Manon Kwon
Infections of the head and neck are both common and potentially life-threatening. Knowledge of the fascial layers and the potential spaces of the neck are important to clinical practice because of the potential complications that may arise.
CLINICAL PRESENTATION
The signs, symptoms, and complications of the infectious disorders of the head and neck are determined largely by the anatomic compartment of origin. The fascial layers serve as important barriers to infection and often determine the path of the spread of infection. In addition, comorbidities frequently found in severe presentations are diabetes mellitus, old age, alcohol abuse, systemic disease, and immunosuppressed states (such as in patients with AIDS or in those undergoing chemotherapy).
Patients with deep neck infections can present in a variety of ways with the most common signs and symptoms being fever, pain, swelling, and a variable period ranging from 1 day to several weeks. Decreased oral intake can result in mild to severe dehydration, and swelling may lead to airway compromise.
Deep neck infections may occur at any age, but there appears to be a somewhat bimodal distribution. Overall there is a predominance in patients over 50 with a higher prevalence in the lower socioeconomic groups mainly due to poor oral hygiene and lack of dental care (2–4,6,7). In pediatric patients, these infections can occur at any age, but most commonly occur between 3 to 5 years of age with a slight male predominance (5).
The most common etiologic sites of infection are the teeth and tonsils. Other common causes are postsurgical and trauma that disrupts the skin and soft tissues. Intravenous drug users can present with jugular vein infections from contaminated injections. Other less common causes include foreign bodies, sialolithiasis, parotid obstruction, osteomyelitis, and epiglottitis. In patients with recurrent deep neck infections, consider underlying congenital anomalies (branchial cleft cysts, lymphangiomas, and thyroglossal duct cysts) (2–7,19).
Although mortality from head and neck infections has decreased significantly since the emergence of antibiotics, resistant organisms are spreading into the community. Most infections are polymicrobial including anaerobic and facultative oral bacteria (5). The most commonly isolated organisms in the head and neck infections are gram-positive aerobes followed by anaerobes, gram-negative aerobes and fungi. Streptococcus viridans and Staphylococcispecies dominate the gram positives, while Klebsiella pneumoniae and Neisseria species are frequently the gram-negative culprits (6). Emergency physicians must also be cognizant that the onset may be insidious secondary to partial treatment with antibiotics.
Facial cellulitis of odontogenic origin usually involves the upper half of the face when the maxillary teeth are the source. Involvement of the middle and lower part of the face and neck suggests a mandibular origin. These infections are generally well contained, but in a compromised host there may be rapid spread of infection, which can be fatal (24,25). Infections that affect the midface are commonly caused by a dental abscess of the anterior maxillary molar teeth and the buccal space. Infections in these areas can lead to cavernous sinus thrombosis because of the pattern of venous drainage, airway compromise, and mediastinal extension (1). Odontogenic sinusitis refers to the secondary infection of the paranasal sinuses originating from dental infection. Although most paranasal sinus infections result from an upper respiratory tract infection, direct spread of the infection from the teeth and associated oral tissues can result in secondary sinusitis. Based on proximity, the maxillary sinuses are most often involved. Symptoms include headache, foul discharge, fever, weakness, and drainage. Osteomyelitis may complicate odontogenic infection typically involving the premolar soft tissues, maxillary sinuses, infratemporal fossa, or the periorbital region.
Ludwig Angina
Ludwig angina is defined as an infection involving the submandibular, sublingual, and submental spaces with marked elevation of the tongue (2,4,10). A characteristic brawny edema, induration, or board-like swelling is present on the floor of the mouth. Tender and firm anterior neck edema without fluctuance is appreciated on physical examination. Patients may also complain of stridor, drooling, difficulty talking, tachypnea, and tender tongue with abnormal protrusion.
Ludwig angina typically begins as an infection of the second and third mandibular molars (odontogenic), progressing rapidly into tissues that cover the small muscles between the larynx and the floor of the mouth. Hemolytic Streptococcus sp is the most commonly identified organism. Mixed flora can also cause an overgrowth of gas-producing organisms such as Bacteroides fragilis. Although Ludwig angina is a cellulitis with diffuse infiltration, subsequent abscess formation is not uncommon. The mode of spread is typically direct and not lymphatic. Thus the infection is classically bilateral, but not always obvious on initial presentation. Ludwig angina may result in a life-threatening airway compromise and obstruction, and these patients tend to be quite toxic.
