Sandbox:Retropharyngeal abscess

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Vishal Devarkonda, M.B.B.S[2]

Synonyms and keywords:

Classification

There is no established classification system for retropharyngeal abscess.

Pathophysiology

The retropharyngeal space extends from the base of the skull to the posterior mediastinum (figure 1). The anterior boundary is the middle layer of the deep cervical fascia (abutting the posterior esophageal wall). The posterior boundary is the deep layer of the deep cervical fascia. These fascia fuse inferiorly at the level between the first and second thoracic vertebrae. The retropharyngeal space communicates with the lateral pharyngeal space. The lateral pharyngeal space is bounded laterally by the carotid sheath, which contains the carotid artery and jugular vein [1].

The retropharyngeal space contains two chains of lymph nodes that are prominent in the young child, but atrophy before puberty [2-4].

Anatomy

Retropharyngeal space is a deep neck space in neck extending from the base of skull to the posterior mediastinum.

Boundaries

Anteriorly: Middle layer of the deep cervical fascia (buccopharyngeal fascia)

Posteriorly: Deep layer of deep cervial fascia

Inferiorly:

laterally It is bounded laterally by the carotid sheaths and extends from the base of the skull to the mediastinum

Communication

Contents

Retropharyngeal space consists two pair of lymphnodes, which drains nasopharynx, adenoids, posterior paranasal sinuses, middle ear, and eustachian tube

Transmission

Transmission of the infection to the retropharyngeal space can be by

Trauma
Lymphatic spread
Direct spread

Microbiology

Polymicrobial infection is often responsible for retropharyngeal abscess. The other predominant species involved in causes in retropharyngeal abscess include:

• Beta-hemolytic streptococcus
• Streptococcus pyogenes (group A streptococcus [GAS])
• Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]),
• Fusobacteria
• Prevotella
• Veillonella
• Haemophilus Influenzae
• Neisseria species
• Bacteroides
• Fusoabcterium
• Salmonella

Infections in these areas may lead to suppurative adenitis of the retropharyngeal lymph nodes [1,2,5,6]. Retropharyngeal abscess is associated with antecedent upper respiratory tract infection in approximately one-half of cases [7].

In approximately one-fourth of cases (usually in older children or adults), retropharyngeal infection is secondary to pharyngeal trauma (eg, penetrating foreign body, endoscopy, intubation attempt, dental procedures) [1,5,7-11]. It also may occur in association with pharyngitis, vertebral body osteomyelitis, and petrositis.

Retropharyngeal infections progress from cellulitis to organized phlegmon to mature abscess [1]. Early institution of appropriate antimicrobial therapy may halt progression to mature abscess [12].

Immune response

Retropharyngeal infections progress from cellulitis to organized phlegmon to mature abscess [1]. Early institution of appropriate antimicrobial therapy may halt progression to mature abscess

Natural History, Complications, and Prognosis

Complications

Complications of its spread include airway compromise, epidural abscess, mediastinitis, carotid artery aneurysm or erosion, internal jugular vein thrombophlebitis, septic pulmonary embolism, cranial nerve dysfunction (IX–XII), cavernous sinus thrombosis, aspiration pneumonia, or a rare but life-threatening descending necrotizing mediastinitis and sepsis 2, 7 and 8.

Diagnosis

Laboratory findings

Laboratory studies may show a non-specific leukocytosis. The diagnosis is ultimately supported by radiographic imaging. An initial study, particularly in a patient with concern for airway compromise, should be a soft tissue lateral neck radiograph. These films may demonstrate soft tissue thickening with possible gas-fluid levels in the pre-vertebral cervical space (5). The amount of swelling seen at the level of C2 may be twice the diameter of the corresponding vertebral body, or greater than one-half the width of the vertebral body of C4 (1). In one case series, the lateral neck radiograph was abnormal and suggestive of RPA in 86% of presentations (6). If a patient is stable enough to have a CT scan with intravenous contrast obtained, it has a greater sensitivity (> 90%) for confirming the diagnosis (3). However, the specificity of CT scan, thought to be approximately 60%, has been called into question, particularly in the ability to differentiate an RPA from retropharyngeal cellulitis or lymphadenopathy/lymphadenitis 3 and 9.

Treatment

General measures

Good hygiene which include retracting the foreskin regularly and gentle cleansing of entire glans, preputial sac, and foreskin were found effective in treating the diseases.