Abstract
If a foreign body is seen on chest or abdominal radiographs, accidental
aspiration or ingestion of a dental-related foreign body may be
suspected. This report describes a case in which vascular embolization
coils seen on radiography were suspected to represent a swallowed dental
prosthesis. A 72-year-old man with a history of endovascular
embolization of portosystemic shunt was admitted for mandibular
fracture. On hospital day 2, a foreign body was noted on chest
radiographs taken to confirm pleural effusion. No foreign body had been
evident on radiographs of the same area the previous day. The foreign
body was suspected to be a dental prosthesis, but intraoral examination
ruled out this possibility, and the foreign body turned out to be metal
coils used to embolize the shunt. Dentists and oral surgeons should be
aware that medical devices such as vascular embolization coils can
produce images similar to a dental-related foreign body on chest or
abdominal radiographs, and dental-related foreign body ingestion or
aspiration should be considered in the differential diagnosis.
Introduction
Accidental ingestion or aspiration of dental-related foreign bodies is
occasionally observed. The rate of accidental ingestion or aspiration
(cases/patients) has been reported as 0.0037–0.0044%, with the
majority of cases representing accidental ingestions.1,2
Although almost all aspirated dental-related foreign bodies have been
successfully removed by bronchoscopy, lobectomy is sometimes performed.3,4 In the case of accidentally ingested
dental-related foreign bodies, blunt foreign bodies ≤2 cm in diameter
can be expected to be expelled spontaneously, but sharp foreign bodies
may perforate the esophagus or other organs, and may need to be removed
by endoscopy or laparotomy. 5 Early detection of
dental-related foreign bodies and early treatment planning are therefore
important.
If ingestion or aspiration is suspected, general chest and abdominal
radiographs are useful to confirm the presence and location of the
foreign body, particularly if the foreign body contains metallic
components. Computed tomography may be necessary for objects with no
metallic components. Similar to dental-related foreign bodies, various
medical devices are opaque on radiography. 6,7 Most
such medical devices are relatively easy to identify by shape. However,
some devices appear similar to dental-related foreign bodies and may
require differentiation. 8
In this report, we describe a case of vascular embolization coils used
in the treatment of a portosystemic shunt that required differentiation
from an accidentally ingested dental prosthesis on radiographs.
Case Presentation
The patient, a 72-year-old man, fell on the street and was admitted to
the emergency department and was subsequently admitted to our department
for mandibular fracture. The medical history of the patient included
congenital portosystemic shunt, surgery for inguinal hernia, heart
failure, and mitral regurgitation with mitral valve replacement, chronic
subdural hematoma, and vascular dementia. The shunt had been embolized
due to the appearance of encephalopathy.
The patient underwent chest radiography on admission (hospital day 1).
Another chest radiograph was taken to confirm pleural effusion on
hospital day 2. No foreign body was seen on the first radiograph
(Figures 1, 2). As about 24 h had elapsed since the first imaging on
hospital day 1, accidental ingestion of a dental prosthesis was
suspected due to the morphology of the foreign body and its position
under the diaphragm. Close examination of the oral cavity revealed no
missing teeth, no fixed prostheses, and no removable dentures. The
possibility of accidental ingestion of a dental-related foreign body was
thus ruled out. Since the foreign body was found in the abdominal cavity
and the patient had a history of the shunt embolization, the patient was
referred to a gastroenterology and hepatology clinic, where the foreign
body was identified as coils used to embolize the portosystemic shunt.
The absence of the foreign object on the initial chest radiograph and
presence on the follow-up radiograph was attributed to a difference in
positioning of the patient and imaging detector during radiography. In
other words, if the initial photograph had shown more of the abdomen as
well as the chest, the foreign body would almost certainly have been
recognized during the initial examination.
Discussion
This report described a case of metallic coils used for embolization of
a portosystemic shunt that were mistaken for an ingested dental
prosthesis when seen as opacities on radiographic images. This case was
confusing because an opaque foreign body was seen on the radiograph
during follow-up of a pleural effusion, unlike the radiograph taken the
previous day. The foreign body was seen under the diaphragm and was thus
suspected to have been accidentally ingested, most likely as a
dental-related foreign body.
During dental procedures, sporadic accidental aspiration and ingestion
of foreign objects has been observed, with ingestion very much more
common than aspiration. 1,2,5 The main subjective
symptoms of aspiration or ingestion of a dental-related foreign body
include cough and pain, but half of aspiration cases and more than 90%
of ingestion cases remain asymptomatic. 5 Determining
from subjective symptoms whether a dental-related foreign body has been
ingested or aspirated is thus difficult.
In general, distinguishing whether a foreign body is a dental-related
foreign body is not very difficult, requiring only examination of the
site in the oral cavity from which the foreign body originated. However,
determination of the defect site from intraoral findings may be
difficult, such as when many teeth are untreated or missing, or when a
defect cannot be confirmed due to intubation or other reasons that do
not allow sufficient opening of the mouth. In this case, no prosthetic
defects were apparent and accidental ingestion of a dental-related
foreign body was ruled out. However, the source of the foreign body
could not be identified. Dentists and oral surgeons do not usually have
detailed knowledge of medical devices from other areas of medicine. The
foreign body in this case was finally identified as a coil used for
embolization of the portosystemic shunt in a consultation with
gastroenterology and hepatology pecialists.
Coils are used for endovascular and aneurysmal embolization. The coil
comprises a primary coil, representing a primary stock wire made of
platinum wound into a spring-like shape, and a secondary coil made of
the same material and wound with further memory of diameter and shape.9 For embolization of portosystemic shunts, a catheter
is inserted, then coils are delivered to the affected area and filled
into the target blood vessel to block blood flow (Figure 3).10 Filled coils may exhibit opacity similar to that of
dental prostheses on radiographs and in some cases may also have a size
and morphology similar to dental prostheses.
A few reports have described radiographic opacities being mistaken for
dental-related foreign bodies.
Adachi et al. described a case of appendicitis caused by retention of
barium sulfate used for gastrointestinal imaging. 11In that case, the radiological findings of the barium deposits mimicked
those of an accidentally ingested dental metal crown. We experienced
another case in which an emergency room physician asked us to
differentiate between a foreign body on a radiograph and a dental
foreign body. In actual clinical practice, differentiation from
dental-related foreign bodies may be needed from time to time.
Conclusion
In conclusion, when dental-related foreign body ingestion or aspiration
is suspected from chest or abdominal radiographs, dentists and oral
surgeons should keep in mind that medical devices such as vascular
embolization coils can produce similar images and form differential
diagnoses accordingly.