giovedì 12 novembre 2009
The left submandibular gland is hypervascular, inflamed and markedly enlarged (Figure 1 and Figure 2). There is dilatation of the submandibular duct leading to a calculus within the distal aspect of the duct (Figure 3 and Figure 4). There are no drainable fluid collections. There is injection and stranding of the overlying dermis (Figure 5). The right submandibular gland is unremarkable (Figure 2).
Diagnosis: Submandibular sialadenitis
Acute sialadenitis may be secondary to a bacterial/viral infection or an obstructing lesion such as a calculus or tumor at the floor of the mouth.
Associated conditions include HIV, sarcoidosis, Sjogren syndrome, dehydration, diabetes mellitus and immunocompromised/postoperative patients.
Imaging is often helpful to delineate the location of the calculus and the presence/absence of subsequent complications (abscess formation, osteomyelitis, etc).
Inflammation of the submandibular gland accounts for approximately 10-15% of cases of sialadenitis involving any of the major salivary glands. Risk factors for submandibular sialadenitis include immunocompromised/postoperative patients, debilitation, elderly patients, dehydration, diabetes mellitus, hypothyroidism, hypercalcemia, radiation/chemotherapy, eating disorders (bulimia, anorexia nervosa), and other concomitant medical problems (malignancy, head and neck infections). Associated conditions also include HIV, sarcoidosis, Sjogren syndrome, tuberculosis, mumps, and cat scratch disease. It is rare in pediatric patients.
Most commonly, acute sialadenitis is a result of a bacterial infection (common organisms include Staphylococcus aureus, Streptococcus, Haemophilus influenzae, and Pseudomonas). Less commonly, the infection may be related to a virus such as mumps, coxsackie virus, herpes and influenza. On the other hand, chronic sialadenitis is usually a result of salivary stasis, ductal stenosis, calculi or other obstructive lesions such as a tumor at the floor of the mouth. Sialolithiasis is most common in the submandibular gland, accounting for approximately 80% of cases. The majority of calculi are radio-opaque, vary in size, and can be single or multiple. Often, the calculus obstructs a duct, resulting in secondary inflammation of the affected salivary gland which then becomes suppurative.
Although plain film radiography can depict the majority of calculi, CT is often first-line imaging. The affected submandibular gland is enlarged, hypervascular and there may be associated cellulitis/myositis. Calculi are easily identified and described as being either distal (towards the ductal opening) or proximal (towards the submandibular hilum). Chronic sialdenitis manifests as a small, fatty gland.
Complications of sialadenitis include abscess formation, bacteremia/septicemia, osteomyelitis, cranial nerve involvement (facial nerve paralysis), and respiratory complications. Management of acute sialadenitis includes both medical (conservative) and surgical options. Antibiotics, analgesics, sialogogues, warm compresses, glandular massage and intravenous fluids are the mainstay of medical management. Surgical options include duct cannulation with subsequent removal of the calculus and complete gland excision.