Abstract
There are multiple etiologies for facial subcutaneous emphysema, including facial trauma, dissection of air along facial planes from a pneumomediastinum, infection, and entry of air through defects in teeth due to decay, trauma, or dental procedure. In addition, air can be forced through lacerations of the oral or pharyngeal mucosa by increased intraoral pressure. An infrequently reported cause of subcutaneous emphysema is autoinsufflation of the parotid duct with extravasation of air into the surrounding tissue. In this report, the authors present a 14-year-old patient treated at the Department of Oral and Maxillofacial Surgery of the Hospital Escuela Universitario due to an increase in size in the buccal region and left masseterine space of 2 months of evolution. Presenting with a sudden evolution, without any possible explanation, which caused displacement of adjacent structures without damage to the bone or surrounding tissues. After a series of echographic and tomographic studies, it showed that inside the submandibular gland there was a hypodense image with gas density (-1100 UH) expanding the gland and its respective excretory duct.
Pneumosialodenitis is a rare cause of salivary gland enlargement, commonly misdiagnosed and therefore handled incorrectly. It is the result of an increase in intraoral pressure with the consequent insufflation of air inside the duct and the affected salivary gland.
Presenting more frequently in the parotid gland and its Stensen duct, it can be unilateral or bilateral. In general, the patient presents with an asymptomatic volume increase; upon palpation of the affected area, it is possible to hear crackling sounds. Also when stimulating the gland by means of a bimanual palpation, we can observe on the exit of the affected salivary gland frothy saliva. 1
As a cause of this pathology, there are different etiological factors, including bad habits of inflating the cheeks, blowing air toward the hand, playing wind instruments, 2 and cases have even been reported after trauma to the affected salivary gland. 3 In ultrasound and tomographic studies, we can observe accumulations of air inside the duct and salivary gland 1 ; this air can be extravasated from the affected salivary gland and spread to the adjacent subcutaneous tissues with the ability to expand through nearby aponeurotic spaces to become a pneumomediastinum or pneumothorax. 2 Typically, it presents as a self-limiting disease but recurrent contamination can occur due to retrograde movement of intraoral bacteria to the duct and salivary gland 4 (Table 1).
Situations or maneuvers reported to cause pneumosialodenitis
Abbreviation: COPD, chronic obstructive pulmonary disease.
Case Report
A 14-year-old male patient with no pathological medical history was referred to Hospital Escuela Universitario to the Oral and Maxillofacial Surgery Department due to an increase of volume in the left buccal and masseterine space of 2 months of evolution; oral aperture was compromised and made it difficult for the patient due to the increase in volume which was even more noticeable when closing the mouth (Figs. 1 and 2).
Initial frontal photography.
Initial left and right lateral photographies.
The increase in volume was spontaneous with recurrent episodes without any apparent cause. Upon palpation, crepitation sounds were heard in the affected area. When exploring salivary glands by means of bimanual palpation, patient referred mild pain on the left submandibular gland and there was also presence of frothy saliva at the exit of the Wharton's duct.
When performing mandibular opening movements, the increase in volume seems to disappear momentarily. Patient did not report having difficulty while breathing or recent fever.
Laboratory blood tests were within normal ranges. Patient came with a radiographic study, a posteroanterior skull radiography (Fig. 3) in which a radiolucent area at the mandibular level with well-defined edges is observed. Ultrasound and contrast computed tomography of the facial skeleton and thorax were requested.
Posteroanterior skull radiography.
Tomography report stated that inside the submandibular salivary gland, a hypodense image, gas density (-1100 UH) was observed, dilating the gland and also the Wharton's duct, measuring 3.95×4.47×4.68 cm considering emphysematous sialoadenitis (Figs. 4 5 6 7 8 9).
Computed tomography three-dimensional reconstruction anteroposterior view.
Computed tomography three-dimensional reconstruction lateral right view.
Computed tomography coronal view.
Computed tomography axial view.
Computed tomography axial view 2.
Computed tomography sagittal view.
It was decided to give the patient a follow-up and treatment with antibiotics. Procaine Penicillin in doses of 1.2 million U.I. one each 24 hours for 10 days as prophylactic means was administered.
At the end of the antibiotic therapy, a slight decrease in volume was observed. Patient was evaluated every 4 weeks for 2 months after antibiotic therapy was finished. (Figs. 10 and 11).
Control frontal photography after antibiotic therapy.
Lateral left and right control photographies after antibiotic therapy.
During the follow-up, a satisfactory evolution was observed, showing a gradual decrease from the initial volume, just as the literature mentions it to be self-limiting pathology. Subsequently, follow-up was performed every 3 months until full remission of the pathology. Currently, patient is in control every 3 months.
Discussion
When reviewing the literature, it can be recognized that the presence of pneumosialodenitis has a higher incidence in the parotid glands. As possible causes of appearances and recurrences of parotid involvement, there is a weakening of the buccinator muscle that does not prevent the retrograde flow toward the Stensen duct and the presence of an abnormal dilation in the ducts path. 8 It is suspected that at the submandibular level, the possible causes would be a dilatation of the duct as anatomical variation or secondary to a trauma.
Conclusion
Pneumosialodenitis is the insufflation of air inside the duct and the affected salivary gland, presenting more frequently in the parotid glands. 9 Its treatment varies and is based on whether there is an infectious process, if the intraglandular air is extravasated to become subcutaneous emphysema or its high recurrence. These transient events can be treated with prophylactic antibiotics with observation, but recurrent cases must be managed by means of surgical techniques of relocation of the secretory duct or even partial or total removal of the affected gland. 2
Footnotes
None.