Can Radiolucent Foreign Bodies Be Identified?

Patient Presentation
A 30 month-old female came to clinic with a history of a cough for 2-3 weeks with rhinorrhea. Her mother was concerned because the day before she had an unwitnessed choking episode where the mother heard what she thought was choking but had stopped when she entered the room. The child was eating crackers at the time. The mother did not see any missing toys or toy parts in the room and the child could not answer if she had swallowed something or put something in her mouth. The mother was quite adamant that she wanted a chest x-ray because she had read on the Internet that aspiration could be diagnosed this way. She had been eating and drinking well since the episode and had no fever. The past medical history was positive for mild intermittent asthma but the mother had not been giving albuterol as it didn’t appear to be helping with this episode.

The pertinent physical exam showed a child with no respiratory distress with normal vital signs, growth parameters and an oxygen saturation of 98%. HEENT showed copious rhinorrhea with some clear fluid behind her tympanic membranes without erythema. Her lungs were difficult to auscultate because she became very fussy and didn’t want to be examined. The rest of her examination was negative.

The diagnosis of a viral syndrome in a setting of previous bronchospasm was made. The resident physician was explaining his findings to the mother who was not very happy with the diagnosis. She then stated, “I think now that she swallowed a toy piece and a want chest x-ray. Besides she’s been coughing for 2 weeks now.” The attending physician also tried to listen to the child who again refused to be examined and the mother became more vocal that she was “sure she had swallowed a toy piece.” The physicians discussed that chest x-rays were not fool-proof for diagnosing foreign bodies. The mother was adamant and the physicians acquiesced. A radiologic evaluation of a chest radiograph was done and was normal. The mother became much less agitated, and verbalized that she was now okay, “because she doesn’t have something in her lungs.”

Foreign bodies are common problems for young children particularly ages 2-4 years who will mouth many objects and aspirate or swallow them. Children will also place foreign objects in other body orifices such as ears or noses. It is also not uncommon that young girls will inadvertently have toilet paper caught in the vaginal area during hygiene. Many of these foreign bodies may work their way out naturally not causing any problems, or may come to attention later because of chronic problems such as a foul-smell or discharge. Older children may tell adults that they have placed a foreign body in an orifice and thus have it come to attention.

Because mouthing food and non-food objects is common in young children, it is not uncommon that the children will cough or choke. Usually this expels the objects and fixes the problem. Parents may not even notice the episode as coughing and choking in general occurs frequently in young children. Some children will have more significant problems if the objects lodges in the airway or at particular points in the gastrointestinal tract, and therefore have continued symptoms and come to medical attention. For example, in a 2013 retrospective review of patients who underwent bronchoscopy for suspected radiolucent foreign body aspiration, most were witnessed events (81%) in a ~2.6 year old (average age), who continued to have problems with wheezing (64%), coughing (43%), choking (39%), stridor (6%) or lethargy (0.7%). Bronchoscopy found a radiolucent foreign body in 93% of the cases which included food (68%), plastic (18%), rock (3%) or unidentifiable object (11%).

Learning Point
For unwitnessed events or when a child admits to the event, radiographs may be used to try to identify the object and location. A radioopaque object is usually easy to identify, and a mnemonic of common radiolucent objects can be found here. A radiolucent object is harder. On chest radiograph (CXR) a radiolucent object in the bronchial tree may show decreased aeration, air trapping or even lung collapse. Often the CXR is normal, which also does not exclude a foreign body. Other methods include visualization with ultrasound, computed tomography, magnetic resonance imaging and even handheld metal scanners. All of these modalities their pros and cons. Some require radiation, are expensive, require a skilled technologist or are very limited to the types of objects that can be identified.

Many, but certainly not all, radiolucent objects can be identified using plain radiographs. In a 2014 study, common radiolucent objects were placed along with control objects in a gelatin slab that was then encased in a water equivalent phantom depicting a child. A plain radiograph was taken and blinded radiologists reviewed the radiograph. Each radiologist correctly identified most of the objects (avg. 8 of 14). 4 objects were not identified by any radiologist. Objects identified were a plastic army figure, lump of clay, crayon, eraser, glass diamond bead, paperclip, drywall anchor, and ring. Items not identified were a plastic barrette, plastic beads and a Lego® brick. The radiologists also were able to identify where some other objects were placed on the radiograph but were unable to identify the specific object. Images of the objects in the study can be found here.

Questions for Further Discussion
1. How would you have handled the adamant parent situation described above?
2. Where do most gastrointestinal or respiratory tract foreign bodies lodge?
3. What types of foreign bodies can be monitored and what need to be removed because of their intrinsic properties?
4. What are some techniques for foreign body removal?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Foreign Bodies and Cough.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Saps M, Rosen JM, Ecanow J. X-ray detection of ingested non-metallic foreign bodies. World J Clin Pediatr. 2014;3(2):14-18. doi:10.5409/wjcp.v3.i2.14

Mortellaro VE, Iqbal C, Fu R, Curtis H, Fike FB, St Peter SD. Predictors of radiolucent foreign body aspiration. J Pediatr Surg. 2013;48(9):1867-1870. doi:10.1016/j.jpedsurg.2013.03.050

Behera G, Tripathy N, Maru YK, Mundra RK, Gupta Y, Lodha M. Role of virtual bronchoscopy in children with a vegetable foreign body in the tracheobronchial tree. J Laryngol Otol. 2014;128(12):1078-1083. doi:10.1017/S0022215114002837

Hamzah HB, James V, Manickam S, Ganapathy S. Handheld Metal Detector for Metallic Foreign Body Ingestion in Pediatric Emergency. Indian J Pediatr. 2018;85(8):618-624. doi:10.1007/s12098-017-2552-5