DISEASES OF SALIVARY GLANDS (PART 1)

SALIVARY GLANDS

Group of simple & compound exocrine glands that secrete saliva into the oral cavit through ducts and are considered as one of the four accessor organs / glands of digestion

• LIVER

• GALLBLADDER

• PANCREAS

• SALIVARY GLANDS

FOUR ACCESSOR ORGANS / GLANDS OF DIGESTION

LIVER

Largest gland of the body that produces bile

GALLBLADDER

Stores & concentrates bile, and secretes enzymes

PANCREAS

produces pancreatic juices

SALIVARY GLANDS

secretes saliva that contains amylase/ptyalin

I. ACCORDING TO SIZE & FUNCTION

II. ACCORDING TO DUCTAL SYSTEM

III. ACCORDING TO THE TYPE OF SECRETION

CLASSIFICATION OF SALIVARY GLANDS

• MAJOR SALIVARY GLANDS

• MINOR SALIVARY GLANDS

I. ACCORDING TO SIZE & FUNCTION

MAJOR SALIVARY GLANDS

Large, paired glands that secrete saliva & accounts for about 90% of salivary glands

• PAROTID GLAND

• SUBMANDIBULAR GLAND

• SUBLINGUAL GLAND

MAJOR SALIVARY GLANDS

PAROTID GLAND

wedge-shape / resembles an inverted pyramid; largest of all salivary glands (15-30 gm.) & secretes about 25% of the total salivary volume

LOCATION OF PAROTID GLAND

• retromandibular fossa, anterior to the ear & sternocleidomastoid muscle

DUCT OF THE PAROTID GLAND

Stensen’s duct (opens inside the cheek opposite the crown of the maxillary second molar)

SUBMANDIBULAR GLAND

• hook-shape & walnut-sized gland (7-15 grams or about ½ the size of the parotid gland) but produces the most saliva at approximately 60 - 65% of the total salivary volume

  
  

LOCATION OF SUBMANDIBULAR GLAND

found on ventral sides of the neck, under the chin & tongue

DUCT OF SUBMANDIBULAR GLAND

Wharton's duct (opens at the lateral side of the lingual frenum)

SUBLINGUAL GLAND

almond-shape & smallest of the major salivary glands (⅕ the size of the submandibular gland); makes the least amount of saliva at about 5% of the total salivary volume

LOCATION OF SUBLINGUAL GLAND

lies on the floor of the mouth, under the tongue & extends posteriorly to the second molar region

DUCT OF THE SALIVARY GLAND

• Ducts of Rivinus which is composed of several small ducts (opens on the floor of the mouth / beneath the tongue) with one main & larger duct known as Bartholin's duct (that opens near, but independently from, the submandibular gland)

MINOR SALIVARY GLANDS

secretes approximately 10% of salivary secretions from 800-1000 small glands that are named according to their anatomic location as they are distributed along the mucosal surfaces of the oral cavity & throat

• LINGUAL GLANDS

• BUCCAL GLANDS/MOLAR GLANDS

• LABIAL GLANDS

• INCISIVE GLANDS

• PALATINE GLANDS

• GLOSSOPALATINE GLANDS

• CARMALT’S GLANDS

MINOR SALIVARY GLANDS

• BLANDIN & NUHN GLANDS / GLANDS OF BLANDIN & NUHN’S

• VON EBNER’S GLANDS / GLANDS OF VON EBNER

• WEBER’S GLANDS / GLANDS OF WEBER

LINGUAL GLANDS

BLANDIN & NUHN GLANDS / GLANDS OF BLANDIN & NUHN’S

anterior lingual glands found at or near the apex of the tongue, and the ducts open on the ventral surface of the tongue

VON EBNER’S GLANDS / GLANDS OF VON EBNER

posterior lingual serous glands located between the muscle fibers of the tongue & below the taste buds (circumvallate papillae), and the ducts open into the trough of the vallate papilla

WEBER’S GLANDS / GLANDS OF WEBER

posterior lingual mucus glands situated in the peritonsillar space superior to the tonsils in the soft palate, and the ducts open on the dorsal surface of the tongue

BUCCAL GLANDS / MOLAR GLANDS

sparse and located in the inner cheek between the mucus membrane & the buccinator muscle

LABIAL GLANDS

numerous; near the midline and situated on the submucosa of the upper & lower lips

INCISIVE GLANDS

located on the floor of the mouth behind the lower incisors

PALATINE GLANDS

found under the mucus membrane of the soft palate, posterolateral part of the hard palate, & uvula

GLOSSOPALATINE GLANDS

located in the isthmus region of the glossopalatine fold, but may extend to the glands of the soft palate

