Salivary gland disorders

Salivary gland disorders

The three major sets of salivary gland – the parotid, submandibular, and sublingual originate in a uniform manner by ectodermal epithelium buds invading the underlying mesenchyme.
Classification of salivary glands :
Exocrine glands: these are glands whose products are carried away by the ducts
Mesocrine glands : the secretory products pass through the cell walls losing the cytoplasm.
Serous salivary glands[ thin watery secretion ](parotid gland)
Mucus salivary glands [ thick , viscous substance ](lingual, and minor salivary glands)
Seromucus salivary glands (submandibular gland)
Major salivary glands
Minor salivary gland
Saliva :
Saliva is secreted by salivary glands ; these glands produce approximately 1.5 liter of saliva daily ; 70% is from the submandibular glands , 25% is from the parotid glands and 5% is from the sublingual glands. Minor salivary glands located on the palate, buccal mucosa and tongue also produce modest amounts of saliva .Saliva is slightly cloudy in appearance due to the presence of cells and mucin . Saliva is slightly acidic and the PH varies from 6.7-7.4. Saliva contain about 99.5% of water and 0.5% of solid{yeast cells, bacteria, protozoa, polymorpho-nuclrar leukocytes, inorganic ions [Na+ , K+ , Cl-, ]&secrotary proteins .
Saliva Collection:
Salivary flow rates provide essential information for diagnostic and research purposes, and gland function should be determined by objective measurement techniques. Salivary flow rates can be calculated from the individual major salivary glands or from a mixed sample of the oral fluids, termed “whole saliva.” The main methods of whole saliva collection include the draining, suction, spitting, and absorbent (sponge) methods. Flow rates are affected by many factors patient position, hydration, diurnal and seasonal variation, and time since stimulation can all affect salivary flow. The resting flow rate of saliva is about 0.3-0.4 ml/min.

Function of saliva :

Digestive function : it is providing fluid environment for solubilization of food and taste substance & through action of enzyme amylase and lipase .
Lubricant , mucus glycoproteins provide lubricant for movement of oral tissues against each other .
Protection of teeth by means of both cleansing and buffering action . It also controls the calcium and phosphate concentration in the saliva and around the teeth .It dilutes hot or irritant substance.
Antibacterial properties by action of lysosome , immunoglobulin IgA , IgG , IgM and lactoferrin .
Debridement and lavage : the physical flow of saliva augmented by muscular activity of lips and tongue , effectively removes a large number of bacteria
Maintenance of tooth integrity .
Maintenance of PH .

Diagnostic tests of the salivary glands

Plain-Film Radiography: Radiographic images may be obtained with standard dental radiographic techniques. Panoramic or lateral oblique and anteroposterior (AP) projections are used to visualize the parotid glands.
Sialometry: Flow rate studies.
Sialochemistry: Saliva is a complex exocrine secretion containing more than 60 constituents. Numerous changes in salivary chemistries have been described with a variety of salivary gland disorders.
Sialography: Sialography is the radiographic visualization of the salivary gland following retrograde instillation of soluble contrast material into the ducts. Sialography is the recommended method for evaluating intrinsic and acquired abnormalities of the ductal system because it provides the clearest visualization of the branching ducts and acinar end pieces. Ductal obstruction, whether by a sialolith, tumor, or stricture, can be easily recognized by sialography. The two contraindications to sialography are active infection and allergy to contrast media (iodine).
Scinitigraphy: Scintigraphy with technetium (Tc) 99m pertechnetate is a dynamic and minimally invasive diagnostic test to assess salivary gland function and to determine abnormalities in gland uptake and excretion. Technetium is a pure gamma ray–emitting radionuclide that is taken up by the salivary glands (following intravenous injection), transported through the glands, and then secreted into the oral cavity.
Ultrasonsgraphy: is a noninvasive and cost-effective imaging modality that can be used in the evaluation of masses occurring in the submandibular gland and the superficial lobe of the parotid gland. It is best at differentiating between intra- and extra glandular masses, as well as between cystic and solid lesions.
Computerized tomography & Magnetic resonance imaging: CT and MRI are useful for evaluating salivary gland pathology, adjacent structures, and the proximity of salivary lesions to the facial nerve. Since calcified structures are better visualized by CT, this modality is especially useful for the evaluation of inflammatory conditions that are associated with sialoliths. Abscesses have a characteristic hypervascular wall that is evident with CT imaging. CT also provides definition of cystic walls, making it possible to distinguish fluid-filled masses (ie, cyst) from abscess. MRI has become the imaging modality of choice for preoperative evaluation of salivary gland tumors because of its excellent ability to differentiate soft tissues and its ability to provide multiplanar imaging.,it demonstrates small differences in soft tissues.
Biopsy: Minor gland biopsy is a minimal operative procedure that can be done with limited morbidity, using appropriate techniques. The incision is made on the inner aspect of the lower lip, near the midline, so that it is not externally visible. When major gland biopsy is indicated for the evaluation of a distinct salivary mass, fine-needle aspiration (FNA) can be attempted.
Positron Emission Tomograph: Positron emission tomography (PET) has been used recently for evaluation of the salivary glands. Preliminary reports suggest that this may be a useful technique for measuring regional salivary gland function and recognizing inflammatory changes.

