Migrating fish bone presenting as a neck fistula

Abstract

The case report describes an extremely rare finding of fish bone migration from the aerodigestive tract causing a neck fistula 2 years after its ingestion. Detailed case study and surgical treatment is presented. This case highlights the need for further assessment in presence of a high clinical suspicion of foreign body ingestion with a normal physical examination of the upper aerodigestive tract, to avoid serious and potential life-threatening complications later on.

Background

Foreign body (FB) ingestion in the upper aerodigestive tract is quite common in daily clinical practice and the correct management of these patients is crucial to prevent associated complications. The case describes a rare and potential life-threatening complication of undiagnosed fish bone lodgment in the upper aerodigestive tract.

Case presentation

An 81-year-old woman, independent in daily living activities, with medical history of hypertension, multinodular goitre and dyslipidaemia. She had no history of tobacco or alcohol consumption.

She presented with a left-side neck fistula, 1 week after she had been submitted to fine-needle aspiration cytology to thyroid nodules. The neck fistula was painless, 1-cm diameter, round in shape, located in posterior border of the left sternocleidomastoid muscle, about 4 cm above the superior border of clavicle (figure 1) and had purulent drainage. She was treated with flucloxacillin 500 mg 8/8 hours and fusidic acid cream 8/8 hours for 8 days. The purulent drainage had ceased, but the neck fistula remained.

Figure 1.

Neck fistula (black arrow): 1-cm round shape, located in the left posterior border of sternocleidomastoid muscle, about 4 cm above the superior border of clavicle.

Two years before, she attended the emergency department of otorhinolaryngology of another hospital with symptoms of stinging and FB sensation after she had eaten fish (snapper).

At that time, a complete otorhinolaryngologic examination was performed, including rigid laryngoscopy, but no FB was identified. No further diagnostic examinations were requested, and she was discharged.

She continued to complain of stinging during deglutition until 5 months after the episode. She also complained of frequent choking episodes during deglutition, that she maintained until our observation.

Investigations

One month after the neck fistula started, neck CT with contrast was performed and revealed a 2.7 centimetres linear bony density FB with its lateral tip in the depth of the neck fistula, in the posterior border of sternocleidomastoid muscle (figures 2–3). The deepest limit of the FB was submucous located in the left hypopharynx, immediately above the upper oesophageal sphincter.

Figure 2.

Neck CT scan (coronal view) revealing a straight left horizontally oriented fish bone (white arrow).

Figure 3.

Neck CT scan (sagittal view) shows the fish bone impaction posterior to the left posterior border of sternocleidomastoid muscle.

The patient was referred to an otorhinolaryngologist consultation 1 month after the CT scan was performed. She was submitted to a complete otorhinolaryngologist examination, including rigid laryngoscopy. Besides neck fistula, no anatomic or physiological abnormalities or FB were seen in the pharynx or in the larynx.

Differential diagnosis

One week prior to the neck fistula appearance, the patient had received fine needle aspiration cytology to the thyroid nodules. Infection was the first aetiology considered and antibiotic was prescribed. In a country with a high prevalence of tuberculosis, such as Portugal, this diagnosis should also be ruled out if the aetiology was not found after CT scan.

ENT evaluation is mandatory in cases of neck fistula, to rule out signs of head and neck tumours. Despite being a non-smoking female, the patient’s age favours the latter diagnosis.

Neck trauma should also be excluded by clinical history.

At last, in the presence of neck fistula, clinician should also ask the patient about previous episodes of FB ingestion. CT scan confirmed the presence of FB in the upper aerodigestive tract in relation to the neck fistula, explaining the clinical case.

Treatment

Prior to the referral to the ENT department, the patient was aware that the neck fistula originated from an impacted FB having previously been detected on CT scan. She precisely remembered the day she went to the ENT emergency department 2 years before, after eating a snapper, due to sting and FB sensation.

Risk of serious complications due to the neck FB were explained and the need for its removal. She was proposal for surgery, after informed consent.

Surgery was performed under general anaesthesia and the patient was positioned supine with head extension and rotation to the opposite side. Five centimetres left lateral horizontal cervicotomy with neck fistula excision was performed. External jugular vein was ligated. Intraoperatively, the surgeon used the neck fistula as a guide to perform the neck dissection. The fish bone was found about two centimetres deeper to cutaneous fistula involved in fibrous tissue (figure 4). The fish bone was located on the subclavian triangle: behind the posterior border of sternocleidomastoid, superior to clavicle and inferior to omohyoid muscle. No communication was found between the neck fistula and the pharynx.

Figure 4.

Fish bone surgical removal: it was found involved in fibrous tissue, about 2 cm deeper to cutaneous fistula.

The fish bone was removed in one big and two smaller pieces (figure 5). Incision closure was performed in platysma and subcutaneous planes with Vicryl 3-0 and skin was closed with staples. No drain was placed. She was discharged on the same day with prophylactic antibiotherapy with amoxicillin clavulanate 875+125 mg twice a day for 8 days.

Figure 5.

Fish bone was removed in one big and two small pieces.

