CASE 2397 Published on 04.11.2005

An uncommon position of a retropharyngeal impacted fishbone

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Giger R, Landis BN, Becker M, Dulguerov P

Patient

34 years, female

Categories
No Area of Interest ; Imaging Technique CT
Clinical History
A 34-year-old woman presented with a two-day history of aphagia and neck stiffness that she had got five days after she had had eaten tuna fish. A nasofibroscopy of the hypopharynx revealed a diffuse inferior-posterior oropharyngeal wall bulging. A lateral soft tissue neck radiography that was done demonstrated an increased dimension of the retropharyngeal tissue, and a thin, vertical white double line. The intravenous contrast-enhanced axial CT image showed clear signs of an enlarged retropharyngeal space containing a hypodense area and the presence of a thin radiodense obstacle. A pharyngoscopic incision for the drainage of the retropharyngeal space and extraction of the obstacle was made under general anaesthesia. The patient showed no post-discharge difficulties.
Imaging Findings
A 34-year-old woman presented with a two-day history of aphagia and neck stiffness. Five days ago, the patient had eaten tuna fish, and since then she experienced a pharyngeal foreign body sensation and odynodysphagia. A nasofibroscopy that was done revealed a diffuse inferior-posterior oropharyngeal wall bulging, without any mucosal lesions. The patient was found to be afebrile, the WBC count was in the normal range, and the CRP was slightly increased (23 mg/l, normal range: 1–10). A lateral soft tissue neck radiography demonstrated an increased dimension (1.5 cm) of the retropharyngeal tissue without any evidence of air, and a thin, 2 cm long, vertical white double line suspected of representing a fishbone (Fig. 1). An emergency CT scan was performed, and intravenous antibiotic treatment (amoxicillin-clavulanic acid and metronidazole) was started. The intravenous contrast-enhanced axial CT image showed clear signs of an enlarged retropharyngeal space containing a hypodense area that was 1 x 2 cm in diameter (Fig. 2, a). The coronal CT image reconstruction of the neck was obtained, which showed a radiodense oblique line of a 2.5 cm length with one end in the left hypopharyngeal region at the C3-4 level. The density was similar to that of a bone (Fig. 2b). A pharyngoscopic examination was performed under general anesthesia and a vertical incision of a 2 cm length at the level of the abscess was made. A moderate amount of pus was drained out. On widening the incision and explorating the wound, the suspected fishbone could be located and successfully removed (Fig. 3). The post-operative course was found to be uneventful, the patient started to eat normally the day after the intervention and was discharged. The patient was maintained on oral antibiotics (amoxycillin-clavulanic acid) for 14 days.
Discussion
In the pre-antibiotic era, the majority of retropharyngeal abscesses (RPA) occurred in children under 6 years of age (95% of RPA) [1]. Nowadays, half of RPA are observed in adults [2]. Even in the era of antibiotic therapy, morbidity and mortality are not to be underestimated, and it is crucial to make the correct diagnosis of RPA . In contrast to children, RPA in adults are usually due to a regional trauma, such as iatrogenic lesions caused by intubation, endoscopic instrumentation (rigid broncho- and esophagoscopy) and by a placement of a nasogastric feeding tube, or due to foreign body ingestion (mostly fishbones) with mucosal and submucosal injuries, respectively [3]. Infection spread from other spaces (pharyngo-tonsillitis), anterior spread of the prevertebral infection (hematogenous pyogenic osteomyelitis after intravenous drug abuse, rarely tuberculous vertebral osteomyelitis), external penetrating trauma, blunt neck trauma, and vertebral fractures are also described as the origin of a RPA [4]. The symptoms and findings may be fever, odynodysphagia, dyspnea, neck tenderness and stiffness (torticollis), a ‘hot potato’ or hyponasal voice, cervical lymphadenopathy, a bulging along the posterior pharyngeal wall, and even sepsis [4]. A true lateral soft tissue radiography of the neck during deep inspiration remains the most important diagnostic procedure in the initial evaluation of RPA, and can demonstrate a widening of the retropharyngeal and retrotracheal space, an air-fluid level, and sometimes a radiodense foreign body. Criteria for the normal dimensions of the retropharyngeal and retrotracheal spaces were determined by Wholey et al. (1958), who defined the normal sagittal measurement of the retropharyngeal space at the C2 level for adults as 3.4 mm (range 1–7 mm) and the normal size of the retrotracheal space at the C6 level as 14 mm (range 9–22 mm) [5]. Measurements in adults showing a widening of the retropharyngeal space greater than 7 mm, and measurements of the retrotracheal space greater than 22 mm are indicative of an inflammatory process in these spaces [3]. A CT scan will often be favored as the next imaging modality. An intravenous contrast-enhanced CT image can help to differentiate between cellulitis and the presence of an abscess. It also provides better localization of the level of the abscess and identification of the possible extension of the inflammatory process across facial planes and deep neck tissues, and can demonstrate the exact position and the course of a foreign body, thus helping in deciding the surgical approach. Complications of RPA include mediastinitis, pyopneumothorax, bronchial erosion, purulent pericarditis, and secondary to a spontaneous rupture of the abscess, bronchial aspiration, empyema, and pneumonia [3]. Once the diagnosis is made, the treatment should not be delayed. An intravenous anti-microbial therapy should be started before surgical drainage to prevent a potential septicemia. Drainage of RPA and removal of a foreign body can be performed by a transoral or external approach depending on the extension of the inflammatory process and the localization described by the CT image [3]. In our case, the preoperative CT scan was helpful to determine the exact position of the incision of the retropharyngeal wall for abscess drainage under a pharyngoscopic visualization, and to know the course of the retropharyngeal fishbone for removing it easily.
Differential Diagnosis List
Retropharyngeal abscess caused by an impacted fishbone.
Final Diagnosis
Retropharyngeal abscess caused by an impacted fishbone.
Case information
URL: https://www.eurorad.org/case/2397
DOI: 10.1594/EURORAD/CASE.2397
ISSN: 1563-4086