-------------------------------------------------------------------------- TITLE: DEEP NECK SPACE INFECTIONS SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: April 11, 1990 RESIDENT PHYSICIAN: Bruce A. Scott, M.D. FACULTY: Charles M. Stiernberg, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. -------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. Anatomy Knowledge of the cervical fascia is essential to understand the etiology, symptoms, complications and treatment of deep neck infections. This fascia directs and limits the spread of these infections. The cervical fascia consists of fibrous connective tissue which invests the organs of the neck, and ensheathes the muscles, nerves and vessels. It divides the neck into a series of planes and potential compartments. A. Superficial Cervical Fascia 1. Extends from head and neck into thorax, shoulders, and axilla. Resembles subcutaneous tissue elsewhere in the body, except it contains voluntary muscles: the platysma in the neck and the muscles of expression in the face. 2. Superiorly, it attaches to the zygomatic process and inferiorly to the clavicle. 3. Contains superficial lymph nodes and external jugular vein. Of minor importance in deep neck infections B. Deep Cervical Fascia (DCF) Three layers: not histologically separate, actually continuous with each other; however, because of clinical patterns and gross anatomical divisions, they have been classically divided. 1. Superficial Layer of DCF - Investing layer, enveloping layer, external layer a. Completely envelopes the neck, extends from the skull to the chest - Begins along nuchal line - Inferiorly attaches to clavicle b. Envelopes i. SCM, trapezius, pterygoid muscles ii. Parotid glands, submaxillary glands 2. Middle Layer of DCF a. Muscular division i. Surrounds the strap muscles (sternohyoid, sternothyroid, thyroid, omohyoid) ii. Attaches to the sternum, clavicle and scapula inferiorly iii. Attaches to the sternum, clavicle, and scapula inferiorly b. Visceral division i. Surrounds the thyroid gland, trachea, and esophagus ii. Extends anterosuperiorly to thyroid cartilage and hyoid bone iii. Extends posterosuperiorly to the base of the skull posterior to the esophagus iv. Inferiorly, it is continuous with the fibrous pericardium and continues as the covering of the thoracic trachea and esophagus v. "Buccopharyngeal Fascia" - that portion of this division of this fascia posterior to the pharynx covering the constrictor muscles and the buccinator muscles from the base of the skull to the cricoid cartilage 3. Deep Layer of DCF - Forms a complete fascia ring around neck, extending from the cervical spine and ligamentum nuchae to attach to the same structures on the other side. Rests on the outer surface of the muscles of the back of the neck, deep to trapezius muscle. - Great vessels of the neck lie on this fascia while phrenic nerve lies just beneath it. - Two divisions a. Prevertebral Layer i. Lies anterior to the vertebral bodies, extending from the base of the skull to the coccyx ii. Fuses laterally with the transverse processes iii. Continues laterally over the scalenes and other deep neck muscles to attach to the vertebral spines posteriorly. b. Alar Fascia i. Lies between the prevertebral layer and the middle layer of the DCF ii. Extends from transverse process to transverse process, then passes anterolaterally to form the medial, posterior and lateral walls of the carotid sheath. iii. Extends from the base of the skull to approximately the second thoracic vertebra where it fuses with the visceral fascia anteriorly. iv. Completes the anterolateral aspect of the retropharyngeal space and separates it from the pharyngomaxillary space. 4. Carotid sheath - All three layers of the DCF contribute to its formation - Extends from the base of the skull through the posterior pharyngomaxillary space and runs along the deep layer of the DCF below the hyoid bone and into the chest II. General Considerations A. Portals of Entry 1. In the pre-antibiotic era, 70% of deep neck infections resulted from infections of the pharynx and tonsils, and approximately 20% were of dental origin. 2. In the post-antibiotic era, an increasing percentage secondary to dental infections (generally considered #1 cause currently) and salivary gland infections. Overall incidence has decreased. 