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The Journal of Laryngology and Otology
October 1990, Vol. 104, pp. 778-782
Radiological diagnosis of aspirated foreign bodies in children:
Review of 343 cases
LIANCAI
Mu, M.D.,
DEQIANG SUN,
M.D.,
PING H E ,
M.D. (Shenyang, China)
Abstract
In our series of 400 Chinese children with foreign body aspiration (FBA), 343 cases were evaluated by
fluoroscopy and/or plain chest X-rays before endoscopic removal of the foreign bodies. The majority of the
foreign bodies (FBs) were organic (378/400, 94.5 per cent). The results showed that mainstem bronchial
foreign bodies were diagnosed correctly in 68 per cent of cases compared with 65 per cent correct diagnoses
with segmental bronchial foreign bodies, but only 22 per cent correct diagnoses with tracheal, and 0 per
cent correct diagnosis in those with laryngeal foreign bodies. Eighty per cent (32/40) of the children with
laryngotracheal FBs had normal X-ray findings, whereas 67.7 per cent (205/303) of the children with bronchial FBs had abnormal chest X-ray findings. The most common positive radiological signs in the children
with tracheobronchial FBs were obstructive emphysema (131/213,62 per cent) and mediastinal shift (117/
213,55 per cent). The incidence of major complications was related not only to the size of the foreign body
and its location but also the duration since aspiration. The most common types of bronchial obstructions by
airway FBs are discussed.
per cent) (Kim et al., 1973; Aytac et al., 1977; Li et al.,
1980; Rothmann and Boeckman, 1980; Banerjee et al.,
1988; McGuirt et al., 1988), pneumonia (8-20 per cent)
(Kim etal., 1973; Li etal., 1980; Rothmann and Boeckman, 1980; McGuirt et al., 1988), normal findings
(6.1-24 per cent) (Kim et al., 1973; Aytac et al., 1977;
Rothmann and Boeckman, 1980; Wiseman, 1984;
Banerjee et al., 1988; McGuirt et al., 1988), and radiopaque FB (6-17 per cent) (Kim et al., 1973; Aytac et al.,
1977; Rothmann and Boeckman, 1980; McGuirt etal.,
1988). The incidence of complications is also related to
the duration of FBA. Esclamado and Richardson (1987)
reported that the incidence of major complications was
45 per cent; however, in patients with a delay in diagnosis of over 24 hours the complication rate was 67 per
cent. Therefore, early diagnosis and treatment can
decrease the number and severity of complications.
The clinical presentation, diagnosis, and treatment of
FBA in children have been well reviewed and documented in recent literature. However, a detailed retrospective analysis of the radiological evaluation of FBA is
still needed.
This study highlights the radiological, especially fluoroscopic, features of airway obstruction due to FB. We
also attempt to detect the relationship between the FB's
size and X-ray findings, and to describe some aspects of
the most common types of bronchial obstructions by
airway FBs.
Introduction
Foreign body aspiration (FBA) is a very serious and lifeendangering emergency which is quite frequently
encountered in small children. Diagnosis of airway FBs
in children is still an important problem. It is well known
that a diagnosis of FBA can be made based on a positive
history of aspiration and particular clinical manifestations such as cough, wheeze, respiratory distress,
and decreased air entry. However, the history of aspiration is sometimes not typical. It has been reported that
a positive history of FBA cannot be obtained 3-27 per
cent of the time (Kim et al., 1973; Li et al., 1980; Rothmann and Boeckman, 1980; Wiseman, 1984; Esclamado
and Richardson, 1987; Banerjee et al., 1988). In nearly
one third of children aspirating FBs, the actual event is
not witnessed (Cohen et al., 1980). In addition, physical
examination may show no abnormality in some cases.
Therefore, radiological evaluation has widely been used
in the diagnosis of FBA clinically although a normal
chest X-ray film was obtained by Aytac et al. (1977) in
about one quarter of such cases.
Many investigations have demonstrated that the
majority of the FBs (66.4-87 per cent) retrieved at endoscopy are organic matter (Kim et al., 1973;Liera/., 1980;
Banerjee et al., 1988). A radiopaque FB is readily identified, but a radiolucent one can be suspected only from
the secondary effects it produces on the lungs.
