Foreign body aspiration (FBA) occurs frequently in children, but rarely in adults [1]. In different series where both children and adults with FBA were included, children represented 46–92% of the total study group [2][3]. Most adult patients who experience FBA have predisposing conditions resulting in a decreased consciousness, such as cerebrovascular accidents, intracranial hemorrhage or septic encephalopathy. Other possible risk factors are tracheostomy handling, emergency intubation, cranioencephalic trauma, intravenous drug abuse, alcohol or sedative use and dental and medical procedures [4]. Furthermore, the occurrence of FBA is dependent on the region where people live. In Islamic countries, aspiration of headscarf pins is quite common. How often FBA in adults occurs in the Netherlands is unknown. In this article we describe two cases of FBA in adults. The first patient presented with acute respiratory failure. The second patient presented with atypical chronic pulmonary symptoms which evolved to acute respiratory failure.

Case 1
A 42-year-old male was presented to the emergency department. His medical history revealed brain surgery for a tumor in the posterior fossa. The surgery was performed years ago, but left him with swallowing disorders for which he needed a permanent tracheostomy tube. In retrospect, it became clear that he had withdrawn himself from the medical follow-up. When presented in the emergency department he was acutely dyspneic caused by a broken and dislocated tracheostomy tube ( (Figure 1), left panel). He had a respiratory rate of >50/min with a peripheral oxygen saturation of 70%, a blood pressure of 115/60 mmHg and a pulse of 165 bpm.

The patient rapidly deteriorated. Therefore, an attempt was made to remove the barely visible tracheostomy tube which was trapped in the larynx under local anesthesia. During this attempt the tube dislocated to more distal airways, which caused an improvement in the vital signs. After dislocation, the patient was alert without experiencing any dyspnea. The pulmonologist performed a flexible bronchoscopy and retrieved the tube from the left main bronchus ( (Figure 1); right panel). After this procedure the patient remained in good condition.

Case 2
An 84-year-old male was admitted in our cardiac care unit with complaints of dyspnea and cough since several weeks. He had a history of chronic obstructive pulmonary disease (COPD), kidney and cardiac failure. At admission to the CCU he was tachypneic, his peripheral oxygen saturation with additional oxygen (>12 L/min) was 88% and bilateral crackles were heard. He had a high blood pressure of 229/103 mmHg, a rapid pulse of 102 bpm and a temperature of 38.0°C. Laboratory investigation showed high inflammatory values (CRP 120 mg/L), renal insufficiency (creatinine 210 µmol/L) and anemia (hemoglobin 7.1 mmol/L). The chest X-ray showed signs of congestive heart failure. The patient was treated with diuretics and amoxicillin/clavulanic acid. Although the patient's condition seemed to improve, five days after admission he suddenly developed respiratory failure with hemoptysis. The patient was transferred to the intensive care unit for mechanical ventilation. After hemodynamic and respiratory stabilization, a chest CT scan was performed which showed a foreign body in the right main bronchus (Figure 2). On bronchoscopy a medication blister pack surrounded by fibrin was identified. It was carefully removed and the patient's condition rapidly improved. When asked later, the patient remembered choking when taking his medication several months ago. His cough had developed afterwards.

The above mentioned cases show that FBA in the adult patient can present in very different ways and the diagnosis can be challenging.

Foreign Bodies
The types of foreign bodies (FB) that have been aspirated vary greatly among different published series. Most commonly described are bones, nutshells, metallic dentures, organic components and food particles. However, there are no limits to what can be retrieved from the airway; pen caps, needles, teeth, headscarf pins and even glass have been described [2] [3][4]. Aspiration of medication tablets has been described in case reports, and represented up to 16% of the total of aspirated foreign bodies [5]. Aspiration of a medication blister has not been described before. In a review in 1994, only 12 reports of synthetic tube fracture were found. A tracheostomy tube can fracture after prolonged use, probably due to a combination of prolonged wear, poor tracheostomy care and the formation of granulation tissue. When tracheostomy tubes fracture this usually occurs at the junction of the tube and neck plate. Patient A had not appeared at follow-up visits and his tracheostomy tube had not been changed for some time.

Symptoms
When patients are choking, FBA is often suspected. However, acute FBA is associated with choking in only 7–23% of patients [4] [6]. Symptoms are usually nonspecific and are dependent on the nature of the FB, the diameter, location and eventually the development of complications. Symptoms that are commonly seen are cough (22–94%), dyspnea (6–35%), chest pain (2–22%), hemoptysis (11–24%), fever (8–31%) and wheezing (2–28%) rare are recurrent or chronic pneumonia, cardiac arrest or no symptom at all (2–9%) [1][2] [4][6][7].

There can be a significant delay in the diagnosis as symptoms can be absent or atypical. The time from aspiration to clinical presentation is determined by the severity of the symptoms. In most studies, a minority of patients (19–53%) present within one week of aspiration [4] [6]. In 58–70% of the patients the delay in diagnosis was more than 1 month [1] [6]. Much longer delays (1–40 years) after aspiration have been described [4] [5] [6]. Twenty-five percent of the patients did not remember FBA, and only 22% remembered it on clinical suspicion [4]. In the geriatric population, only 30% could remember FBA at the first visit to the doctor [7]. Again, the physical examination is non-specific, clinical signs are absent in 39–87% of patients. Decreased breath sounds were noted in 13–47% of patients and respiratory distress was seen in only 5% [2].

