What Is Sialolithiasis?
Sialolithiasis refers to the salivary gland condition characterized by the formation of sialoliths or calculus deposits most commonly occurring in the submandibular salivary glands (almost accounting for up to 90 % of cases). The other frequent location of occurrence is the parotid salivary gland. Less commonly, they are also found in the sublingual salivary gland.
What Causes Sialoliths?
Sialoliths are also colloquially known as salivary stones and are calcified masses due to an obstruction in the gland itself. Pre-existing oral infections, chronic systemic infections or childhood infections (like mumps), Sjogren's syndrome, and chronic oral infections can also be attributed as causative elements of this condition.
What Is the Pathogenesis of Sialolith Formation?
Though research is elusive regarding elevated calcium levels causing sialolith formation, it is hypothesized to be a contributing factor for sialolith formation. Irregularities of the salivary gland's ductal system or local irritants causing increased pressure and consequent obstruction are also other hypothesized factors for sialolith formation.
Recent research also indicates tobacco smoking can be considered a potential risk factor for salivary stone formation as the inflammatory mediators increased by smoking affects the salivary enzyme amylase that may be significantly reduced in production, thus impacting its formation.
The pressure created within the salivary glands leads to the partial or sometimes complete obstruction of the salivary gland ducts resulting in these calcifications. The saliva thus gets trapped within these mineralized concrete structures restricting the free flow of saliva in the oral cavity and predisposing it to be latent or pre-existing infections (bacterial as in Staphylococcus infections, or they would be viral or autoimmune as well in origin).
Further, the issue can be complicated by the pain and swelling that are common clinical symptoms in the patient as a result of glandular obstruction. The inflammation of the glands is clinically termed sialadenitis, which would again depend on the pathophysiology. It would be an acute manifestation of chronic nature. In chronic inflammation, the pain and swelling are more recurrent rather than pain alone when compared to acute cases. This is seen more during meal times and hence referred to as the mealtime syndrome. The maximum salivary stimulation of an individual occurs during or before the food timings that can be brought by thought, smell, or taste.
What Does Physical Examination and Medical History Reveal?
-
Patients with sialolithiasis often have a history of unilateral or one-sided salivary gland swelling.
-
Patients presenting with a previous history of sialadenitis or salivary gland inflammation can also be at increased risk of developing sialoliths as well.
-
The patients may present most commonly with an asymmetric swelling of the submandibular salivary gland, more commonly or the parotid gland, and upon dental or oral examination by the dental surgeon, these stones are evidently found to be of a round or oval-shaped structure, which is usually palpable.
-
The diameter of these stones may range anywhere from 2 mm to 10 mm approximately (varying from small to large dimensions).
-
The weight of the stone may approximately range depending on their size in between 1 mg to 5 g.
-
The color of the stones may be either white or yellowish and are easily recognizable by the dental or the oral and maxillofacial surgeon. If they cannot be visually demarcated in the oral cavity at the level of the salivary gland, they can be palpated.
-
Patients' main clinical features of this condition are acute onset pain and swelling, which usually aggravates or worsens during or before mealtimes.
How Are Sialoliths Diagnosed?
-
The gold standard diagnostic technique to confirm the presence of sialoliths in the oral cavity is sialography. The ductal course of the gland can be clearly visualized by contrast radiography which is by injecting a contrast agent in this technique. However, this technique may not be indicated, especially in pregnancy or in certain immunosuppressive individuals, due to the risk of radiation exposure and reactions induced by the contrast agent.
-
NCCT (non-contrast computed tomography) is another evaluative diagnostic tool that similarly uses a contrast agent but is faster to perform (lesser acquisition time) and has increased specificity for identifying the obstructed masses.
-
Sialendoscopy is a mainstream diagnostic tool still widely preferred by many surgeons to correctly detect sialoliths for therapeutic purposes. Compared to surgical techniques for accessing the sialolith, sialendoscopy is a procedure deemed to be a reliable and safe alternative both for diagnosis and surgical resection or removal. This technique performed under local anesthesia generally uses an endoscope directly accessing the ductal system and can be used effectively against salivary gland obstruction disorders.
-
The physician may sometimes consider ultrasonography a less invasive technique than the procedures mentioned above or criterion, wherein the sialoliths are identified as hyperechoic images with shadowing. Ultrasound imaging also offers increased specificity and sensitivity compared to NCCT and sialendoscopy.
How Is Sialolithiasis Treated?
-
The physician or dental surgeon or oral and maxillofacial surgeon may recommend the treatment of smaller-sized salivary stones or sialoliths primarily with NSAIDs (nonsteroidal anti-inflammatory drugs) and sialogogues.
-
The salivary gland is also massaged suitably to promote its flow and relieve any minor obstructions.
-
However, if an underlying infection or the sialoliths causes a subsequent infection presenting with clinical features like virulent or foul-smelling discharge from the oral cavity, redness or erythema, or cervical lymph node swelling (cervical lymphadenopathy), then antibiotic therapy can also be indicated by the dentist simultaneously.
-
Sialendoscopy is the most preferred technique generally. However, for sialoliths that are not easily palpable and are too small to be endoscopically visualized, a technique called ESWL (extracorporeal shock wave lithotripsy) can be used.
-
The dental or maxillofacial surgeon would recommend the removal or surgical resection of the affected salivary gland only as a final option in severe or chronic cases of large sialoliths.
What Is the Prognosis of Sialoliths?
Timely treatment always yields a good prognosis in this condition, and minimally invasive treatment is always preferred over traditional surgery techniques or resection unless absolutely indicated or necessary.
Conclusion:
Sialolithiasis is a non-malignant condition characterized by the creation of stones within the ducts of the major salivary glands, which include the parotid, submandibular, and sublingual glands. It is a must to educate patients about typical early signs such as swelling of the glands and discomfort during meals, which may indicate the development of a new sialolith. Interprofessional planning involving collaborative communication among healthcare providers ensures patients receive suitable initial treatment, leading to a more rapid alleviation of symptoms. Sialoliths, if intervened at the early stages, have an excellent prognosis, and for larger sialoliths, timely surgical intervention by the surgeon can always offer a long-term and symptomatic clinical relief to the patient.
