PROLOGUE: A MYSTERY CASE

Courtesy of BCM Dept. OTO-HNS. Grand Rounds Archives. 16 Sept 2010 CASE: HPI BV. 14 year old F Remote tonsillectomy and ESS x 2 In the ED with 9 d h/o sore throat and odynophagia. Antecedent ‘head cold’ 4 d prior, has since resolved with conservative measures. Developed intense L otalgia 2 d ago. Treated with amoxicillin for putative AOM → no improvement. Last night, spiked fevers to 101. 5 F. Had emesis. Not tolerating PO. Courtesy of BCM Dept. OTO-HNS. Grand Rounds Archives. 16 Sept 2010

CASE: PHYSICAL VITALS: T 102.5 | BP 138/66 | HR 116 | R 24 | SpO2 97% RA GEN: Sitting comfortably. Phonation is normal. No drooling. EARS: L pre-auricular tenderness. External ears normal. TMs quiet bilaterally. NOSE: Normal nares, septum, and turbinates. MOUTH: Mandible centered. Moderate trismus. Tonsils surgically absent. Posterior pharynx with L > R fullness, no erythema or exudates. NECK: No meningismus. Mildly restricted active ROM to L. Tenderness at Level II on L > R. PULM: Respirations relaxed. No stridor. Lung fields clear throughout. NEURO: Mental status is clear. No lateralizing deficits.

CASE: LABS and STUDIES CBC: WBC 21,000 with 85% PMNs, 15% band forms BMP: Na 149, K 5.1, Cr 1.4, BUN: 30 Rapid Strep: Non-reactive AP Neck Film: Unremarkable CXR: Unremarkable

Common Infections of the Deep Neck Spaces: An Overview Victor Tseng, MS-3 OTO-HNS Subrotation

DEFINITIONS DEEP NECK SPACES: Eleven anatomic or potential compartments created by interfascial planes within the neck DEEP NECK INFECTION: A supperative (usually bacterial) infection within the deep neck spaces of the deep cervical fascia

AXIAL ANATOMY

SAGITTAL ANATOMY

SAGITTAL ANATOMY

HEAD AND NECK AXIAL MRI FLYTHROUGH (LINK) RADIOLOGIC ANATOMY HEAD AND NECK AXIAL MRI FLYTHROUGH (LINK)

A MENU OF SPACES: PEARLS SUPRAHYOID PARAPHARYNGEAL (PP): A major nexus of contiguous spread. Transmits the carotid sheath. Isolated involvement is uncommon. SUBMANDIBULAR (SM): Infection may lead to upper airway obstruction MASTICATOR: Most closely associated with trismus. Almost exclusively secondary to odontogenic causes. PAROTID: Most likely seen in dehydrated and decrepit patients with poor dentition TEMPORAL: Between temporalis fascia and temporal bone periostium PERITONSILLAR (PTS): Most common site overall, but not aknowledged as a true DNI, since it is not defined by fascial apposition INFRAHYOID RETROPHARYNGEAL (RPA): Extends from skull base to level of carina (T2). Does not communicate with the pleural space. DANGER: Infection easily escapes into the mediastinum and pleural space PREVERTEBRAL (PV): Extends to coccyx and may develop into psoas absess. CAROTID: Associated with IVDA and septic thromboembolism PRETRACHEAL (PT): Associated with anterior perforation of the esophageal wall

HOOFBEATS: COMMONS PERITONSILLAR (49%) RETROPHARYNGEAL (22%, 43% non-PTS) Most common DNI across all age groups But it is predominantly a pediatric infection SUBMANDIBULAR (14%, 27% non-PTS) PAROTID (11%)

RETROPHARYNGEAL ABSCESS (RPA) EPIDEMIOLOGY > 75% of cases occur < 6 years old. 50% of cases occur by 12 mos. Overall (treated) mortality approximately 1% ETIOLOGY Children (< 18 years): 60% related to supperative LAD due to URI, AOM, acute sinusitis Adults: Mostly due to trauma, foreign body, instrumentation, or contiguous extension from primary DNI MICROBIOLOGY >90% are polymicrobial. Average n = 5 microbes isolated from culture. >50% of isolates grow anerobes S. pyogenes > S. aureus > oropharyngeal anaerobes > H. influenzae PATHOPHYSIOLOGY supperative lymphadenitis → organized phlegmon → mature abscess Morbidty and mortality is due to development of complications