Classification of salivary gland disorders

Developmental disorders
Functional disorders
Obstructive disorders
Cyst
Asymptomatic enlargement
Infection
Autoimmune disorders

Developmental disorders

Aberrancy: the situation in which the salivary gland tissue develops at a site where it is normally not found . it also called as ectopic salivary gland .
Aplasia and Hypoplasia: aplasiais the congenital absence of the salivary gland . patient complain of xerostomia . computed tomography will be able to diagnose this lesion.
Hyperplasia: is the increase in the size of the salivary gland due to hormonal disorder, metabolic disorder, autoimmune disease, heerfordt`s syndrome, and miscellaneous (hepatic disease,starvation and alcoholism ). It is more common in minor salivary glands of the palate. It is appears as small localized swelling of varying size, measuring from several millimeters to 1CM , usually on the hard palate. It its usually asymptomatic. It can be diagnosed by computed tomography .
Atresia: it is the congenital occlusion or absence of one or two major salivary gland duct .
Accessory duct
Diverticuli: they are out pocketing of the ductal system of one of the major salivary glands . Their presence leads to recurrent episodes of acute parotitis .
Congenital fistula: patients with branchial cleft anomalies usually present with unilateral , painless swelling .
Developmental salivary gland defect: also called stafne`scyst or defect , lingual mandibular bone cavity. It is the developmental inclusion of glandular tissue

Functional disorders of salivary gland:

Sialorrhea (ptylism) : an increased salivary secretion . stimulation of the parasympathetic system causes profuse secretion of saliva .The etiology of sialorrhea
drugs---lithium ,cholinergic agonists
local factors ---ANUG, erythema multiform
systemic disease ---alcoholic neuritis , Parkinson`s disease , paralysis , down`s syndrome
protective-- buffering system to neutralize stomach acid in individual with gastroesophageal reflux disease
miscellaneous ---- metal poisoning , facial paralysis
The management of sialorrhea is by removal of local factor , the anticolinergic drug ,atropine sulfate , has been shown to reduce the amount of resting secretion (0.4 mg every 6 hours ).
Xerostomia : it is the subjective clinical condition of less than normal amount of saliva . The etiology of xerostomia
ionizing radiation to head and neck region
pharmacologically induced xerostomia – there are 500 drugs which can cause xerostomia like anticonvulsant, antiemetic, antihistaminic and antihypertensive
local factor–smoking and mouth breathing
systemic alterations –pernicious anemia , iron deficiency anemia and deficiency of vitamin A .
Fluid loss associated with hemorrhage , sweating and diarrhea .
Diabetes mellitus .
Sjogren syndrome .
Xerstomia may also be found in HIV infection , sarcoidosis and graft versus host resistance . patient may notice complain thirst , increased up take of fluid , difficulty in swallowing , speech and eating . There is also complaint of frequent oral infection and abnormal taste .Painful salivary gland enlargement is also present . Oral mucosa appears thin , pale and feels dry .Pseudo membranous and hyperplastic form of candidiasis occurs .Xerstomia can be managed by
local stimulation (chewing gums, paraffin and citric acid )
systemic stimulation (bromhexine, anetholetrithione and pilocarpine) and salivary substitute

Obstructive disorders :