The commonest radiographic findings in the published reports have been mediastinal shift (4—71 per
cent) (Aytac et al., 1977; Li et al., 1980), obstructive
emphysema (17-60 per cent) and atelectasis (12-34.4
Subjects and methods
During the seven years from June 1982 to Novembet
From the Department of Otolaryngology, 3rd Affiliated Hospital, China Medical University, Shenyang, Liaoning, People's Republic of
China.
Accepted for publication: 31 July 1990.
778
779
RADIOLOGICAL DIAGNOSIS OF ASPIRATED FOREIGN BODIES IN CHILDREN
TABLE I
TABLE II
LODGEMENT SITE OF ASPIRATED FOREIGN BODIES
X-RAY FINDINGS IN FOREIGN BODY ASPIRATION
Cases
Cases
Site
No.
%
X-ray
No.
%
Larynx
Trachea
Right mainstem bronchus
Left mainstem bronchus
Right segmental bronchi
Left segmental bronchi
4
48
150
117
36
45
1
12
38
29
9
11
Positive
Negative
No X-ray
213
130
57
53
33
14
Total
400
100
Total
400
100
1989 inclusive, 400 children with FBA were treated at
the Department of Otolaryngology, 3rd Affiliated Hospital, China Medical University, Shenyang, People's
Republic of China.
The medical charts of the 400 cases of FBs in the airway were reviewed. We noted the age and sex of each;
the nature, size, and location of the FBs; the time lag
between the aspiration and diagnosis; the results of
radiological examination on admission; and endoscopic
findings.
Radiological investigation consisted of chest fluoroscopy in 264 (66 per cent) children, plain chest X-rays in
25 (6.3 percent) cases, and a combination of fluoroscopy
with plain chest X-ray film in 54 (13.3%) cases. Fiftyseven children (14.4 per cent) did not require X-ray
examination before endoscopy because they had a definite history of aspiration and had to be operated upon as
emergencies.
Results
Of the 400 children, 359 (89.8 per cent) were under
three years. Their ages ranged from 7 months to 13
years. The malerfemale ratio was 1.2:1.
Table I shows the various locations of the FBs in our
400 cases. Laryngotracheal FBs were relatively uncommon. Of the bronchial FBs, right-side FBs were more
common (186/400, 47%) compared with left-side FBs
(162/400,40 per cent). The FBs were most often found in
the mainstem bronchi (267/400, 67 per cent).
The majority of the FBs were organic (378/400, 94.5
per cent), 61 per cent of them being peanuts (232/378).
Bean and sunflower seeds were next most common, seen
in 101 cases (26.7 per cent, 101/378). The remainder
included corn (20/400, 5 per cent), watermelon seeds
(17/400,4.2 per cent), pieces of fruits and vegetables (8/
400, 2 per cent). Among the inorganic substances, plastic and metallic objects, glass, eggshell, piece of bone,
etc., were encountered (22/400, 5.5 per cent).
The radiological findings encountered are summarized in Tables II, III, IV, and V. Over one third (130/343,
38 per cent) of the children with airway FBs had normal
X-ray findings (Table II).
Eighty per cent (32/40) of the children with laryngotracheal FBs had normal X-ray findings, whereas 67.7
per cent (205/303) of the children with bronchial FBs had
positive X-ray findings (Table III).
Tables IV and V show the positive X-ray findings in
213 cases with airway FBs. As Table V shows, the most
common complication of FBA was obstructive emphysema (131/213, 62 per cent). Inspiratory shift of the
mediastinal shadow was seen in 55 per cent of the cases,
pneumonia in 26 per cent, and atelectasis in 18 per cent.
More than one of these positive findings were present in
some cases. Radiopaque FBs were seen in 7 cases (3 per
cent). In those children with mainstem bronchial FBs, 40
per cent (106/267) had obstructive emphysema, and 35
per cent (94/267) had inspiratory shift of mediastinal
shadow (Tables I, V).
Table VI shows the mean duration of aspiration of
FBs in 400 cases. The mean duration of aspiration of
bronchial FBs was the longest. Table VII shows the
relationship between X-ray findings and interval since
aspiration of FBA. Considerable differences in X-ray
findings were observed between children diagnosed
early and late. In patients with early diagnosis of less
than 24 hours the incidence of complications was 44 per
cent (28/63). In contrast, the complication rate in those
patients who had a delay in diagnosis of more than 24
hours was over 60 per cent. In 21 cases the time interval
from either known aspiration or onset of symptoms to
diagnosis was more than 30 days. All but one (20/21,
95%) had positive radiological findings. The complication rate increased with the length of FB's sojourn in the
airways.
