{{Infobox medical condition (new) | name = Sialolithiasis | image = Sialolithiasis.jpg | caption = Calculi (salivary gland stones) removed from the sublingual gland | pronounce = | field = | synonyms = | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }}
'''Sialolithiasis''' (also termed '''salivary calculi''',<ref name="Neville 2001">{{cite book|vauthors=Neville BW, Damm DD, Allen CA, Bouquot JE |title=Oral & maxillofacial pathology|year=2002|publisher=W.B. Saunders|location=Philadelphia|isbn=0721690033|pages=393–395|edition=2nd}}</ref> or '''salivary stones''')<ref name="Neville 2001" /> is a crystallopathy where a calcified mass or ''sialolith'' forms within a salivary gland, usually in the duct of the submandibular gland (also termed "Wharton's duct"). Less commonly the parotid gland or rarely the sublingual gland or a minor salivary gland may develop salivary stones.
The usual symptoms are pain and swelling of the affected salivary gland, both of which get worse when salivary flow is stimulated, e.g. with the sight, thought, smell or taste of food, or with hunger or chewing. This is often termed "mealtime syndrome."<ref name="Capaccio 2007">{{cite journal|last=Capaccio|first=P|author2=Torretta, S |author3=Ottavian, F |author4=Sambataro, G |author5= Pignataro, L |title=Modern management of obstructive salivary diseases.|journal=Acta Otorhinolaryngologica Italica|date=August 2007|volume=27|issue=4|pages=161–72|pmid=17957846|pmc=2640028}}</ref> Inflammation or infection of the gland may develop as a result. Sialolithiasis may also develop because of the presence of existing chronic infection of the glands, dehydration (e.g. use of phenothiazines), Sjögren's syndrome and/or increased local levels of calcium, but in many instances the cause is idiopathic (unknown).
The condition is usually managed by removing the stone, and several different techniques are available. Rarely, removal of the submandibular gland may become necessary in cases of recurrent stone formation. Sialolithiasis is common, accounting for about 50% of all disease occurring in the major salivary glands and causing symptoms in about 0.45% of the general population. Persons aged 30–60 and males are more likely to develop sialolithiasis.<ref name="Capaccio 2007" />
==Classification== The term is derived from the Greek words ''sialon'' (σίαλον, saliva) and ''lithos'' (stone), and the Greek ''-iasis'' meaning "process" or "morbid condition". A ''calculus'' (plural ''calculi'') is a hard, stone-like concretion that forms within an organ or duct inside the body. They are usually made from mineral salts, and other types of calculi include tonsiloliths (tonsil stones) and renal calculi (kidney stones). ''Sialolithiasis'' refers to the formation of calculi within a salivary gland. If a calculus forms in the duct that drains the saliva from a salivary gland into the mouth, then saliva will be trapped in the gland. This may cause painful swelling and inflammation of the gland. Inflammation of a salivary gland is termed ''sialadenitis''. Inflammation associated with blockage of the duct is sometimes termed "obstructive sialadenitis". Because saliva is stimulated to flow more with the thought, sight or smell of food, or with chewing, pain and swelling will often get suddenly worse just before and during a meal ("peri-prandial"), and then slowly decrease after eating, this is termed ''meal time syndrome''. However, calculi are not the only reasons that a salivary gland may become blocked and give rise to the meal time syndrome. Obstructive salivary gland disease, or obstructive sialadenitis, may also occur due to fibromucinous plugs, duct stenosis, foreign bodies, anatomic variations, or malformations of the duct system leading to a mechanical obstruction associated with stasis of saliva in the duct.<ref name="Capaccio 2007" />
Salivary stones may be divided according to which gland they form in. About 85% of stones occur in the submandibular gland,<ref name="Hupp 2008">{{cite book|vauthors=Hupp JR, Ellis E, Tucker MR |title=Contemporary oral and maxillofacial surgery|year=2008|publisher=Mosby Elsevier|location=St. Louis, Mo.|isbn=9780323049030|pages=398, 407–409|edition=5th}}</ref> and 5–10% occur in the parotid gland.<ref name="Capaccio 2007" /> In about 0–5% of cases, the sublingual gland or a minor salivary gland is affected.<ref name="Capaccio 2007" /> When minor glands are rarely involved, caliculi are more likely in the minor glands of the buccal mucosa and the maxillary labial mucosa.<ref name="Rice 1984">{{cite journal|last=Rice|first=DH|title=Advances in diagnosis and management of salivary gland diseases.|journal=The Western Journal of Medicine|date=February 1984|volume=140|issue=2|pages=238–49|pmid=6328773|pmc=1021605}}</ref> Submandibular stones are further classified as anterior or posterior in relation to an imaginary transverse line drawn between the mandibular first molar teeth. Stones may be radiopaque, i.e. they will show up on conventional radiographs, or radiolucent, where they not be visible on radiographs (although some of their effects on the gland may still be visible). They may also symptomatic or asymptomatic, according to whether they cause any problems or not.
