpatient antibiotics

— Drooling, ipsilateral otalgia, neck pain in a young adult

— Fever with neck stiffness — distinguish from meningitis by lateralized oropharyngeal findings

— A "viral pharyngitis" patient who returns 3–5 days later worse, not better, should trigger PTA evaluation rather than another rapid strep test

— Missed PTA can progress to airway compromise, parapharyngeal/retropharyngeal extension, mediastinitis, internal jugular thrombophlebitis, or carotid erosion

Board pearl: The classic triad — trismus, uvular deviation away from the abscess, and muffled "hot potato" voice — in a young adult with unilateral throat pain is PTA until proven otherwise; do not delay drainage waiting for imaging if exam is diagnostic and airway is stable.

Definition: Peritonsillar abscess (PTA, "quinsy") is a collection of pus between the palatine tonsil capsule and the superior pharyngeal constrictor muscle — the most common deep neck space infection in adolescents and young adults.

Epidemiology:

Microbiology — polymicrobial:

When to suspect on Step 3:

Risk factors: Recent/recurrent tonsillitis, smoking, periodontal disease, immunosuppression (diabetes, HIV), prior PTA (10–15% recurrence).

Why it matters (Step 3 ambulatory framing):

Presentation Patterns and Key History

— Typically 3–7 days of progressively worsening sore throat

— Often a history of "treated strep" or pharyngitis that initially improved then re-escalated unilaterally

— Abrupt worsening over 24–48 h with new trismus or voice change signals abscess formation rather than simple cellulitis

— Severe unilateral throat pain — out of proportion to visible findings on the contralateral side

— Odynophagia and dysphagia — patient cannot swallow secretions, leading to drooling

— Trismus — limited mouth opening from pterygoid muscle irritation; near-pathognomonic when paired with unilateral pharyngitis

— "Hot potato" muffled voice — not hoarseness (which suggests laryngeal involvement)

— Ipsilateral referred otalgia via cranial nerve IX (Jacobson's nerve)

— Fever, malaise, fetid breath (halitosis), neck pain with rotation

— Children may present primarily with refusal to eat, drooling, neck stiffness mimicking meningitis

— Adolescents/adults more often verbalize classic symptoms

— Duration and laterality of symptoms

— Prior episodes of PTA or recurrent tonsillitis (informs tonsillectomy discussion)

— Antibiotic exposure in last 30 days (resistance risk, treatment failure)

— Immunocompromise: diabetes, chemotherapy, HIV, biologics

— Dental work or periodontal disease (odontogenic deep neck infection differential)

— Smoking and vaping (independent risk factor)

— Anticoagulation, bleeding disorders (impacts drainage approach)

— Stridor, tripod positioning, severe respiratory distress → airway emergency, consider epiglottitis or retropharyngeal abscess

— Torticollis, neck mass, or pain with neck extension → parapharyngeal/retropharyngeal extension

— Rigors, hypoxia, pleuritic chest pain → Lemierre syndrome (septic IJ thrombophlebitis with septic pulmonary emboli)

Key distinction: Trismus + uvular deviation = PTA; drooling + tripoding without trismus = think epiglottitis instead — the management algorithms diverge immediately.

Time course:

Cardinal symptoms (high-yield stem cues):

Pediatric vs adult nuance:

History to obtain:

Red flags suggesting complication or alternate diagnosis:

Physical Exam Findings and Airway Assessment

— Ill-appearing, febrile (38–40°C), tachycardic, often dehydrated from poor oral intake

— Anxious posture, may sit forward and drool

— Assess hydration: dry mucosa, capillary refill, orthostatics in adolescents

— Stridor (inspiratory) — impending obstruction, call anesthesia/ENT urgently

— Voice quality: "hot potato" = supraglottic swelling; hoarseness = laryngeal involvement (different diagnosis)

— Ability to handle secretions; pooling saliva is a red flag

— Neck mobility: marked limitation suggests deep space extension

— Sniffing position, tripoding → do not force supine; maintain position of comfort

— Trismus — interincisor distance often <2–3 cm; severe trismus can prevent adequate exam and is itself diagnostic adjunct

— Bulging, erythematous, fluctuant peritonsillar tissue — typically superior pole of one tonsil

— Uvular deviation to the contralateral side

— Soft palate edema and erythema

— Tonsillar exudate may or may not be present

— Foul breath (anaerobic component)

— Tender ipsilateral cervical lymphadenopathy (jugulodigastric node)

— Palpate for induration, crepitus (gas-forming organisms, necrotizing infection), or fluctuant mass extending below the mandible — suggests parapharyngeal extension

— Torticollis with rotation away from affected side

— Lungs: rales or hypoxia → consider septic pulmonary emboli from Lemierre

— Skin: rash (scarlatiniform suggests GAS), petechiae

CCS pearl: First three orders for a suspected PTA in the ED — pulse oximetry, IV access with isotonic fluids, and ENT consult — before ordering CT or attempting drainage. Airway and resuscitation always precede the abscess.

General appearance:

Airway assessment FIRST (before any oral procedure):

Oropharyngeal exam (after airway cleared):

Neck exam:

Systemic exam:

Severity grading: Centor criteria are for pharyngitis, not PTA — do not anchor on them when classic PTA features are present.

