Sonographic diagnosis of gastric-outlet foreign body: case report and review of literature.

The diagnosis of unsuspected foreign body ingestion is a common problem in children. We describe a toddler who presented with persistent vomiting and dehydration. A plain radiograph of the abdomen did not reveal a foreign body. However, abdominal ultrasonography promptly identified a funnel-shaped foreign body obstructing the gastric outlet. This was extracted by upper endoscopy. A recent review of the literature shows increasing evidence that abdominal ultrasonography is an equally complementary diagnostic modality for ingested foreign bodies in children.

INTRODUCTION

Foreign bodies are frequently ingested by young children, mostly by ambulatory toddlers who explore their surroundings orally. Almost 40 percent1 of the ingestion of the foreign bodies are unwitnessed and 50 percent2 are asymptomatic. Depending on the size, shape, content and nature, most ingested small objects on reaching the gastrointestinal tract pass through spontaneously3 within 2-6 days, but may take up to four weeks. While serious complications such as bowel obstruction or perforation can occur, gastric outlet obstruction by the ingestion of a foreign body is uncommon.45

We report a case of a toddler presenting with persistent vomiting caused by an ingested foreign body obstructing the gastric outlet. A plain radiograph of the abdomen did not reveal the presence of a foreign body; however, abdominal ultrasonography detected the obstructing foreign object which was extracted by upper gastroscopy.

CASE PRESENTATION

A 19-month old toddler presented with a one- week history of persistent non-bilious vomiting and intolerance of oral fluids and solids. The vomiting was associated with abdominal distention and a low-grade fever. There was no history of diarrhea, choking or the witnessing of the ingestion of a foreign body. Physical examination revealed a distended abdomen with increased bowel sounds, but no tenderness and no organomegaly. The patient was hospitalized with the clinical diagnosis of gastritis with moderate dehydration. The vomiting ceased with intravenous hydration and keeping the patient on nil by mouth. As he was restarted on clear oral fluids, the vomiting recurred. Flat film of the abdomen showed paucity of gas in the gut which was reported as normal. The suspicion of a faint radio-density projecting over the stomach was seen retrospectively following the results of the abdominal sonography (Figure 1).

Figure 1

Abdominal radiograph showed a relative paucity of gas in the gut. The faint radio-density (arrow) which represented the foreign body was noted retrospectively.

An abdominal ultrasound done showed a small echogenic structure localized to the region of the pyloris. The structure was obstructing the gastric outlet (Figure 2) as evidenced by a distended fluid filled stomach.

Figure 2

Abdominal sonogram demonstrated the presence of a small echogenic structure casting an acoustic shadow localized to the region of the pylorus. The structure appeared to be creating a gastric outlet obstruction as evidenced by a massively distended fluid filled stomach.

An urgent upper gastroscopy was performed under general anaesthesia. The procedure revealed a normal but hugely dilated stomach with a funnel-shaped plastic foreign body impacting and completely obstructing the pylorus (Figure 3). The foreign body was extracted (Figure 4) with a snare and forceps. The patient was discharged home 24 hours following gastroscopy on a regular diet and ranitidine for mild esophageal erosions. The specimen was examined by the pathologist who confirmed a pink funnel-shaped structure measuring 2.3×2×2 centimeters. Similar plastic objects are typically fixed to balloons as handles and are readily available to children.

Figure 3

On upper gastroscopy, the stomach looked normal but hugely dilated with a foreign body partly impacted in the pyloric channel. The major part of the foreign body was lodged in the stomach

Figure 4

Extracted specimen was identified as a plastic funnel-shaped structure, pink in color measuring 2.3×2×2 cm with bite marks.

DISCUSSION

Foreign body ingestion occurs commonly in children, especially toddlers. Small colorful toys are attractive ingestion hazards for toddlers. Once past the lower esophageal sphincter (LES), the majority of regularly-shaped smooth foreign bodies usually pass spontaneously through the gastrointestinal tract within 4-6 days, but may take up to 4 weeks. Gastric outlet obstruction as seen in our patient, causes persistent vomiting with dehydration.

While 80% of ingested foreign bodies pass through spontaneously, 10-20% require intervention and 1% need surgical removal.6 Conventional radiography will identify most radio-opaque metallic objects, but may not detect radiolucent objects such as plastic objects, wood, glass, fish or chicken bones. Hence, the diagnosis of radiolucent foreign bodies in the gastrointestinal tract can be challenging.

Oral contrast studies have been utilized to locate ingested non-opaque foreign bodies which appear as filling defects.3 However, oral contrast studies have the potential risk of aspiration in cases of a high grade obstruction or poor control of secretions. They are to be avoided if esophageal perforation is suspected. If perforation is suspected and a study is necessary, an isotonic contrast agent may be used, whereas Gastrograffin and Barium are contraindicated. Moreover, the coating of the foreign object may compromise the endoscopic findings.

Sonography, unlike conventional radiography, is not dependent on radiographic density and does not involve ionizing radiation. Despite its ease of use and relative low cost, sonography has been considered a poor imaging modality to detect abdominal foreign bodies as an air-filled bowel is difficult to visualize.

The sonographic diagnosis of a foreign body depends on primary and secondary signs. The foreign object elicits its own primary signs by casting an echogenic mass with a dense acoustic shadow. The secondary signs due to tissue edema or hemorrhage result in a hypoechoic area surrounding the foreign body. Distension of the stomach or the bowel segments is a further important secondary sign of an obstructing foreign body. Fluid-filled bowel loops allow sonographic demonstration of the foreign body. Multiple studies6–11 have shown the effectiveness of sonography in detecting soft tissue foreign bodies. Ginsburg et al12 demonstrated that sonography is the most reliable method of detecting non-opaque soft tissue foreign bodies. Caspi et al13 revealed that sonography is effective in detecting foreign bodies in vaginal orifices.

Several cases of abdominal foreign bodies detected by ultrasonography have been reported. Isaac14 reported the detection of a ball point pen by abdominal ultrsonography in a 4-year-old female. It appeared as a hyperechoic linear mass with a strong acoustic shadow. Asad et al15 diagnosed a case of appendicitis due to an accidentally ingested endodental file which lodged in the appendix. The graded compression technique was used in abdominal sonography to detect the precise location of the missing object. In a 5-year-old boy, ileal perforation occurring secondary to an ingested fragment of a skewer was identified by Rathaus et al16 by using abdominal sonography. The abdominal sonogram revealed the presence of a hyperechoic straight-line foreign body embedded within a hypoechoic inflammatory mass. An earlier case of gastrointestinal perforation due to a swallowed toothpick was recognized sonographically by Chau et al.17

In a review of 23 cases of abdominal foreign bodies diagnosed sonographically, Kuznetsov et al18 concluded that ultrasonic examination provided the maximal information about sizes, structure, location of foreign abdominal bodies, their depth of location and relationship with abdominal organs. This case report adds to the increasing evidence that the skilled use of ultrasonography, a noninvasive painless diagnostic modality, can detect abdominal foreign bodies.

Ingestion of foreign bodies should be considered in the evaluation of persistent vomiting in a toddler. Some objects may not be radio-opaque and may be difficult to find by plain radiographic views. This report, along with the literature review, shows that abdominal ultrasonography is preferred to plain film19 and oral contrast studies in the diagnosis of suspected foreign body ingestion.