Descending Neck Infections

DESCENDING NECK INFECTIONS

Introduction

Descending neck infections (DNI) : Bacterial infections originating from the upper

aero digestive tract and involving the deep neck spaces.

Advent of antibiotics – decreased incidence and mortality of deep space infection of the neck.

Delay in diagnosis or inappropriate treatment – complications , mediastinitis.

Introduction

Descending necrotizing mediastinitis is the most feared complication.

It results from retropharyngeal extension of infection into the posterior mediastinum.

Septic shock is associated with a 40-50% mortality rate.

Pleural and pericardic effusion may accompany this condition, frequently leading to cardiac tamponade.

Introduction

Associated complications: Suppurative thrombophlebitis of the internal

jugular vein

Pulmonary septic embolism,

Thrombosis of the cavernous sinus, and

Erosion of the carotid artery

Etiology

In the era before antibiotics - 70% of deep neck infections caused by spread from pharyngeal and tonsillar infections.

An increasing percentage of infections are caused by dental and salivary gland infections

Odontogenic sources - most common origin of deep neck infections among adults.

Etiology

Distribution according to gender:

Deep neck infection – analysis of 80 cases BRAZILIAN JOURNAL OF OTORHINOLARYNGOLOGY 74 (2) MARCH/APRIL 2008

Etiology

Distribution according to age:


Etiology

Habits and associated disorders:


Etiology

Intravenous drug abusers:

often inject drugs into the major vessels of the neck, violating the protective cervical fascia, contaminating the deep neck spaces, vascular space, contains the carotid artery, diluents in illegal drugs, such as talcum powder,

lactate, and quinine, may contribute to the patient's morbidity.

Etiology

Causes of deep neck infections:


Etiology

Spread of a dentoalveolar abscess into contiguous fascial spaces

1 Submandibular abscess,

2 Pterygomandibular abscess,

3 Parapharyngeal abscess,

4 Retropharyngeal abscess

Bacteriology

Neck-facial infection sites

Clinical presentation of deep neck-facial disorders.

Complications of deep neck and facial infections.

Anatomy Of The Cervical Fascia

Presentation, spread, and management of infection of the deep spaces of the neck based on the anatomic configuration of the cervical fascia.

The cervical fascia: composed of fibrous connective tissue layers that

enclose organs, muscles, nerves, and vessels separate the neck into a series of planes and

potential spaces.

Anatomy Of The Cervical Fascia The fascia is divided

into:

a superficial cervical fascia

a deep cervical fascia - 1. superficial,2. middle, and3. deep layers.


Superficial cervical fascia: extends from its superior

attachment on the zygomatic process down to the thorax and axilla

composed of a continuous sheath of fatty subcutaneous tissue

ensheathes the platysma muscle and voluntary muscles of expression in the face.


The space between the superficial cervical fascia and deep cervical fascia contains superficial lymph nodes, nerves, and vessels, including the external jugular vein.


The superficial layer of the deep cervical fascia:

also known as the enveloping or investing layer

completely surrounds the neck. extends from its insertion at the

nuchal line of the skull to the chest and axillary region.

spreads anteriorly to the face and attaches to the clavicles.

This continuous fibrous tissue sheath envelops the sternocleidomastoid and trapezius muscles and the parotid and submandibular glands.

Anatomy Of The Cervical Fascia Middle layer of the deep cervical

fascia:

Two divisions: muscular division and visceral division

Muscular division: Continuous sheath below the

superficial layer of the deep cervical fascia and surrounds the strap muscles

Attaches superiorly to the hyoid bone and thyroid cartilage and inferiorly to the sternum, clavicle, and scapula


Visceral division: Surrounds the anterior

viscera of the neck - thyroid gland, trachea, and esophagus

posterosuperior origin - base of the skull posterior to the esophagus,

anterosuperior attachment - at the thyroid cartilage and hyoid bone


Visceral division:

Continues inferiorly into the thorax, Covers the trachea and esophagus, blends with

the fibrous pericardium. The buccopharyngeal fascia is a portion of the

visceral division posterior to the pharynx that covers the constrictor muscles and buccinator muscles.


Deep layer of the deep cervical fascia:

Forms a complete ring with the great vessel outside the ring and the phrenic nerve inside the ring.

deep layer is divided into : prevertebral and alar divisions.