Outcome and follow-up

Ten days after surgery, the wound was completely closed. The patient’s complaint of frequent choking episodes during deglutition disappeared and she became asymptomatic. Until the article was written, the follow-up period was 6 months, without any patient’s complaints or complications.

Discussion

FB ingestion is one of the most common diagnoses in otorhinolaryngology emergency department.

Tonsils and base of tongue are the most common locations for fish bone lodgment, but they can also be trapped in epiglottis, vallecula, pyriform sinus, larynx and oesophagus.¹

Symptoms of fish bone ingestion include odynophagia, dysphagia, FB sensation and pricking pain during swallow.

Most of the ingested fish bone are correctly identified after careful examination of oral cavity, pharynx and larynx, sometimes with the use rigid or flexible laryngoscopy. If a FB is identified in the upper aerodigestive tract, it should be promptly removed.

However, in rare cases, fish bones can be trapped in submucosal tissues of the upper aerodigestive tract, and they cannot be identified, unless radiological examination is requested.

Due to fish bone’s sharp surface, it can puncture the mucosa of the upper aerodigestive tract, become lodged and not be visible on physical examination.

Pathophysiological mechanisms for fish bone extraluminal migration are not completely understood, but some identified risk factors are horizontally oriented fish bone, muscle contraction and tissue changes with granulation or inflammation.^2–5 Besides, fish bone extraluminal migration is more common in cases of late seeking medical attention.⁶

Transversely oriented impacted fish bones are also less probably detected on X-ray.⁷

If FB in the upper aerodigestive tract is suspected, the patient should first be observed by an otorhinolaryngologist. If no FB is identified, imaging is advised if symptoms justify.

Neck and chest X-ray has a low sensibility and specificity for FB detection in the upper aerodigestive tract, so CT scan is the recommended imaging study.^8–11 Besides, CT scan provides precise size and location of FB, its relationship with other neck structures being essential to plan its surgical removal. The measurement of FB also assures that it has been completely removed during the procedure.

Drooling, accumulation of saliva in the pyriform sinus and age over 65 years are considered clinical predictors of fish bone impaction.⁹

Fish bone lodgment can present extraluminal migration and cause complications, such as deep neck abscess (retropharyngeal, parapharyngeal abscess), oesophageal perforation, mediastinitis, thyroid abscess or thyroid retention and vocal fold paresis.^12–15

Vascular complications have also been described, namely carotid artery rupture, vascular oesophageal fistula (aortic-oesophageal, innominate artery oesophageal fistula, subclavian oesophageal fistula), thromboembolism and brachial plexus injury.¹⁶

Risk factors for fish bone ingestion complications increase with a longer duration of impaction (>24 hours), fish type and length (>3 cm).^17–19

No relation exists between duration of FB and mortality.²⁰

The case report describes a rare migrating fish bone (snapper) ingested 2 years prior, later complicated by a neck fistula. The patient was observed in an ENT emergency department on the same day of fish bone impaction. At that time, otorhinolaryngology examination including rigid laryngoscopy was performed, without detection of the FB impaction. Despite persistent complaints of stinging and FB sensation, no further diagnostic examinations were requested at that time, and she was discharged without any recommendations or follow-up visits.

CT scan analysis shows that the fish bone long axis is horizontally oriented, and the puncture site probably occurred at the hypopharynx, near the upper oesophageal sphincter. As previously described, the orientation of the fish bone in relation to pharynx is one of the most important factors for impaction.

If fish bone is parallel to the pharynx, it is more frequently expelled, while if it is perpendicular or oblique, it is more likely to have extraluminal migration.²¹

As patient reported, neck fistula became noticeable 1 week after she was submitted to fine-needle aspiration cytology to thyroid nodule. The authors’ hypothesis is that this temporal relationship can be explained by eventual dislodgment of fish bone by the needle trauma of FB’s adjacent tissues.

This case emphasises that FB can be lodged in the upper aerodigestive tract for many years until a complication occurs. In the management of a patient with neck fistula, clinicians should also ask the patient about history of FB impaction in the last months or years.

This case also highlights the need to request neck and chest CT scan in a patient with persistent complaints after FB ingestion, especially fish bone, if no FB is detected after complete otorhinolaryngology endoscopic examination. The authors also proposed an algorithm for management approach of patients with clinical suspicion of FB impaction (figure 6).

Figure 6.

Proposed management approach for patients with clinical suspicion of foreign body (FB) ingestion. *Red flag signals are considered worsening of FB impaction symptoms (eg, increase in the severity of odynophagia or dysphagia, fever and/or neck swelling or pain) or continuation of FB impaction symptoms 48–72 hours after initial observation.

Learning points.

• Neck fistula could be the first sign of a misdiagnosed foreign body (FB) in the neck.

• In the management of patients with a high clinical suspicion of FB ingestion and a normal upper aerodigestive tract examination, neck and chest CT scan should be performed to rule out a misdiagnosed FB.

• FB lodged in the neck could be almost asymptomatic many years until a complication appears.

• Neck FB impaction could lead to serious and life-threatening complications.

• FB impaction in the upper aerodigestive tract should be promptly removed, even if surgery is needed.

Ethics statements

Patient consent for publication

Obtained.