Esophageal Foreign Body

Esophageal foreign body (EFB) is a clinical condition characterized by the lodgment of an ingested object within the lumen of the esophagus, leading to partial or complete obstruction, mucosal injury, and potentially severe complications such as perforation, mediastinitis, and sepsis. The esophagus is a muscular tube extending from the pharynx to the stomach, composed of striated muscle in dogs and a mix of striated and smooth muscle in cats, with a relatively thin wall and no serosal layer, making it vulnerable to pressure necrosis and perforation. EFBs are common in dogs, particularly in breeds with a tendency to swallow large objects, and less frequent in cats. The condition requires prompt diagnosis and intervention to prevent life-threatening sequelae. Surgical management is indicated when endoscopic retrieval fails or when complications such as perforation, stricture, or abscessation are present. The surgical approach may involve esophagotomy, esophageal resection and anastomosis, or in severe cases, esophageal bypass or salvage procedures. Perioperative management focuses on stabilization, antimicrobial therapy, nutritional support, and meticulous surgical technique to minimize postoperative complications such as dehiscence, leakage, and stricture formation.

The primary etiology of esophageal foreign bodies is the ingestion of objects that are too large to pass through the esophageal lumen or become entrapped due to anatomical narrowing. Common foreign bodies include bones, rawhide chews, toys, fishhooks, needles, and in cats, linear foreign bodies such as string or thread. Predisposing anatomical sites include the thoracic inlet, the base of the heart, and the diaphragmatic hiatus, where the esophagus narrows. Traumatic ingestion can occur during rapid eating, play, or scavenging behavior. Iatrogenic causes are rare but may include retained surgical sponges or instruments. Congenital anomalies such as vascular ring anomalies (e.g., persistent right aortic arch) can predispose to foreign body entrapment by causing esophageal dilation and narrowing. Additionally, esophageal motility disorders, strictures, or neoplasia can increase the risk of impaction. The biomechanical trigger involves the object becoming lodged, causing pressure on the esophageal wall, leading to ischemia, inflammation, and necrosis if not relieved.

Esophageal foreign bodies are most commonly diagnosed in dogs, with a higher incidence in certain breeds such as Labrador Retrievers, Golden Retrievers, and other large-breed dogs that are prone to indiscriminate eating. Terriers and other small breeds may also be affected, particularly with linear foreign bodies. Cats are less commonly affected but can present with linear foreign bodies, especially in households with string or thread. There is no significant sex predilection, but young to middle-aged animals are more frequently affected due to exploratory behavior. Working dogs, such as hunting or police dogs, may have increased risk due to exposure to bones and other objects. The incidence is higher in animals with behavioral issues like pica or those fed a diet that encourages rapid eating. Breed-specific anatomical factors, such as a relatively narrow thoracic inlet in some breeds, may contribute. Overall, EFBs account for a significant proportion of esophageal emergencies in small animal practice.

The pathophysiology of esophageal foreign body involves a cascade of events initiated by mechanical obstruction. The object exerts pressure on the esophageal mucosa, leading to local ischemia, inflammation, and edema. If the obstruction is complete, saliva and ingested material accumulate proximal to the foreign body, causing regurgitation and aspiration risk. Prolonged pressure can lead to pressure necrosis, ulceration, and eventually perforation of the esophageal wall. Perforation results in leakage of esophageal contents into the mediastinum, causing severe mediastinitis, pleuritis, and sepsis. In cases of partial obstruction, chronic irritation can lead to esophageal stricture formation due to fibrosis and scarring. Linear foreign bodies can cause plication of the esophagus and intestinal tract, leading to linear foreign body syndrome, with potential for perforation at multiple sites. The systemic inflammatory response syndrome (SIRS) may develop secondary to mediastinitis or sepsis, leading to multi-organ dysfunction. The anatomical lack of a serosal layer in the esophagus impairs healing and increases the risk of dehiscence after surgical repair.

Intrinsic predisposing factors include breed-specific anatomical variations, such as a relatively narrow esophageal lumen at the thoracic inlet or base of the heart, which can increase the likelihood of foreign body entrapment. Congenital anomalies like vascular ring anomalies (e.g., persistent right aortic arch) cause esophageal dilation and narrowing, predisposing to impaction. Esophageal motility disorders, such as megaesophagus, can lead to poor bolus transport and increased risk of foreign body lodgment. Acquired conditions like esophageal strictures, diverticula, or neoplasia can also predispose to foreign body entrapment. Age is a factor, with young animals more likely to ingest inappropriate objects. Extrinsic factors include dietary habits, such as feeding bones or rawhide chews, and behavioral issues like rapid eating, scavenging, or pica. Environmental factors, such as access to toys or household items, increase risk. Prior esophageal surgery or trauma may lead to scarring and narrowing, predisposing to future impactions.

