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Wireless capsule endoscopy is an emerging new method of examining the small bowel. Its indications are currently widening, and occult and gastrointestinal bleeding of obscure origin, chronic diarrhoea and malabsorption syndromes, and suspicion of a small bowel neoplasm are now accepted indications.1 Complications are rare, the main one being that it can become struck in strictures or diverticulae inaccessible to flexible endoscopic retrieval.2 The incidence in published series range from 1% to 5%, and all were managed with a surgical or endoscopic procedure.2,3
We present a complication seen in two of our patients, with no consequences to their health or management, but with an impact on examination accuracy and usefulness: oesophageal entrapment in an extra oesophageal vascular compression.
Patient 1 was a 74 year old man with a history of a prosthetic metallic mitral valve and congestive heart failure who had suffered three episodes of obscure overt gastrointestinal bleeding. In his community hospital he had undergone upper and lower endoscopy twice, radioisotope bleeding scans, magnetic resonance imaging angiography, and conventional angiography but the source of the gastrointestinal bleeding was not found. He needed oral iron supplementation but this did not correct his iron deficiency anaemia. Previous radiographic contrast studies of the small bowel had been normal. It was then referred to our unit for a capsule endoscopy examination. After the patient swallowed the capsule, we could see that without an apparent intrinsic stricture, the capsule was retained in the second third of the oesophagus for approximately four hours, progressing to the stomach after this time with no apparent manoeuvre or fluid ingestion (fig 1). The study could not be completed to the terminal ileum because the capsule batteries became exhausted at the level of the proximal ileum. Nevertheless, we could see three bleeding jejunal ulcers as the cause of his gastrointestinal bleeding.
Our second patient was a 72 year old woman with a mitral prosthetic valve and chronic auricular fibrillation. She had undergone upper and lower gastrointestinal endoscopy and mesenteric angiography because she had passed dark stools, with severe anaemia, on repeated occasions. A plain chest x ray showed marked cardiomegaly. She was referred to our centre for a small bowel capsule endoscopy examination. The capsule got struck at a pulsate area in the distal oesophagus, staying there for up to three hours and passing afterwards without a specifically related cause (fig 2). The study was also suboptimal because the patient had ingested some fluids and food that interfered with small bowel vision.
This complication of wireless capsule endoscopy has not previously been reported. An elongated aorta was probably the cause of extrinsic pulsate compression of the thoracic oesophagus in our first case, and a dilated auricular cavity in the second. In both patients upper endoscopy had been performed twice and no strictures were identified.
Although not a life threatening complication, it limited the procedure results in both cases, leading to suboptimal results. A plain chest x ray or accurate oesophageal radiographic contrast studies, previous to the wireless capsule endoscopy procedure, could have provided clues. In such patients, it is advisable to assure passage into the stomach of the capsule on x ray. If the capsule is retained, water could be given to the patient to drink followed by a repeated plain chest x ray to exclude oesophageal entrapment of the capsule. Nevertheless, in a previous report, capsule impaction at the cricopharyngeus was described and the solution adopted by clinicians was endoscopic placement of the capsule in the stomach.4 This could be a feasible solution for patients in whom the capsule is struck in an extrinsic vascular stenosis in the oesophageal lumen.
Conflict of interest: None declared.
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