Paratracheal abscess after traumatic tracheal intubation

Summary

Major complications of laryngoscopy and tracheal intubation are rare. However, mucosal trauma during airway management can lead to the introduction of oropharyngeal bacterial flora into the deep neck spaces, with the potential for fatal complications. This report describes the development of a paratracheal abscess in a healthy 62‐year‐old man following an outpatient herniorrhaphy. The patient was treated with intravenous antibiotics and underwent ultrasound‐guided needle aspiration of the abscess. He was later re‐admitted to the hospital with re‐accumulation of the abscess, which was successfully treated by open surgical drainage. Though deep neck space infection following laryngoscopy is more common in patients with significant comorbidities and when tracheal intubation has been difficult, this case highlights the need for careful airway management in all patients.

Introduction

Laryngoscopy and tracheal intubation during general anaesthesia exposes patients to the risk of injury to the aerodigestive tract, including to the posterior pharynx and piriform sinuses. Disruption of the pharyngeal mucosa can potentially lead to complications including bacteraemia or abscess formation through translocation of the microbes that comprise the oropharyngeal flora. Bacteria can subsequently travel along fascial planes in the neck, known as ‘deep neck spaces’, with potentially life‐threatening consequences. The muscular structure of the neck is complex and there are at least 11 deep neck spaces, including the parapharyngeal spaces which are shaped like inverted pyramids, extending from the skull base to the hyoid bone, posterolateral to the pharynx. In this report, we describe a case in which an abscess of the parapharyngeal space developed following tracheal intubation for a routine operation.

Report

A 62‐year‐old man with a history of well‐controlled hypertension presented to the university medical centre with worsening throat pain, hoarseness, dysphagia and odynophagia five days after uncomplicated outpatient abdominal herniorrhaphy. The anaesthesia team did not document difficulty with tracheal intubation but noted bloody secretions at extubation and the patient was therefore counselled regarding the possibility of a postoperative sore throat. The patient presented to his primary care physician on the third postoperative day and was referred to a local otolaryngologist. A computed tomographic (CT) scan of the neck with contrast was obtained, which showed an irregular fluid collection containing air collections measuring 4.5 x 2.3 cm overlying the cricoid cartilage, displacing the left lobe of the thyroid anteriorly. There was also a soft tissue fullness at the left posterior hypopharyngeal wall with slight effacement of the left piriform sinus (Fig. 1). The patient was subsequently referred to the university medical centre for further care.

Figure 1.

Contrast computed tomography scan of the neck showing axial (a), coronal (b) and sagittal (c) images of the left paratracheal abscess. The red arrowheads indicate the abscess.

On physical examination the patient had moderate anterior neck tenderness and a palpable left‐sided mass at the level of the thyroid without subcutaneous emphysema. Flexible fibreoptic laryngoscopy demonstrated fullness of the left piriform sinus, but no perforation was observed. The patient was admitted to hospital and treated with intravenous (i.v.) ampicillin‐sulbactam and i.v. dexamethasone. A Gastrografin swallow study was obtained, revealing normal deglutition with no evidence of penetration or aspiration, and only slight residual accumulation of contrast in the left piriform sinus. The following day, an ultrasound‐guided needle aspiration of the collection was performed, and 6 ml of purulent fluid was removed. Group C Streptococcus; Haemophilus parainfluenzae; and mixed anaerobic flora were cultured from the fluid, consistent with pathogenic growth of normal respiratory flora within the abscess cavity. A narrow‐bore nasogastric tube was placed under visualisation with fibreoptic nasopharyngoscopy for enteral nutrition and antibiotic therapy with amoxicillin‐clavulanate. The patient was discharged three days after abscess drainage following clinical improvement. A modified barium swallow was performed three days later and was negative for gross pharyngeal leak. The narrow bore nasogastric tube was removed, and the patient resumed a normal diet.

A week later, the patient was readmitted to hospital for increased neck swelling and pressure. A CT scan of the neck showed a complex irregular and ill‐defined rim‐enhancing fluid collection in the left visceral neck compartment posterior to the left thyroid lobe and lateral to the thyroid cartilage with mass effect displacing the trachea to the right. An additional, smaller, loculated collection of fluid was present posterior to the left piriform sinus. The patient was listed for surgical drainage the next day.

Following pre‐medication with i.v. midazolam 2 mg, and with standard monitoring and venous access secured, the patient was pre‐oxygenated and anaesthesia was induced with 100 mg of propofol. Mask ventilation was straightforward to perform. After neuromuscular blockade with succinylcholine 100 mg, a Cormack‐Lehane grade 1 view of the glottis was obtained with a GlideScope videolaryngoscope (Verathon Inc., Bothell, WA, USA). The patient’s trachea was intubated using a 7.5 mm cuffed tracheal tube; placement was verified by capnography and auscultation. No other neuromuscular blocking drugs were used. Anaesthesia was maintained using sevoflurane (up to 2.3% end‐tidal concentration), nitrous oxide (1.1 l.min⁻¹ towards the end of the case) and fentanyl (three boluses of 50 μg; 25 μg; and 25 μg). Dexamethasone 10 mg i.v. was given to minimise postoperative oedema. Following open surgical drainage of the paratracheal abscess, the wound bed was irrigated with gentamycin‐bacitracin‐saline mix, and a Penrose drain was placed. Following discontinuation of anaesthesia and the resumption of spontaneous breathing and appropriate response to verbal instructions, tracheal extubation was performed uneventfully.