Diagnostic Workup — Initial Labs and Bedside Studies

— CBC with differential — leukocytosis with neutrophilic predominance; significant left shift or bandemia raises concern for systemic spread

— Basic metabolic panel — assess hydration, electrolytes (vomiting, poor PO), creatinine before contrast

— CRP — elevated; useful for trending if admitted

— Blood cultures — obtain if febrile, toxic-appearing, or immunocompromised; routine in admitted patients

— Lactate if signs of sepsis

— Coagulation studies (PT/INR, PTT) only if anticoagulated or planning operative drainage

— Pregnancy test in reproductive-age females (informs imaging and medication choices)

— Low yield once abscess has formed but reasonable; positive GAS supports antibiotic coverage and household contact considerations

— Heterophile (monospot) or EBV serology — mandatory consideration in adolescents with bilateral tonsillar hypertrophy or hepatosplenomegaly; EBV mononucleosis can mimic or coexist with PTA and changes management (avoid ampicillin/amoxicillin rash; cautious sports return)

— Intracavitary (transoral) probe with sterile sheath

— Differentiates cellulitis (no drainable collection) from abscess (hypoechoic or anechoic fluid pocket)

— Identifies carotid artery position to avoid catastrophic aspiration injury

— Reduces unnecessary CT and procedural failure rates

Step 3 management: In a stable young adult with classic PTA exam findings, bedside ultrasound + needle aspiration is the preferred initial diagnostic-therapeutic step — CT is reserved for trismus too severe to examine, suspected deep neck extension, immunocompromise, or failed bedside drainage.

Diagnosis is primarily clinical in a cooperative patient with the classic exam triad — imaging is adjunctive, not mandatory.

Baseline labs (ED workup):

Rapid strep / throat culture:

HIV testing: Offer per opt-out USPSTF guidance, especially in atypical or recurrent presentations.

Bedside intraoral ultrasound (high-yield, increasingly board-tested):

Transcutaneous neck ultrasound: Alternative when trismus prevents intraoral probe placement.

Pulse oximetry, continuous monitoring in any patient with airway concern.

Diagnostic Workup — Advanced and Confirmatory Imaging

— Indications:

— Severe trismus preventing intraoral exam or drainage

— Suspected parapharyngeal, retropharyngeal, or prevertebral extension

— Failed initial drainage or persistent symptoms after 24–48 h of antibiotics

— Pediatric patient with limited cooperation

— Immunocompromised host or atypical presentation

— Concern for Lemierre syndrome (extend to chest if pulmonary symptoms)

— Findings: rim-enhancing hypodense collection in peritonsillar space with mass effect, displacement of tonsil medially, surrounding soft tissue edema

— Also evaluates airway patency, carotid sheath, internal jugular vein (filling defect = thrombophlebitis)

— Superior soft-tissue resolution; useful when vascular complications suspected and iodinated contrast contraindicated

— Limited by availability and longer scan time — not first-line in unstable patients

— Largely supplanted by CT but may show prevertebral soft tissue widening if retropharyngeal extension; not sensitive enough to exclude PTA

— Add if Lemierre suspected — look for septic pulmonary emboli (peripheral cavitary nodules) and IJ thrombosis

— Send pus for Gram stain, aerobic and anaerobic culture, and sensitivities

— Particularly important in treatment failure, immunocompromise, or community MRSA prevalence

— Routine culture in uncomplicated first episodes is debated but reasonable

— Do not delay drainage of a clinically obvious abscess waiting for CT in a stable patient

— Avoid blind transoral aspiration in patients with severe trismus or aberrant carotid anatomy without imaging guidance

— Avoid contrast in pregnancy unless benefits outweigh risks (use ultrasound or non-contrast MRI when feasible)

Board pearl: A rim-enhancing hypodense fluid collection lateral to the tonsil with medial tonsillar displacement on contrast CT is the classic imaging finding; a filling defect in the ipsilateral internal jugular vein on the same scan is Lemierre syndrome until proven otherwise and mandates anticoagulation discussion and prolonged IV antibiotics.

Contrast-enhanced CT of the neck (with IV iodinated contrast):

MRI neck with contrast:

Lateral neck radiograph:

CT chest:

Microbiology from aspirate:

What NOT to do:

Risk Stratification and Management Logic

— Outpatient management — appropriate for select uncomplicated PTA after successful ED drainage in well-appearing patient who:

— Tolerates PO fluids and antibiotics after drainage

— Has reliable follow-up within 24–48 h

— No airway compromise, no signs of deep neck extension

— No immunocompromise, no significant comorbidity

— Observation / short-stay admission — patients unable to tolerate PO, requiring IV antibiotics, severe trismus, pediatric patients post-drainage

— Inpatient admission with IV antibiotics ± OR drainage — airway concern, deep neck extension, sepsis, failed bedside drainage, immunocompromise, bleeding diathesis, age <5 (often require general anesthesia for drainage)

— Needle aspiration — 18-gauge needle, less invasive, well-tolerated under local anesthesia; ~85–90% success

— Incision and drainage (I&D) — small stab incision at point of maximal fluctuance, blunt dissection with hemostat

— Quinsy tonsillectomy ("hot" tonsillectomy) — same-admission tonsillectomy; reserved for recurrent PTA, failed drainage, or pediatric patients under anesthesia

— Acceptable in early phlegmon/cellulitis stage without drainable collection on ultrasound

— Requires close 24-hour reassessment; failure rate higher than drainage + antibiotics

— ≥2 episodes of PTA

— PTA + recurrent tonsillitis meeting Paradise criteria

— Complicated PTA (deep neck extension, Lemierre)

— Discuss as elective outpatient ENT referral after acute resolution

Step 3 management: The ambulatory pathway after successful ED needle aspiration is oral amoxicillin-clavulanate or clindamycin × 10–14 days, hydration, analgesia, and ENT follow-up in 24–48 hours — document airway clearance, PO tolerance, and return precautions before discharge.

