Peritonsillar, Retropharyngeal, Parapharyngeal Abscess

Refers to the collection of pus within the peritonsillar space. This space is located between the tonsillar capsule and the superior constrictor muscle of the lateral pharyngeal wall.

It often results from peritonsillitis, which is an acute inflammatory process involving cellulitis and the spread of infection into the loose areolar tissue around the tonsil.

Aetiology

It may occur de novo or follow:

• Recurrent attacks of acute tonsillitis
• Penetrating trauma or foreign body in the peritonsillar region
• Dental infection (e.g., periodontitis)
• Tonsillolith
• Tonsillar cyst
• Infectious mononucleosis
• Leukemia
• Immunocompromised states

Pathogenesis

Recurrent acute tonsillitis may cause obstruction of the crypta magna, leading to intra-tonsillar abscess and subsequent spread of infection to the peri-tonsillar space.

The site of initial infection may also be the supra-tonsillar space of the soft palate immediately above the superior pole of the tonsil and the surrounding muscles, especially the internal pterygoid.

Common causative organism is Group A beta-hemolytic streptococcus.

Symptoms - General

• High-grade fever with chills and rigor.
• Malaise, body ache, toxic symptoms.

Symptoms - Local

• Odynophagia (usually acute, severe, unilateral).
• Referred otalgia.
• Neck pain.
• Muffled (hot potato) speech.
• Trismus (due to pterygoid muscle spasm).
• Halitosis.
• Dribbling of saliva.

Signs

• Edematous mucosa.
• Edematous, swollen anterior pillar.
• Downward and medially pushed tonsil due to supra-tonsillar space swelling with pus.
• Congested tonsil (prominent follicles or membrane may be present on the surface/crypts).
• Congested uvula, deviated to the opposite side.
• Trismus.
• Tender enlarged, discrete cervical lymphadenitis.
• Abscess may rupture with purulent fetid discharge.

Differential Diagnosis - Unilateral Tonsillar Enlargement

• Peri-tonsillar abscess
• Peri-tonsillar cellulitis (peritonsillitis)
• Para-pharyngeal abscess
• Severe tonsillitis with intratonsillar abscess
• Tumor and tumor-like conditions
• Para-pharyngeal neoplasm
• Non-Hodgkin’s lymphoma
• Kaposi’s sarcoma
• Squamous cell carcinoma
• Aneurysm of the internal carotid artery
• Tonsillolith
• Tonsillar cyst
• Fibroma, Papilloma
• Trauma:
• Surgical trauma
• Hematoma
• Foreign body in the tonsil

Investigation

• Throat swab M/C/S
• FBC and differential
• FBS to exclude DM
• Lentiviral screen
• Exclude other immunosuppressive diseases
• CT scan with contrast if suspecting parapharyngeal neoplasm

Treatment

Admit to Ward

If the patient is very ill and dysphagia is severe:

• Place on IV fluids
• IV Antibiotics (e.g., Amoxiclavulanic, cefuroxime sodium injection, ceftriaxone)
• Analgesics (Diclofenac, paracetamol)

Abscess management options:

• Abscess may be aspirated with a wide bore needle
• Incision and drainage using a St Clair Thompson Quinsy forceps
• Or a pointed size 11 blade wrapped with plaster to expose only the tip to prevent deep penetration.

I&D can be done by placing a stab incision at:

Incision and Drainage

Interval tonsillectomy may be done 6 weeks after treating the acute infection.

Hot tonsillectomy done during the active phase of infection is often complicated with severe bleeding and dissemination of infection. It is therefore not advised.

Fascia of the Head and Neck

The neck is divided into two anatomical parts:

1. Cervical spine and musculature
2. Visceral segment (where all serious infections occur)

Cervical Fascia

The cervical fascia is divided into two:

1. Superficial cervical fascia (Tela subcutanea)
2. Deep cervical fascia

Superficial Cervical Fascia (Tela Subcutanea)

This sheet extends from the head and neck into the shoulders and axilla. It contains a layer of voluntary muscles (platysma in the neck and muscles of facial expression in the face).

There is a layer of fatty tissue superficial to the muscle, and the deep fascia is located deep to the platysma.

Deep Cervical Fascia

It is made up of three layers:

1. Superficial (Investing)
2. Middle (Visceral)
3. Deep

Superficial Investing Layer

It is attached superiorly to the nuchal ridge, zygoma, mandible, mastoid, and hyoid bones.

