Key points
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Understanding fascial planes and potential spaces within the neck is integral to determining routes of spread and mandatory when surgical intervention is necessary.
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Imaging is critical in the stable patient to determine the location and severity of infection as well as provide a guide when surgery is indicated.
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Pharmacologic treatment initially includes empiric broad-spectrum antibiotics against gram-positive, gram-negative, and anaerobic bacteria—later refined based on culture and sensitivity results.
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Surgical intervention is reserved for complicated or unstable patients, or those who are unresponsive to medical therapy.
Etiology
Most neck infections arise from extension from the upper aerodigestive tract. Dental infections are the most common etiology, followed by oropharyngeal infections. Occasionally, cervical lymphadenitis can lead to neck abscess, especially in undertreated or inadequately treated infections. Surgical manipulation of the upper airway and pharynx can cause spread of oral and oropharyngeal flora to the deep neck spaces, thus potentiating infection. Other causes of neck infection include spread of infection from the paranasal sinuses, mastoid, and skin, as well as intravenous drug use, penetrating trauma, foreign bodies, malignant necrotic lymph nodes, and congenital cysts.
Etiology
Most neck infections arise from extension from the upper aerodigestive tract. Dental infections are the most common etiology, followed by oropharyngeal infections. Occasionally, cervical lymphadenitis can lead to neck abscess, especially in undertreated or inadequately treated infections. Surgical manipulation of the upper airway and pharynx can cause spread of oral and oropharyngeal flora to the deep neck spaces, thus potentiating infection. Other causes of neck infection include spread of infection from the paranasal sinuses, mastoid, and skin, as well as intravenous drug use, penetrating trauma, foreign bodies, malignant necrotic lymph nodes, and congenital cysts.
Anatomy
Regardless of the source of infection, understanding the fascial planes and potential spaces of the neck is key to diagnosis and management of neck infections ( Figs. 1 and 2 , Table 1 ). The fascial planes provide real and potential spaces ( Table 2 ) for the containment and/or spread of infection from the neck to other parts of the body.
| Fascial Plane | Common Name | Structures Within the Plane |
|---|---|---|
| Superficial cervical fascia | Superficial musculoaponeurotic system (SMAS) | Platysma, muscles of facial expression |
| Superficial layer of the deep cervical fascia | Investing layer | Trapezius, sternocleidomastoid, parotid and submandibular glands, anterior belly of the digastric, masseter |
| Middle layer of the deep cervical fascia | Visceral fascia | Strap muscles, buccinator, pharyngeal constrictors, larynx, trachea, esophagus, thyroid, and parathyroid glands |
| Deep layer of the Deep cervical fascia | Prevertebral fascia | Paraspinous muscles, cervical vertebrae, scalene muscle |
| Carotid sheath | Confluence of each layer of the deep cervical fascia | Common carotid artery, internal jugular vein, vagus nerve, ansa cervicalis |
| Space | Location | Structures Within the Space |
|---|---|---|
| Parapharyngeal | Suprahyoid neck | Prestyloid: fat, styloglossus, stylopharyngeus, lymph nodes, internal maxillary artery, deep lobe of parotid, V3 Poststyloid: carotid artery, jugular vein, sympathetic chain, CN IX, X, XI, XII |
| Submandibular and sublingual | Suprahyoid neck | Sublingual gland, Wharton’ duct, submandibular gland, lymph nodes—teeth apices anterior to the mylohyoid (usually secon molar) involve the sublingual space |
| Peritonsillar | Suprahyoid neck | Loose connective tissue between palatine tonsil and superior constrictor muscle |
| Masticator | Face | Muscles of mastication, V3, buccal fat pad |
| Parotid | Face | Parotid gland, facial nerve, external carotid artery |
| Anterior visceral | Infrahyoid neck | Pharynx, esophagus, larynx, trachea, thyroid gland |
| Retropharyngeal space | Entire neck | Lymph nodes and connective tissue between the middle and deep layers of the deep cervical fascia |
| Danger/Prevertebral | Entire neck | Sympathetic chain, lymph nodes, extends from skull base to mediastinum and coccyx |
| Carotid | Entire neck | Carotid artery, internal jugular vein, vagus nerve, sympathetic chain, ansa cervicalis |
Microbiology
Oropharyngeal flora, including aerobic and anaerobic bacteria, are the most common isolates seen in culture from neck infections. Common bacteria and fungi cultured from neck infections are shown in Box 1 .
| Staphylococcus epidermidis and aureus | Haemophilus |
| Streptococcus viridans and pyogenes | Actinomyces |
| Bacteroides spp. | Tuberculosis |
| Fusobacterium | Mycobacteria |
| Neisseria | Bartonella henselae |
| Pseudomonas | Histoplasmosis |
| Escherichia | Coccidioides |
Treatment of these organisms requires an understanding of the responsiveness of the bacteria or fungus to antibiotics. For instance, atypical Tuberculosis and Mycobacteria often cause chronic fistulae if treated surgically, while Staphylococcus and Streptococcus species usually respond more favorably to surgery when required.
Diagnosis
History
Recent dental or surgical procedures in the upper aerodigestive tract; sick contacts; animal and insect exposures; intravenous drug use; trauma; and past medical history, including immunomodulating medicines, allergies, and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), hepatitis, diabetes, malignancy, and chemotherapy.
Symptoms include:
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Onset and duration of symptoms
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Pain, fever, and redness at the site
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Dysphagia, odynophagia, drooling, hot potato voice, trismus, otalgia
Physical examination should include
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Palpation of the neck mass, evaluating for tenderness, fluctuance, crepitus
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Nasal cavity, oral cavity, oropharynx, and ear canal visual inspection (see Fig. 3 )
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Bimanual examination of the oral cavity and oropharynx and teeth
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Flexible fiberoptic awake upper airway evaluation
See Table 3 for findings associated with neck infections.
| Finding | Clinical Importance |
|---|---|
| Nasal cavity purulence | Retropharyngeal lymphadenopathy or swelling, foreign body |
| Uvular deviation | Peritonsillar or parapharyngeal space involvement, oropharyngeal malignancy ( Fig. 3 ) |
| Teeth abscess | Odontogenic source, check for crepitus from gas-producing organisms |
| Posterior deflection of the tongue | Sublingual space involvement; “Ludwig angina” ( Fig. 5 ) |
| Unilateral pharyngeal wall swelling with no erythema or fever | Parapharyngeal space tumor |
| Cranial neuropathy | Intracranial/neural extension |
| Hoarseness, dyspnea, stridor | Need to determine if airway is patent, midline, noninflamed or requires intubation or tracheostomy prior to imaging |
Laboratory evaluation should include
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Complete blood count:evaluate presence ofleukocytosis and pancytopenia
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Complete metabolic panel: evaluate for hyperglycemia, renal function, and hydration status
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