Aspiration of a metallic-crowned tooth in the left main bronchus in a neurocritical patient: A case report

Abstract

BACKGROUND

Aspiration of dental elements in adults is an uncommon but clinically significant event, which is typically associated with iatrogenic airway manipulation or impaired airway protective reflexes. The right main bronchus is the most common site of foreign-body aspiration, while left-sided aspiration is less common. Dental crowns containing metallic components are usually easily identifiable on imaging because of their radiopacity. However, they may also generate artifacts that complicate accurate radiological interpretation.

CASE SUMMARY

We present the case of a 71-year-old neurocritical care patient with a large left thalamic intracerebral hemorrhage of unknown etiology and a previous history of pulmonary hydatid cyst. The patient aspirated a natural tooth with a metallic crown following tracheostomy. Initially, there was no suspicion of dental loss or aspiration and the foreign body was incidentally identified on routine post-procedural imaging one day after the tracheostomy. A dense radiopaque endobronchial object in the left main bronchus was identified on computed tomography. Beam-hardening artifacts limited immediate identification. Flexible bronchoscopy confirmed the diagnosis and allowed safe removal using tripod forceps.

CONCLUSION

This case highlights that even radiopaque foreign bodies may remain clinically unsuspected, particularly in neurocritical care patients. Aspiration into atypical anatomical locations such as the left main bronchus should be considered. Early bronchoscopy is an essential tool in the diagnosis and management of such cases.

Key Words: Foreign-body aspiration; Dental crown; Left main bronchus; Neurocritical care; Flexible bronchoscopy; Diagnostic pitfall; Case report

Core Tip: Aspiration of dental crowns in adults is rare and frequently occurs in patients with impaired consciousness or following airway manipulation. Despite their radiopacity, metallic crowns may be misinterpreted on imaging. This case emphasizes the importance of maintaining diagnostic vigilance for foreign-body aspiration in atypical anatomical locations and highlights the role of early bronchoscopy in these patients.

INTRODUCTION

Adult foreign-body aspiration is relatively uncommon compared with pediatric populations but carries a risk of significant morbidity in cases which the diagnosis or treatment is delayed[1]. In adults, aspiration is most often associated with neurological impairment, sedation, intoxication, craniofacial trauma, or iatrogenic airway manipulation[2]. In patients who are in coma or those who mechanically ventilated, the usual manifestations of aspiration may be absent. This can cause delays in recognition, leading to occult aspiration[3]. The exact incidence of occult foreign body aspiration in this population is not known. Dental elements, such as natural teeth, crowns, and prosthetic restorations, are a distinctive cause of aspirated foreign bodies. This is due to their rigidity, irregular shape, and frequent metallic composition[4].

From an anatomical standpoint, the right main bronchus is the most common location of foreign body aspiration. This happens because of the wider diameter, shorter length, and more vertical orientation of the right bronchial tree[5]. As a result, impaction in the left main bronchus is considered uncommon and may not be immediately anticipated[6].

Although metallic dental crowns are highly radiopaque and are usually considered to be easily identifiable on imaging, the presence of streak and beam-hardening artifacts on computed tomography (CT) may paradoxically complicate their exact characterization[7].

Here, we report a case of silent aspiration of a metallic-crowned tooth into the left main bronchus of a neurocritical care patient with intracerebral hemorrhage. We also provide a brief review of the literature on adult aspiration in the left bronchial tree, with a focus on the diagnostic challenges, anatomical considerations, and therapeutic approaches.

CASE PRESENTATION

Chief complaints

The patient was sedated and mechanically ventilated and was unable to report symptoms due to impaired consciousness.

History of present illness

A 71-year-old male was brought to the emergency department after being found unresponsive at home. On arrival, neurological examination revealed a Glasgow Coma Scale score of 8.

History of past illness

The patient had a known history of a hydatid (echinococcal) cyst in the left lung, which was followed and managed conservatively. There was no documented history of chronic obstructive pulmonary disease, recurrent aspiration, or prior history of airway foreign body aspiration.

Personal and family history

The patient was a farmer; no pertinent personal or family history was identified.