Three-tier disposition decision:

Three drainage modalities (all acceptable first-line per IDSA/AAO-HNS):

Antibiotics alone (no drainage):

Tonsillectomy referral criteria (long-term):

Pharmacotherapy — First-Line Antibiotic Regimens

— Must cover Group A Streptococcus, oral anaerobes (Fusobacterium, Prevotella, Bacteroides), and Staphylococcus aureus

— Add MRSA coverage if local prevalence >10–15%, IV drug use, recent hospitalization, or treatment failure

— Penicillins remain backbone unless allergy

— Ampicillin-sulbactam 3 g IV q6h (first-line, excellent anaerobic and streptococcal coverage)

— Clindamycin 600–900 mg IV q8h — alternative for penicillin allergy; covers anaerobes and most GAS, but rising clindamycin resistance in GAS (5–20% regionally) limits monotherapy reliability

— Add vancomycin 15–20 mg/kg IV q8–12h (trough 15–20) or linezolid 600 mg IV/PO q12h if MRSA risk

— Piperacillin-tazobactam reserved for deep neck space extension, sepsis, or immunocompromise

— Amoxicillin-clavulanate 875/125 mg PO BID × 10–14 days (first-line)

— Clindamycin 300–450 mg PO QID for penicillin allergy

— Penicillin VK + metronidazole is acceptable but rarely used due to pill burden

— Single dose dexamethasone 10 mg IV (0.6 mg/kg pediatric, max 10 mg) reduces pain, trismus, and time to symptom resolution (multiple RCTs and meta-analyses)

— Especially helpful when PO intake is limiting discharge

— Caution in diabetes, immunocompromise, or active GI bleeding

— Scheduled acetaminophen + ibuprofen; opioids sparingly for breakthrough

— Viscous lidocaine swish-and-spit for short-term odynophagia

— IV isotonic fluids for dehydration

— Antiemetics PRN

Board pearl: A single dose of IV dexamethasone added to antibiotics and drainage in PTA significantly shortens pain and trismus duration — a high-yield Step 3 evidence-based adjunct, but it does not replace drainage.

Empiric coverage principles:

Inpatient / IV regimens:

Outpatient / PO regimens (after successful drainage):

Adjunctive corticosteroids:

Analgesia and supportive care:

Duration: Total 10–14 days of antibiotics (IV transitioned to PO once afebrile, tolerating PO, clinical improvement).

Procedural Management — Drainage Techniques

— Informed consent including risks: bleeding, aspiration, carotid injury (<1%), recurrence, need for repeat drainage

— Suction immediately available with Yankauer

— Adequate lighting (headlamp), patient seated upright

— Topical anesthesia: benzocaine or lidocaine spray, then 1% lidocaine with epinephrine injected into mucosa

— Anxiolysis with low-dose IV midazolam if needed (monitor airway)

— IV access, monitoring

— 18-gauge needle on 10 mL syringe; needle guard (cut needle cap exposing only 1 cm) prevents deep penetration toward carotid (located ~2.5 cm lateral and posterior)

— Aspirate at point of maximal fluctuance, typically superior pole of tonsil first

— If dry tap, attempt middle and inferior pole sequentially

— Send aspirate for Gram stain and culture

— #11 or #15 blade scalpel, shallow stab (~0.5 cm depth) at point of maximal fluctuance

— Spread with curved hemostat to break loculations

— Have patient lean forward, suction continuously to prevent aspiration of pus

— Observe 1–2 h for bleeding, airway compromise, vasovagal response

— Confirm PO tolerance before discharge

— Saltwater gargles starting day 1

— Recurrent PTA (≥2 episodes)

— Failed bedside drainage

— Pediatric patients <8 who require general anesthesia for cooperation

— Concurrent obstructive symptoms

— Bleeding (usually self-limited; rare carotid injury catastrophic)

— Aspiration of pus → pneumonitis/pneumonia

— Incomplete drainage requiring repeat procedure (5–10%)

— Recurrence within 30 days (~10–15%)

CCS pearl: If bedside drainage yields no pus despite classic exam, reassess with ultrasound or CT — you may be dealing with peritonsillar cellulitis (no abscess yet), in which case IV antibiotics + steroids + 24-hour reassessment is appropriate before repeat attempt.

