CASE 3396 Published on 19.10.2005

Retropharyngeal abscess

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Kaushik V, Simmons M, Kaushik V, Willatt DJ

Patient

64 years, male

Categories
No Area of Interest ; Imaging Technique CT
Clinical History
A 64-year-old man presented with a four day history of increasing dysphagia. A physical examination was done, and found to be unremarkable. Two weeks earlier, he had fallen down a flight of stairs and had developed a weakness in the right upper limb.
Imaging Findings
A 64-year-old patient presented with a four day history of increasing dysphagia. He was found to be apyrexial, was not drooling and did not have stridor. An examination of the mouth and the oropharynx wasfound to be unremarkable. Two weeks earlier, he had fallen down a flight of stairs at home and had developed a weakness in the right upper limb. A cervical spine X-ray performed at the time had shown no evidence of fracture. An MR scan had also been performed, and had shown multi-level spondylosis with canal narrowing and an effacement of the subarachnoid space, but no cord compression or intrinsic change within the cord. A diagnosis of right brachial plexus neuropathy had been made and confirmed by the results of neurophysiological studies. On this admission, a repeat soft-tissue lateral neck X-ray was requested. This showed a widening of the retropharyngeal space. The patient was referred for a CT study of the neck. This showed a low density ring enhancing lesion in the retropharyngeal space. Air bubbles were also noted. There was no evidence of a vertebral body infection, neoplasm, or recent fracture. A surgical drainage of this retropharyngeal abscess was scheduled and performed through a trans-oral approach. Over one-hundred millilitres of pus was drained. The patient was kept nil by mouth postoperatively and fed via a nasogastric tube inserted at the time of operation. The intravenous administration of antibiotics was continued and an oral diet re-introduced a few days later. The patient made an uneventful recovery. No organisms were cultured.
Discussion
Retropharyngeal abscesses are uncommon but potentially lethal infections. An early diagnosis and the widespread use of antibiotics have led to a considerable reduction in the incidence of major complications and mortality which were previously associated with this condition (1). A significant proportion of untreated cases used to dissect into the posterior mediastinum causing mediastinitis, pleuritis, and pericarditis. Spontaneous rupture into the pharynx have resulted in aspiration pneumonia and empyema. Other reported complications include upper airway obstruction, sepsis, and major vessel erosion. The patients may present with a sore throat, dysphagia, reduced oral intake with or without drooling, odynophagia, ‘hot potato’ or hyponasal speech, trismus, otalgia, headache, neck pain, cervical rigidity, torticollis, malaise, fever, and partial or rarely total airway obstruction. An examination reveals a bulging of the posterior pharyngeal wall. It is important to note that this does not necessarily occur in the midline, as the raphe of the superior constrictor muscle attaches to the prevertebral fascia here. The aetiology of retropharyngeal abscesses differs in adult and paediatric populations (1). In children, the retropharyngeal space contains lymph nodes which drain the ears, nasopharynx, paranasal sinuses and the soft palate. Abscesses are usually related to the spread of infection to these nodes, typically following an upper respiratory tract infection. Children under the age of six years are most likely to be affected. In contrast, abscesses in adults are usually secondary to trauma (e.g. intubation and oesophagoscopy) and foreign bodies. The upper respiratory tract infections and idiopathic groups also account for a significant proportion (2). Abscesses in adults have occurred following odontogenic infection and cervical vertebrae fracture, and have been observed in patients with tuberculosis, syphilis, diabetes, malignancy and chronic alcoholism. The most commonly cultured organisms include Staphylococcus aureus, Group A Beta-haemolytic streptococcus, Klebsiella species, and anaerobes such as Bacteroides. The antibiotic chosen for treatment must provide cover for both aerobes and anaerobes, and be adjusted according to the microbiological culture and the sensitivity data. The lateral soft tissue neck plain film is a quick and reliable method of confirming the diagnosis (3). The characteristic features seen include a widening of the retropharyngeal space, loss of the normal cervical lordosis, and the presence of air in the soft tissues. A CT scan provides further detailed information which may be useful to the surgeon. It can differentiate between cellulitis and abscesses in most cases. It can accurately localise the level of the abscess, define its relationship to the surrounding vascular structures, and determine if other neck spaces are involved. The management of this condition consists of ensuring airway safety, the administration of intravenous antibiotics, and surgical drainage. In most cases, trans-oral drainage can be done. For situations in which there is the involvement of other deep neck spaces or a proximity to great vessels, external drainage is preferred.
Differential Diagnosis List
Retropharyngeal abscess.
Final Diagnosis
Retropharyngeal abscess.
Case information
URL: https://www.eurorad.org/case/3396
DOI: 10.1594/EURORAD/CASE.3396
ISSN: 1563-4086