Sialolithiasis: it is the formation of calcific concentration within the ductal system of major or minor salivary glands . submandibular calculi(83%) are more commonly seen than the parotid (10%)or sublingual calculi (7%) . The predisposing factors for sialolithiasis are
anatomic factors (the length and irregular course of duct , the orifice is much smaller than duct lumen)
physiochemical factors ( high mucin content , great degree of alkalinity , great concentration of calcium and phosphate , low content of carbon dioxide ) .
Many patients complain of moderately severe pain . patient also complains of intermittent transient swelling during meals . Pus may exude from the duct orifice. The soft tissues surrounding the duct show a severe inflammatory reaction. It usually occurs as a solitary concretion varying in size from a few millimeter up to several centimeters. Sialolithiasis of minor salivary gland is a rare occurrence . Projection for submandibular duct stone is mandibular occlusal view and for parotid gland, periapical view in the buccal vestibule. Silography is indicated when sialolithiasis are radiolucent. In case of small stone , gentle massage of the gland should be done , it will help to move the stone toward the duct orifice. If the stone is palpated near the orifice of the submandibular duct it can be removed by an incision made over it. In case of stone in the submandibular gland , excision of the gland is advised . Salivary gland endoscopy is newer method which is useful in removal of sialoliths . Lithotripsy (fragmentation of stone in the gland ) ,nowadays , extracorporeal shock wave lithotripsy has been successful in many patients .
Strictures and stenosis : these are the rare conditions occurring in the salivary gland area . The etiology of stenosis may be due to irritation (prosthetic appliances, maloccluded teeth ) , acute trauma and tumor
Foreign bodies : rarely , foreign bodies become lodged within Wharton`s duct and less commonly in stensen`s duct . Tooth brush bristles , tooth picks , fish bone and portion of fingernail .
Extraductal causes : muscle pressure , tumors , enlarged lymph nodes and denture flanges associated with obstructive singe and symptoms.
Parotid fistula : it may arise from parotid gland or duct . It may be internal (when it opens inside the mouth) and external ( when it opens to the exterior) . The causes of fistula may traumatic or a complication of superficial parotidectomy .The main complaint is opening in the cheek with discharge which come out only during meals . There may be excoriation of the neighborhood skin . It can be managed by reconstruction of the duct by surgical approach .

Cysts of salivary gland :

Mucocele : it is a term used to describe the swelling caused by pooling of saliva at the site of injured salivary gland . It is not true cyst it lacks an epithelial lining . It is caused by laceration of a minor salivary gland duct by trauma . It is occur in the younger patients as they are more prone to trauma that induce mucin spillage . Patient may complain of painless swelling which is frequently recurrent and suddenly develop at meal time . The mucocele may be only (1-2)mm in diameter ,majority of them being between (5-10)mm in diameter .Superficial mucocele appear as bluish mass, while deeper lesions have the color of the normal mucosa and are firmer . The swelling is dome shaped .It is either soft or hard depending upon the tension in the fluid . Complete excision of the mucocele should be done under local anesthesia . Surgery with cryoprobe is also helpful in the managing the mucocele.

Ranula : the term ranula is used for the mucocele occurring in the floor of the mouth , in association with ducts of submandibular or sublingual glands . There are two type of ranula ,
superficial which may develop as a retention or extravasation phenomenon associated with trauma to one or more of the numerous excretory ducts
cervical ,which is ramifies deeply into the neck .
The typical position is on the floor of the mouth , below the tongue and on the side of the frenum . It develops as slowly enlarging painless mass ,blue shaped swelling like a frog`s belly and may cause difficulty in speech or eating . On CT , the lesion is observed as a homogeneous , water density mass with clear boundary .They are best treated by surgical excision and partial excision with marsupialization .

Asymptomatic enlargement of the salivary gland :

Sialosis (sialadenosis): it is characterized by non –neoplastic non-inflammatory enlargement of the salivary gland . The condition is found in association with
systemic diseases especially cirrhosis , diabetes , ovarian and thyroid insufficiency .
alcoholism ,
general malnutrition ,
anorexia nervosa
neurogenic medication (antihypertensive drugs , psychotropic drugs and sympathomimetic drugs ).
It more commonly affects the females . The enlargement is usually bilateral and parotid gland is more frequently affected . On sialography , leafless tree appearance is seen . Significant elevation of salivary potassium and concomitant decrease in salivary sodium is observed . Control of underlying cause is most important management for sialosis .
Allergic sialadenitis : Is a toxic reaction to drugs that cause decreased salivary flow , resulting in secondary infection . Various drugs which have been reported to cause allergic sialadenitis include sulfisoxazol , phenothiazine , iodine containing compounds , mercury and thiouracil . Most of the drugs cause decrease in capillary permeability , whereas others cause sodium and chloride retention . The enlargement may be painful and is usually associated with conjunctivitis and skin rashes . There is bilateral parotid gland enlargement following the administration of the drug . It is self-limiting disease .

