Abcès rétropharyngé

Retropharyngeal abscess is usually seen in infants or young children. It may be caused by an upper respiratory tract infection that results in adenitis in the retropharyngeal nodes, which then suppurate and form an abscess. The abscess is limited to one side of the midline because of the median raphe of the buccopharyngeal fascia.

• Acute retropharyngeal abscess results from suppuration of retropharyngeal lymph nodes from infected tonsil, adenoid, tooth or penetrating foreign body. It is more common in children. Acute abscesses are most often caused by:¹

  • Beta-haemolytic streptococci, Staphylococcus aureus, Haemophilus parainfluenzae.

  • Anaerobic organisms - eg, Bacteroides spp.

• Early recognition and aggressive management are essential because there is a significant morbidity and mortality.

• Chronic retropharyngeal abscess is rare but is usually due to tuberculosis of the spine.²

Épidémiologie

• Uncommon and occurs much less commonly today than in the past because of the widespread use of antibiotics for suppurative upper respiratory infections.

• Once almost exclusively a disease of children, but is now seen increasingly in adults.

• Acute retropharyngeal abscess presents with severe sore throat, dysphagia, trismus, stridor, dribbling of saliva, and a high fever. It may rapidly progress to airway obstruction.

• It is usually seen in an infant or young child with high fever, agitation, neck pain, malaise, fever, dysphagia, drooling, cough, respiratory distress, and stridor.³

• There is a stiff neck with the head tilted to one side. There is a smooth bulge on one side of the midline of the posterior pharyngeal wall. Associated signs include tonsillitis, peritonsillitis, pharyngitis and otitis media.

• Symptoms in adults: sore throat, fever, dysphagia, neck pain, and dyspneoa.

• Physical signs in adults: posterior pharyngeal oedema, neck stiffness, cervical adenopathy, fever, drooling, and stridor.

• Retropharyngeal la cellulite.

• Angio-œdème.

• Dental infections.

• Épiglottite.

• Foreign bodies.

• Poche pharyngée.

• Mediastinitis.

• Mononucléose infectieuse.

• Otite moyenne, pharyngitis, pneumonie.

• Croup.

• Abcès péri-amygdalien.

• FBC: white cell count very high.

• C-reactive protein (CRP) may also be very high.

• Blood cultures: but often negative.

• Culture of pus aspirated at the time of surgical drainage.

• Lateral neck X-ray (lateral neck X-ray findings may be misleading, especially in young children):
  

  • Increased prevertebral soft tissue shadow.

  • Air and fluid level in the prevertebral area.

  • Concavity or straightening of the cervical vertebral column.

  • The air column is pushed forward.

• CT scan of the neck with intravenous (IV) contrast:
  

  • Retropharyngeal abscess appears as a hypodense lesion in the retropharyngeal space with peripheral ring enhancement.

  • Obtain a CT scan of the neck with IV contrast when the findings on the lateral neck X-ray are equivocal but CT scan of the neck with IV contrast can also differentiate between retropharyngeal abscess and cellulitis.

  • The CT scan also shows the extent of the abscess and its relation to the great vessels.

• CXR: to identify aspiration pneumonia and mediastinitis.

• Oxygen and attention to maintaining upper airway patency. If a patient with signs of upper airway obstruction cannot be intubated, a surgical or needle cricothyrotomy may be required. A tracheostomy may also be required; however, this is rare.⁵

• IV fluids are required if the patient is dehydrated because of fever and difficulty with swallowing.

• The patient should be seen by an ear, nose and throat (ENT) specialist as soon as the diagnosis is established.

• Peroral surgical drainage of the abscess by incision under anaesthetic (or without anaesthetic in an emergency) is often required.⁶ An ENT specialist may also perform a tracheostomy if required.

• Surgery may be required urgently but not all patients with retropharyngeal abscesses require surgery.⁷ One study found that of 162 paediatric patients with retropharyngeal abscess, 126 required surgery initially and, of the 36 patients initially treated conservatively with high-dose antibiotics, 17 required surgery.⁴

• High-dose antibiotics: initially, high-dose IV ampicillin, clindamycin, cefuroxime, ceftriaxone, metronidazole or co-amoxiclav and, later, changed if necessary in line with culture results and clinical progress. Clindamycin has also been shown to be an effective initial treatment.⁸ Combination regimens of these antibiotics may be necessary (eg, ceftriaxone plus metronidazole, or clindamycin plus cefuroxime).⁹

• Airway obstruction.

• Mediastinitis.

• Péricardite.

• Pneumonie par aspiration.

• Epidural abscess.

• Septicémie.

• Adult respiratory distress syndrome (ARDS).

• Erosion of the second and third cervical vertebrae.

• Cranial nerve IX and/or XII deficits.

• Septic thrombosis of the jugular vein or haemorrhage secondary to erosion into the carotid artery,

• Prognosis is generally good if the condition is diagnosed early, is managed promptly and effectively and if no complications occur.

• Mortality rate may be as high as 40-50% if any serious complications do occur.