| Highlights |
- A diverse set of etiologies can lead to isolated or diffuse salivary gland disease and make it a common medical consultation. - Lack of intervention for salivary discomfort can lead to increased dental caries, bacteremia, and eventually systemic disease. - The diagnosis is made through clinical history, physical examination and imaging or sialendoscopy. Patients should be referred to an otolaryngologist if a salivary gland-related problem is suspected that has been refractory to conservative treatment. - Historically, therapy involved surgical removal of the gland, an operation that inherently compromised function and carried the risk of complications, such as nerve injury and sialocele. - Current treatment models have shifted toward preservation techniques, specifically through the use of sialendoscopy (salivary endoscopy) and botulinum toxin injection. |
| Introduction, history, definitions and background |
The major salivary glands include the parotid, submandibular, and sublingual glands. There are also minor salivary glands scattered in the oral cavity.
Salivary pathology should be included in the differential diagnosis when a patient presents with periprandial pain or discomfort that is located in the head and neck (classic obstructive symptoms) or alterations in secretion that include too much or too little saliva production (salorrhea and xerostomia respectively). ).
Evaluation begins with a complete history and physical examination and may require additional imaging. Treatment options, depending on the cause, include medical management; gland resection; and, more recently, minimally invasive methods such as endoscopy and botulinum toxin A (Botox) injection.
This update covers an overview of salivary gland pathologies, with emphasis on recent therapeutic advances that have allowed otolaryngologists to relieve symptoms while preserving gland function.
| The role of salivary diseases in a person’s total health |
Salivary disease often initially presents with symptoms that are bothersome, but not debilitating. However, it is important to consider the possible downstream outcomes and greater impact on the overall health of a patient with untreated salivary disease. Chronic oral inflammation and discomfort can lead to tooth decay and poor nutrition as a result of decreased or altered saliva.
| Nature of the problem |
One of the broadest categories of salivary disease is sialadenitis , and it is useful to think of it as either obstructive or inflammatory.
Obstructive pathology is most frequently caused by the presence of sialoliths, or stones in the salivary glands, by the presence of a scar or by stenosis of the salivary duct system. These obstructive etiologies frequently present as periprandial discomfort; however, they can also be painless.
Inflammatory causes of sialadenitis often cause bilateral and multiglandular disease, making its presentation unique from obstructive processes. These causes may be part of a larger systemic metabolic or autoimmune process, as in Sjögren’s syndrome, or be isolated to the salivary glands, as in juvenile relapsing parotitis.
Other salivary conditions include sialadenosis . Like inflammatory sialadenitis, sialadenosis is associated with systemic conditions leading to bilateral disease. The swelling and glandular hypertrophy characteristic of sialadenosis are linked to disorders that affect the body’s metabolism, such as anorexia, bulimia, alcoholism, and cirrhosis. It usually presents with markedly enlarged parotid glands. It is occasionally painful but does not change the quantity or quality of saliva.
| Observation, assessment and evaluation |
For patients presenting with salivary complaints, it is important to obtain a systemic history. It is important to consider the timing of symptoms in relation to mealtime. Patients with an obstructive cause often present with recurrent periprandial pain, bloating, or discomfort. Patients with an inflammatory cause are more likely to have bilateral disease, with swollen glands or complaints of dry mouth.
It is essential to review past medical history with emphasis on any autoimmune or inflammatory conditions, or any prior radiation exposure. Tobacco use, caffeine consumption, diabetes, gout, and chronic dehydration can also increase a patient’s risk of developing obstructive or inflammatory sialadenitis.
The physical examination should include an otolaryngologic evaluation of the head and neck. After a complete history and management of salivary discomfort, hydration, sialagogues, warm compresses, and massages are initiated. If there are signs of infection, the use of antibiotics may be necessary. For patients in whom conservative treatment fails, additional workup is indicated.
| Images |
If there is concern for a mass or tumor, an MRI is best to characterize these lesions. Otherwise, CT is the preferred scan to visualize calcifications, bone erosion, or inflammatory processes, including abscesses. Ultrasound is adequate to detect masses, lymphadenopathy, stones, obstruction or dilation, but may be insufficient to evaluate processes that affect deeper portions of the gland.
| Conservative treatment options for salivary symptoms |
> Sialendoscopy
This procedure is diagnostic and therapeutic in some cases. Sialendoscopy allows the doctor to directly visualize the gland and intervene endoscopically to remove small sialoliths (salivary stones), dilate areas of stricture or inject therapeutic medications, such as steroids or Botox.
In the appropriate clinical scenario, sialendoscopy can be performed in the office under local anesthesia. For patients with more complex diseases or who cannot tolerate the procedure in the clinic, the intervention is carried out in the operating room under general anesthesia.
Lithotripsy traditionally describes extracorporeal shock waves to fragment a stone, but novel techniques use a hybrid approach with sialendoscopy-targeted intraductal lasers or pneumatic devices to fragment the material and then retrieve pieces using endoscopic tools.
Stenosis is the second most common obstructive cause. Sialendoscopy has made it possible to differentiate inflammatory stenosis from fibrotic stenosis through direct visualization of the tissue, thus guiding treatment.
Inflammatory stricture is treated with steroids and cortisone irrigations, often guided by sialendoscopy. Fibrotic stenosis involves scar tissue in the ductal system and, although it can be resolved with cortisone injections, it often requires instrumentation to release the obstruction. When stenosis is not treated promptly, it can cause irreversible damage to the gland.
> Botox
It has become an effective treatment for a variety of salivary complaints and, like sialendoscopy, has provided patients with an alternative treatment that is less invasive and more functional than traditional surgical approaches.
It works by temporarily blocking the release of acetylcholine, thus inhibiting neural signal conduction. The average duration of the effect is 3 months.
Sialadenosis describes hypertrophy of the salivary acinar tissue and the resulting typically painless swelling of the salivary glands. If it is painful, it is believed to be caused by obstruction and stasis. Botox injection with or without additional salivary endoscopy, irrigation, and dilation can control these symptoms.
Botox injection has been found to improve sialoceles. A sialocele is defined as a cavity containing saliva, resulting from trauma to the salivary duct network that disrupts its normal outflow and allows it to accumulate. This is caused by penetrating trauma or iatrogenically by parotid or submandibular gland surgery. By injecting botulinum toxin into these sacs and adjacent salivary tissue, saliva production is reduced, allowing the abnormal collecting ducts to close.
Botox has also proven effective in treating drooling, a condition that results from a lack of muscle coordination that leads to oral secretions pooling in the mouth. It is important to differentiate drooling from sialorrhea, the condition in which the actual quantity and quality of saliva is altered. Drooling is often seen in patients with neurological impairment, where their swallowing is uncoordinated.
| Complications of treatment |
Historically, surgical intervention was the standard for medically refractory sialadenitis and carried the risk of salivary fistulas, hypertrophic scarring, infection, hematoma, sialocele, and skin paresthesia. Additionally, parotid gland surgery carries the risk of facial paresis, whether temporary or permanent.
Removal of the submandibular gland risks injury to the marginal mandibular, hypoglossal, or lingual nerves. With salivary endoscopy, the greatest risk is salivary duct perforation, which resolves within 2 weeks. Botox is generally considered low risk when used within appropriate dosing guidelines, and adverse outcomes are rare and temporary, including transient mild dysphagia.
