Submandibular Sialadenitis with Abscess

Coronal and sagittal CT images show an enlarged left submandibular gland with two well-defined rim enhancing fluid collections in the anterior aspect of the gland, representing abscesses. There is adjacent subcutaneous fat stranding.

Sialadenitis

• Most common salivary gland abnormality is infection, either bacterial or viral
• Bacterial infection ascends from oral cavity. Most common pathogens are S. aureus, S. viridans, H. influenza
• Most common viral infection is mump
• Most common site = parotid > submandibular gland
• Predisposing factors are dehydration, radiation, immunosuppression
• Other causes of sialadenitis include inflammation (sialolithiasis, radiation), autoimmune (Sjogren, lupus), granulomatous (TB), drug, etc.

Sialadenitis vs Abscess

• Sialadenitis is treated with antibiotics, while abscess usually needs surgery
• Abscess may spread to deep neck spaces and progress to Ludwig angina
• CT can differentiate the two entities. Abscess is seen as localized low attenuation, walled-off region in contrast to dense, enhanced gland
• CT can show calcified sialolithiasis, and in some cases noncalcified sialolithiasis as a cause of duct obstruction

References:

1. Yoskovitch A. Submandibular sialadenitis/sialadenosis. emedicine Jul 23, 2008.

2. Silvers AR, Som PM. Salivary glands. Radiol Clin North Am 1998;36:941-966.