Bizarre journey of a sharp metallic foreign body

A 15-year-old girl with no previous co-morbidities accidentally ingested a straight metallic pin following which she had no complaints of dysphagia or shortness of breath. Initial X-ray chest revealed certain findings for which a bronchoscopy was planned, however, a repeat x-ray taken the same day revealed unusual findings due to which the procedure was deferred.

Initial x-ray chest posteroanterior view showed a thin linear radio-opaque foreign body lying along the course of left main bronchus in an oblique manner (Fig 1). There was no evidence of atelectasis involving left lung. Follow up chest radiograph posteroanterior view on the same day showed no evidence of previously visualised foreign body with bilateral clear lung fields (Fig 2).  A follow up abdominal radiograph erect anteroposterior view on the 2nd day showed the thin linear radiopaque foreign body oriented in a horizontal manner in pelvic ileal loops (Fig 3). Another follow up abdominal x-ray erect anteroposterior and lateral view on the 3rd day showed further migration of the foreign body, with foreign body now being located in the ascending colon in a vertical oblique manner.  (Fig 4 and 5)

Foreign bodies (FB) can be ingested, inhaled or inserted into body cavities with ingestion being most common and around 10-20 % of them requiring intervention [1]. The most commonly ingested items include coins and magnets, and the most commonly inhaled object is food items like peanuts [2, 3]. 

The most common site for lodgement of an ingested foreign body is at the level of cricopharyngeus muscle resulting in classic symptoms of dysphagia, odynophagia and chest pain [4]. Other less common sites include the natural sites of constriction of esophagus at the level of the aortic arch, left main bronchus, or gastroesophageal (GE) junction. Once they negotiate the GE junction, the FB usually passes through the gastrointestinal tract without further complications with extreme rare sites of impaction being pylorus, duodenal C-loop, and ileocecal valve [4]. Right main bronchus, due to its shorter, stouter and wider calibre is the most common site of impaction of an inhaled FB. FB aspiration shows nonspecific symptoms like intractable cough delaying the diagnosis and predisposing to complications like pneumonia, atelectasis, and bronchomalacia. 

The imaging approach for an ingested FB starts with a plain radiograph with two opposing views of the chest, neck, and abdomen. Computed tomography (CT) can be considered for an ingested symptomatic FB or those FB with troubling features like large size, length greater than 5 cm, or sharp edges [5]. Sharp metallic objects as in our case are radio-opaque (except for aluminium) on x-rays and appears hyperdense with HU > 3,000 with adjacent streak artefact on CT. Examples of radiolucent objects include wood and plastic, with wood initially exhibiting negative HU and HU rising gradually as it absorbs more water [6]. As majority of inhaled FB are radiolucent, secondary signs of aspiration like atelectasis, hyperinflation of the affected lung, consolidation or pneumonia and mediastinal shift are crucial in decision making [7]. 

The management of an endobronchial foreign body as in this case depends on clinical status with emergent rigid bronchoscopy warranted in tachypneic patients [8]. Emergency endoscopic removal of the FB is always necessary for a symptomatic sharp FB located in the oesophagus or stomach [9]. 

Apparent migration of an aspirated FB from bronchus back into the gastrointestinal tract as a consequence of cough reflex is an extremely rare event which needs to be kept in mind while investigating inhaled or ingested FB, emphasising the need for follow up abdominal radiographs. 

Written informed patient consent for publication has been obtained.