The explosion of a drink bottle is a very rare cause of traumatic pharyngoesophageal perforation. Pharyngoesophageal perforation may occur when one removes a bottle cap with their teeth. The rapid pressure increase in the closed oral cavity not only causes laceration of the oral and pharyngoesophageal soft tissues, but also cervical emphysema, pneumothorax, and pneumomediastinum. Pharyngoesophageal perforation by an exploding bottle was first reported by Bowsher et al.1 in 1982. Subsequently, twenty-three cases have been documented in English literature.1-12 This study reports two additional cases of pharyngoesphageal perforation by an exploding bottle, and a review of the literature pertaining to this condition.

Barotrauma in the aerodigestive tract causes mucosal perforation. Once an abnormally high air pressure is introduced into the potential space of the head and neck, it may extend to deeper structures and to the mediastinum. Through the perforation, normal floras in the aerodigestive tract contaminate the deep space of the head and neck, which may result in deep neck infection or mediastinitis.

Etiologic agents of barotrauma have been reported as follows: bicycle inner tube,11 tractor tire,13 fire extinguisher,14 and exploding bottle.1 Pharyngoesophageal injury by bottle explosion can develop when patients remove the cap of a bottle with their teeth. Commercially made soft drinks, wine, or beer are safe unless they have been stored under adverse conditions, but home-produced wine and beer are often manufactured in less than ideal circumstances, with considerable build-up of carbon dioxide.7 To date, 24 cases of barotraumatic pharyngoesophageal perforation by an exploding bottle have been reported in English literature and are summarized in Table 1.1-12 The patients were aged 5 to 75 years and consisted of 17 males and 7 females. Most of the cases (22/24) were less than 15 years old, which suggests that educating children and adolescents is essential for prevention.

The pathogenesis of injuries caused by compressed air has been clearly described: the escaping gas enters the mouth and forcibly distends the pharynx and esophagus, causing them to rupture.13 The hurtled cap and broken bottle are also involved in pharyngoesophageal injuries.

Because of its anatomy, the exceedingly friable esophagus is particularly vulnerable at the proximal and distal ends.15 Support for the last 2 inches of the posterior pharynx is somewhat deficient where transverse and oblique fibers of the inferior constrictor muscle converge. This is similarly true in the upper part of the posterior esophagus, where the longitudinal muscle fibers split and leave the mucosal support largely to the circular muscle fibers.13 The distal part of the esophagus has been shown to have segmental defects in the circular muscle layer where the longitudinal muscles end in a conical fashion.13,16 It seems clear that the esophagus at the distal portion is either weaker or less supported by surrounding mediastinal structures.17

When there is a sudden, rapid rise in air pressure in the mouth, the pressure is transmitted to the laryngopharynx and enters the respiratory passages, causing a reflex closure of the glottis. As the cricopharyngeus gives way under the air pressure, it gives rise to a sudden distention of the esophagus.14 The cardia fails to relax as it does in the slower, coordinated, reflex act of swallowing, and the dilated esophagus ruptures.14 Most of the ruptures reported occurred at the lower end of the esophagus (66.6%).18 It appears that the lower end of the esophagus is more vulnerable to bursting from the introduction of pressurized gas.18 If the pressure is slowly released, it may even bring about closure of the cricopharyngeus, creating a closed space between this muscle and the lips, thus causing perforation of the pharynx.9 The posterior wall is the least supported part of the pharynx and is therefore most vulnerable to perforation. In our review, the pharynx was injured in 18 cases,1-7,9-12 the pharynx and esophagus in 5 cases,4,8,11 and the esophagus in 1 case.8 Of 6 cases with esophageal injury, only one had lower esophageal perforation.4 These findings suggest that the explosive pressure of a drink bottle may be insufficient to perforate the lower esophagus.

Pain during swallowing and bleeding from the pharynx are the most common symptoms of perforation. Respiratory compromise may pose an imminent threat to life. In the reported cases, there were 5 cases necessitating endotracheal intubation or a tracheotomy.2-4,11 Subcutaneous emphysema of the neck may be seen on palpation and reflects perforation of the aerodigestive tract. Pneumomediastinum and pneumothorax may occur. Four cases had peumothorax and underwent chest drainage.3-5,9 Fever and leukocytosis suggest complicated infections or abscess formation. Complications of transmural pharyngeal and esophageal injuries include deep neck abscess, mediastinitis, pleural empyema, lung abscess, peritonitis, and sepsis.19 Rubikas reported that overall postoperative mortality in pharyngeal and esophageal injuries was 19%, and the main causes of death were the dissemination of infections and multiple organ insufficiency.19 In the review article of Brinster et al., cervical esophageal perforations were associated with a mortality of 6% (0-16%), whereas thoracic and abdominal perforations were associated with the mortality of 27% (0-44%), and 21% of patients (0-43%), respectively.20 Mediastinitis is one of the fatal complications and is well-known for its high rate of mortality and morbidty. In barotraumatic pharyngoesophageal injury by an exploding bottle, five cases had mediastinitis and one of these cases died of truncal fasciitis and sepsis, postoperatively.2,5,8,12 The overall rate of deep neck infection or mediastinitis was 25% (6/24); these complications occurred in 22% (4/18) of pharyngeal injuries,2,5,6,12 20% (1/5) of pharyngoesophageal injuries,8 and 100% (1/1) of esophageal injuries.8

A physical examination and flexible endoscopy of the oral cavity and laryngopharynx show a laceration on the involved site. Plain radiographs show cervical subcutaneous emphysema, air in the retropharyngeal space, pneumomediastinum, pneumothorax, pleural effusion, and/or pulmonary infiltrates. Gastrograffin swallow defines the site and extent of the perforation and the CT detects the extent of emphysema, infection, and abscess formation.

These patients require immediate attention to the airway, to provide unobstructed breathing and to check for a pneumothorax. Pharyngoesophageal perforation should be repaired as soon as possible, but patients with a small laceration or delay in diagnosis can be strictly observed. Conservative treatment was given in eight patients (33%, 8/24) with no mortality.2,4,7,10,11 If cervical or mediastinal abscess is present, it should be drained externally. Supportive care includes prophylactic antibiotics, nasogastric feeding, and oxygen. Based on a review of literature, most of the patients have a good prognosis if they are properly managed for airway compromise and complications such as mediastinitis.

Suggested measures to prevent injuries from a bottle explosion include the storage of bottles in a cool place, avoidance of jostling or hitting bottles together, directing the cap away from the body or face when opening, storage of bottles on the floor or lowest shelves to reduce the hazards in case the bottle falls or explodes, and avoidance of shaking carbonated drinks.21 School campaigns should be waged because children are the most susceptible. Conspicuous warning labels should be placed on all carbonated drink bottles, and the use of plastic bottles and caps is helpful in reducing incidence of this injury.