Mediastinitis
Although the most common cause of acute mediastinitis is esophageal rupture (due to instrumentation, foreign body, or trauma), descending necrotizing fasciitis from the retropharyngeal space, prevertebral space, or other anterior visceral spaces can also spread into the mediastinum. Symptoms include increased respiratory difficulty, tachycardia, chest pain, back pain, erythema/edema of the neck and chest, crepitus, and shock. It is important to have a low threshold for further workup in patients with these symptoms (12,13,14,16). Comorbid conditions such as diabetes and immunocompromised patients are at higher risk for this severe infection. Mediastinitis may also result from direct extension from an adjacent source of infection, including osteomyelitis of the sternoclavicular joint, pulmonary infections, and spread of granulomatous disease from mediastinal lymph nodes.
Salivary Infections
Salivary infections can develop in three ways: (a) retrograde migration into the duct from the oral cavity, (b) contagious spread of a local infection, or (c) as a suppurative complication of salivary stasis secondary to an obstructing stone. New literature suggests that the infection is polymicrobial, consisting of Streptococcus sp, Staphylococcus sp, aerobes, anaerobes, or viral etiology (mumps, AIDS, influenza, coxsackieviruses) (2,3). Sialoadenitis is a suppurative inflammation of the Stensen duct or the Wharton duct. Infectious parotiditis is often seen in elderly, dehydrated, diabetic, or patients with granulomatous disease. This entity is usually bilateral and associated with fever and a toxic appearance. Drugs with anticholinergic and diuretic properties can contribute to the development of sialoadenitis (6,25).
Lemierre Syndrome
Lemierre syndrome is a form of septic thrombophlebitis, with or without metastatic abscesses, typically involving the internal jugular vein ipsilateral to a neck or throat infection. First described in 1936, however most cases have occurred in the postantibiotic era, and it was termed in 1984 as the “forgotten disease.” However, recent reviews of the literature suggest an increasing incidence. The offending organism is most commonly a Fusobacterium anaerobic gram-negative bacillus, which is part of the normal flora of the mouth. Predisposing factors include trauma, edema, anoxia, or tissue destruction after dental disease (18,20).
Cavernous Sinus Thrombosis
The cavernous venous sinuses are bilateral structures that communicate with the pterygoid plexus as well as the superior ophthalmic vein. Because these sinuses anastomose with facial veins which have no valves, paranasal sinus, odontogenic, and facial infections may spread into the cavernous sinus. Patients with cavernous venous sinus thrombosis often have a history of midface infection for the past 5 to 10 days. Presenting signs and symptoms include headache, fevers, and cranial nerve deficits, specifically CN III to VI. The patient may have orbital pain, visual disturbances, and fullness with periorbital edema or discrete abscess. Other symptoms include confusion, drowsiness, and coma as a result of central nervous system involvement and/or sepsis.
DIFFERENTIAL DIAGNOSIS
In addition to the processes discussed above, the differential diagnosis of head and neck infections is broad and includes simple pharyngitis, dental infections, and referred pain. Tumors may present as nonspecific swelling and can be difficult to differentiate from advanced primary infections. Viral infections involving the salivary glands (e.g., mumps) can present as facial swelling. Less common infections include tuberculous cervical lymphadenitis (scrofula), cytomegalovirus, catscratch disease, and actinomycosis. Failure to respond to conventional therapy should lead the clinician to suspect a complication or an alternative diagnosis. Certain fungal infections, such as mucormycosis, although rare, are more common in the head and neck regions and should be considered in the immunocompromised patient. Autoimmune diseases such as Sjögren syndrome and Mikulicz disease can also lead to facial swelling caused by enlargement of the salivary glands. Trauma-induced swelling (vascular and nonvascular), can also mimic facial infections (4).
ED EVALUATION
The initial evaluation must focus on an assessment of the ABC’s, as some patients with a deep neck infection present in septic shock and require emergent airway management. The patient’s alertness, posture, work of breathing, stridor, and quality of voice may be assessed in the first few seconds. Once this assessment has been made, more stable patients may have a more detailed physical examination and diagnostic testing.
Protective eyewear, mask, and gloves should be worn when evaluating the oral cavity. Positioning the patient is also important, ideally at a 45-degree angle. Consider examining children on a parent’s lap for patient comfort. It is important to have the following equipment readily available: a good light source, a tongue blade, gauze, suction, and a dental mirror. Providing topical anesthesia of the oropharynx may facilitate the examination in some cases. A MacIntosh laryngoscope blade is an excellent tongue depressor and light source for examination and or procedure.
Patients with dental pain should be examined for the presence of infection and localized dental pain. Pain to percussion with a tongue blade indicates involvement at the apex of the tooth (such as a periapical abscess). Tender swelling of the gingiva adjacent to a tooth may indicate either a periodontal abscess or extension of a periapical abscess through the cortex of bone into the subperiosteal space.