Pre-procedure checklist:

Needle aspiration technique:

Incision and drainage:

Post-procedure care:

Quinsy tonsillectomy indications:

Complications of drainage:

Special Populations — Elderly and Renal/Hepatic Impairment

— PTA is uncommon over age 60; when it occurs, suspect underlying pathology — head and neck malignancy (especially tonsillar squamous cell carcinoma), immunosuppression, undiagnosed diabetes, or HIV

— Lower physiologic reserve: dehydration and sepsis develop faster

— Presentation may be atypical — less trismus, less pronounced fever, more confusion/delirium

— Higher complication rate: airway compromise, deep neck extension, mortality

— Mandatory ENT follow-up with direct laryngoscopy post-resolution to evaluate for occult malignancy if persistent unilateral tonsillar asymmetry or risk factors (smoking, HPV, alcohol)

— Adjust antibiotic dosing:

— Ampicillin-sulbactam: extend interval to q8h or q12h if CrCl <30

— Piperacillin-tazobactam: reduce dose with CrCl <40

— Vancomycin: weight-based loading, trough-guided maintenance

— Clindamycin: no renal adjustment (hepatically cleared) — useful in ESRD/AKI

— Avoid NSAIDs in CKD ≥ stage 3 — use acetaminophen for analgesia

— Contrast CT: weigh benefit vs contrast nephropathy risk; alternatives include MRI or ultrasound

— Clindamycin requires caution in severe hepatic dysfunction (consider dose reduction with monitoring)

— Metronidazole: reduce dose in Child-Pugh C

— Acetaminophen: limit to ≤2 g/day in significant cirrhosis

— Watch for coagulopathy → bleeding risk with drainage; correct INR with vitamin K or FFP if procedural bleeding expected

— Hyperglycemia impairs immune function and wound healing

— Steroids worsen glucose control — monitor and adjust insulin

— Higher risk of necrotizing infection and Klebsiella involvement

— Lower threshold for inpatient admission and IV antibiotics

Key distinction: A persistently asymmetric tonsil after PTA resolution in an older smoker is a red flag for tonsillar SCC — refer for outpatient ENT evaluation with biopsy, not just routine follow-up.

Elderly patients:

Renal impairment:

Hepatic impairment:

Diabetes:

Special Populations — Pregnancy and Pediatrics

— Safe antibiotics:

— Amoxicillin-clavulanate (category B) — first-line oral

— Ampicillin-sulbactam IV — preferred inpatient

— Clindamycin (category B) — alternative for penicillin allergy

— Avoid or use cautiously:

— Fluoroquinolones (cartilage concerns)

— Tetracyclines (fetal teeth/bone, after first trimester)

— Metronidazole — traditionally avoided in first trimester though data reassuring

— Imaging: prefer ultrasound; if CT essential, shield abdomen — neck CT delivers minimal fetal dose but document indication

— Steroids: single dose dexamethasone acceptable; betamethasone reserved for fetal lung maturity indications

— Multidisciplinary involvement: OB consultation if admission required; DVT prophylaxis given hypercoagulability

— PTA is rare under age 5; consider retropharyngeal abscess in this age group instead

— Adolescents most affected; presentation similar to adults

— Weight-based dosing:

— Amoxicillin-clavulanate 45 mg/kg/day PO divided BID (max adult dose)

— Ampicillin-sulbactam 200 mg/kg/day IV divided q6h

— Clindamycin 30–40 mg/kg/day IV divided q6–8h

— Dexamethasone 0.6 mg/kg IV/IM/PO, max 10 mg

— Younger children often cannot cooperate with bedside drainage → operative drainage under general anesthesia by ENT

— Screen for infectious mononucleosis — concurrent EBV is common in adolescents; affects activity restrictions (avoid contact sports 3–4 weeks due to splenic rupture risk) and antibiotic choice (avoid amoxicillin → morbilliform rash)

— Consider immunodeficiency workup in recurrent deep infections

— Return precautions: difficulty breathing, drooling worsening, neck stiffness, high fever despite antibiotics

— Hydration emphasis; popsicles, cold fluids

— School return when afebrile 24 h and tolerating diet

— Discuss elective tonsillectomy after recurrent episodes

Board pearl: In a teenager with PTA and bilateral tonsillar exudates plus splenomegaly, check EBV heterophile — coexisting mononucleosis changes antibiotic choice (avoid aminopenicillins) and mandates sports restriction counseling.

Pregnancy:

Pediatrics:

Counseling families:

Complications and Adverse Outcomes

— Airway obstruction — from mass effect, supraglottic edema, or spontaneous rupture with aspiration of pus

— Spontaneous abscess rupture — risk of aspiration pneumonia; suction immediately, position laterally

— Recurrence — 10–15% within first year; higher with inadequate drainage or persistent tonsillar crypts

— Parapharyngeal abscess — bulging of lateral pharyngeal wall, trismus, neck swelling at angle of mandible

— Retropharyngeal abscess — neck stiffness, posterior pharyngeal bulge, dysphagia; can extend to mediastinum

— Prevertebral / "danger space" infection — direct path to posterior mediastinum

— Mortality 20–40% even with treatment

— Chest pain, dyspnea, sepsis, pneumomediastinum on imaging

— Requires emergent thoracic surgical drainage + broad-spectrum antibiotics

— Lemierre syndrome — septic thrombophlebitis of internal jugular vein, classically from Fusobacterium necrophorum; presents with persistent fever, neck pain/tenderness along SCM, septic pulmonary emboli (peripheral cavitary nodules), rigors

— Treatment: prolonged IV antibiotics (4–6 weeks, often with metronidazole + beta-lactam), anticoagulation is controversial but commonly used for 3 months if extending or embolic