Both our cases show that FBA can result in respiratory failure as a result of the aspiration itself or in a later stage due to dislocation of the FB. When respiratory failure develops and a FB is expected, rapid bronchoscopic removal is indicated.

Radiology
Not only the signs and symptoms of FBA are nonspecific, chest X-ray findings are atypical as well. The chest X-ray is completely normal in 10–32% of patients. The FB was visible on the chest X-rays in a fraction of cases (11–31%). Bones or needles are relatively easy to see, whereas radiolucent FB are only "seen" due to secondary changes. Common findings on chest X-ray are atelectasis (2–50%), air trapping, emphysema (1–17%) or pneumonia (2–37%). Other, less common findings are pneumomediastinum, lung abscess, pleural effusion, lobar collapse and bronchiectasis [1] [4] [5].

The sensitivity of computed tomography for diagnosing FBA ranges from 90–100%, its specificity from 75–100% [8]. The slice thickness of the CT scan has to be taken into account [7] [8]. Atypical findings, such as atelectasis (63%), hyperlucency (44%), thickened bronchial wall adjacent to the FB (44%), bronchiectasis (31%), pleural effusion (19%) and hilar lymphadenopathy (31%) can be found [5].

Virtual bronchoscopy, in which high resolution CT scan is used to depict the bronchi from an endoscopic viewpoint, has shown high sensitivity and specificity in the diagnosis of a foreign bodies in children. However, no studies were found for this indication in adult patients [9].

Treatment
When the patient is choking and acute FBA is suspected, the initial management should focus on maintaining the patency of the airway and stabilizing the vital signs. If necessary, securing the airway by intubation (or surgical if needed) should be performed promptly to reverse hypoxia. Ventilation strategy should be used with caution to prevent pressure associated lung injury. In acute asphyxiating FBA, rigid bronchoscopy, performed under general anesthesia, is the treatment of choice [1].

Bronchoscopy
In the case of a suspected chronic presence of a FB the history, physical examination and radiology findings are often inconclusive and a bronchoscopy should be performed. It is both diagnostic and therapeutic, as it shows 85% of the inhaled FB [1]. Removal of a FB can be performed by rigid or flexible bronchoscopy.

In the past, a rigid bronchoscopy was mostly used with a high success rate of 98%. However, for chronic aspiration flexible bronchoscopy is as effective as rigid bronchoscopy and causes fewer complications. Therefore, flexible bronchoscopy is now often used as first option. Flexible bronchoscopy can be performed under local anesthesia and has a success rate of 60–97% [1] [6]. Another advantage of flexible bronchoscopy is that it visualizes segmental airways to the third generation of branching, and rigid bronchoscopy only visualizes the trachea and proximal bronchi. Therefore, when the FB is impacted in distal airways, flexible bronchoscopy is the treatment of choice. Flexible bronchoscopy is also indicated in patients with cervicofacial trauma. Computed tomography scan can help distinguishing which technique should be used first [8].

When removal with flexible bronchoscopy is unsuccessful, a repeat procedure should be performed [4]. Usually a rigid bronchoscopy under general anesthesia [1]. Reasons for failure include entrapment of the FB in the bronchial wall, serious granulation with bronchial atresia or serious hemorrhage [6]. Complications after bronchoscopy are laryngeal edema, subcutaneous emphysema and pneumothorax [1]. The FB is usually located in the right lung, probably because the right main bronchus is more in line with the trachea [2] [5]. However, abnormalities on chest X-ray that are not right-sided should not lead to questioning the diagnosis since up to 25% of FB are located in the left bronchus and 6% in the trachea [4] [6].

Pathology
In 88% of the patients with chronic FBA of particulate matter, a cryptogenic organizing pneumonia (COP), which is a nonspecific reaction to toxic insults, was found. On biopsy, multinucleated giant cells were seen in 67%, granulomas in 33%, peribronchial fibrosis and chronic inflammation in 7%, and acute bronchiolitis in 5% [10]. When objects are aspirated, granulations form around them, which might first appear as a malignancy.

Complications
Complications associated with FBA are found in almost 80% of patients, and are often the presenting symptoms. The complications most commonly found are obstructive pneumonia (22%), bleeding (14.5%), atelectasis (10%) and endobronchial stenotic scarring (8%). Pneumonia can be complicated by empyema. The incidence of complications significantly increases from 32% when the FB is removed within three days after aspiration to 63–90% when it is removed later [1] [6]. After a difficult bronchoscopy, development of mediastinitis should be anticipated.

The presented cases show the different clinical presentations in patients presenting with foreign body aspiration (FBA), varying from chronic nonspecific to acute life-threatening clinical conditions. Importantly, chronic nonspecific presentations may evolve into acute life-threatening events. Maintaining the airway patency is essential in the acute setting. The diagnosis of FBA can be difficult, since history, physical examination and chest X-ray are often atypical. When suspicion is high, a bronchoscopy should be performed. Chest computed tomography scan can be helpful in distinguishing between flexible and rigid bronchoscopy. When patients present with nonspecific pulmonary findings, FBA should be included in the differential diagnosis.

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