Physical examination

The patient had Glasgow Coma Scale 8, unconscious, afebrile, hemodynamically stable without active respiratory failure.

Laboratory examinations

The lab results upon admission included a normal hematocrit of 27%, mild elevation of inflammatory markers (C-reactive protein: 4.2), as well as normal liver function tests (serum glutamic oxaloacetic transaminase: 30, serum glutamate pyruvate transaminase: 22, alkaline phosphatase: 95, gamma-glutamyltransferase: 24).

Imaging examinations

Urgent cranial CT revealed a 4 cm × 3 cm × 4 cm intracerebral hemorrhage in the left thalamus with intraventricular extension, compression of the left lateral and third ventricles, and a 6 mm midline shift. An external ventricular drain was inserted, and the patient was admitted to the intensive care unit for neurocritical monitoring and mechanical ventilation. The cause of the intracranial hemorrhage was not identified and the patient had no known precipitating factors. Baseline chest CT demonstrated a well-circumscribed cystic lesion in the left lower lobe consistent with the known hydatid cyst, without evidence of airway obstruction or endobronchial foreign material.

FINAL DIAGNOSIS

During hospitalization, given the anticipated need for prolonged ventilatory support, a surgical tracheostomy was performed. One day after the procedure, routine post-tracheostomy chest radiography (Figure 1A) unexpectedly revealed a sharply marginated radiopaque structure projected over the region of the left main bronchus.

Figure 1 Imaging results. A: Post-tracheostomy chest radiograph demonstrating a sharply marginated radiopaque foreign body projected over the region of the left main bronchus (within the orange circle); B: Chest computed tomography showing a dense endobronchial object within the proximal left main bronchus. The high radiodensity of the object with associated beam-hardening artifacts limited precise morphological characterization on imaging alone; C: Flexible bronchoscopic view revealing a natural tooth with an attached metallic crown partially embedded in the left main bronchus; D: Extracted foreign body consisting of a natural tooth with a metallic crown following successful removal by flexible bronchoscopy using tripod grasping forceps.

Subsequent chest CT (Figure 1B) confirmed the presence of a dense endobronchial object within the proximal left main bronchus. The object exhibited intense radiodensity with associated beam-hardening artifacts, limiting immediate identification of its exact nature on imaging alone[7]. No official dental examination was performed before bronchoscopy because the imaging findings were not compatible with dental aspiration.

TREATMENT

Flexible bronchoscopy (Figure 1C) was performed at the bedside and revealed a natural tooth with an attached metallic crown partially embedded in the left main bronchus. Using tripod grasping forceps, the foreign body was successfully extracted (Figure 1D) without mucosal injury, bleeding, or distal migration. Post-extraction inspection confirmed complete removal and intact bronchial mucosa.

OUTCOME AND FOLLOW-UP

The patient remained hemodynamically stable throughout the procedure. No post-obstructive pulmonary complications were observed.

DISCUSSION

Aspiration of dental elements in adults represents a rare but clinically relevant phenomenon, most frequently occurring in patients with impaired airway protective reflexes[1,2]. In neurocritical care patients, sedation, reduced consciousness, and airway instrumentation significantly increase the risk of silent aspiration[6,8].

Notably, tooth aspiration following traumatic brain injury has been described as an entirely silent event, discovered incidentally during imaging or bronchoscopy[3]. Similarly, in the present case, aspiration was not clinically suspected and was identified incidentally on routine post-procedural imaging one day after tracheostomy. Importantly, in our case, the tooth may have been dislodged during emergency airway management at the time of endotracheal intubation, with subsequent entry into the airway during cuff deflation for tracheostomy. Alternatively, it may have been dislodged during the tracheostomy procedure itself.

The right main bronchus is traditionally considered the most common site of foreign-body impaction because of its anatomical configuration. Aspiration into the left main bronchus has also been increasingly recognized in adult case reports, particularly in patients with altered consciousness or recent airway manipulation. Foreign bodies located in the left bronchial tree, including the left upper lobe, remain relatively uncommon. Their distribution may be influenced by patient-related factors such as prolonged recumbent positioning, neurological deficits, or unilateral hemiparesis, which can alter gravitational forces and airway clearance mechanisms[9].