RETROPHARYNGEAL ABSCESS (RPA) CLINICAL PRESENTATION Adults: Sore Throat > Fever > Dysphagia > Odynophagia > Nuchal Pain > Dyspnea > Hoarseness Children: Sore Throa (84%) > Fever (64%) > Odynophagia (55%) > Cough Infants: Neck Fullness (97%) > Fever (85%) > Poor PO (55%) DIFFERENTIAL DIAGNOSIS Epiglottitis, PTA, Croup, Diphtheria Angioedema Respiratory lymphagiomas or hemangiomas Traumatic esophagus or airway, foreign body impaction COMPLICATIONS Acute Mediastinitis: very high (>50%) mortality Empyema Pericardial effusion with tamponade physiology Mass effect: supraglottic airway obstruction (anterior) or epidural abscess (posterior)

RETROPHARYNGEAL ABSCESS (RPA) PHYSICAL FINDINGS Adults: pharyngeal edema > cervical LAD > nuchal rigidity > drooling > stridor Children: fever and nuchal rigidity (64%) > retropharyngeal bulge and neck mass (55%) > agitation or lethargy > drooling (22%) > respiratory distress or stridor Other: dystonic reactions (torticollis), dysphonia (‘hot potato’ voice), trismus In a drooling or stridorous patient, be minimally invasive when examining the pharynx LABORATORY CBC: 20% of cases may not show leukocytosis or relative left shift Standard GAS rapid throat swab and culture Blood cultures: rarely return positive growth Wound culture: 91% sensitivity for polymicrobial infection CRP and ESR to follow baseline. CRP is actually prognostic of hospitalization legnth. Pre-operative labs in anticipation of surgical intervention (coagulation panel, metabolic panel, type and cross)

RETROPHARYNGEAL ABSCESS (RPA) IMAGING Lateral Neck Film: look for widened AP diameter of retropharyngeal tissue. Maximal reported sensitivity of 88%. CT Neck with Contrast Most important imaging test to consider Hypodense lesion of retropharyngeal space with rim enhancement Absolute Indications: equivocal LNF, negative LNF with high clinical suspicion Sensitivity 77 – 100% , Specificity 95% High-Resolution U/S Maybe used to track abscess during hospitalization. Some anatomic insight into surrounding vascular structures. Proof of concept. No data to support routine use. MRI: Not recommended for initial evaluation due to untimeliness Flexible Endoscopy: not recommended

RETROPHARYNGEAL ABSCESS (RPA)

RETROPHARYNGEAL ABSCESS (RPA) MEDICAL MANAGEMENT PARENTERAL ANTIBIOTIC THERAPY is guided by suspected source of infection! Must have MRSA coverage if strain is endemic, poor clinical response to clindamycin, or in patients with very severe disease SUSPECTED SOURCE FIRST-LINE THERAPY ALTERNATIVE Odontogenic Ampicillin-Sulbactam 3 g IV q6h Penicillin G 2-4 MU IV q4-6h + Metronidazole 500 mg IV q6-8h Clindamycin 600 mg IV q6-8h Imipenem 500 mg IV q6h Meropenem 1 g IV q8h Rhinogenic and Otogenic Ampicillin-sulbactam 3 g IV q6h Ceftriaxone 1 g IV q24h + Metronidazole 500 mg IV q6-8h Ciprofloxacin 400 mg q12h + Clindamycin 600 mg IV q6-8h As above Immuncompromised Cefipime 2 g IV q12h + Metronidazoole 500 g IV q6h Piperacillin-Tazobactam 4.5 g IV q6h

RETROPHARYNGEAL ABSCESS (RPA) SURGICAL INDICATIONS Important: > 50% of patients with uncomplicated RPA achieve spontaneous resolution with medical therapy alone Respiratory distress Urgent complication of RPA (e.g. mediastinitis, empeyema, septic thrombophlebitis) Diameter of abscess > 2 cm on CT Neck No response to ABx therapy at 48 hrs SURGICAL APPROACH U/S guided FNA: preferred in hemodynamically unstable patients, or those with small and accessible loculations I/D: Usually requires trans-cervical entry. Small abscesses may be drained via trans-oral aspiration.

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