==Signs and symptoms== thumb|Swelling of the submandibular gland as seen from the outside thumb|The stone seen in the submandibular duct on the person's right side
Signs and symptoms are variable and depend largely upon whether the obstruction of the duct is complete or partial, and how much resultant pressure is created within the gland.<ref name="Neville 2001" /> The development of infection in the gland also influences the signs and symptoms.
* Pain, which is intermittent, and may suddenly get worse before mealtimes, and then slowly get better (partial obstruction).<ref name="Hupp 2008" /> * Swelling of the gland, also usually intermittent, often suddenly appearing or increasing before mealtimes, and then slowly going down (partial obstruction).<ref name="Hupp 2008" /> * Tenderness of the involved gland.<ref name="Hupp 2008" /> * Palpable hard lump, if the stone is located near the end of the duct.<ref name="Neville 2001" /><ref name="Hupp 2008" /> If the stone is near the submandibular duct orifice, the lump may be felt under the tongue. * Lack of saliva coming from the duct (total obstruction).<ref name="Hupp 2008" /> * Erythema (redness) of the floor of the mouth (infection).<ref name="Hupp 2008" /> * Pus discharging from the duct (infection).<ref name="Hupp 2008" /> * Cervical lymphadenitis (infection).<ref name="Hupp 2008" /> * In advanced cases, a fistula may form to the skin of the neck or cheek.<ref>{{cite journal | author = Salilkumar K, Gopakumar KP, Divya GM, Sindhu BS | date = Jul 2006 | title = An unusual sequel of submandibular gland calculus – A case report | journal = Indian Journal of Otolaryngology and Head & Neck Surgery | volume = 58 | issue = 3| pages = 303–4 | doi = 10.1007/BF03050851 | pmid = 23120324 | pmc = 3450422 }}</ref> See adjacent image demonstrating cutaneous fistulization. * Bad breath.<ref name="Hupp 2008" />
thumb|Chronic submandibular sialadenitis with skin fistula formation on the neck thumb|Acute parotid sialadenitis with skin fistula formation on the cheek
Rarely, when stones form in the minor salivary glands, there is usually only slight local swelling in the form of a small nodule and tenderness.<ref name="Neville 2001" />
==Causes== thumbnail|left|The major salivary glands (paired on each side). 1. Parotid gland, 2. Submandibular gland, 3. Sublingual gland. There are thought to be a series of stages that lead to the formation of a calculus (''lithogenesis''). Initially, factors such as abnormalities in calcium metabolism,<ref name="Hupp 2008" /> dehydration,<ref name="Capaccio 2007" /> reduced salivary flow rate,<ref name="Capaccio 2007" /> altered acidity (pH) of saliva caused by oropharyngeal infections,<ref name="Capaccio 2007" /> and altered solubility of crystalloids,<ref name="Capaccio 2007" /> leading to precipitation of mineral salts, are involved. Other sources state that no systemic abnormality of calcium or phosphate metabolism is responsible.<ref name="Neville 2001" />
The next stage involves the formation of a nidus which is successively layered with organic and inorganic material, eventually forming a calcified mass.<ref name="Capaccio 2007" /><ref name="Hupp 2008" /> In about 15-20% of cases the sialolith will not be sufficiently calcified to appear radiopaque on a radiograph,<ref name="Hupp 2008" /> and will therefore be difficult to detect.
