History
A 1.5-year-old 4.38-kg (9.6-lb) neutered male domestic shorthair cat was referred because of a 3-day history of retching, ptyalism, and inappetence. Clinical signs were refractory to medical management (ie, administration of maropitant citrate, famotidine, and crystalloid fluid at unknown dosages).
At the time of hospital admission, the cat was alert, responsive, and euhydrated with a body condition score of 5/9. The cat had a body temperature of 38.7°C (101.6°F). The heart rate (170 beats/min; reference range, 120 to 140 beats/min) and respiratory rate (60 breaths/min; reference range, 16 to 40 breaths/min) were mildly high, likely attributable to stress or discomfort. On physical examination, the cat would lick its lips when its neck was palpated. No abnormalities were detected on abdominal palpation or examination of the oral cavity.
Results of a CBC were within reference ranges. Serum biochemical analysis revealed a slightly high total bilirubin concentration (0.8 mg/dL; reference range, 0.1 to 0.5 mg/dL), hypomagnesemia (1.3 mg/dL; reference range, 1.9 to 2.6 mg/dL), and a high creatine kinase activity (626 U/L; reference range, 50 to 225 U/L). The mild hyperbilirubinemia was likely the result of sample hemolysis, and the hypomagnesemia was considered a spurious finding. The high creatine kinase activity was attributed to hemolysis, hyporexia, or increased muscle activity from coughing and retching.
Orthogonal thoracic and abdominal (not shown) radiographs taken 1 day earlier by the referring veterinarian were submitted for consultation (Figure 1).
Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 1.5-year-old 4.38-kg (9.6-lb) neutered male domestic shorthair cat evaluated because of a 3-day history of retching, ptyalism, and inappetence.
Citation: Journal of the American Veterinary Medical Association 253, 11; 10.2460/javma.253.11.1405
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Image Findings and Interpretation
On the lateral view, a 3.5-cm-long, thin, linear, sharply marginated, soft tissue opaque structure is superimposed over the dorsal aspect of the nasopharynx (extending from the tympanic bullae to the glottis) with concurrent abnormal, overt gas distention of the laryngopharynx and nasopharynx. Mild esophageal gas attributable to aerophagia is also evident, as is generalized mild cardiac enlargement (Figure 2).
Same right lateral radiographic image as in Figure 1. A 3.5-cm-long, linear, sharply marginated, soft tissue opaque structure (encircled) is seen within the pharynx. Notice the severe distention of the nasopharynx.
Citation: Journal of the American Veterinary Medical Association 253, 11; 10.2460/javma.253.11.1405
Clinical signs and radiographic findings prompted further imaging of the neck. On subsequent radiographs, pharyngeal findings were confirmed. Additionally, 2 small (2 and 4 mm in diameter), ovoid gas bubbles were found superimposed over the soft tissues ventral to C3; these were dismissed as incidental esophageal gas (Figure 3).
Lateral radiograph of the neck of the same cat as in Figure 1 obtained a day after the initial radiographs. The persistent foreign body is seen within the dorsal aspect of the pharynx (long arrow). The nasopharyngeal gas distention is still evident. The highlighted gas (short arrows) is incidental and esophageal.
Citation: Journal of the American Veterinary Medical Association 253, 11; 10.2460/javma.253.11.1405
Differential diagnoses for the linear, soft tissue opaque structure included a migrated or inhaled foreign body within the nasopharynx. Anomalous congenital or traumatic soft tissue septation of the pharynx was considered less likely. No evidence of nasopharyngeal stenosis, polyp, cellulitis, edema, or abscessation was seen. Although incidental luminal esophageal gas was suspected, hypaxial muscle or surrounding soft tissue emphysema secondary to a penetrating wound, tissue necrosis, or gas-producing bacteria was not excluded. No murmur was auscultated, and further cardiac evaluation was not pursued. Differential diagnoses for the mild cardiac enlargement included sedation at the time of previous imaging or underlying occult cardiomyopathy or congenital cardiac disease, but neither was confirmed.
Treatment and Outcome
The patient was admitted to the hospital for supportive care. The perceived discomfort was managed with buprenorphine hydrochloride (0.02 mg/kg [0.009 mg/lb], IV, q 12 h). The radiographic evidence of a pharyngeal foreign body prompted retroflexed nasolaryngopharyngoscopic examination with a flexible endoscope. A 10.2-cm-long, barbed grass blade partially embedded within the nasopharyngeal mucosa was easily removed with hemostats and gentle traction. Mild pharyngeal erythema was observed. On subsequent esophagoscopic examination, no evidence of associated complications or abnormalities were found. The patient recovered uneventfully and was discharged from the hospital the following day with owner instructions to continue the buprenorphine hydrochloride (0.02 mg/kg, sublingually, q 8 h) administration for 3 days. The cat was monitored for 1 year, and no further clinical signs developed.
Comments
The nasopharyngeal region is a common location for foreign body entrapment in dogs and cats.1 Reported clinical signs include retching, gagging, ptyalism, and stertor.1 In the authors' experience, signs can be mild (transient sneezing and epistaxis) to severe with progression to airway obstruction, asphyxiation, respiratory failure, and death. Patient history does not typically allude to the possibility of foreign body inhalation, and the incident is usually not witnessed.