Prevertebral division: begins immediately anterior to the

vertebral bodies, spreads laterally to fuse with the transverse processes, and extends posteriorly to enclose the deep muscles of the neck.


Prevertebral division: It sends septa out between

these muscles and attaches to the vertebral spines posteriorly.

Extending from the base of the skull to the coccyx, the prevertebral division forms the posterior wall of the danger space and the anterior wall of the prevertebral space.


Alar division: lies between the prevertebral

division and the middle layer of the deep cervical fascia.

Course: From transverse spinous

processes on one side to the contralateral transverse processes

Extends from the base of the skull to the second thoracic vertebra: fuses with the visceral fascia of the middle layer of the deep cervical fascia.


Carotid sheath: All three layers of the deep

cervical fascia are involved in formation of the carotid sheath

runs from the base of the skull through the pharyngomaxillary space and along the deep layer of the deep cervical fascia into the chest.

Anatomy Of Deep Neck Spaces

The deep cervical fascia separates the neck into a series of potential spaces

The spaces communicate with one another

The potential spaces of the neck are classified according to their relation with the hyoid bone


Spaces that can lead to deep neck infections: Submandibular space Sublingual space Submental space Lateral pharyngeal space Retropharyngeal space Visceral vascular space Danger space Pretracheal space Prevertebral space

Spaces Limited to Above the Hyoid Bone

Submandibular Space: Composed of the sublingual space

superiorly and the submaxillary space inferiorly, divided by the mylohyoid muscle.

Entire compartment lies between the mucosa of the floor of the mouth above and the superficial layer of the deep cervical fascia below.

Mandible forms an inflexible anterior and lateral boundary, the hyoid bone limits the inferior aspect, and the intrinsic muscles of the base of the tongue compose the posterior border.


Submandibular Space: The submaxillary space is

subdivided by the anterior bellies of the digastric muscles into:

a central compartment, the submental compartment, and two lateral compartments,

(submaxillary compartments).


Submandibular Space: All these divisions freely

communicate because the submandibular gland extends from the submaxillary space around the posterior border of the mylohyoid muscle into the sublingual space to provide a direct communication for spread of infection.

Infection spreads freely beyond the limiting belly of the digastric muscle from the submental to the submaxillary compartments.

Submandibular Space Infection:

In 1836 Wilhelm von Ludwig, a German surgeon, described Ludwig Angina:

“Repeated recent occurrences of a certain type of inflammation of the throat, which, despite the most skillful treatment, is almost always fatal.“

The mortality rate historically was more than 50%,

With widespread use of antibiotics and timely surgical intervention, the mortality has fallen to less than 5%.

Submandibular Space Infection

70% continue to be caused by dental or periodontal disease.

Infections originating anterior to the second molar drain initially through the inner cortex of the mandible into the sublingual space.

Infections of the last two molars drain into the submandibular space - the mylohyoid muscle inserts more rostrally on the posterior aspect of the mandible


Early manifestations : involvement of the oral tissue near

the dental origin and tender swelling of the sublingual and submental area.

Untreated : progresses to severe cellulitis with a

board-like firmness ofthe floor of the mouth and brawny induration of the suprahyoid soft tissue characteristic of Ludwig angina.


True Ludwig angina: All the sublingual and bilateral

submaxillary spaces are involved. Characterized by: Swelling in the submaxillary area

associated with severe pain, drooling, trismus, dysphagia, and difficulty breathing.

The tongue displaced posteriorly and superiorly against the palate - respiratory embarrassment.


Management: Intravenous antibiotics can be curative in the early

stage of disease.

Rapid surgical intervention: Imperative if there is increasing airway

obstruction, Localized abscess with fluctuation, or Failure to improve with antibiotics.


Surgical procedure: A horizontal submental incision

just above the hyoid bone is carried down through the platysma.

The deep cervical fascia and mylohyoid muscle are incised vertically from symphysis to hyoid bone.


Ludwig angina: a straw-colored, weeping exudate, rather than true abscess fluid, is released.

Drains placed in a position deep to the mylohyoid muscle within the sublingual space.


Prevention of airway obstruction -primary concern of care.