Inferiorly, it is attached to the clavicles, sternum, scapula, and acromion.

It splits to envelope the sternocleidomastoid, trapezius, and masseter muscles. It also invests and blends with the capsule of the parotid and submandibular glands.

Deep Cervical Fascia and Related Neck Spaces

About 1-3cm superior to the sternum, the investing fascia divides into two layers, forming the suprasternal space of Burns.

The investing layer also forms the floor of the submental region and the stylomandibular ligament.

Other Spaces Formed by Splits of the Investing Fascia

• Submental space
• Submandibular space
• Parotid space
• Mastication space

Visceral Layer

It has two divisions:

1. Muscular division: surrounds the strap muscles.
2. Visceral division: encloses all the viscera of the neck - thyroid, trachea, esophagus, and pharyngeal constrictors.

Anterosuperiorly, it is attached to the hyoid bone and thyroid cartilage. Posteriorly to the skull base and inferiorly to the sternum, clavicle, and scapula.

It is continuous with the fibrous pericardium and the covering of the thoracic trachea and esophagus.

The part of the investing fascia lying posterior to the pharynx and buccinator from the skull base to the level of the cricoid is called Buccopharyngeal fascia.

It also forms the fascia lying anterior to the thyroid gland (prethyroid fascia) and trachea (pretrachea fascia).

Deep Layer

This layer has two sub-layers:

1. Prevertebral: This layer lies anterior to vertebral bodies and spreads laterally from transverse processes. It attaches to the spinous process posteriorly. It extends from the skull base to the coccyx. It forms the anterior wall of the vertebral space and the posterior wall of the danger space.
2. Ala Layer: It is the superficial portion, lying between the middle layer and the prevertebral division. It extends from the base of the skull to T2 where it fuses with the visceral layer. It forms the posterior boundary of the retropharyngeal space and the anterior wall of the danger space.

Risk Factors/Aetiology of Deep Neck Space Infections

• Immunocompromised state:
• HIV
• Chemotherapy
• DM (Diabetes Mellitus)
• Infants
• Elderly
• Intravenous drug abusers
• Odontogenic infection
• Salivary gland infection
• Trauma
• Foreign body
• Potts disease
• Retropharyngeal lymphadenitis
• Peritonsillar cellulitis
• Unknown

Also known as:

• Posterior visceral space
• Retroesophageal space
• Retrovisceral space
• Space of Gillette or
• Lincoln’s highway

Boundaries

• Anterior: Buccopharyngeal fascia
• Posterior: Alar fascia
• Lateral: Carotid sheath/parapharyngeal space
• Medial: Midline septum divides it into 2 spaces
• Superior: Skull base
• Inferior: Extends to superior mediastinum where the alar fascia fuses with the visceral fascia (buccopharyngeal)

Content

• Loose areolar tissue
• Fat
• Lymph nodes

Causes

• Paediatrics: Infections in drainage area of the lymph nodes
• Adult: Foreign body, vertebral fracture, esophageal instrumentation, TB spine

Types

• Acute: e.g., impacted FB at the cricopharyngeus muscle at upper esophagus
• Chronic: e.g., TB cervical vertebrae

Synonyms:

• Pharyngomaxillary space
• Lateral pharyngeal space

Compartments:

Pre-styloid (anterior)

• Contains: fat, lymph nodes, internal maxillary artery, and loose areolar tissue

Post-styloid (posterior)

• Contains: carotid artery, IJV (internal jugular vein), cervical sympathetic chain, cervical nerves IX, X, XI, and XII

Clinical Features

Symptoms

• History of odontogenic disease, Tonsillitis, Sialadenitis
• Dysphagia
• Dyspnea
• Lymph node suppuration

Signs

• Firm induration and erythema lateral and anterior to sternocleidomastoid muscle.
• Neck rigidity. Difficulty in flexing and turning neck
• Trismus (pterygoid muscle involvement)
• Bulging of lateral pharyngeal mucosa/soft palate
• Medialization of tonsil

Investigations

• CT-scan

Treatment

• IV antibiotics
• Airway protection
• Early surgical drainage
• Transcervical by incision at the level of hyoid across sternocleidomastoid muscle
• Blunt dissection above the hyoid