Viral infection :

Mumps: It is also called as epidemic parotitis. It is an acute contagious viral infection ,characterized by chiefly unilateral or bilateral swelling of the salivary gland . It mainly affects major salivary gland , but also affect the testis , meninges , pancreas ,heart and mammary gland . It is caused by paramyxovirus . It usually spreads from human reservoir by airborne infection of infected saliva and possibly urine . It is more common in boys than in girls . Incubation period is of (2-3) weeks and patient is contagious from one day before clinical appearance of the lesion . It is preceded by onset of headache , chills . moderate fever , vomiting and pain below the ear which lasts for about one week . It is then followed by sudden onset of salivary gland swelling which is firm somewhat rubbery or elastic and without purulent discharge . It produce pain upon mastication . The enlargement of the parotid gland causes elevation of ear lobule . Most of cases are self – limiting . When mumps occur in adult male , orchitis (inflammation of the testis ) is of great danger and ensues in 20% of the cases . Involvement of pancreas producing acute pancreatitis and causes an elevation in serum lipase . Meningitis and encephalitis can occur as complication of the disease . Deafness , mastoiditis and myocarditis have also been reported . It can be diagnosed by clinical feature and laboratory examination , salivary amylase level is increased , a paramyxovirus may be isolated from saliva for as long as 6 days before and up to 99 days after the appearance of the salivary swelling . Vaccine is the best method of controlling the disease . Symptomatic treatment is given to control the pain and swelling , bed rest is recommended and patient should avoid sour foods .

Cytomegalovirus inclusion disease : It is caused by cytomegalovirus. It is common in immunosuppressed adult. In newborn, infection is generalized and usually fatal.

Bacterial infection :

Acute bacterial sialadenitis: It is also called as acute suppurativeparotitis . It is most commonly caused by penicillin resistant staphylococcus aureus or streptococci viridians . It can occur in condition such as dehydration , malnutrition , cancer and surgical infections . Drugs like antiparkinson`s , diuretics and antihistaminic have been reported to be a contributory factor for acute bacterial sialadenitis . It begins with elevation of body temperature and sudden onset of pain at angle of the jaw . Parotid gland is tender , enlarged and the overlying skin is warm and red . The parotid papilla may be inflamed and pus may exude or be milked from the duct of the affected gland .Cervical lymphadenopathy usually develops . If infection is not eradicated , pus may penetrate the gland and spread into the surrounding tissues .On enhanced CT ,the affected gland are seen with a higher CT values compared with the normal side because of the increased vascularity . Treatment usually start with high dose of parenteral antibiotics active against penicillin resistant staphylococcus .Oral hygiene should be maintained by debridement and irrigation .Soft diet should be given as chewing is painful . Usually starts with high dose of parenteral antibiotics active against penicillin resistant staphylococcus . The patient must be adequately hydrated and the electrolyte balance should be maintained with intravenous fluids . If improvement does not occur , surgical drainage of the affected gland should be performed .

Sub-acute necrotizing sialadenitis :It is salivary inflammation occur in teenage and young adult . It involves minor salivary gland . It present as painful nodules which is covered by intact erythematous mucosa .The pain is usually minimal and antibiotic therapy resolve the infection within a week.
Chronic sclerosingsialadenitis : It is chronic inflammatory disease . It is also called Kuttne`r disease and its common in submandibular gland. It is caused by salivary ductal calculi causing subsequent pyogenic bacterial infections . There is enlargement of the gland , resulting in fibrous tumor like masses . There is no specific treatment for this disease .

Autoimmune disorders:

Sjogren`s syndrome :It is chronic inflammatory disease that predominately affects salivary , lacrimal and exocrine glands. It predominately affects middle aged and elderly women. There are two types:
primary sjogren`s syndrome (it also called sicca syndrome and consists of dry eyes and dry mouth )
secondary sjogren`s syndrome (it consists of dry eyes ,dry mouth and collagen disorders usually rheumatoid arthritis, systemic lupus erythematous and scleroderma ) .
The effect on eye is called as keratoconjunctivitissicca, patient usually complain of continuous irritation in the eye. In patients with secondary sjogren`s syndrome , rheumatoid arthritis is typically long standing and clinically obvious feature , patients may have small joint and ulnar deviation of fingers and rheumatoid nodules .
Oral manifestation of sjogren`s syndrome
Xerostomia is a major complaint in most of the patients , also they complain of an unpleasant taste and difficulty in eating .
Pus may be emitted from the duct . Angular stomatitis and denture stomatitis also occur .
Unilateral or bilateral enlargement of parotid gland which occur in about one third of the patients .
In advanced cases , the mucosa is glazed , dry and tends to form fine wrinkles .
The tongue typically develops a characteristic lobulated , usually red surface with partial or complete depapillation .
There is also decrease in number of taste buds , which leads to an impaired sense of taste .
Dental caries is sever and gross accumulation of plaque . Periodental disease can also occur .
Sjogren`s syndrome is the most common underlying cause of acute bacterial sialadenitis .
The regional lymph node may be enlarged and tender .
Diagnosed by measuring lacrimal function, quantifying salivary function, another the labial minor salivary gland biopsy, the presence of autoantibodies against anti-SS-A (Ro) and anti-SS-B (La). In sialography the most typical finding in sjogren`s syndrome is a snowstorm appearance as a result of leakage of contrast medium. Salivary scintiscanning with technetium pertechnetate may be useful in demonstrating impaired salivary function. It can be managed by ocular lubricant, oral hygiene maintenance, salivary stimulant ( bromhexine , pilocarpine and cevimeline ) salivary substitute (artificial saliva) and surgery .