In general, potential complications of inhaled foreign bodies include fever, granuloma or abscess formation, sepsis, and migration to other body regions such as the CNS.2 Migrated aerodigestive foreign bodies may cause soft tissue and osseous reactions that can mimic the radiographic and clinical signs of deep tissue infections, fungal granulomata, bacterial or fungal osteomyelitis, or neoplasia.2 When complications of pharyngeal or tracheal foreign bodies arise, secondary thoracic radiographic findings of such inhaled foreign bodies may be most evident during inspiration. This is caused by increased inspiratory effort and combined partial or total upper airway obstruction. Additional thoracic radiographic findings may include hiatal herniation, dynamic dorsal displacement of the sternum, noncardiogenic pulmonary edema, unilateral emphysema (air trapping with ipsilateral rib flaring and diaphragmatic depression), and atelectasis.3,4
Radiography is the initial imaging modality of choice when aerodigestive foreign bodies are suspected, but radiography alone is neither sensitive nor specific enough to completely exclude an inhaled foreign body. Metal, glass, and stone may be obvious because of their inherent mass densities and consequent radiopacities.4,5 Plant material (grass awns or sticks) and some synthetic plastics are soft tissue opaque and undetectable on radiographs without surrounding gas.5 Detection of foreign material can be further impaired by summation artifact and observer inexperience.5,6 In people, radiographic signs of aerodigestive foreign bodies are often overlooked by emergency room doctors and ear, nose, and throat specialists (79% and 67% of the time, respectively).7 An additional confounding interpretation factor in the cat of the present report was that the lesion was at the periphery of the radiograph. Despite these challenges, gas distention of the nasopharynx (and more specifically the contrasting gas surrounding the structure) were key findings for establishing the definitive diagnosis of this patient's inhaled pharyngeal foreign body.
Although radiographic findings mitigated the need for further imaging modalities in the case described in the present report, other imaging modalities can be useful. When radiography is insufficient for airway foreign body detection, additional imaging modalities (fluoroscopy, ultrasonography, and contrast-enhanced CT or MRI) may be used. Radiography and fluoroscopy can detect hemithoracic lung volume differences, immobilization of the affected lung on inspiration-expiration, and paradoxical movement of the diaphragm (when foreign body–related, lateralized bronchial obstruction is present).3,4 Fluoroscopic digital subtraction can aid in detecting radiolucent foreign bodies. Additionally, radiographic, fluoroscopic, or CT fistulography with a nonionic iodinated contrast agent can enhance detection of occult foreign material in gas tracts or soft tissue swellings. Ultrasonography is limited for respiratory system evaluation but may aid in detection of foreign bodies that are partially within or juxtaposed to an airway or are located within inflamed or abscessed soft tissue. In such instances, the foreign body may appear as a hyperechoic border with distal acoustic shadowing.5
In general, cross-sectional imaging is superior to radiography for foreign body and adjacent soft tissue differentiation.2,6 Computed tomography evaluation can be used to investigate potential foreign body density. Adjacent emphysema can improve conspicuity, especially in the lung window (−1,250 to 250 Hounsfield units), and evaluation of multiple image planes aids in mitigating anatomic noise from superimposed structures.2 Virtual CT bronchoscopy may preclude unnecessary bronchoscopy or aid in retrieval planning. When MRI is pursued, plastic, porcelain, glass, and dry wood may be obvious given superior contrast resolution. These materials are generally hypointense to muscle, but the appearance of plant material or wood can vary because of water content.6 Additionally, certain pulse sequences such as short tau inversion recovery and 3-D fast spin gradient recall can exploit surrounding inflammation and gas, respectively.
In the young cat of the present report, early detection of an inhaled pharyngeal foreign body resulted in an excellent outcome. Common clinical signs of airway foreign bodies can be mistaken for respiratory or gastrointestinal disease, especially in cats. Misdiagnosis and delayed detection can result in unnecessary diagnostic tests or interventions and complications. Survey radiography is essential in screening for obvious aerodigestive foreign bodies, being especially useful in pets with nonproductive gagging, retching, or vomiting that lack signs of abdominal discomfort. Endoscopy and removal of airway foreign material is typically curative in uncomplicated cases.
Acknowledgments
The authors declare that there were no conflicts of interest.
References
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2. Jones JC, Ober CP. Computed tomographic diagnosis of non-gastrointestinal foreign bodies in dogs. J Am Anim Hosp Assoc 2007;43:99–111.
3. Gambino JM, Sivacolundhu R, DeLucia M, et al. Repair of a sliding (type I) hiatal hernia in a cat via herniorrhaphy, esophagoplasty and floppy Nissen fundoplication. JFMS Open Rep 2015;1:2055116915602498.
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5. Aras MH, Miloglu O, Barutcugil C, et al. Comparison of the sensitivity for detecting foreign bodies among conventional plain radiography, computed tomography, and ultrasound. Dentomaxillofac Radiol 2010;39:72–78.
6. Pattamapaspong N, Srisuwan T, Sivasomboon C, et al. Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot. Radiol Med 2013;118:303–310.
7. Karnwal A, Ho EC, Hall A, et al. Lateral soft tissue neck x-rays: are they useful in management of upper aero-digestive tract foreign bodies? J Laryngol Otol 2008;122:845–847.