3. IV Drug Abuse a. Increasingly common etiology - Most common single cause in USC Study (1981-1987) - 28% vs. 14% from dental source. b. High risk of carotid space involvement c. Diluents (quinine, lactate, talcum powder) may contribute to sequela. 4. Other etiologies include upper respiratory tract infections, trauma, foreign bodies, instrumentation, spread of localized infection, and congenital deformities (e.g. brachial cleft sinuses). 5. Source remains unknown in significant number of patients (22% unknown etiology, USC Study) 6. Pediatric Population - Most common source is acute tonsillitis (peritonsillar space abscess) - Second most common source is dental (submandibular - submental space abscess) B. Bacteriology 1. Most abscesses with mixed bacteria. Rare fungal etiology. 2. Anaerobics most likely underrepresented by bacteriology studies, higher percent in abscesses of odontogenic origin 3. Bacteriology BACTERIA ISOLATED FROM NECK ABSCESSES Aerobes Anaerobes Streptococci 32 Peptostreptococcus 7 Alpha not group D 13 Anaerobicus 4 Group D 1 Other species 3 Beta group A 7 Bacteroides 11 Not group A,B, or D 4 Melaninogenicus 4 Gamma not group D 3 Ruminicoli 2 Microaerophilic 4 Oralis 2 Bivius 1 Staphylococcus 9 Other species 2 Aureus 6 Veillonella parvula 3 Epidermidis 3 Eikenella corrodens 3 Diptheroids 3 Fusobacterium species 1 Neisseria species 2 Propionibacterium 1 Klebsiella pneumoniae 2 Anaerobic gram-positive cocci 3 Hemophilus parainfluenza 1 Anaerobic gram-negative bacilli 1 *Tom and Rice, 1988, Univ. of Southern California 4. IV drug abuse population - Higher rates of staph and strep - USC Study: Strep - 50%, Staph - 22% - Espirita and Medina (1980) Staph - 72% C. Diagnosis 1. Presentation a. Symptoms on Presentation:* Pain 76% Fever 94% Swelling 62% Dysphagia/odynophagia 42% Trismus 14% Respiratory difficulties 14% Dental (toothache, extraction) 8% - Duration of symptoms was 1 - 14 days (mean 5.9 days) - 50 patients, 1981-1987 b. Physical Examination Findings* Swelling 90% Dental abnormality 29% Fluctuance 27% Oropharyngeal abnormalities 22% Trismus 18% Laryngeal abnormality 18% - Mean temperature on admission was 101.3 oF (range 98.2 F to 104 F) - 50 patients, 1981-1987 * Tom and Rice, 1988, Univ. of Southern California - Horner's Syndrome - close proximity of sympathetic chain to the internal jugular vein (intended site of intravenous drug abuse) - PE should include examination of extremities and groin area for needle tracks - Findings depend on progression of disease - septic shock, mediastinitis, pericarditis, etc. c. Use of antibiotics may mask "classic" presentation. Local manifestations (pointing abscess, edema, fluctation) are reduced. Delay may cause otherwise preventable complication. d. Blood and wound cultures for identification and sensitivity. 2. Imaging Studies a. Plain films i. Lateral neck - Soft tissue swelling - Air and/or fluid in cervical soft tissue ii. AP neck - Tracheal deviation - Air and/or fluid in cervical soft tissue - Foreign body (i.e. needle, bone) iii. CXR - Pulmonary edema - Pneumothorax, pneumomediastinum - Hilar adenopathy b. Ultrasound i. Adds little to diagnostic sensitivity and specificity of good physical exam (Siegert, 1987). Useful to follow clinical course. ii. Inexpensive and non-invasive iii. Unable to visualize medial to bones (i.e. mandible) iv. Failed to demonstrate 4/7 abscesses clearly shown by CT and MRI (Healy, 1989). c. CT Scan (study of choice) i. Excellent sensitivity and specificity - Accurately describes anatomical dimensions and involved structures - Better resolution than conventional tomography or plain films ii. Characteristics - Single cystic or multiloculated appearance - Low-density CT number - Air and/or fluid at center of abscess - Contrast enhancement of abscess wall - Tissue edema surrounding abscess wall d. MRI i. Increased soft tissue sensitivity (better contrast of normal vs. inflamed, abscess vs neoplasm) - Reconstruction in any plane (helps with surgical planning) ii. Advantages - no contrast injection - No ionizing radiation - Dental amalgrams don't distort iii. Disadvantages - costly - time consuming - not readily available ** Not routinely indicated D. Treatment 1. Airway Control - Tracheostomy (6/50 in USC series) - Intubation - Humidified oxygen 2. Parenteral antibiotics - Pen G - Penicillinase - resistant penicillin - +/- Clindamycin (anaerobic coverage) * Only 10-15% resolve with medical management. 