— Carotid artery erosion / pseudoaneurysm — rare but catastrophic; herald bleed in mouth precedes massive hemorrhage

— Cavernous sinus thrombosis (very rare)

— Sepsis, septic shock

— Post-streptococcal sequelae if GAS confirmed: acute rheumatic fever (rare in adults), post-streptococcal glomerulonephritis

— Toxic shock syndrome (streptococcal) — fever, rash, hypotension, multiorgan dysfunction

Step 3 management: A patient with treated PTA who returns with persistent fevers, rigors, pleuritic chest pain, and hypoxia after 5–7 days has Lemierre syndrome until proven otherwise — order CT neck and chest with contrast, start IV beta-lactam/beta-lactamase inhibitor + metronidazole, consult ID and hematology regarding anticoagulation.

Local complications:

Deep neck space extension:

Mediastinitis (descending necrotizing mediastinitis):

Vascular complications:

Systemic complications:

Procedural complications: Bleeding, aspiration, carotid injury, incomplete drainage.

When to Escalate Care — ICU, Consults, and Inpatient Triage

— Airway compromise: stridor, accessory muscle use, hypoxia, inability to manage secretions

— Sepsis with hemodynamic instability or lactate >2 despite resuscitation

— Suspected/confirmed deep neck infection with mediastinal extension

— Lemierre syndrome with septic pulmonary emboli requiring close pulmonary monitoring

— Post-operative airway concern after operative drainage or quinsy tonsillectomy

— Difficult airway anticipated (severe trismus, distorted anatomy)

— Plan for awake fiberoptic intubation if intubation required — avoid paralytics until airway secured

— Surgical airway (cricothyroidotomy/tracheostomy) backup ready

— Failed bedside drainage

— Severe trismus preventing exam

— Pediatric patients requiring OR drainage

— Suspected deep neck extension

— Recurrent PTA (planning tonsillectomy)

— Concerning oropharyngeal lesion / mass

— Infectious Disease — Lemierre, immunocompromise, treatment failure, unusual organisms

— Vascular surgery / interventional radiology — carotid pseudoaneurysm or massive bleeding

— Hematology — anticoagulation decisions in Lemierre

— Thoracic surgery — mediastinitis

— Unable to tolerate PO

— IV antibiotic requirement

— Significant comorbidities (diabetes, immunosuppression)

— Unreliable follow-up or social barriers

— Pediatric patients after operative drainage

— Successful drainage with pus obtained

— Tolerating PO fluids and oral antibiotic dose

— Stable airway, no stridor or hypoxia

— Reliable follow-up in 24–48 h with ENT or primary care

— Understanding of return precautions

— Adequate analgesia regimen

CCS pearl: Order set for admitted PTA — NPO until tolerating PO, IV isotonic fluids, ampicillin-sulbactam IV q6h, dexamethasone 10 mg IV × 1, scheduled acetaminophen/ibuprofen, head-of-bed elevation, continuous pulse oximetry, ENT consult, advance diet as tolerated — then advance the clock and reassess.

ICU admission criteria:

Anesthesia consultation:

ENT (otolaryngology) consultation — when:

Other consults:

Admission criteria (general inpatient floor):

Discharge from ED criteria:

Key Differentials — Same-Category (Oropharyngeal/Deep Neck) Causes

— Same clinical picture as PTA but no drainable collection on ultrasound/CT

— Treat with IV antibiotics + steroids, reassess in 24 h

— Distinguishing feature: no fluctuance, no aspirated pus

— Bilateral tonsillar erythema and exudate

— No trismus, no uvular deviation, no muffled voice

— Centor-guided management; GAS rapid antigen testing

— Posterior pharyngeal wall bulge, neck stiffness/torticollis, dysphagia

— More common in children <5 (retropharyngeal nodes regress after age 5)

— Lateral neck radiograph: prevertebral soft tissue widening

— CT diagnostic; requires surgical drainage

— Lateral neck swelling at angle of mandible, trismus, medial displacement of lateral pharyngeal wall (rather than tonsil)

— Risk of carotid sheath involvement

— Surgical drainage usually required

— Submandibular space infection, typically odontogenic

— Brawny, board-like submandibular swelling, elevated tongue, drooling

— Rapid airway compromise; early definitive airway management critical

— Toxic appearance, tripod position, drooling, no trismus

— "Thumbprint sign" on lateral neck radiograph

— Adult cases increasingly common (H. flu vaccinated children less affected)

— Avoid throat exam in children; secure airway in OR

— Posterior tongue base swelling, muffled voice without trismus

— Identified on flexible laryngoscopy

— Bilateral, kissing tonsils, posterior cervical lymphadenopathy, hepatosplenomegaly

— Heterophile positive; airway management may require steroids

Key distinction: Trismus + unilateral uvular deviation = PTA; midline posterior pharyngeal bulge + neck stiffness in a child = retropharyngeal abscess; brawny floor-of-mouth swelling with elevated tongue = Ludwig angina. Each demands a different airway plan and surgical consultant.

