Laboratory Studies
See the list below:
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Chemical analysis of saliva
Anti-SS-A, anti-SS-B, and rheumatoid factor may be present in autoimmune diseases. Saliva may be cultured, which is helpful, and it may be analyzed chemically, which is rarely helpful.
Most laboratories cannot perform useful tests on saliva. Dental researchers had hopes for several decades that analysis of saliva would be of diagnostic importance. Saliva has such wide variations in composition that analysis has produced little of diagnostic value.
Imaging Studies
CT scanning and MRI with gadolinium enhancement
These studies may be used to determine the size, shape, and some qualities of neoplasms or swelling within the gland. Either method reliably differentiates between solid masses, cystic lesions, and diffuse involvement of the gland.
Sialography
Sialography is used to demonstrate the anatomy of the drainage system and is a very useful test. Injury to the ducts or acini is demonstrated with this study. Many radiologists no longer perform the test, which is unfortunate. Most dentists can perform sialography in the office. The otolaryngologist can cannulate the duct and inject the dye in the radiology suite. A scout radiograph should be made to rule out radiopaque stones or calcification within the gland.
A special cannula or #90 polyethylene tubing is inserted into the duct, and iodinated oil such as Ultravist (iopromide) oily Dionosil is injected into the ductal system.
The normal ducts can accommodate 0.50-0.75 mL without discomfort. The authors inject until the patient reports discomfort and then posteroanterior and lateral radiographs are obtained. The study is repeated 5 minutes later. Usually, all of the contrast media has been evacuated.
The normal ductal system looks like a deciduous tree in winter. In sialectasis, the radiographs may have the appearance of a tree with scattered leaves (as seen in the image below). The ductal system may be dilated and demonstrate numerous small strictures giving the appearance of "sausaging."
Sialogram of patient with sialectasis. Notice the appearance of a tree with leaves.
Scintigraphy
A study by Wu et al indicated that technetium-99m (99mTc) pertechnetate salivary gland scintigraphy can play an important part in the diagnosis of chronic obstructive parotitis and other salivary gland disorders. The study, which involved 25 patients with chronic obstructive parotitis, 12 patients with sialolithiasis, and 10 patients with Sjögren syndrome, found reduced excretion but near-normal uptake of 99mTc-pertechnetate in parotitis-affected glands, while in sialolithiasis, excretion was reduced, and in five sialolithiasis patients, uptake was decreased as well, with excretion and uptake also being reduced in Sjögren syndrome. [23]
Ultrasonography
Ultrasonography is much easier to perform than sialography and seems to be replacing sialography in many institutions. It demonstrates solid masses or fluid collections within the gland. It also can detect hypoechoic areas that correspond to punctate sialectasis by sialography. It is not as sensitive as sialography, but this is probably not clinically significant.
Procedures
Interventional sialendoscopy
This technique is growing in popularity and availability and seems to be the best method of treatment. [24] The duct is anesthetized and dilated to insert a telescope for inspection of the large ducts. A working channel in the telescope permits irrigation, suction, and insertion of forceps, wire loop, or even laser energy via a glass fiber to remove the calculi. The clinician has much more information as to the condition of the duct system. This instrument is useful for the assessment and treatment of several inflammatory disorders of the gland.
Advances in the management of chronic sialoadenitis include endoscopic-assisted approaches. Initially, salivary endoscopy is performed to identify any stones. If none is located, ultrasonography or CT imaging is recommended. The endoscopic-assisted management technique is a safe and often effective means of evaluating the anatomy, administering various irrigations (eg, saline, antibiotics, steroids), performing sialodochoplasty, removing stones, and placing stents. In Europe, this technique is mainly performed with the patient under local anesthesia, but in the United States, general anesthesia is preferred since more aggressive procedures can be readily performed at a single setting with the patient under anesthesia if the endoscopic approach is not successful. Studies suggest a high rate of symptom control, and future studies are underway to further address a possibly larger role for this technique. [25, 26, 27, 28]
A retrospective study by Mikolajczak et al indicated that chronic recurrent juvenile parotitis can be safely and effectively treated with a combination of sialendoscopy and intraductal corticosteroid application. The study involved nine children with recurrent parotitis (10 affected parotid glands total) who underwent the treatment, with no sialendoscopy-associated side effects occurring. After an average follow-up period of 15 months, the investigators found that eight of the children were symptom free. Although the ninth patient still had slight parotid gland swelling at follow-up, antibiotic therapy was not required. [29]
However, a 12-patient retrospective study by Roby et al indicated that ductal corticosteroid infusion alone produces a similar outcome to the sialendoscopy/intraductal corticosteroid combination in the treatment of juvenile recurrent parotitis. [30]
A prospective study by Jokela et al indicated that sialendoscopy can also reduce symptoms in adults with chronic recurrent parotitis. The study, which included 49 adult patients with the condition but without sialolithiasis, found a significantly reduced visual analogue scale score and decreased symptom frequency at 3-, 6-, and 12-month follow-up. However, the incidence of complete, permanent symptom resolution was small. [31]
Incisional biopsy
Under local anesthesia, a biopsy of the tail of the gland may be obtained by an experienced surgeon without injury to the facial nerve. Fine-needle aspiration biopsy frequently is diagnostic for tumors and may be helpful to identify cell types and to obtain material for cultures when the clinical picture suggests infection. Excisional biopsy of a labial minor salivary gland may be diagnostic when the clinical picture suggests Sjögren syndrome.
Histologic Findings
Excision of parotid tissue is infrequently used for diagnosis. When removed for acute infection, acute necrosis of the glandular elements is observed. Autoimmune parotitis occasionally progresses to lymphoma, and biopsy is performed when suspected. Invasion by lymphocytes and destruction of the glandular elements are observed.
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Elderly man with parotid abscess.
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Six-year-old girl with recurrent parotitis of childhood.
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Sialogram of patient with sialectasis. Notice the appearance of a tree with leaves.
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Incision outlined for incision and drainage of parotid abscess.
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Parotid gland anatomy.
