Definition: It is a condition that occurs due to infection and suppuration of the retropharyngeal lymph nodes in the retropharyngeal space.
The retropharyngeal space lies behind the pharynx between the buccopharyngeal fascia and prevertebral fascia. It extends from base of skull to the tracheal bifurcation.
Types of retropharyngeal abscess:
1) Acute retropharyngeal abscess.
2) Chronic retropharyngeal abscess.
Aetiology of Acute retropharyngeal abscess:
1) Age: Usually in children below 1 year of age.
2) Sex: M > F.
3) Oral infection or nasopharyngeal infection.
4) Trauma by a sharp foreign body like a fish bone.
5) Rarely pus from acute mastoiditis tracks along the petrous bone to form retropharyngeal abscess.
Aetiology of Chronic retropharyngeal abscess:
- Tuberculous caries of the cervical spine which is central.
- Tuberculous infection of the retropharyngeal lymph nodes which is usually on one side of the midline.
Clinical features in acute retropharyngeal abscess:
- Dysphagia especially in acute cases.
- Dyspnea as abscess causes pressure symptoms on the larynx.
- Torticollis due to spasm of neck muscles.
- High grade fever.
- Tender cervical lymphadenitis.
- Croupy cough.
- Child has a quacking voice.
- Abscess presents as a bulge on the posterior pharyngeal wall.
Clinical features of Chronic retropharyngeal abscess:
- Dysphagia present but not fever.
- Neck shows tuberculous lymph nodes.
- Restricted neck movements.
- Low grade fever, as seen in tuberculosis.
- Routine blood investigations.
- X-ray cervical spine lateral view: It shows increase in the retropharyngeal space with straightening of the cervical spine.
- CT Scan neck with chest shows extent of abscess superiorly and inferiorly.
- MRI cervical spine for any neural compression and cervical spine lesions.
Acute Retropharyngeal abscess
- Incision and drainage of abscess– This is usually done without anesthesia as there is risk of rupture of abscess during intubation. Child is kept supine with head low. Mouth is opened with a gag. A vertical incision is given in the most fluctuant area of the abscess. Suction should always be available to prevent aspiration of pus.
- Systemic antibiotics– Suitable antibiotics are given.
- Tracheostomy– A large abscess may cause mechanical obstruction to the airway or lead to laryngeal oedema. Tracheostomy becomes mandatory in these cases.
Chronic Retropharyngeal abscess
- Incision and drainage of abscess– It can be done through a vertical incision along the anterior border of sternomastoid (for low abscess) or along its posterior border (for high abscess).
- Full course of antitubercular therapy should be given.
- Laryngeal oedema.
- Rupture and aspiration of the abscess.