3. Surgical drainage a. Gold standard - "Treatment is dependent upon the principle of proper drainage of abscess cavities...Both the primary space involved and any secondary compartments where infection have spread must be properly drained...Surgery of the neck is not primarily cosmetic. A large incision with well loosened and well retracted flaps is essential." (Levitt, 1970) b. Landmarks (modified from Mosher) - severe swelling often causes marked distortion of anatomy i. Bony landmarks: cricoid cartilage in the midline, tip of the great horn of the hyoid latterally, and the styloid process deep and high in the neck. ii. Muscular landmarks: The anterior border ot the sternomastoid muscle, the posterior belly of the digastric muscles. c. Establish proper airway, vascular control, and adequate visualization. - Gentle manipulation to avoid septicemia 4. Needle aspiration a. Therapeutic - Herzon 1988 - 24 patients - 83% resolved without surgery - 8/10 "Large Volume Abscesses" (>10ml of pus) were controlled without surgery - 58% needed multiple aspirations - In dwelling catheters (constant, painless access, 4 patients - none required surgery) - Better cosmetic result, eliminates major surgical procedure, decreased cost b. Used to confirm diagnosis - Obtain material for culture - Average hospitalization - 9.2 days c. CT - guided needle aspiration III. Specific Deep Neck Spaces and Infections - Fascia separate one area from another and provide communication routes from one to another. - The Hyoid bone is the most important structure in the neck which limits the spread of infection. A. Pharyngomaxillary space (lateral pharyngeal space, parapharyngeal space) 1. Boundaries and Anatomy a. Boundaries - Inferior - hyoid bone - Superior - base of skull along the sphenoid bone - Medial - lateral pharyngeal wall - Lateral - Superficial layer of DCF over the mandible, internal pterygoid, and parotid gland. - Anterior - pterygomandibular raphe - Posterior - prevertebral and visceral layers of fascial and carotid sheath b. Anatomy i. Carotid sheath runs through this space to the mediastinum ii. Divided into two compartments by the styloid process: a. Anterior (pre-styloid, muscular) - In close relation to tonsillar fossa medially and internal pterygoid laterally. May find dumbbell tumor of the parotid here b. Posterior (Retro-styloid, neurovascular) - Traversed by the carotid sheath and its contents - Also contains CN IX, XI, XII and the cervical sympathetic chain 2. Pathology a. Most common sources are tonsils or pharynx. Also the teeth, parotid gland, lymph nodes that drain nose and pharynx b. May communicate inferiorly with the submandibular space, posteromedially with the retropharyngeal space, laterally with the masticator and parotid spaces. c. Prior to antibiotics, it was the most frequent space involved. 3. Clinical Features a. Initial manifestations are fever, sore throat, and odyngphagia, b. Anterior space involvement - trismus (irritation of ptergoid muscles), tonsil and lateral pharyngeal wall displaced medially (possibly resembling peritonsillar abscess), and possible parotid swelling. c. Middle ear infections with associated mastoiditis may break through the bone on the inner aspect of the mastoid tip in the region of the digastric groove and spread into this space (Bezold's Abscess). d. Posterior space involvement - swelling of the posterior pillar and posterolateral pharyngeal wall. Minimal trismus or tonsillar displacement usually. e. If both compartments are involved, all the above symptoms may be present. As the infection spreads inferiorly to the hyoid limit, swelling of the neck will be noted. f. Often tonsillitis or pharyngitis is resolved before the pharyngomaxillary space infection is manifest. Every peritonsillar space abscess is a potential pharyngomaxillary space abscess due to local invasion. 