Various mechanisms for left-sided aspiration have been proposed in the literature. Eliçora et al[10] suggested that the parameters such as, patient’s position, temporary blockage of the airway, preferential ventilation of the right bronchus, and changes in airflow during a procedure, can push or redirect material in the left bronchial tree. Strong coughing or sneezing may also contribute. If we consider the Bernoulli effect, forceful expiration may create greater negative pressure in the narrower left bronchus, causing foreign bodies to move into and remain within the left bronchial system. Regarding dental foreign bodies, their irregular shape and the presence of metallic components may further affect how they move during aspiration. This could increase the chance that they become aspirated in atypical locations, such as the left main bronchus[11].

In Islamic regions, a specific subgroup of aspiration has been described in young women who wear headscarves. Women in these regions aspirate metallic pins held between the teeth during veil adjustment. This usually happens during talking, laughing, or sudden head movement[11]. Interestingly, in these cases, the left bronchial tree has been reported to be more frequently involved[12]. One possible explanation is that the sharp end of the pin becomes stuck in the bronchial mucosa. Another is that the sharper angle of the left main bronchus may make this more likely. Body and head position during veil adjustment have also been proposed as factors affecting the trajectory of aspiration and contributing to left-sided aspiration[12].

Regardless of the nature of the foreign body, prolonged retention of it within the bronchial tree may cause local inflammation and granuloma formation. This, in turn, could potentially complicate the extraction of the foreign body through bronchoscopy[13].

From a diagnostic perspective, metallic dental elements are often thought of being easily recognized because of their radiopacity. However, as Hadad et al[14] have reported, these metallic objects can produce beam-hardening and streak artifacts on CT imaging, which can complicate accurate morphological characterization. This is especially relevant in left main bronchus aspiration, because mediastinal structures and coexisting pulmonary pathology may make interpretation even more difficult. In adults, foreign-body aspiration may escape detection on initial imaging and mimic other endobronchial lesions, delaying diagnosis unless bronchoscopy is performed[15]. This delay has been associated with post-obstructive pneumonia, chronic bronchitis, and irreversible bronchiectasis[16]. On the other hand, early recognition and removal are typically followed by excellent outcomes. Previous work by our group has similarly highlighted the value of early bronchoscopic intervention in adult airway aspiration of rare foreign bodies, including tooth aspiration in traumatic brain injury and large metallic foreign bodies in the bronchial tree[3,17].

Bronchoscopy remains the gold standard for diagnosis and management of tracheobronchial foreign-body aspiration[18,19]. Rigid bronchoscopy has historically been considered the modality of choice, but increasing evidence supports the use of flexible bronchoscopy as an effective and safe first-line modality in some adult patients[20]. With flexible bronchoscopy, the specialist can achieve superior visualization of distal airways and can typically perform the intervention under local anesthesia with moderate sedation. This is less invasive and more comfortable for adults[21]. Rigid bronchoscopy, while more invasive and generally requiring general anesthesia, remains a better choice in some situations. It is generally preferred in children and adolescents and is better in adults when the foreign body is hard, impacted or has been present for a long duration or after a failed previous attempt. Rigid instruments provide better control and force transfer for extracting difficult foreign-bodies and allow access to larger suction for managing potential bleeding. Clinical decision making depends on multiple factors, including the patient’s age, comorbidities, the location, the size and consistency and the anticipated difficulty of removal. Flexible bronchoscopy is often preferred for distal or small foreign bodies, while rigid bronchoscopy is favored for proximal, large or hard foreign bodies or when rapid and secure removal is critical.

CONCLUSION

Aspiration of a metallic-crowned tooth in adults is rare and may occur silently following airway manipulation in neurocritical patients. Despite their radiopacity, dental crowns may present diagnostic challenges due to imaging artifacts. Clinicians should remain alert to atypical anatomical locations such as the left main bronchus and pursue early bronchoscopic evaluation when unexplained endobronchial findings are detected.