Clinical signs of esophageal foreign body vary depending on the location, degree of obstruction, and duration. Acute signs include sudden onset of regurgitation, dysphagia, excessive salivation, pawing at the mouth, retching, and gagging. Animals may show signs of pain, such as crying or restlessness. Anorexia and lethargy are common. If the obstruction is complete, regurgitation of food and water occurs shortly after ingestion. In cases of partial obstruction, animals may be able to swallow small amounts of liquid but regurgitate solid food. Chronic cases may present with weight loss, recurrent pneumonia due to aspiration, and signs of esophageal stricture, such as progressive dysphagia. If perforation occurs, signs of systemic illness develop, including fever, depression, tachycardia, tachypnea, and signs of mediastinitis or pleuritis, such as respiratory distress. On physical examination, palpation of the cervical esophagus may reveal a firm mass if the foreign body is in the cervical region. Thoracic auscultation may reveal crackles or muffled heart sounds if pleural effusion is present.

Differential diagnoses for esophageal foreign body include: 1) Esophageal stricture: presents with progressive dysphagia and regurgitation, often history of previous esophageal insult; imaging shows narrowing without a discrete foreign body. 2) Esophageal neoplasia (e.g., squamous cell carcinoma, leiomyosarcoma): older animals, weight loss, imaging shows mass lesion, biopsy confirms. 3) Megaesophagus: generalized esophageal dilation, regurgitation, often due to myasthenia gravis or idiopathic; radiography shows diffuse dilation. 4) Vascular ring anomaly: congenital, young animals, regurgitation after weaning, radiography shows esophageal dilation cranial to the heart base. 5) Esophagitis: inflammation due to reflux or caustic ingestion, signs of pain and regurgitation, endoscopy shows mucosal changes. 6) Hiatal hernia: regurgitation, respiratory signs, imaging shows displacement of stomach into thorax. 7) Gastric foreign body: may cause vomiting rather than regurgitation, but can be concurrent. 8) Pharyngeal foreign body: signs of dysphagia and gagging, but localization to pharynx on exam. 9) Tracheal foreign body: respiratory signs, cough, but may mimic esophageal signs. 10) Mediastinal mass: may cause esophageal compression, signs of regurgitation, imaging shows mass. Definitive diagnosis is made via imaging (radiography, contrast studies, endoscopy) and response to treatment.

The diagnostic algorithm for suspected esophageal foreign body begins with a thorough history and physical examination, including assessment of the cervical esophagus. Initial diagnostic imaging includes plain radiographs of the cervical and thoracic esophagus in two views (lateral and ventrodorsal). Many foreign bodies are radiopaque and can be identified directly. If the foreign body is not visible, contrast radiography using barium sulfate or iohexol (if perforation is suspected) can outline the obstruction. Esophagoscopy is the gold standard for diagnosis and often allows simultaneous retrieval. If endoscopy is not available or if perforation is suspected, advanced imaging such as computed tomography (CT) may be used to assess the extent of injury and plan surgical intervention. Laboratory tests, including complete blood count, serum biochemistry, and electrolytes, are performed to assess systemic health and identify complications such as dehydration, electrolyte imbalances, or sepsis. Thoracic ultrasound may be useful to detect pleural effusion or mediastinal changes. In cases of suspected perforation, thoracocentesis and fluid analysis may be performed. The diagnostic approach should be rapid to minimize the risk of complications.

Laboratory findings in esophageal foreign body are often nonspecific but can reflect the severity and duration of the condition. Complete blood count may show leukocytosis with a left shift in cases of inflammation or infection, or leukopenia in severe sepsis. Hematocrit may be elevated due to dehydration. Serum biochemistry may reveal electrolyte imbalances, particularly hyponatremia, hypochloremia, and hypokalemia, due to loss of saliva and gastric contents through regurgitation. Metabolic alkalosis may be present due to loss of hydrogen ions. In cases of perforation and mediastinitis, inflammatory markers such as C-reactive protein (CRP) and serum amyloid A (SAA) may be elevated. Blood gas analysis may show metabolic alkalosis or acidosis depending on the severity of systemic illness. Coagulation panel (PT/aPTT) and thromboelastography (TEG) may be indicated if sepsis or disseminated intravascular coagulation (DIC) is suspected. Urinalysis may show ketonuria or signs of dehydration. In cases of aspiration pneumonia, arterial blood gas may show hypoxemia. Synovial fluid analysis is not relevant in this condition.