Other sources suggest a retrograde theory of lithogenesis, where food debris, bacteria or foreign bodies from the mouth enter the ducts of a salivary gland and are trapped by abnormalities in the sphincter mechanism of the duct opening (the papilla), which are reported in 90% of cases. Fragments of bacteria from salivary calculi were reported to be Streptococci species which are part of the normal oral microbiota and are present in dental plaque.<ref name="Capaccio 2007" />
Stone formation occurs most commonly in the submandibular gland for several reasons. The concentration of calcium in saliva produced by the submandibular gland is twice that of the saliva produced by the parotid gland.<ref name="Hupp 2008" /> The submandibular gland saliva is also relatively alkaline and mucous. The submandibular duct (Wharton's duct) is long, meaning that saliva secretions must travel further before being discharged into the mouth.<ref name="Hupp 2008" /> The duct possesses two bends, the first at the posterior border of the mylohyoid muscle and the second near the duct orifice.<ref name="Hupp 2008" /> The flow of saliva from the submandibular gland is often against gravity due to variations in the location of the duct orifice.<ref name="Hupp 2008" /> The orifice itself is smaller than that of the parotid.<ref name="Hupp 2008" /> These factors all promote slowing and stasis of saliva in the submandibular duct, making the formation of an obstruction with subsequent calcification more likely.
Salivary calculi sometimes are associated with other salivary diseases, e.g. sialoliths occur in two thirds of cases of chronic sialadenitis,<ref name="Rice 1984" /> although obstructive sialadenitis is often a consequence of sialolithiasis. Gout may also cause salivary stones,<ref name="Rice 1984" /> although in this case they are composed of uric acid crystals rather than the normal composition of salivary stones.
== Diagnosis == thumb|Ultrasound image of sialolithiasis thumb|Stone resulting in inflammation and dilation of the duct<ref>{{cite web|title=UOTW #70 - Ultrasound of the Week|url=https://www.ultrasoundoftheweek.com/uotw-70/|website=Ultrasound of the Week|access-date=27 May 2017|date=24 April 2016}}</ref>
Diagnosis is usually made by characteristic history and physical examination. Diagnosis can be confirmed by x-ray (80% of salivary gland calculi are visible on x-ray), by sialogram, or by ultrasound.
== Treatment == thumb|right|Salivary gland stone and the hole left behind from the operation Some current treatment options are:
Non-invasive: * For small stones, hydration<!-- that is a disambiguation page, but none it seems right -->, moist heat therapy, NSAIDs (nonsteroidal anti-inflammatory drugs) occasionally, and having the patient take any food or beverage that is bitter and/or sour. Sucking on citrus fruits, such as a lemon or orange, may increase salivation and promote spontaneous expulsion of stones within the size range of 2–10 mm. <ref>[https://www.semanticscholar.org/paper/Oral-surgery%3A-Self-milking-the-sialolith-Bhansali-Sarrami/74511eae0eee08fbd3f2c751d4c412a6b26c632d] – Oral surgery: Self-milking the sialolith (UK)</ref> * Some stones may be massaged out by a specialist. * Shock wave therapy (Extracorporeal shock wave lithotripsy).<ref>[https://www.medlineplus.gov/ency/article/001039.htm] – Overview of stones by the National Institutes of Health (US)</ref>
Minimally invasive: * Sialendoscopy
Surgical: * An ENT or oral/maxillofacial surgeon may cannulate the duct to remove the stone (sialectomy). * A surgeon may make a small incision near the stone to remove it. * In some cases when stones continually reoccur the offending salivary duct is removed.
Supporting treatment: * To prevent infection while the stone is lodged in the duct, antibiotics are sometimes used.
==Epidemiology== The prevalence of salivary stones in the general population is about 1.2% according to post mortem studies, but the prevalence of salivary stones which cause symptoms is about 0.45% in the general population.<ref name="Capaccio 2007" /> Sialolithiasis accounts for about 50% of all disease occurring in major salivary glands, and for about 66% of all obstructive salivary gland diseases.<!-- <ref name="Capaccio 2007" /> --> Salivary gland stones are twice as common in males as in females.<!-- <ref name="Hupp 2008" /> --> The most common age range in which they occur is between 30 and 60, and they are uncommon in children.<ref name="Capaccio 2007" />
==References== {{Reflist}}
== External links == {{Medical resources | DiseasesDB = 29364 | ICD10 = {{ICD10|K|11|5|k|00}} | ICD9 = {{ICD9|527.5}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D015494 }} {{Commons category|Sialolithiasis}}
{{Oral pathology}}
Category:Salivary gland pathology