TABLE III
CORRELATION OF X-RAY FINDINGS WITH ENDOSCOPY AND REMOVAL OF FOREIGN BODIES FROM THE AIRWAYS
Foreign body location
Trachea
Larynx
X-ray
No.
(%)
Mainstem bronchi
No.
(%)
No.
(%)
Segmental bronchi
No.
(%)
Positive
Negative
No X-ray
0
3
1
(0)
(75)
(25)
8
29
11
(17)
(60)
(23)
160
74
33
(60)
(28)
(12)
45
24
12
(55)
(30)
(15)
Total
4
(100)
48
(100)
267
(100)
81
(100)
780
LIANCAI MU, DEOIANG SUN AND PING HE
TABLE IV
DISTRIBUTION OF POSITIVE X-RAY FINDINGS IN 213 CASES
Cases
Location
No.
%
Trachea
Mainstem bronchi
Segmental bronchi
8
160
45
4
75
21
Total
213
100
Table VIII shows the correlation of negative X-ray
findings with duration of FBA. More than one half (56
per cent) of the patients with early diagnosis (=S24 hours)
had normal X-rays. By comparison, only one third of
patients with a delay in diagnosis of over 24 hours had
normal chest X-rays. Table IX shows the location, type
and size of organic airway FBs with negative X-ray findings. Small pieces of peanut (67/130, 52 per cent), sunflower seed and. watermelon seed (25/131, 19 per cent),
and small piece of bone (18/130, 14 per cent) were the
most frequently found airway FBs with negative X-ray
findings.
Discussion
Although ultrasonography, CT scanning, and xeroradiographic examinations have all been advocated in
the diagnosis of aspirated FBs, they are of limited usefulness. Clinically, chest fluoroscopy and X-rays that
include inspiratory and expiratory, anteroposterior and
lateral films, have been used widely by many
investigators.
We prefer to use fluoroscopy as a routine diagnostic
procedure. In our series, 80 per cent of the cases were
examined fluoroscopically before bronchoscopy. We
have found that fluoroscopy plays an important role in
the diagnosis of organic bronchial FBs. As our results
show, fluoroscopy increases the accurate diagnosis in
over two-thirds of the cases of bronchial FBs, whereas
the discrepancy between the fluoroscopic and bronchoscopic findings is less than one third. We feel that
fluoroscopy is much better than chest X-rays in determining whether there is abnormal behaviour of the
mediastinal shadow. In some cases with a normal chest
X-ray, inspiratory-expiratory mediastinal shift indicating a unilateral bronchial obstruction was observed
by means of fluoroscopy. Although fluoroscopy is the
classic laboratory diagnostic measure used, it has n o r
been uniformly helpful. In this study, 80 per cent of the
children with laryngotracheal FBs had normal X-ray
findings. Therefore, one must pay attention to the
history of aspiration and clinical manifestations in those
cases with normal X-ray findings.
Meanwhile, we have to accept the fact that in determining whether mild pneumonia or atelectasis caused by
aspirated FBs is present chest X-rays seem better than
fluoroscopy. In some cases with normal fluoroscopic
findings, complications such as pneumonia and/or
atelectasis were discovered only on X-ray. Recurrent
pneumonia as a common complication is usually caused
by a long-standing bronchial FB. The combination of
fluoroscopy with X-ray is very useful for those cases with
suspicious or unusual fluoroscopic findings.
As our results show, main bronchial FBs are diagnosed correctly 68 per cent of the time compared with 65
per cent correct diagnoses with segmental bronchial FBs
and with only 20 per cent correct diagnoses with laryngotracheal FBs. Our findings are similar to those (86.4 per
cent, 66.7 per cent, and 35 per cent, respectively) presented by Jiang et al. (1984).
We found that the X-ray findings are related to the following factors: the size of the FB (Table IX), the site of
its lodgement (Tables III, IV, V), and the length of its
sojourn in the airway (Tables VII, VIII). The development of the pulmonary complications by FBA is related
to the pattern of bronchial obstruction, whereas that of
airway obstruction depends upon the FB's size relative
to that of the bronchus in which it lodges.
