CASE 16585 Published on 28.11.2019

Pneumoparotid

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Dr. Shanmuga Jayanthan S

Consultant Radiologist, Department of Radiology and Imaging Sciences, Meenakshi Hospital.

Patient

11 years, male

Categories
Area of Interest Salivary glands ; Imaging Technique CT
Clinical History

An 11-year old boy presented with recurrent painless bilateral cheek swelling for 8 months. Despite multiple courses of antibiotics, the swelling continued to re-occur. On examination, enlargement of right parotid gland noted. In addition, he had crepitus over the right parotid region. His blood counts were within normal limits.

Imaging Findings

Ultrasound imaging of right parotid gland showed linear hyper echoic areas with posterior shadowing. Computed tomography (CT) showed enlargement of the right parotid gland with multiple intraglandular air pockets without signs of inflammation (Fig. 1). Air pockets were also seen in the Stensen’s duct, up to the level of buccinator muscle (Fig. 2). The left parotid, bilateral submandibular and sublingual glands were normal. No evidence of sialolithiasis noted in any of the salavary glands.

Discussion

Pneumoparotid is associated with retrograde airflow into the Stenson’s duct, secondary to increase in intraoral pressure. In normal instances, the mucosal flap covering the orifice of the duct and the compression effect of buccinator muscle during contraction prevent such an entry [1]. Pneumoparotid is thus seen in conditions with supra-normal increase in intraoral pressures, in association with dental instrumentation, positive pressure ventilation during anaesthesia or wind instruments [1,2]. Psychological disorders like nervous tics and adolescent adjustment disorder are also found to be associated in some cases [3]. Imaging for buccal malignancy with puff cheek technique in CT can also lead to this normal phenomenon.

Absence of pain and signs of inflammation differentiate this condition from more common suppurative parotitis [4,5]. Occassionally, air can rupture through the parotid acini and extend into parapharygeal space, resulting in subcutaneous emphysema. This can even progress to involve the retropharyngeal space and life-threatening complications like pneumothorax and pneumomediastinum [2]. Although ultrasound is the initial imaging modality of choice in cheek swelling, CT is confirmative in finding the air pockets within the parotid gland and in its duct. Absence of inflammation and sialolith further strengthen the diagnosis [5]. Treatment is mainly conservative and includes warm compression, although some prefer to add antibiotics to prevent progression to suppurative parotitis [5]. Psychological counselling can be helpful in appropriate cases.

Written informed patient consent for publication has been obtained.

Differential Diagnosis List
Pneumoparotid
Acute suppurative parotitis
Parotitis with abscess
Final Diagnosis
Pneumoparotid
Case information
URL: https://www.eurorad.org/case/16585
ISSN: 1563-4086

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