4. Treatment a. IV antibiotics b. Surgical therapy (Must use external approach) - Approach via submaxillary fossa as described by Mosher in 1929. Key structure is carotid sheath, "The Lincoln Highway of the Neck," follow it to the pus. "T" shaped incision with horizontal limb parallel to body of mandible and the vertical limb just anterior to the sternomastoid muscle. The surgeon's finger is inserted under the submaxillary gland and carried toward the styloid process along the posterior belly of the digastric muscle, and deep to the mastoid tip. From the styloid process, which is located within the pharyngomaxillary fossa, the finger may pass easily to the base of the skull. Drains are then placed in the superior and the inferior portions of this space. 5. Complications a. Internal jugular thrombophlebitis b. Erosion of carotid artery - requires immediate surgical intervention, ear hemorrhage is a grave prognostic sign of vascular involvement. c. Extension to adjacent spaces B. Retropharyngeal Space 1. Boundaries and Anatomy a. Lies between the middle layer of DCF and deep layer of DCF. b. Encloses retropharyngeal nodes (nodes of Henley), which regress by age 4-5. c. Extends from the base of the skull to about the level of T1 or T2 in the mediastinum, where the middle layer of DCF fuses with the alar layer. d. Midline raphe formed where the superior constrictor is adherent to the prevertebral fascia. 2. Pathology a. Most common sources of infection are the nose, adenoids, nasopharynx, and the paranasal sinuses. b. May also be secondary to trauma from foreign bodies or instrumentations. c. May spread laterally to pharyngomaxillary space or become infected from extension from this space. d. Adults: Must rule out tuberculosis, syphilis, vertebral fractures 3. Clinical Features a. Children: Majority of cases less than 4 years old i. Complicated acute URI, ear infection, throat or nasal infection, insidious onset. ii. Presenting symptoms - Swallowing difficulties, fever, interference with breathing occurs early. - Retrospective review of 65 children with RPA: Fever - 88% Painful neck swelling - 62% Anorexia - 51% Throat pain - 49% (Thompson, 1988) iii. Presenting signs - May develop muffled "hot potato" voice and nuchal rigidity with tilting of the head towards the uninvolved side, minimal trismus - Thompson, 1988 Cervical adenopathy - 69% Retropharyngeal bulging - 43% Tonsillitis or peritonsillitis - 28% Otitis media - 28% Stridor - 23% iv. Bulging of the posterior pharyngeal wall; if seen early, swelling is offset to one side owing to the retropharyngeal nodes involved being distributed in 2 chains, one on either side of the midline fascial raphe. v. Bacteriology - Alpha hemolytic strep 25/50 Neisseria species 21/50 Staph aureus 14/50 Klebsiella 8/50 H. influenza 8/50 Bacteroides 6/50 (Thompson, 1988) b. Adults - signs and symptoms point to pharyngeal condition. - Most common symptoms - pain, dysphagia, snoring, noisy breathing, limitation of motion. c. Characteristic x-ray findings: i. abnormal thickness of prevertebral soft tissue - soft tissue > 7mm at C2 or > 22 mm at C6 - greater than 1/2 width of vertebrae in postpharyngeal region ii. Air in prevertebral soft tissue. - Possibly an air-fluid level iii. Reversal of cervical spine curvature iv. Erosion or absorbtion of the vertebral bodies 4. Treatment a. IV antibiotics - Mainstay of therapy classically considered surgical drainage with antibiotics as an adjunct - After reviewing 65 children with RPA from 1950 to 1986, Thompson reports: "The most startling finding was that 25% of the patients were treated medically and required no surgical drainage. In the earlier part of the series the surgical drainage percentage was 80%. It appears that, as diagnostic techniques improved and antibiotics became more sophisticated and available, a steady decrease of approximately 5% per year has been seen in the number of patients who receive surgical care. This trend may be a reflection of the successful use of oral antibiotics early in the course of the disease, preventing the need for surgical intervention." b. If airway is compromised, may need tracheostomy. - 5/65 children with RPA required trach (Thompson, 1988) c. Surgical therapy i. Peroral approach - in early cases - Avoids contamination of tissue plains and visible scar - Risk of aspiration, must protect airway (Rose position) ii. External approach - Dean approach -----------------------------END--------------------------------------