Mikulicz`s disease: ( benign lympho-epithelial lesion ): It is a symmetric or bilateral, chronic, painless enlargement of lacrimal and salivary glands. It occurs more commonly in women in middle and later life. It is manifested as a unilateral or bilateral enlargement of parotid and /or submandibular gland. The onset of the lesion is some time associated with fever, upper respiratory tract infection, oral infection and tooth extraction. There is often diffuse, poorly outlined enlargement of salivary gland. The duration of the mass may be only a few months or many years. It can be diagnosed by clinical feature and biopsy. Surgical removal of the involved gland should be done.

Uveoparotid fever : It is a form of sarcoidosis and is also called as heerfordt`s syndrome . It consist of a triad of
uveitis ( inflammation of the uveal tract of the eye )
parotid swelling ( firm , painless and bilateral )
facial palsy .
Tuberculosis was earlier thought to be the causative agent. Hereditary factor also play an important role in this syndrome, autoimmune mechanism of the body can also be responsible. It usually occur in 3th and 4thdecades of life. The initial signs of the disease are fever, malaise, weakness, nausea and night sweat which lasting from a few days to several weeks. It appears as a bilateral , painless parotid swelling which lasts from several months to several years. Submandibular, sublingual and lacrimal gland swelling may develop independently or during the parotid swelling. Sarcoidal lesion may also be found in the oral cavity. There is unilateral or bilateral seventh nerve paralysis. There is trigeminal paresthesia, eyelid ptosis, polyneuritis, intercostal neuralgia and spinal nerve impairment have been reported .The sialographic picture shows the severity and duration of the disease process within the particular gland. It is largely asymptomatic as it may undergo spontaneous remission, corticosteroid can be used in case of acute exacerbation .

Recurrent non –specific parotitis : It occurs in children as well as adults . Male are more commonly affected than female . The disease is characterized by a sudden onset of parotid swelling . Both unilateral and bilateral parotid involvement has been reported , swelling persist for few days to a year .

Benign tumors of salivary glands :

Pleomorphic adenoma (mixed tumors) : It mean unusual histological pattern of the lesion . It is most common salivary gland tumor . Women to men ratio is 6:4 , it is common in 4th to 6th decades but also seen in young adult and children . About 90% of cases occur in parotid ,start as small , painless , quiescent nodule which slowly begins to increase in size .The tumor tends to be round or oval when it is small , as it grows bigger it becomes lobulated . In some cases , intr aoral swelling may be observed . It may increase in size to cricket ball size . It is firm and rubbery to feel . In sialographyball in hand appearance can be seen . CT will help to know exact extension of location . biopsy shows cuboidal cells arranged in tubes . It can be managed by surgical excision . Can be managed by surgical excision .
Monomorphic adenoma
Warthin`stumor: papillary cystadenoma lymphomatosum.
Oncocytoma
Basal cell adenoma
Canalicular adenoma
Ductuspapillomas

Malignant tumors :

Mucoepidermoid carcinoma
Acinic cell tumor
Adenoid cystic carcinoma
Malignant pleomorphic adenoma

Necrotizing sialometaplasia :

is a benign, self-limiting, reactive inflammatory disorder of the salivary tissue. Clinically, this lesion mimics a malignancy. The etiology is unknown, although it likely represents a local ischemic event, infectious process, or perhaps an immune response to an unknown allergen.
Clinical Presentation: Necrotizing sialometaplasia has a rapid onset. Lesions occur predominantly on the palate; however, lesions can occur where any salivary gland tissue exists, including the lips and the retromolar region. Lesions initially present as a tender erythematous nodule. Once the mucosa breaks down, a deep ulceration with a yellowish base forms. Even though lesions can be large and deep, patients often describe only a moderate degree of dull pain. Lesions often occur shortly after oral surgical procedures, restorative dentistry, or administration of local anesthesia, although lesions also may develop weeks after a dental procedure or trauma. It is not uncommon for lesions to develop in an individual with no obvious history of trauma or oral habit.