Peritonsillar cellulitis (phlegmon):

Severe acute tonsillitis / pharyngitis:

Retropharyngeal abscess:

Parapharyngeal abscess:

Ludwig angina:

Epiglottitis:

Acute lingual tonsillitis / lingual tonsil abscess:

Infectious mononucleosis with massive tonsillar hypertrophy:

Key Differentials — Other-Category Causes

— Squamous cell carcinoma, often HPV-related in younger non-smokers

— Persistent unilateral tonsillar enlargement, neck mass, otalgia, weight loss

— May present with superimposed infection

— Red flag: PTA that fails to resolve or recurs in an adult >50 — direct laryngoscopy and biopsy

— Non-Hodgkin lymphoma of Waldeyer's ring

— Unilateral tonsil enlargement without significant inflammation

— B symptoms (fevers, night sweats, weight loss)

— Biopsy is diagnostic

— Fish bone, chicken bone — sudden onset, localized pain, no fever initially

— Direct visualization or flexible laryngoscopy

— Preauricular swelling, pus from Stensen's duct

— Distinct from peritonsillar findings

— Tender, fluctuant cervical node; intraoral exam relatively unremarkable

— Often Staphylococcus or atypical mycobacteria in children

— Severe pharyngitis with mucocutaneous ulcers, fever, lymphadenopathy, rash

— Test HIV viral load (antibody may be negative early)

— Grayish pseudomembrane covering tonsils/pharynx that bleeds when scraped

— Unimmunized or travel history

— Toxin-mediated myocarditis, neuropathy

— Fever ≥5 days, conjunctivitis, mucositis, rash, extremity changes, cervical adenopathy

— Not a true abscess, but oropharyngeal mimic

— Recurrent oral ulcers + genital ulcers + ocular involvement

— Not infectious

— Gum hypertrophy, mucosal bleeding, oropharyngeal infection from neutropenia

— CBC with peripheral smear; blasts

Board pearl: Persistent unilateral tonsillar asymmetry in an adult after resolution of acute infection demands tissue diagnosis — do not attribute it to scarring without ENT evaluation; HPV-related oropharyngeal SCC is the fastest-growing head-and-neck cancer in middle-aged adults.

Tonsillar / oropharyngeal malignancy:

Lymphoma:

Foreign body impaction:

Salivary gland infection (parotitis, sialadenitis):

Cervical lymphadenitis with suppuration:

Acute HIV seroconversion:

Diphtheria:

Kawasaki disease (pediatric):

Behçet disease / aphthous ulceration:

Acute leukemia:

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Amoxicillin-clavulanate 875/125 mg PO BID × 10–14 days (or clindamycin 300–450 mg QID if PCN-allergic)

— Scheduled acetaminophen 1 g q6h + ibuprofen 400–600 mg q6h for 5–7 days

— Short course low-dose opioid (e.g., oxycodone 5 mg q6h PRN) for breakthrough pain — limited quantity, opioid stewardship documented

— Antiemetic PRN (ondansetron 4 mg)

— Optional dexamethasone short course (single ED dose typically sufficient)

— Hydration: 2–3 L/day of cool fluids

— Saltwater gargles 3–4 times daily

— Soft, cold diet; avoid spicy/acidic foods

— Sleep with head of bed elevated

— Smoking cessation counseling — smoking is a modifiable risk factor for recurrence

— Alcohol moderation

— Dental hygiene optimization (referral to dentist if periodontal disease)

— Indications:

— ≥2 episodes of PTA

— PTA + recurrent tonsillitis (Paradise criteria: ≥7 episodes/year × 1 year, ≥5/year × 2 years, or ≥3/year × 3 years)

— Complicated PTA (deep neck infection, Lemierre, airway compromise)

— Persistent unilateral tonsillar asymmetry (rule out malignancy with histology)

— Discuss timing: typically 4–6 weeks after acute resolution to allow tissue healing

— Inform patient of risks: bleeding (primary <24 h, secondary 5–10 days post-op), pain, dehydration

— Tdap if not current

— Influenza annually

— COVID-19 per current recommendations

— Pneumococcal if indicated by age/comorbidity

— Glycemic optimization in diabetes (HbA1c goal individualized)

— HIV screening if not done

— Evaluate for immune deficiency in recurrent deep infections

Step 3 management: Every patient discharged after PTA should leave with antibiotic prescription, multimodal analgesia plan, written return precautions, scheduled 24–48 h ENT or PCP follow-up, smoking cessation counseling if applicable, and a discussion of elective tonsillectomy if this is a recurrent episode.

Discharge medication bundle (post-ED drainage):

Lifestyle and supportive measures:

Tonsillectomy referral (elective outpatient ENT):

Vaccinations to update:

Address underlying conditions:

Follow-Up, Monitoring, and Counseling

— 24–48 hours post-discharge: ENT or primary care visit

— Reassess pain, trismus, PO intake, hydration

— Examine oropharynx for residual collection

— Confirm antibiotic tolerance and adherence

— 7–10 days: Mid-course check — symptom resolution expected

— 4–6 weeks: Definitive ENT follow-up

— Examine for residual tonsillar asymmetry

— Discuss tonsillectomy candidacy

— Direct or flexible laryngoscopy in adults >40 or with risk factors

— Daily symptom diary: pain (0–10), ability to swallow, fever, fluid intake

— Weight (especially pediatric) — flag >5% loss as dehydration

— Return immediately if: worsening trismus, new neck swelling, drooling, stridor, persistent fever >72 h on antibiotics, chest pain, rigors