Airway problems: Patients with trismus, an indurated neck, displaced

tongue, glottic edema, or pharyngeal edema. Intubation: Orotracheal intubation difficult - swelling of the

floor of the mouth and trismus limit visualization


Awake blind nasal intubation: Precipitate obstruction, Can cause laryngeal trauma.

Establishment of an artificial airway: To be carried out in operating rooms under sterile

conditions. Narcotics avoided - can exacerbate respiratory

difficulty


Inhalation anesthesia: To relieve pain and muscle spasms, Wide mouth opening possible,and Larynx visualized for intubation.

Elective tracheotomy under local anesthesia is acceptable to secure the airway

Ludwig angina necessitate tracheotomy than other infection of the deep spaces of the neck.

Pharyngomaxillary Space

Also known as: the lateral pharyngeal, parapharyngeal, or peripharyngeal space.

Analogous to an inverted cone lying in the lateral aspect of the neck.

Base is situated superiorly at the base of the skull, and the apex inferiorly at the hyoid bone.

Pharyngomaxillary Space Infection Infections originating in the parotid, masticator, peritonsillar,

or submandibular spaces can reach this space and spread to the retropharyngeal space and into the chest

Local invasion from other portals of entry include odontogenic sources and the lymph nodes that drain infections of the nose and throat

Mastoiditis with bony destruction in the mastoid tip can extend to this space (Bezold abscess).

Pharyngomaxillary Space Infection Pharyngomaxillary space is divided into: the anterior and posterior compartments by the styloid

process and its muscles The prestyloid or anterior compartment: Also known as the muscular compartment Contains no vital structures Is closely related to the tonsillar fossa medially and the

internal pterygoid muscle laterally Typically manifests as displacement of the lateral

pharyngeal wall in the tonsillar area and early trismus

Pharyngomaxillary Space

Medial border is the lateral pharyngeal wall, and the lateral border is the superficial layer of the deep cervical fascia over the mandible, internal pterygoid muscle, and parotid gland.

The pterygomandibular raphe and prevertebral fascia, respectively, form the anterior and posterior limits

Pharyngomaxillary Space Infection The retrostyloid or posterior compartment : Also known as the neurovascular compartment. Is traversed by the carotid sheath, cervical

sympathetic chain, and cranial nerves IX through XII and

Typically manifests as: edema, sore throat, and odynophagia.

Swelling in the neck can be caused by inferior extension to the lower limit of the hyoid bone.

Pharyngomaxillary Space Infection External drainage is through the submaxillary fossa

as described by Mosher in 1929. A T-shaped incision made with the horizontal limb

parallel to and below the body of the mandible and the vertical limb along the anterior border of the sternocleidomastoid muscle.

Follow the carotid sheath to find the abscess cavity within the pharyngomaxillary space.

Pharyngomaxillary Space Infection Finger is inserted below the submandibular gland

and used to dissect bluntly along the posterior belly of the digastric muscle deep to the mastoid tip toward the styloid process.

Separate drains are placed in the superior and inferior portions of the opened space.

Pharyngomaxillary Space Infection Important neurovascular structures traverse the

pharyngomaxillary space.

Serious complications of abscesses can occur in this area:

Thrombosis of the internal jugular vein (Lemierre syndrome)

carotid rupture

Retropharyngeal Space

Also known as the retrovisceral, retroesophageal, and posterior visceral space

Potential space between the visceral division of the middle layer of the deep cervical fascia, and the alar division of the deep layer of the deep cervical fascia posteriorly

Extends from the base of the skull inferiorly to the level of the first or second thoracic vertebra, where the visceral and alar layers fuse

Retropharyngeal Space

The retropharyngeal nodes are contained within this space and separated into two lateral chains by the midline raphe.

The raphe forms where the superior constrictor muscle adheres to the prevertebral division of the deep layer of the deep cervical fascia.

Retropharyngeal Space Infections:

Common sources of infection : infections of the nose, adenoids, nasopharynx, and paranasal sinuses that drain to the retropharyngeal nodes.

