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Diagnosis Please |
1 From the Department of Radiology, University of Michigan Health System, 1500 E Medical Center Drive, Taubman Center 2910, Ann Arbor, MI 48109-0326. Received April 12, 1999; revision requested June 7; revision received July 15; accepted July 30. Address correspondence to E.A.K. (e-mail: ellakaz@umich.edu).
Index terms: Bronchi, CT, 671.1211 • Bronchi, stenosis or obstruction, 671.743 • Diagnosis Please • Foreign bodies, in air and food passages, 671.743
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HISTORY |
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Work-up at presentation demonstrated leukocytosis of 20,000 white cells/mm3 (20.0 x 109/L), thoracentesis with a pleural fluid white cell count of 6,830/mm3 (6.8 x 109/L), and flexible bronchoscopic examination with biopsy results negative for malignancy. Portable chest radiography was performed on the day of admission (Figure, part a). Computed tomographic (CT) scans were also obtained (Figure, parts b and c).
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IMAGING FINDINGS |
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Intravenous contrast-enhanced chest CT demonstrated a large loculated right pleural effusion with adjacent right lower lobe consolidation (Figure, parts b and c). Right middle lobe consolidation was evident on more cephalic images. There was a high-attenuation lesion in the bronchus intermedius, with thickening of the bronchial wall. Closer inspection of the lesion, especially at the bone window settings, revealed the shape of a vertebral body in transverse cross section. This was a chicken vertebra, as demonstrated on the specimen radiograph of the foreign body extracted from the patient’s bronchus intermedius at rigid bronchoscopy (Figure, part d). Close questioning the patient after the procedure elicited a history of aspiration 10 years earlier.
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DISCUSSION |
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Less commonly, broncholithiasis may occur as a consequence of calcification of the bronchial cartilage, with subsequent sequestration of the calcified material into the bronchial lumen (1). Calcified lymph nodes in sarcoidosis or silicosis; ovarian, thyroid, and breast papillary (psammomatous) adenocarcinomas; and mucinous adenocarcinoma of the colon may account for peribronchial calcification (2). Although some airway foreign bodies are in themselves radiopaque, calcium may deposit around the nucleus of an otherwise nonradiopaque endobronchial foreign body. Calcification of the bronchial cartilage plates occurs commonly with aging and in patients with hypercalcemia and/or hyperphosphatemia. Endobronchial carcinoid tumors are not commonly calcified at CT but more than 30% have ossification histologically (3). Focal areas of high attenuation within carcinoid tumors represent ossification with bone deposition in fibrous septa traversing the tumor. In one CT study (4), 26% of patients had intratumoral calcification of the carcinoid tumor. Less common calcified or ossified endobronchial or peribronchial lesions include endobronchial hamartomas, amyloidomas, osteomas, osteosarcomas, chondromas, and chondrosarcomas.
The differential diagnosis of high-attenuation endobronchial lesions can be narrowed by carefully obtaining patient history and examining the shape of the lesion. A history of choking with vomiting, the penetration syndrome, favors the presence of an endobronchial foreign body (5). A careful history is imperative in revealing cases of aspiration, whether recent or remote. The distribution and character of calcification also helps in narrowing the differential diagnosis. Attention to the shape of the calcified lesion is useful, as demonstrated in this case. Lymph node calcification is usually amorphous and irregularly distributed throughout the node or may involve the entire node and may be round or ovoid in shape. In some cases, there may be peripheral eggshell calcification of the nodes. Calcified lymph nodes are usually medial to the bronchus intermedius and may subsequently erode into it.
Foreign body aspiration into the lower airways of adults is uncommon, and the diagnosis may be made remote to the actual aspiration event (6). In a 20-year series (5) involving 112 patients at one center, 75% of patients were children younger than 8 years, and 25% were adults. In that series, the peak age of foreign body aspiration in the children was 2 years, and in adults the peak age was the 6th decade. Most foreign bodies are not radiopaque; only 16% of foreign bodies found in one series (7) of 74 patients were radiopaque at chest radiography. The most commonly reported airway foreign body in two large Asian series (6,8) was bone, which was attributed to food preparation, table customs, and utensils used by the Chinese. It was also seen more commonly in the elderly population owing to an impaired swallowing reflex.
The nature of foreign bodies in the Western population is different (6,9). In children, 91% of foreign bodies are organic, half of which are peanuts (5). In adults, 59% of foreign bodies are organic, with the remainder being miscellaneous, ranging from a dental file to tooth material, amalgam, a toy wheel, a pen cap, a swab, and chicken bone (5). The nature of other foreign bodies can vary from pills to metal fragments, plastic fragments, stones, or parasites (6,9). Several of these, particularly bones, stones, metal fragments, and denture and teeth fragments usually show high attenuation at CT.
Foreign body aspiration in adults with a normal swallowing reflex is rare. Risk factors leading to aspiration are neurologic dysfunction, trauma with loss of consciousness, facial trauma, intubation, dental procedures, underlying pulmonary disease, alcohol consumption, and sedative use (6,9). In the United States, approximately 500 to 2,000 deaths per year occur from foreign body aspiration, half of which are in children younger than 4 years (9).