— Afebrile 24 h + tolerating diet → school/work return

— Avoid strenuous activity for 5–7 days after drainage

— If concurrent mononucleosis: no contact sports × 3–4 weeks (splenic rupture risk)

— Recurrence risk (~10–15%) and warning signs

— Importance of completing full antibiotic course even if symptoms resolve early

— Smoking and vaping cessation — link to recurrence and head/neck cancer risk

— Dental hygiene

— Tonsillectomy discussion: risks/benefits, recovery 10–14 days post-op

— Sexual health discussion if HPV-related oropharyngeal cancer risk relevant (HPV vaccination if age-eligible up to 45)

— Discharge summary to PCP and ENT

— Drainage technique used, microbiology results

— Antibiotic regimen and duration

— Follow-up plan with specific dates and contacts

— Return precautions in patient's preferred language and literacy level

Board pearl: HPV vaccination is now recommended through age 26 routinely and may be considered up to age 45 through shared decision-making — leverage the PTA visit as an opportunity to discuss oropharyngeal cancer prevention in eligible adolescents and young adults.

Follow-up cadence:

Monitoring parameters during recovery:

Activity and return-to-work/school:

Counseling topics:

Documentation for transitions of care:

Ethical, Legal, and Patient Safety Considerations

— Document understanding of risks: bleeding, aspiration, carotid injury, recurrence, need for repeat procedure or operative drainage

— Discuss alternatives: needle aspiration vs I&D vs operative drainage, antibiotics alone

— In minors, obtain consent from parent/legal guardian; adolescent assent should also be documented

— Mature minor doctrine may apply in some states for emancipated minors or specific situations

— Patients presenting with PTA after alcohol or substance use — assess decision-making capacity

— If incapacitated and condition emergent (airway threat), proceed under implied consent / emergency doctrine; document rationale

— Use certified medical interpreters — not family members, especially for procedural consent

— Provide discharge instructions in patient's preferred language at appropriate literacy level

— Teach-back method to confirm understanding of antibiotic regimen, return precautions

— PTA patients discharged from ED have high return rates if follow-up gaps occur

— Confirm follow-up appointment is scheduled before discharge, not just recommended

— Provide direct contact for ENT clinic; consider ED nurse callback at 24 h

— Medication reconciliation — check for drug interactions (e.g., warfarin + antibiotics → INR monitoring)

— Never attempt blind oral instrumentation in suspected epiglottitis or severe trismus

— "Double setup" — have surgical airway equipment ready before intubation attempts in distorted anatomy

— Avoid paralytics until you are confident in airway visualization

— Document microbiology when available; narrow therapy based on cultures

— Avoid unnecessary broad-spectrum coverage

— Group A Strep outbreaks in schools/dorms may warrant public health notification

— Diphtheria suspicion → immediate reporting

— Use multimodal analgesia first; limit opioid quantity and duration

— Check state PDMP before prescribing

— Carotid artery injury or airway loss should trigger root-cause analysis and morbidity/mortality review

Step 3 management: A patient with PTA who arrives intoxicated and refuses drainage but has a stable airway — document capacity assessment, offer reassessment in 4–6 hours, provide IV antibiotics and analgesia, and obtain ethics consultation if persistent refusal in deteriorating condition rather than forcing a procedure on a refusing competent adult.

Informed consent for bedside drainage:

Capacity and intoxicated patients:

Language and health literacy:

Transitions of care risk (high Step 3 yield):

Patient safety in airway management:

Antibiotic stewardship:

Mandatory reporting and public health:

Opioid stewardship:

Sentinel event recognition:

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: If the stem says "young adult, unilateral sore throat 5 days, trismus, muffled voice, fever, deviated uvula" — the next best step is needle aspiration of the peritonsillar abscess (after airway clearance), not CT, not just antibiotics, and not throat swab.

Classic triad: Trismus + uvular deviation + muffled "hot potato" voice = PTA

Most common organism (single): Group A Streptococcus; infections are typically polymicrobial with anaerobes

Lemierre syndrome organism: Fusobacterium necrophorum

Adjunctive medication with evidence: Single-dose dexamethasone reduces pain and trismus duration

First-line outpatient antibiotic: Amoxicillin-clavulanate × 10–14 days

Penicillin allergy alternative: Clindamycin

Drainage options (all acceptable): Needle aspiration, I&D, quinsy tonsillectomy

Imaging modality of choice when needed: Contrast-enhanced CT neck

Bedside imaging that reduces CT use: Intraoral ultrasound

Recurrence rate: ~10–15% within a year

Tonsillectomy indication: ≥2 episodes of PTA, or PTA + recurrent tonsillitis

Avoid in mono: Aminopenicillins (amoxicillin/ampicillin) → morbilliform rash

Airway emergency mimic: Epiglottitis — tripod, drooling, no trismus

Pediatric mimic in <5: Retropharyngeal abscess

Adult >50 with persistent unilateral tonsil: Rule out tonsillar SCC (often HPV-related)

Mortality of descending mediastinitis: 20–40%

Carotid artery location: ~2.5 cm posterolateral to tonsillar fossa — use needle guard