Retropharyngeal nodes regress by the age of 4 or 5 years - most abscesses in the retropharyngeal space occur among children

History of preceding acute upper respiratory tract infection

Retropharyngeal Space Infections

Characterised by : fever, cervical adenopathy, dysphagia, odynophagia, nuchal rigidity, and occasionally airway compromise

Bilateral distribution of the retropharyngeal nodes on either side of the midline fascial raphe – swelling of the posterior pharyngeal wall to one side may be noticed

Spread of tuberculosis or syphilis from the cervical vertebrae has become rare but must be excluded


Characteristic radiographic findings: Abnormal thickening of the prevertebral soft tissue, Reversal of the normal cervical spine curvature, Air in the prevertebral soft tissue, and Erosion of the associated vertebral body At the second cervical vertebra: posterior pharyngeal soft

tissue thicker than 7 mm is abnormal. At the sixth cervical vertebra: tissue thicker than 22 mm in

adults or 14 mm in children is abnormal


Surgical drainage is considered the mainstay of therapy

Transoral approach: Abscesses localized to the parapharyngeal space Avoid visible scarring and contamination of the

tissue planes in the neck Surgeon must protect the airway from aspiration

by placing the patient in the Rose position with the neck in extreme extension.


Extension of Infection: Into the anterior or posterior mediastinum and

necessitate drainage by means of external thoracotomy.

Characterized by: Severe dyspnea, chest pain, persistent fever, and a

widened mediastinum on a chest radiograph. Adjacent spaces susceptible : The danger space, and The pharyngomaxillary space.

Danger Space

potential space between the alar and prevertebral divisions of the deep layer of the deep cervical fascia.

It is posterior to the retropharyngeal space and anterior to the prevertebral space.

Danger Space

Name reason: extends from the base of the skull into the posterior mediastinum to the level of the diaphragm and offers little resistance to the spread of infection.

The alar and prevertebral divisions of the fascia fuse with the vertebral transverse processes to limit the space laterally.

Danger Space Infections

Caused by: Infectious spread from the retropharyngeal,

pharyngomaxillary, and prevertebral spaces or, more rarely, by lymphatic extension from the nose and throat.

Infection spreads rapidly through the loose areolar tissue within this space to the posterior mediastinum and thorax.

Danger Space Infections

Toxic conditions: Mediastinitis or empyema. Treatment consists of drainage and intravenous

antibiotics with thoracotomy for mediastinal spread.

Prevertebral Space

Compact potential space anterior to the vertebral bodies and posterior to the prevertebral division of the deep cervical fascia.

It extends from the base of the skull to the coccyx.

Prevertebral Space

Lying just posterior to the danger space, it is limited laterally by the fusion of the prevertebral division of the deep cervical fascia with the transverse processes of the vertebra.

Prevertebral Space Infections

Commonly caused by : Pyogenic or tuberculous involvement of the

vertebral bodies Penetrating trauma Infection of this space can cause vertebral

osteomyelitis and spinal instability. Therapy includes antibiotics, stabilization of the

spine, and surgical drainage through an external approach

Visceral Vascular Space

Potential space within the carotid sheath

Contains the carotid artery, the internal jugular vein, and the vagus nerve (cranial nerve X)

Compact space contains little areolar connective tissue : infection remains relatively localized.

Lymphatic vessels within this space receive secondary drainage from most of the lymphatic vessels of the head and neck

Visceral Vascular Space

All three layers of the deep cervical fascia contribute to the carotid sheath.

Mosher in 1929 called this fascia the "Lincoln Highway" of the neck. (The Lincoln Highway was the first paved transcontinental highway in the United States.)

Visceral Vascular Space Infections

Infections of the pharyngomaxillary space spread to the visceral vascular space

Complications : thrombosis of the internal jugular vein or carotid rupture

Pretracheal space

Lies in the anterior aspect of the neck from the thyroid cartilage down to the superior mediastinum at the level of the fourth thoracic vertebra, near the arch of the aorta.

Enclosed by the visceral division of the middle layer of the deep cervical fascia, the anterior visceral space begins just deep to the strap muscles

Completely surrounds the trachea, and reaches the anterior wall of the esophagus.

Pre Tracheal Space Infection

Caused by perforations of the anterior esophageal wall during instrumentation, a foreign body, or external trauma.

Rarely spread from the thyroid gland or other deep neck spaces.

Patients initially report swallowing difficulties.

Infection progresses - hoarseness, dyspnea, and airway obstruction.