Occult foreign body aspiration in adults may remain undetected for years and lead to an erroneous clinical diagnosis of bronchitis, asthma, chronic pneumonia, bronchiectasis, or even tumor (6,9). Patients usually present with persistent respiratory symptoms and are examined for alternative diagnoses, unless there is a definite history of aspiration. Both adults and children present with similar symptoms, with the exception of the delay in diagnosis common in adults (5).
In a recent series (6) of 43 adults with foreign body aspiration, chronic cough was present in 67%, hemoptysis in 23%, fever in 19%, and dyspnea in 16%, whereas a history of choking was given in only 7%. A characteristic clinical feature of bone aspiration in adults is an asymptomatic interval that results in diagnostic delay (10). Early complications of foreign body aspiration include dyspnea, asphyxia, cardiac arrest, laryngeal edema, and pneumothorax (11). Late complications include obstructive pneumonitis, atelectasis, lung abscess, empyema, bronchiectasis, bronchial stricture, hemoptysis, development of inflammatory polyps at the site of lodgment, and decreased perfusion of the lung on the side of foreign body aspiration (6,9,10). Bronchoscopy not only aids diagnosis but in many cases is also therapeutic (10).
During the acute stage, the chest radiographic signs of foreign body aspiration are hyperinflation due to a ball-valve phenomenon, volume reduction with atelectasis, and the possible presence of a radiopaque foreign body. Atelectasis is considerably more common in adults, occurring in 50% of patients, whereas air trapping is more common in children (5). During the chronic stage, there may be atelectasis, postobstructive pneumonia or bronchiectasis, lung abscess, and/or empyema. The chest radiograph may be normal in up to a third of patients (12). In children, foreign bodies are commonly found in the proximal airways owing to the smaller size of the airway, whereas in adults they lodge in the peripheral airways (5). The right lower lobe bronchus and the bronchus intermedius are the most common sites for airway foreign bodies to lodge in adults owing to the vertical orientation of the right-sided airway (9).
Chest CT is often used in the diagnostic work-up of patients with unresolved pneumonia, bronchiectasis, possible tumor, empyema, and persistent atelectasis. Thin-section or helical chest CT images viewed at bone window settings are particularly valuable in assessing the morphology of calcified or ossified endobronchial lesions and in the identification of foreign bodies.
Close questioning of the patient whose case is presented herein revealed an episode of aspiration that occurred approximately 10 years earlier while sucking on cooked chicken vertebrae. A heavy bout of alcohol consumption may have been a factor. His hospital admission was precipitated by the onset of pleuritic chest pain, which was secondary to the development of postobstructive pneumonia and empyema due to chronic airway occlusion. No medical attention had been sought previously in this case, as the patient had been relatively asymptomatic.
The initial flexible bronchoscopic examination revealed exuberant reactive tissue within the bronchus intermedius, which caused obstruction of the bronchus intermedius and collapse of the right middle and lower lobes. Because of the florid reactive tissue, the foreign body was not visible at the initial flexible bronchoscopic examination. Inflammatory polyps or granulation tissue may develop with chronic impaction and may obscure the endobronchial foreign body. Removal of the impacted foreign body requires resection of the granulation tissue before it can be extracted (9). At intraoperative rigid bronchoscopy, the foreign body was identified and removed. Bronchoplasty of the bronchus intermedius was performed, and the patient received a long course of antibiotics. The patient recovered fully.
Careful clinical history is the mainstay of diagnosis in cases of unrecognized foreign body aspiration. Chest radiography and chest CT are often used as diagnostic tools in evaluating the clinical signs and symptoms in patients who are later proved to have an endobronchial foreign body. Attention to the morphology of the high-attenuation endobronchial lesion may reveal its identity as a foreign body. However, the single most important factor leading to the diagnosis of tracheobronchial aspiration is a high clinical index of suspicion.
Our congratulations to the 11 individuals who submitted the most likely diagnosis (foreign body aspiration—chicken vertebra) for Diagnosis Please, Case 31. Credit was given only if chicken bone or foreign body aspiration was mentioned. The names and locations of the individuals, as submitted, are as follows:
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FOOTNOTES |
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This article has been cited by other articles:
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  M. Boyd, F. Watkins, S. Singh, E. Haponik, A. Chatterjee, J. Conforti, and R. Chin Jr Prevalence of flexible bronchoscopic removal of foreign bodies in the advanced elderly Age Ageing, July 1, 2009; 38(4): 396 - 400. [Abstract] [Full Text] [PDF]
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 J. B. Seo, K.-S. Song, J. S. Lee, J. M. Goo, H. Y. Kim, J.-W. Song, I. S. Lee, and T.-H. Lim Broncholithiasis: Review of the Causes with Radiologic-Pathologic Correlation RadioGraphics, October 1, 2002; 22(90001): S199 - 213. [Abstract] [Full Text] [PDF]
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