CN IX referred pain: Ipsilateral otalgia

Centor criteria: For pharyngitis, not PTA

Paradise criteria: Tonsillectomy thresholds — 7/5/3 episode rule

HPV vaccination range: Routine through 26, shared decision-making through 45

Mono + contact sport restriction: 3–4 weeks for splenic rupture risk

Septic pulmonary emboli on CT: Peripheral cavitary nodules → Lemierre

First lab in toxic-appearing PTA: CBC, BMP, lactate, blood cultures

First treatment in unstable airway: Position, oxygen, anesthesia/ENT bedside — not the abscess

Most missed diagnosis next to PTA: Peritonsillar cellulitis (no drainable pus)

Steroid caveat: Caution in poorly controlled diabetes

Smoking effect: Independent risk factor for recurrence

Board Question Stem Patterns

— 22-year-old with 5 days of worsening right-sided throat pain, fever, muffled voice, trismus, drooling. Exam: right peritonsillar bulge, uvula deviated left. → Needle aspiration + ampicillin-sulbactam + dexamethasone

— Adult with sore throat, drooling, tripod position, no trismus, no oropharyngeal asymmetry, stridor. → Epiglottitis, secure airway in OR; not needle aspiration

— 3-year-old with fever, neck stiffness, refusal to extend neck, drooling. Lateral neck radiograph: prevertebral widening. → Retropharyngeal abscess, CT + ENT for OR drainage

— 19-year-old treated for "strep throat" 1 week ago, returns with rigors, pleuritic chest pain, hypoxia, neck tenderness. CT: IJ thrombus, cavitary lung nodules. → Lemierre syndrome, IV beta-lactam + metronidazole, ID consult, consider anticoagulation

— Adolescent with bilateral tonsillar exudates, posterior cervical lymphadenopathy, splenomegaly, rash after amoxicillin. → Infectious mononucleosis (avoid amoxicillin), supportive care, sport restriction

— 58-year-old smoker with persistent right tonsillar enlargement 3 months after "treated PTA," now with ipsilateral neck mass and weight loss. → Direct laryngoscopy with biopsy, not antibiotics

— Successful ED needle aspiration of PTA in stable 25-year-old, tolerating fluids, no airway concern. → Discharge on amoxicillin-clavulanate × 10–14 days, ENT follow-up 24–48 h, return precautions

— PTA drained 24 h ago, returns with persistent fever, worsening trismus, neck swelling. → CT neck with contrast, IV antibiotics, ENT for operative drainage — concern for deep neck extension

— Most appropriate adjunct to reduce pain and trismus duration in PTA? → Single-dose IV dexamethasone

— Best technique to avoid carotid artery injury during transoral needle aspiration? → Needle guard limiting depth to 1 cm, aspirate at superior pole

— Patient with third PTA in 18 months. Next step after acute treatment? → Elective ENT referral for tonsillectomy 4–6 weeks after resolution

Key distinction: Recognize the pivot questions — same "sore throat + fever" stem can branch to PTA, epiglottitis, retropharyngeal abscess, Ludwig angina, mononucleosis, or tonsillar SCC depending on age, trismus, anatomic asymmetry, neck findings, and time course. Anchor your answer in those discriminators.

Classic PTA stem:

PTA vs epiglottitis trap:

Pediatric retropharyngeal stem:

Lemierre stem:

Mono mimicker:

Tonsillar SCC stem:

Outpatient discharge stem:

Drainage failure stem:

Steroid evidence stem:

Carotid safety stem:

Tonsillectomy referral stem:

One-Line Recap

Peritonsillar abscess is a clinical diagnosis in a young adult with unilateral sore throat, trismus, uvular deviation, and muffled voice — managed with airway assessment, bedside needle aspiration or I&D, amoxicillin-clavulanate (or clindamycin), single-dose dexamethasone, and 24–48 hour ENT follow-up, with escalation to CT and operative drainage for deep neck extension or treatment failure.

Board pearl: When in doubt on the test, the next best step in a stable patient with classic PTA findings is needle aspiration — not CT, not just antibiotics, not throat culture — and always assess the airway before touching the oropharynx.

Diagnosis: Trismus + uvular deviation + muffled "hot potato" voice + unilateral peritonsillar bulge — no imaging needed in classic stable cases; bedside intraoral ultrasound distinguishes abscess from cellulitis; contrast CT for severe trismus, suspected deep neck extension, or treatment failure.

Treatment trifecta: Drainage (needle aspiration, I&D, or quinsy tonsillectomy) + antibiotics (amoxicillin-clavulanate PO or ampicillin-sulbactam IV; clindamycin if PCN-allergic; add MRSA coverage selectively) + adjunctive dexamethasone single dose.

Don't miss: Epiglottitis (no trismus, tripod, drooling), retropharyngeal abscess (children <5, posterior bulge), Ludwig angina (submandibular brawny edema), Lemierre syndrome (Fusobacterium IJ thrombophlebitis with septic pulmonary emboli), and tonsillar SCC (persistent unilateral tonsil asymmetry in older adults or smokers).

Disposition and prevention: Discharge stable patients with PO tolerance and 24–48 h ENT follow-up; admit for airway concern, sepsis, deep neck extension, or pediatric operative drainage; refer for elective tonsillectomy after ≥2 PTAs or complicated episode; counsel on smoking cessation, hydration, HPV vaccination, and return precautions.