Imaging plays a crucial role in the diagnosis and management of esophageal foreign bodies. Plain radiography of the cervical and thoracic esophagus is the first-line imaging modality. Radiopaque foreign bodies, such as bones, metal objects, and some toys, are readily visible. Radiographic signs may include a foreign body, esophageal dilation proximal to the obstruction, and gas accumulation. In cases of perforation, pneumomediastinum, pleural effusion, or pneumothorax may be observed. If the foreign body is radiolucent, contrast radiography using barium sulfate (if perforation is not suspected) or water-soluble iodinated contrast (iohexol) is indicated. Contrast studies can delineate the level of obstruction and identify mucosal irregularities. Esophagoscopy is both diagnostic and therapeutic, allowing direct visualization and retrieval. Computed tomography (CT) is increasingly used to evaluate the extent of esophageal injury, detect perforation, and plan surgical intervention. CT can provide detailed information about the foreign body's location, size, and relationship to surrounding structures. Ultrasonography may be useful for detecting pleural effusion or mediastinal changes but is limited by gas in the esophagus. Fluoroscopy can be used during endoscopic retrieval or to assess esophageal motility postoperatively.

Cytology and histopathology are not typically required for the diagnosis of esophageal foreign body, but they may be indicated if there is suspicion of an underlying neoplastic process or to evaluate tissue samples obtained during surgery. If a mass is identified, fine-needle aspiration (FNA) or biopsy may be performed. Cytological examination of aspirates can help differentiate inflammatory from neoplastic conditions. Histopathological evaluation of esophageal tissue may be performed if a biopsy is taken during endoscopy or surgery. In cases of chronic inflammation, histopathology may show mucosal ulceration, fibrosis, and inflammatory infiltrate. If a foreign body has caused perforation, tissue samples from the margins of the perforation may be submitted for culture and histopathology to guide antimicrobial therapy and assess for neoplasia. Special stains, such as Masson's trichrome, may be used to evaluate fibrosis. However, in most cases, the diagnosis is made based on imaging and endoscopic findings, and histopathology is reserved for cases with atypical presentations or suspected neoplasia.

The treatment of esophageal foreign body depends on the size, location, and duration of the foreign body, as well as the presence of complications. Initial stabilization includes intravenous fluid therapy to correct dehydration and electrolyte imbalances, and administration of broad-spectrum antibiotics if perforation is suspected. The first-line treatment is endoscopic retrieval, which is successful in the majority of cases. If endoscopic retrieval fails or is not feasible, surgical intervention is indicated. Surgical options include esophagotomy, where the esophagus is incised directly over the foreign body, and esophageal resection and anastomosis for severely damaged segments. The surgical approach depends on the location: cervical esophagotomy for cervical foreign bodies, and thoracic esophagotomy via intercostal thoracotomy or median sternotomy for thoracic foreign bodies. In cases of perforation, debridement of necrotic tissue, lavage, and drainage of the mediastinum or pleural space are performed. Postoperative management includes nutritional support via esophagostomy tube or gastrostomy tube, strict rest, and analgesia. Complications such as stricture formation may require balloon dilation or surgical revision. In severe cases, esophageal bypass procedures or salvage esophagectomy may be considered, but these are associated with high morbidity.

The prognosis for esophageal foreign body is generally good if treated promptly and without complications. The success rate for endoscopic retrieval is high, with most animals recovering without long-term sequelae. However, the prognosis worsens with delayed presentation, presence of perforation, mediastinitis, or sepsis. The mortality rate for esophageal perforation is significant, ranging from 20-50% in some studies. Postoperative complications such as esophageal stricture, dehiscence, and leakage can adversely affect the outcome. The prognosis is also influenced by the underlying cause; for example, animals with vascular ring anomalies may have a guarded prognosis due to concurrent esophageal dysfunction. Negative prognostic indicators include severe esophageal necrosis, need for resection and anastomosis, and development of systemic inflammatory response syndrome. With appropriate surgical intervention and intensive postoperative care, many animals can achieve a good quality of life, but long-term complications such as stricture may require ongoing management.

Postoperative follow-up for esophageal foreign body is crucial to monitor for complications and ensure optimal recovery. After surgical intervention, the animal should be hospitalized for at least 24-48 hours for monitoring of vital signs, pain management, and nutritional support. An esophagostomy or gastrostomy tube may be placed for feeding during the initial healing period. Suture removal for skin incisions is typically at 10-14 days. Serial radiographs may be taken at 4, 8, and 12 weeks postoperatively to assess esophageal healing and detect stricture formation. Contrast esophagography may be performed at these intervals to evaluate luminal diameter and motility. If a stricture develops, balloon dilation may be required, and follow-up endoscopy is recommended. Activity restriction is advised for 2-4 weeks to allow healing. Nutritional management includes feeding a soft or liquid diet initially, gradually transitioning to a normal diet as healing progresses. Long-term monitoring for signs of regurgitation, dysphagia, or weight loss is essential. In cases of underlying conditions such as megaesophagus, ongoing management and regular rechecks are necessary.