Pretracheal Space Infection

Laryngoscopy: swelling and erythema of the hypopharyngeal wall, and

Palpation of the neck: crepitus from subcutaneous emphysema.

Therapy consists of intravenous antibiotics, nasogastric suction, and external drainage.

Aggressive treatment and close observation: high risk of airway compromise and mediastinitis

Diagnosis

Studies have shown that one half of patients have received some form of antibiotic as an outpatient before returning with a deep neck abscess.

Local signs, such as edema, fluctuation, and pointing of an abscess, can be reduced

Systemic symptoms often are masked, which can result in a missed or delayed diagnosis

Diagnosis

Localized symptoms, septic shock, or mediastinitis, depends on the degree of progression of the disease

Fever, pain, and swelling are the most common presenting symptoms

Physical examination : confirms the presence of swelling, elevated temperature, and dehydration

Diagnosis

Findings related to compromise of the upper aerodigestive tract: odynophagia, dysphagia, or trismus.

Growing incidence of infection of the deep spaces of the neck caused by intravenous drug abuse: physical examination should include a survey of the extremities and groin area for scarring from previous injections

Horner syndrome, (ipsilateral ptosis, miosis, and facial anhidrosis), can be caused by infection in proximity to the sympathetic chain

Diagnosis

Plain lateral and anteroposterior radiographs of the neck:

Foreign bodies, tracheal deviation, subcutaneous air, fluid within the soft tissues or soft-tissue edema, suggest infection or an abscess

Radiographs of the chest: Pulmonary edema, pneumothorax, pneumomediastinum, or

hilar adenopathy

Diagnosis

Computed tomography (CT): To differentiate cellulitis from abscess, and clearly depicts the

spaces involved Definitive differentiation between cellulitis and abscess often

necessitates needle aspiration or surgical drainage

CT characteristics of an abscess in the deep neck spaces: Low attenuation (low Hounsfield units), Contrast enhancement of the abscess wall, Tissue edema surrounding the abscess, and Cystic or multiloculated appearance

Diagnosis

Ultrasound :

Noninvasive and is less expensive than CT.

Useful for supplementing clinical examination for patients with soft-tissue inflammation

Can guide needle aspiration

Management

Securing and maintaining an adequate airway - first objective of treatment for a patient with infection of the deep spaces of the neck.

Most patients need only humidified oxygen and close observation.

If an artificial airway is necessary, endotracheal intubation can be difficult because the abscess distorts or obstructs the upper airway.

Management

If intubation is not possible, tracheotomy or cricothyrotomy is performed

After the airway is secure, therapy is aimed at controlling the infection and preventing complications

Specimens for blood culture are obtained, needle aspiration of the abscess for culture is performed, and parenteral antibiotics are administered

Management

These infections usually are polymicrobial (gram negative, gram positive, aerobic, and anaerobic), and both aerobic and anaerobic bacteria have increased b-lactamase production.

Therapy with ampicillin-sulbactam or clindamycin with a third-generation cephalosporin such as ceftazidime is begun pending culture results.

Empiric use of an antistaphylococcal penicillin is indicated when an abscesses is thought to be of salivary gland origin

Management

Fluid resuscitation often is indicated. For most patients, medical therapy alone is

inadequate, and surgical drainage is necessary. Surgical drainage: Indicated for patients with abscesses or impending

complications and those whose condition does not improve after 48 hours of therapy with parenteral antibiotics

Management

The primary space involved and any additional spaces to which the abscess has spread must be drained.

Surgical anatomic relations often are distorted by inflammation and edema,

The bony and muscular landmarks described by Mosher in 1929 are useful guides for the surgeon.

Landmarks: tip of the great horn of the hyoid bone in the lateral aspect, the cricoid cartilage in the midline, and the styloid process at the base of the skull

Management

The anterior border of the sternocleidomastoid muscle and the posterior belly of the digastric muscle are valuable muscular landmarks.

Successful surgical therapy depends on: good visualization, adequate vascular control, wide incision, and open drainage

Management

Needle aspiration is an accepted method for obtaining material for culture.

Herzon described the therapeutic use of needle aspiration of abscesses of the deep neck spaces.

