Deep Neck Infections

1

What are deep neck space infections?

Deep neck space infections (DNSI) encompass a wide spectrum of infectious disorders of the neck. DNSI are typically classified by the fascial space that the infection occupies.

2

What risk factors are associated with the development of DNSI?

Risk factors of DNSI include a low level of education, living more than 1 hour from a tertiary care center, presence of tonsils, Streptococcus infections, substance abuse, and poor dental hygiene.

3

Describe how the neck is organized in terms of fascial planes.

The neck is compartmentalized in two main divisions of fascia: the superficial cervical fascia and the deep cervical fascia.

The superficial cervical fascia includes subcutaneous tissue and envelops the muscles of facial expression. It is continuous with the superficial musculoaponeurotic system (SMAS) and extends inferiorly to involve the platysma.

The deep cervical fascia is divided into superficial, middle, and deep layers.

• The superficial layer invests the parotid and submandibular glands, muscles of mastication, trapezius, and sternocleidomastoid and forms the stylomandibular ligament.

• The middle layer is composed of two divisions: the visceral division invests the larynx, pharynx, trachea, esophagus, thyroid, and parathyroid; the muscular division invests the strap muscles.

• The deep layer is also composed of two divisions: the prevertebral division envelops the paraspinal muscles and vertebrae; the alar division lies atop the prevertebral layer and covers the sympathetic trunk. The carotid sheath represents the confluence of the deep layers of the deep cervical fascia ( Fig. 3.1 ).

  

4

Identify the deep neck spaces and anatomic sites that contribute to the infections within these spaces.

Deep neck spaces can be suprahyoid, infrahyoid, or span the entire length of the neck. It is important to understand the boundaries of the deep neck spaces because infections often follow these boundaries (or lack thereof) as they spread. DNSI typically are the result of suppuration of lymph nodes from infection at a primary anatomic site.

• Suprahyoid:

  • Peritonsillar: tonsil

  • Parapharyngeal: tonsil, pharynx

  • Submandibular: odontogenic, gingiva, submandibular gland

  • Sublingual: odontogenic, gingiva, sublingual gland

• Infrahyoid: visceral (esophageal perforation)

• Spanning the entire length of the neck

  • Retropharyngeal: nasal cavity, paranasal sinuses, nasopharynx, vertebral bodies

  • Prevertebral: hematogenous spread from vertebrae and intervertebral discs

  • “Danger” space: parapharyngeal, retropharyngeal space infections

  • Carotid sheath: parapharyngeal, retropharyngeal space infections

5

What conditions can present in a similar fashion to DNSI?

Congenital anomalies can either masquerade as a DNSI or become more clinically apparent when they become infected. Thyroglossal duct cysts, lymphatic malformations, and branchial cleft cysts can rapidly increase in size and present with signs and symptoms identical to DNSI. Prior history of a mass or fullness that waxes and wanes suggests the presence of an underlying congenital lesion.

Neoplastic processes can also present with rapid neck swelling and features consistent with an infectious process. Fevers, night sweats, and weight loss can be presenting signs of lymphoma. New neck masses in adults are more likely to be malignant when compared to pediatric patients.

6

What is the “danger space”?

The danger space is bound by the alar fascia anteriorly and the prevertebral fascia posteriorly. It extends from the skull base to the thoracic cavity, providing an unrestricted path for the spread of infection into the mediastinum, causing mediastinitis. Infections of the parapharyngeal, retropharyngeal, and prevertebral space can easily extend to this space.

7

What is the most common major complication of DNSI?

Mediastinitis is the most common major complication of DNSI. It typically presents with tachycardia, dyspnea, and pleuritic chest pain. Chest x-ray can demonstrate mediastinal widening. Further evaluation with contrast chest CT is necessary to identify fluid collections that require drainage. Broad-spectrum intravenous antibiotics, early consultation with the thoracic surgery service, and close surveillance in the intensive care unit are recommended.

8

How are prevertebral space infections different from infections of other deep neck spaces?

Prevertebral space infections are generally the result of hematogenous seeding or contiguous spread of infection from discitis or vertebral osteomyelitis. Gram-positive bacteria, especially Staphylococcus aureus , are the most common pathogens in these infections; anaerobes are uncommon.

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