Clinical pearls: 1) Always obtain orthogonal radiographs of the entire esophagus, including the cervical and thoracic regions, to avoid missing a foreign body. 2) If a foreign body is suspected but not visible on plain radiographs, consider contrast studies or endoscopy early. 3) Endoscopic retrieval is preferred, but have a surgical plan ready in case of failure or complications. 4) When performing esophagotomy, use a stay suture to stabilize the esophagus and make a longitudinal incision over the foreign body, as the esophagus is thin and friable. 5) Use meticulous two-layer closure with absorbable monofilament suture (e.g., polydioxanone) in a simple interrupted pattern, with the mucosal layer apposed and the muscular layer closed separately. 6) Consider placing an omental or pericardial patch to reinforce the esophageal closure if there is concern for leakage. 7) Postoperative nutritional support via a feeding tube is essential to allow esophageal rest. Pitfalls: 1) Delaying surgery in cases of perforation can lead to fatal mediastinitis. 2) Inadequate debridement of necrotic tissue can result in dehiscence. 3) Using non-absorbable suture or excessive tension can increase the risk of stricture. 4) Failure to recognize and treat concurrent aspiration pneumonia. 5) Overlooking the possibility of a linear foreign body in cats, which may require multiple enterotomies. 6) Not providing adequate analgesia, leading to stress and delayed healing.

Perioperative pharmacological protocols for esophageal foreign body are based on Plumb's Veterinary Drug Handbook. Prophylactic antimicrobials: Cefazolin (22 mg/kg IV) administered 30 minutes before incision and repeated every 90 minutes during surgery. If perforation is present, continue broad-spectrum antibiotics such as ampicillin/sulbactam (20 mg/kg IV q8h) or enrofloxacin (5 mg/kg IV q24h) and metronidazole (10 mg/kg IV q12h) for 7-10 days. Analgesics: Opioids such as hydromorphone (0.05-0.1 mg/kg IV q4-6h) or fentanyl CRI (2-5 mcg/kg/hr) for intraoperative and postoperative pain. NSAIDs such as carprofen (2.2 mg/kg PO q12h) or meloxicam (0.1 mg/kg PO q24h) may be used after 24 hours if no contraindications. Local anesthetic blocks: For cervical esophagotomy, a cervical paravertebral block with bupivacaine (1-2 mg/kg) can provide analgesia. For thoracic esophagotomy, intercostal nerve blocks with bupivacaine (1-2 mg/kg) are useful. Muscle relaxants: Not routinely used, but if needed, diazepam (0.2-0.5 mg/kg IV) may be used. Chondroprotectants: Not applicable. Gastroprotectants: Sucralfate (0.5-1 g PO q8h) and omeprazole (0.7-1 mg/kg PO q24h) may be used to reduce esophageal irritation. Antiemetics: Maropitant (1 mg/kg SC q24h) may be used to prevent vomiting. Nutritional support: If a feeding tube is placed, a balanced liquid diet such as Hill's a/d or Royal Canin Recovery is used. Fluid therapy: Balanced crystalloids (e.g., Lactated Ringer's solution) at maintenance rates (60-100 ml/kg/day) with adjustments for deficits.

Evidence-based literature on esophageal foreign bodies in small animals is limited but includes several key studies. A retrospective study by Rousseau et al. (2007) reported that endoscopic retrieval was successful in 87% of dogs with esophageal foreign bodies, with a complication rate of 10%. Another study by Gianella et al. (2012) found that the most common foreign bodies were bones, and the most common location was the thoracic inlet. Surgical intervention was required in 13% of cases, with a higher complication rate compared to endoscopic retrieval. A study by Bissett et al. (2009) evaluated the use of computed tomography in diagnosing esophageal perforation, showing high sensitivity and specificity. Consensus guidelines from the American College of Veterinary Surgeons (ACVS) recommend prompt endoscopic retrieval as the first-line treatment, with surgical intervention reserved for cases of perforation, failed retrieval, or severe esophageal damage. The use of omental patching to reinforce esophageal closure has been described in experimental studies and case reports, showing reduced leakage rates. Postoperative stricture formation is a common complication, with a reported incidence of 10-30% after surgical repair. Balloon dilation is the treatment of choice for strictures, with success rates of 70-90%. Overall, the literature emphasizes the importance of early diagnosis and intervention to improve outcomes.