One aspiration procedure on small abscesses or placement of indwelling catheters to allow repeated aspiration of larger abscesses are alternatives to surgical incision and drainage.

Treatment algorithm in Neck Infections

Complications

Commonly are causedby a delay in diagnosis and extension of the infection beyond the primary space involved.

Spread of infection to the carotid sheath can erode the carotid or cause thrombosis of the internal jugular vein.

Hemorrhage can be heralded by bleeding from the external auditory canal - mandates immediate surgical intervention.

Complications

Lemierre syndrome: Thrombosis of the internal jugular vein associated

with oropharyngeal infection Usually caused by the anaerobe Fusobacterium

necrophorum and is heralded by spiking fevers, tenderness of the sternocleidomastoid muscle, neck stiffness, and metastatic abscesses typically to the lung, but septic arthritis also is common.

Retrograde thrombophlebitis can lead to cavernous sinus thrombosis.

Complications

The diagnosis is confirmed with the CT finding of ring enhancement with central lucency in the internal jugular vein

Treatment is centered on antibiotics and surgical drainage of the abscess.

Lustig et al. recommend ligation or excision of the vein for persistent sepsis with embolism and anticoagulation for retrograde cavernous sinus thrombosis

Complications

Patients with involvement of the sympathetic chain or cranial nerves may have Horner syndrome or other neurologic deficits.

Osteomyelitis of the mandible or cervical spine can occur with infection of the associated deep neck spaces.

Delay in treatment can cause local complications or spread of infection beyond the neck

Complications

Most dreaded complications of infection of the deep spaces of the neck is mediastinitis.

All patients with infection of the deep spaces of the neck are at risk of mediastinitis.

Chest radiographs : to rule out a widened mediastinum, pneumothorax, pneumomediastinum, or pulmonary edema.

Patients usually have dyspnea, hypoxia, and increasing infectious symptoms.

Complications

Wheatley et al. found transcervical mediastinal drainage to be inadequate in 79% of cases.

Marty-Ane et al. recommended all patients with mediastinitis undergo thoracotomy with placement of several drainage tubes that can be irrigated with 0.5% povidone-iodine solution.

Complications can occur during operations on patients with obscured surgical planes and inflamed soft tissues

Complications

Undesirable scarring can be caused by traditional placement of incisions

Partial closure of the incision is possible after adequate breakdown of loculation, irrigation, and drainage.

Scar revision techniques can be used after full recovery to augment appearance.

Highlights

Odontogenic sources are the most common origin of deep neck infections and typically involve anaerobic pathogens.

Staphylococcal infections of the salivary gland also are frequent sources.

Intravenous drug abuse has become an increasingly common cause of deep neck infection.

The vascular space containing the carotid artery is especially vulnerable.

Commonly sequelae of deep neck infections, including trismus, cervical rigidity, upper airway edema, laryngotracheal deviation, and pain, make intubation difficult.

Highlights

If an artificial airway becomes necessary, tracheotomy or cricothyroidotomy is considered.

Mediastinitis, characterized by severe dyspnea, chest pain, persistent fever, and evidence of a widened mediastinum on a chest radiograph, can occur by means of extension of deep neck infections.

Ludwig angina is infection of the submandibular space characterized by a boardlike firmness of the floor of mouth, posterosuperior displacement of the tongue, drooling, and rapid airway compromise.

Signs and symptoms of peritonsillar abscess include trismus, dysphagia, drooling, fever, a "hot potato" voice, deviation of the midline palate and uvula, and bulging of the posterolateral soft palate.

References

Oral and maxillofacial infections – Topazian Text book of OMFS - Laskin Fonseca – surgical pathology vol 5 Lore & Medina an atlas of Head & Neck Surgery- vol 2 Text book of Oral Surgery - Fragiskos D. Fragiskos Deep neck infection – analysis of 80 cases ( BRAZILIAN JOURNAL OF

OTORHINOLARYNGOLOGY 74 (2) MARCH/APRIL 2008 ) Mediastinitis from odontogenic and deep cervical infection. Anatomic

pathways of propagation - Chest 1978;73;497-500 Deep Facial Infections of Odontogenic Origin: CT Assessment of Pathways

of Space Involvement - Am J Neuroradiol 19:123–128, January 1998

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Descending Neck Infections

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