【临床病史】：患者，15岁，出现头痛和急剧恶化的精神状态。15-year-old with headaches and acutely worsening altered mental status.
Figure 1: Noncontrast head CT in brain window demonstrates no other abnormality.
Figure 2: Noncontrast head CT demonstrates small foci of gas within the right parotid gland. The parotid gland is otherwise normal without any definite inflammatory changes.
【诊断要点】：Pneumoparotid can be an incidental finding or associated with acute or chronic unilateral or bilateral parotid gland swelling 腮腺积气可以是偶然发现或伴有急性或慢性的单侧或双侧腮腺肿胀。
Pneumoparotid is caused by increased intraoral pressure and reflux of air into the parotid gland via Stensen's duct and multiple mechanisms have been reported.腮腺肿胀是由于口腔内压力增高导致空气通过腮腺导管倒流至腮腺内，有多种发病机制被报道；
Symptoms usually resolve in a few days. Most authors suggest treatment with prophylactic antiobiotics. Surgical intervention is reserved for chronic, recurrent cases. 症状通常在数天后消退，大多数的作者建议预防性的使用抗生素。外科手术被用于慢性和复发性病例。
【讨论】：Pneumoparotid (also called pneumoparotitis and pneumoparotidis) refers to air within the parotid gland without any demonstrable inflammation or infection. This is caused by reflux of intra-oral air into the parotid gland through Stenson's duct. It is associated with any process that significantly increases intra-oral pressure. Intra-oral pressure must increase enough to overcome the small, slit like orifice of Stensen's duct with surrounding redundant mucosal folds that normally prevent reflux of salvia and air into the duct and the parotid gland.
Iatrogenic causes, underlying medical conditions, occupational hazards and self-induced mechanisms have been reported. Iatrogenic causes include: dental instrumentation, general anesthesia with endotracheal intubation, spirometry. Pneumoparotid has been descibed with conditions associated with chronic cough including COPD, cystic fibrosis and allergic rhinitis. Additionally, wind instrument players, SCUBA divers and glass blowers can develop this condition. Finally, pneumoparotid has been reported to be self-induced to simulate mumps to avoid school or military duty and in children who obsessively puff their cheeks in response to psychological stress.
If intra-oral pressure increases adequately, often in the setting of chronic or recurrent cases, rupture of air through parotid acini and dissection into surrounding soft tissues including the retropharyngeal space, facial and neck soft tissues as well as pneumomediastinum can occur.
Pneumoparotid can be an incidental finding as in the current case or associated with unilateral or bilateral parotid swelling. The swelling is generally painless, however occasionally can be tender with associated mild warmth and erythema. Crepitus and air bubbles at Stensen's duct with palpation may be observed at physical examination. Symptoms usually resolve spontaneously in a few days. Occasionally this process can be recurrent and lead to superimposed infection and/or inflammation secondary to reflux of oral bacteria and some authors recommend treatment with prophylactic antibiotics. Treatment also involves avoidance of further increases in intra-oral pressure. Surgery is indicated only in chronic and recurrent cases.
腮腺积气可以是偶然发现，就像本例一样，或者伴有单侧或双侧的腮腺肿胀，这种肿胀通常是无痛性的，然而偶尔也可以是有触痛伴有轻微的发热和红斑。体格检查时可以触及捻发音和腮腺导管内气泡。症状通常在数天后自行消退。偶尔病程可以反复并且导致重复感染和/或继发于口腔细菌返流所致的感染，因此一些作者认为需要预防性的使用抗生素。治疗也要包括防止口腔内压力的进一步增高。外科手术仅用于慢性和复发性病例。(参考来源:,医影志ACR, February, 2010,作者:freemanpyw编译)