Four types of bronchial obstructions by airway FBs,
namely, the check-valve, stop-valve, ball-valve, and
bypass-valve obstructions, have been described by
Chatterji and Chatterji (1972). According to the description of airway obstructions, the commonest radiological
findings produced by aspirated FBs may be explained as
follows:
1. Normal X-ray findings
The bypass-valve obstruction, caused by the organic
FBs which partially obstruct the respiratory tract (larynx, trachea, or bronchus) in both phases of respiration,
leads to diminished aeration and opacity on the affected
side. If there is no marked pressure difference on the two
sides of the mediastinum, mediastinal shift cannot be
observed. Therefore, no abnormality appears on both
the X-rays and fluoroscopy. Organic FBs with negative
TABLE V
POSITIVE X-RAY FINDINGS IN 2 1 3 CASES WITH FOREIGN BODY ASPIRATION
Site of foreign bodies
Main bronchi
(N=160)
Trachea
(N=8)
X-ray findings
Obstructive emphysema
Mediastinal shift
Pneumonia
Atelectasis
Radiopaque object
Segmental bronchi
(N=45)
Total
No.
(%)
No.
(%)
No.
(%)
No.
(%)
4
4
2
0
0
(2)
(2)
(1)
(0)
(0)
106
94
35
24
5
(50)
(44)
(16)
(11)
(2)
21
19
19
15
2
(10)
(9)
(9)
(7)
(1)
131
117
56
39
7
(62)
(55)
(26)
(18)
(3)
*More than one of these positive findings were present in some cases.
781
RADIOLOGICAL DIAGNOSIS OF ASPIRATED FOREIGN BODIES IN CHILDREN
from it on expiration. In this case, no abnormality
appears on the X-rays, but fluoroscopy can show mediastinal shift.
TABLE VI
MEAN DURATION OF FOREIGN BODY ASPIRATION IN 4 0 0 CASES
Duration.
Location of
foreign bodies
Mean days (range)
Larynx (N=4)
Trachea (N=48)
Mainstem bronchi (N=267)
Segmental bronchi (N=81)
3.8 (1-8)
4.6 (1 hr-17)
10.9 (30 min-365)
14.3 (2 hrs-120)
X-ray findings are usually small in size and flat or oblong
in shape, such as sunflower or watermelon seeds, eggshell, corn, and small pieces of bean or peanut (Table
IX).
2. Obstructive emphysema
The check-valve obstruction, by which air can be
inhaled and cannot be expelled, gives rise to obstructive
emphysema on the involved side. It has been wellknown that the diameter of a bronchus increases during
inspiration and decreases during expiration. The FB
may be of a size that it occludes the bronchus during
expiration but not during inspiration; thus it acts like a
valve, so that the lung beyond the obstruction becomes
inflated. Poor airflow out of an obstructed lung or lobe
will result in unequal emptying and will be visualized as
obstructive emphysema on radiological examination,
and the FB can be located in the supplying bronchus.
3. Mediastinal shift
The types of bronchial obstructions which can cause
mediastinal shift are as follows: (1) The ball-valve
obstruction, which dislodge during expiration and reimpact during inspiration, leads to early atelectasis. In the
latter cases, the mediastinal shift towards the affected
side can be observed. This type of obstruction is named
as 'ball-valve obstruction' because it is usually associated
with rounded smooth FBs. (2) The check-valve obstruction can also cause early mediastinal shift towards the
opposite side. (3) The bypass-valve obstruction may give
rise to slight mediastinal shift. With the bronchus partially occluded, less air flows in and out. If the pressure
difference on the two sides of the mediastinum is created, it causes the mediastinum to swing from side to
side—towards the affected lung on inspiration and away
4. Atelectasis
The types of bronchial obstructions which can cause
atelectasis are as follows:
(1) The stop-valve obstruction, associated with obstruction of a large air passage in both inspiration and expiration, results in collapse or consolidation of the affected
bronchopulmonary segment. This may be caused either
by a large FB which leads to complete occlusion from the
time of aspiration or by a gradually swollen, small,
organic body which had previously resulted in a check
valve type of obstruction. In this case, all air in the
involved part of the lung will be gradually absorbed,
leaving the lung airless and collapsed. The mediastinal
shift towards the affected side can be observed in the
latter cases. The chest X-rays will show signs of atelectasis. The FB can then be found in the supplying bronchus.
(2) The ball-valve obstruction can also cause early
atelectasis.
5. Pneumonia
Each type of the bronchial obstructions by aspirated
FBs mentioned above can cause pneumonia if the
impaired outflow of secretions has persisted for several
days or weeks.
6. Pneumothorax
This complication caused by aspirated FBs is uncommon. It may result either from the obstructive emphysema or from the penetration through a bronchial wall of
a sharp FB.