The EM physician should evaluate for facial swelling which can be subtle in some cases as well as adenopathy and other signs of infection. In patients with sialoadenitis, pus may be expressed from the meatus of the salivary duct with gentle pressure to the gland or “milking” along the duct. In severe head and neck infections such as Ludwig angina, trismus, the inability to open the mouth because of involvement of the internal pterygoid or masseter muscle, may be present. Overall, this sign is present in less than 20% of patients even in advanced head and neck infections. More commonly in severe infections, patients will have a toxic presentation or appear in respiratory distress with impending upper airway obstruction or concomitant pneumonia. Other significant clinical signs include torticollis from sternocleidomastoid (SCM) inflammation, neck pain with neck movement, drooling of secretions, stridor, otalgia, headache, and vocal quality changes (2–7,19). Advanced infections may also extend down to the mediastinal area or present as facial cellulitis with closure of the eye indicating potential spread of infection to the periorbital spaces.
Imaging studies provide important information in identifying infection, discerning abscess versus edema, mass, or lymphadenopathy, guiding drainage procedures, and diagnosing complications. Computed tomography (CT) scanning with intravenous contrast is the most helpful and readily available advanced imaging study in most hospitals. Depending on the soft tissues involved, one should consider a maxillofacial CT with 1-mm cuts and/or a neck CT with intravenous contrast. MRI may be superior to CT in assessing the origin of infection and it is less prone to interference from dental artifacts. However most studies note that CT venography seems to be superior to MR venography in the identification of the cerebral venous sinuses and at least equivalent in the diagnosis of cerebral venous sinus thrombosis (1,2,5,9,11). Overall, CT remains the advanced imaging study of choice in most instances.
A lateral soft tissue radiograph of the neck may be a helpful screening tool for deep space infections since it may reveal a thickened prevertebral stripe, enlarged epiglottis, or soft tissue gas. However it gives little information on abscess, and CT is preferred. For patients with chest symptoms, a plain chest radiograph or a chest CT may be indicated to search for evidence of mediastinitis. For patients with evidence of cellulitis or phlegmon by CT but no definitive abscess, IV antibiotics alone are effective. Patients with Ludwig angina can develop complications including internal jugular thrombophlebitis, intracranial extension, and carotid hemorrhage. Findings on CT for sinusitis may include thickening of sinus walls, sclerosis, and perforation (12–16). Since most stones are radiopaque, CT is likely to demonstrate sialolithiasis and its infectious complications if present. The salivary gland demonstrates enlargement, hypodensity on precontrast scan, and avid postcontrast enhancement, with adjacent inflammatory stranding and fascial thickening. The salivary duct may be dilated and thick walled due to a stone obstructing the duct. MR imaging can display inflammation and edema, but is poor in detecting the actual stone. In Lemierre’s, CT scan with contrast demonstrates enlargement and thrombosis of the internal jugular vein, with enhancement of the walls of the vein and perivenular soft tissues.
KEY TESTING
Imaging studies are critical:
CT scan is the imaging study of choice in most cases
Plain films may be a useful screening tool, but should not be relied upon
Consider imaging the chest, as infections may spread to the mediastinum
ED MANAGEMENT
In the patient with a head and neck infection, the emergency physician must determine the following: (a) the potential for airway compromise, (b) the extent of involvement of contiguous structures, and (c) the potential for spread of infection to the fascial planes of the head and neck. If the patient is in need of immediate stabilization, the initial resuscitation takes precedence over further evaluation or diagnostic imaging. See Table 63.1.
TABLE 63.1
Essential Features of Odontogenic and Parapharyngeal Infections
Patients with acute airway compromise or signs of sepsis must be treated quickly and skillfully to prevent further deterioration. Securing the airway is a priority in the ED treatment and should be done in the initial resuscitation. All patients with trismus must be presumed to be difficult intubations. Trismus may be due to muscle spasm, edema, or both, and may not respond to paralytic agents. Patients with Ludwig angina, other deep space infections, postoperative swelling or bleeding present difficult challenges in airway management. Oral intubation can be attempted, although the normal anatomic relationships may be distorted because of swelling or obscured by bleeding. A “backup airway” or alternative measures such as video laryngoscopy, nasotracheal intubation, tracheostomy, cricothyroidotomy, gum elastic bougie, or fiberoptic techniques should be carefully considered before attempts are made. Consultation with the appropriate services should be obtained as time and availability permit.