Postoperatively, the patient was treated with i.v. ampicillin‐sulbactam. The abscess fluid culture grew Group C Streptococcus; Eikenella corrodens; and mixed anaerobes, again consistent with normal flora of the mouth and upper respiratory tract. The patient was discharged home on the third postoperative day with a course of oral amoxicillin‐clavulanate after an uneventful postoperative recovery. He noted marked improvement in his neck pain and swelling at follow‐up in clinic, and the drain was removed at that time. The patient has not experienced further neck abscesses or complications in the year that has passed since treatment.

Discussion

The development of a paratracheal abscess is an underappreciated complication of tracheal intubation. In the literature, most occurrences of deep space neck abscess following complications of laryngoscopy and tracheal intubation are found in patients with difficult airways and significant comorbidities [1, 2]. The development of a retropharyngeal abscess following routine tracheal intubation has been previously reported [3]. However, in this case, a parapharyngeal space abscess formed following routine and uneventful tracheal intubation in a healthy adult.

Tracheal intubation is considered a safe procedure; the most commonly reported complication is postoperative sore throat, occurring after up to 62% of intubations. This is largely a self‐limiting condition, with symptoms usually lasting no more than 48 h [4]. If sore throat persists for more than a week, it is suggestive of pharyngeal or oesophageal injury [5, 6]. Trauma from tracheal intubation can occur anywhere along the aerodigestive tract and at any step of the process of airway management. Injury can occur from the laryngoscope blade; stylet; or tracheal tube. A 0.015% incidence of pharyngoesophageal injury due to tracheal intubation has been reported, with the most common injury location involving the tonsillar pillars [7]. More serious complications of traumatic intubation, such as infection and deep neck space abscesses, can lead to significant morbidity and mortality. Difficult or traumatic intubation is associated with bacteraemia [8]. Descending contiguous spread through cervical fascial planes can lead to necrotising mediastinitis, which is associated with a mortality rate of up to 40% [9]. Mass effect from an abscess can cause airway obstruction, and erosion of the tracheal cartilage can make airway management difficult even with tracheostomy [5].

The most common locations for pharyngoesophageal perforation are the posterior pharynx and piriform sinus. Risk factors for perforation include history of difficult airway, tracheal intubation by less‐experienced clinicians and emergent tracheal intubation. Hoarseness; dysphagia; sore throat; fever; and subcutaneous emphysema are often the presenting symptoms. Clinical signs of perforation can be absent in 50% of cases when tracheal intubation is thought to be atraumatic [5, 7, 8]. Diagnosis of a suspected piriform sinus perforation can be made by flexible endoscopy or swallow study, though small perforations can be missed with Gastrografin swallow as oedema of the damaged tissues may occlude the tract. If there is still a high index of suspicion of perforation after a negative Gastrografin study, a barium swallow can be revealing as the greater density of barium can expose small perforation tracts [6].

Although not definitively diagnosed on flexible endoscopy or swallow study, the patient in this report likely sustained a piriform sinus perforation either from the blade of the laryngoscope while attempting to visualise the glottis before intubating the trachea, or else from trauma caused by the tip of the tracheal tube during attempts to pass the tube into the trachea. Prevention of mechanical trauma to the aerodigestive tract and airway complications requires a gentle and unhurried approach and the avoidance, if possible, of ‘blind’ instrumentation of the airway. These may be facilitated by thorough patient assessment; development of individualised airway strategies; maintaining oxygenation throughout airway management; and optimising laryngoscopy [9]. Recognised traumatic tracheal intubation may warrant additional surveillance to prevent delays in potentially life‐threatening complications [5, 8].

The mainstay of treatment for deep neck space infections is surgical drainage of the abscess cavity and treatment with broad‐spectrum antibiotics covering oral flora, including both aerobes and anaerobes. Minimally invasive ultrasound‐guided needle aspiration of deep neck infections can be an effective alternative to surgical incision and drainage for treatment of well‐defined deep neck abscesses in patients without airway compromise. For patients presenting with airway compromise, multi‐loculated ill‐defined deep neck abscesses, or recurrent cases, surgical incision and drainage with washout is typically required [10].

Clinicians should be aware of the potential complications that can occur even when a case of tracheal intubation is considered routine. This case report describes the development of an abscess in the parapharyngeal space following traumatic tracheal intubation in a healthy patient. A high index of suspicion for neck abscess is warranted in a patient presenting with characteristic signs and symptoms after a traumatic tracheal intubation.