It has been accepted that airway FBs should be
strongly suspected in children who present with a suggestive history, even when physical findings and radiological studies are negative. One must remember the
fact that more than half of the children with laryngotracheal FBs have normal radiological findings and this
may lead one to a false sense of security. The presentation and complications of FBs can be determined by
the history of aspiration, physical examination, and
radiological studies. Bronchoscopy of the airway is an
TABLE VII
RELATIONSHIP BETWEEN X-RAY FINDINGS AND DURATION OF FOREIGN BODY ASPIRATION IN 3 4 3 CASES
X-ray findings
24hrs
1-3 days
4-7 days
8-14 days
15-30 days
31-365 days
(N=63)
(N=94)
(N=75)
(N=34)
(N=56)
(N=21)
Negative (N= 130, 38%)
Positive (N=213, 62%)
obstructive emphysema
mediastinal shift
pneumonia
atelectasis
35
38
27
12
17
1
19
20
3
2
35
34
10
4
26
25
11
11
18
12
8
5
23
18
16
9
10
8
8
8
Complication rate
44%
60%
64%
65%
70%
95%
*More than one of these positive X-ray findings was present in some cases.
782
LIANCAI MU, DEQIANG SUN AND PING HE
TABLE VIII
CORRELATION OF NEGATIVE X-RAY FINDINGS WITH DURATION OF
FOREIGN BODY ASPIRATION IN 1 3 0 CASES
Cases with negative
X-ray findings
(days)
X-ray examination
No.
%
63
94
75
34
56
21
35
38
27
12
17
1
56
40
36
35
30
5
<1
1- 3
4- 7
8-14
15-30
>30
3. The combination of fluoroscopy with chest X-rays is
very useful for some cases with suspicious or unusual
fluoroscopic findings.
4. Over two-thirds of the children with laryngotracheal
FBs had normal X-ray findings in this series. Therefore,
a negative X-ray finding cannot rule out the diagnosis of
FBA.
5. The positive X-ray findings of an organic FB are
related to six factors, namely, the size and shape of FB;
the site of its lodgement; the pattern of bronchial
obstruction; the length of its sojourn in the airways; and
the technique or radiographic evaluation used.
6. The diagnosis of airway FB should not be dismissed
without bronchoscopy.
TABLE IX
DISTRIBUTION OF 1 3 0 ORGANIC FOREIGN BODIES WITH NEGATIVE X-RAY
FINDINGS IN THE AIRWAYS
Acknowledgement
Cases
Location of foreign
bodies
Type and size of the foreign bodies
No.
Larynx
i bean
piece of eggshell
Trachea
i-i peanut
1 sunflower seed
1 watermelon seed
1 bean
piece of eggshell
1 corn
miscellaneous
11
4
4
3
2
2
3
Mainstem bronchi
^—i peanut
ibean
i-1 sunflower seed
j-1 corn
1 watermelon seed
miscellaneous
39
14
9
4
3
5
Segmental bronchi
small piece of peanut
i sunflower seed
miscellaneous
1
2
3
29
74
Total
(%)
This research was supported by Postgraduate
Research Grants from China Medical University,
Shenyang, P.R. of China.
(2)
References
Aytac, A., Yurdakul, Y., Ikizler, C , Olga, R., Saylam, A. (1977)
Inhalation of foreign bodies in children: Report of 500 cases.
Journal of Thoracic and Cardiovascular Surgery, 74: 145—151.
(22)
(57)
17
5
2
24
(19)
130
(100)
effective way of establishing the diagnosis of FBA. In
any suspected cases, bronchoscopic evaluation should
be performed as early as possible to diminish severe
complications by aspirated FBs.
Conclusions
The results obtained from the study are contributory
to the following conclusions:
1. Radiological examination is essential for detection
and localization of FBs in the airways. However, the
physician must be aware of the advantages and pitfalls of
radiological diagnosis of aspirated FBs.
2. Fluoroscopy plays an important role in the diagnosis
of organic bronchial FBs. In determining whether there
is abnormal behaviour of mediastinal shadow fluoroscopy is much better than chest X-rays.
Banerjee, A., Subba Rao, K. S. V. K., Khanna, S. K., Narayanan,
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Address for correspondence:
Liancai Mu, M.D.,
Lecturer,
Sahlgren's Hospital,
ENT Clinic,
University of Goteborg,
S-413 45, Goteborg,
Sweden.
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