Parapharyngeal space infections (sublingual, submandibular, submaxillary, lateral pharyngeal, retropharyngeal, and pretracheal) are usually polymicrobial. Appropriate antibiotic therapy includes penicillin G (high dose) plus metronidazole or cefoxitin. Alternative therapy may include ticarcillin/clavulanate (Timentin), piperacillin/tazobactam (Zosyn), or clindamycin in the penicillin-allergic patient.
Patients with suspected deep neck infections require aggressive, early, empiric broad spectrum antibiotic therapy. Most patients are given IV antibiotics targeting gram-positive cocci and anaerobes, but broader coverage for gram-negative aerobes should be considered in diabetics and immunosuppressed patients. For deeper soft tissue head and neck infections like Ludwig angina, high-dose penicillin G (12 million units/d) is required. Unasyn (Ampicillin/Sulbactam) or Clindamycin also provide excellent anaerobic coverage. Chloramphenicol is reserved for extreme situations with few other alternatives (2,4,11). If the patient does not respond to treatment with antibiotics in the first 24 hours, surgical drainage may be required. Most of these cases require admission and consultation with appropriate services. There is no consensus on duration of oral antibiotic therapy but most recommend 7 to 10 days.
Mediastinitis is a surgical emergency in which IV antibiotics, surgical debridement, drainage, and airway management are typically necessary.
Patients with simple dental-related infections can be managed as outpatients with oral antibiotics, analgesia, and rinses. A simple incision and drainage may be indicated for abscesses and follow-up should be arranged the next day with the oral and maxillofacial surgeon (OMFS) or the family dentist (2,3). Penicillin V (phenoxymethyl penicillin) is an effective and inexpensive first-line choice, and unless penicillin allergy exists, it is the antibiotic of choice for outpatient therapy. Clindamycin has become a favorite in dentistry because of its bactericidal activity and its excellent penetration into soft tissue and bone. Clindamycin covers oral pathogens and can be an alternative choice in penicillin-allergic patients (1,2,4,5,10).
Sialoadenitis may be treated on an outpatient basis with an antibiotic that has gram-positive coverage (cephalexin, dicloxacillin), oral hygiene, and a sialagogue such as lemon juice. For immunocompromised patients, consider broader coverage with antibiotics like third-generation cephalosporins, piperacillin/tazobactam (Zosyn), imipenem, or meropenem (1,2,4,5,10).
The incidence of complications from deep neck space infections has remarkably decreased since the advent of antibiotic therapy. Despite this, the potentially devastating outcomes associated with these complications remind the physician to remain vigilant for subtle signs and symptoms. Airway obstruction and asphyxia is a potential complication of any deep neck infection, but has been most commonly associated with Ludwig angina. Other complications include sepsis, internal jugular vein thrombosis, upper GI bleeding, mediastinitis, and vocal cord palsy (4,6,7,19). Carotid artery rupture, although rare, carries a mortality rate between 20% and 80%. This can occur when infection involving the carotid sheath leads to arterial wall weakening, erosion, and eventual hemorrhage. Arterial rupture may be heralded by recurrent small bleeds from the ear, nose or mouth, the onset of shock, a protracted clinical course, and hematoma in the nearby tissue, Horner syndrome or unexplained cranial neuropathies (4,19). The EM physician should be wary of patients at risk for complications (e.g., advanced age, comorbid conditions including HIV, myelodysplasia, cirrhosis, and diabetes) (6,8).
CRITICAL INTERVENTIONS
• Initiate early parenteral broad-spectrum antibiotic coverage in the patient with a suspected deep neck or parapharyngeal infection.
• Assess and manage the airway early in patients with airway compromise. Be prepared to utilize alternate “difficult airway” techniques.
• Consult appropriate services early in the management of critically ill patients.
DISPOSITION
Patients with minor infections can be discharged home with oral antibiotics and close follow-up. Patients with deep neck infections or clinical toxicity generally require admission, and some will need surgical intervention. Depending on the institution, consultants may include Dentistry, Oral Maxillofacial surgery, Ear Nose and Throat, critical care, anesthesia, or a general surgeon. Patients with Ludwig angina or those at risk for immediate airway obstruction should be admitted to a critical care setting for close observation. If appropriate physicians and resources are not available, the patient should be transferred expeditiously to an appropriate facility. Advanced life-support personnel should be used for monitoring the airway, and consideration should be given to establishing a definitive airway prior to transfer.
Common Pitfalls
• Failure to carefully examine patients to identify the source and follow the spread of infection along the fascial planes.
• Underestimation of the potential for spread of infection to the mediastinum.
• Failure to initiate appropriate antibiotics and consultation.
• Failure to recognize the potential for airway compromise from swelling or infection, leading to delay in early airway protection.
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