CARMALT'S GLANDS

situated at the retromolar area

• SIMPLE GLANDS

• COMPOUND GLANDS

II. ACCORDING TO DUCTAL SYSTEMS

SIMPLE GLANDS

refers to a single or unbranched ductal system of complex glands which are present in some minor salivary glands

COMPOUND GLANDS

pertains to branched ductal systems of complex glands as seen in major salivary glands

• SEROUS GLANDS / PURE SEROUS GLANDS

• MUCOUS GLANDS / PURE MUCOUS GLANDS

• MIXED GLANDS

III. ACCORDING TO THE TYPE OF SECRETION

SEROUS GLANDS / PURE SEROUS GLANDS

• consists of serous acinar cells which secretes thin & watery saliva

• includes the following: parotid gland & von Ebner's glands

MUCOUS GLANDS / PURE MUCOUS GLANDS

• made of mucous acinar cells that discharge thick & viscous saliva with high mucin (glycoprotein) content

• includes the following: Weber's glands, palatine glands, glossopalatine glands, carmalt’s glands

MIXED GLANDS

• composed of both serous acinar cells & mucous acinar cells

• includes the following: submandibular glands, sublingual glands, labial glands (with predominant mucous cells), buccal glands / molar glands (with predominant mucous cells), blandin & Nuhn's glands (with predominant mucous cells)

SALIVA

complex biological fluid from salivary glands to maintain the structure & function of the oral cavity

PROPERTIES OF SALIVA

• VOLUME: 0.5 - 1.5 liters/day or approximately 1mL/minute

  • UNSTIMULATED FLOW RATES: 0.3 - 0.4mL/minute

  • STIMULATED FLOW RATES: 1.5 - 2mL/minute

• CONSISTENCY: clear to slightly cloudy (due to the presence of mucins & other cells)

• pH LEVEL: mixed saliva from all glands is slightly acidic at a 6.7-7.4 pH level (but may be alkaline at high salivary secretion rates)

• TONICITY: hypotonic to plasma

• SPECIFIC GRAVITY: ranges between 1.002 - 1.012

COMPOSITION OF SALIVA

I. 99.5% WATER

II. 0.5 % SOLIDS

• organic substances

• enzymes

  • includes the three main digestive enzymes in saliva (salivary amylase / ptyalin, maltase, & lingual lipase); lysozyme; phosphatase; carbonic anhydrase; and kallikrein

• Other organic substances

  • such as mucin; albumin; proline-rich proteins; lactoferrin; immunoglobulin A (main antibody in saliva); blood group antigens; and non-protein nitrogenous substances (such as urea, uric acid, creatinine, xanthine, & hypoxanthine)

• inorganic substances

  • includes sodium, calcium, potassium, bicarbonate, bromide, chloride, fluoride, & phosphate

• gases

  • such as oxygen, carbon dioxide, and nitrogen

*Glucose is normally absent in saliva, except in the patients with diabetes mellitus.

1. lubrication of teeth & mucosa

2. aids in bolus formation of food for swallowing

3. facilitates the mastication of food

4. serves as a solvent for molecules to stimulate the taste & detection of food

5. initiates digestion through enzymes

6. cleanses the mouth, teeth, & gums

7. buffering function to keep salivary pH levels within normal limits

8. prevents infections through its antimicrobial components

9. protects the mucus membranes from injury by diluting hot or irritating substances

10. maintains the integrity of the mucous membranes

1. its anti-carcinogenic activity limits the penetration of potential toxins & hazardous agents

2. contributes to articulation & phonation during speech

3. helps in the remineralization of teeth including protection against demineralization

4. accelerates soft tissue repair in the presence of oral cavity & in cases of esophageal damage

5. excretory function for heavy metals, alkaloids, microorganisms, & antibiotics

6. regulation of body temperature

7. regulation of water balance

FUNCTIONS OF SALIVA

1. HISTORY TAKING & CLINICAL/PHYSICAL EXAMINATION

2. PLAIN-FILM RADIOGRAPHS

3. ULTRASONOGRAPHY (USG)

4. COMPUTED TOMOGRAPHY (CT) SCAN

5. MAGNETIC RESONANCE IMAGING (MRI) SCAN

6. POSITRON EMISSION TOMOGRAPHY (PET) SCAN

7. SEROLOGIC EVALUATION

8. HISTOPATHOLOGY

9. ANGIOGRAPHY/ARTERIOGRAPHY

10. SIALOGRAPHY/PTYALOGRAPHY

11. SALIVARY SCINTIGRAPHY/SIALOSCINTOGRAPHY/RADIONUCLIDE IMAGING/RADIOACTIVE ISOTOPE SCANNING

12. SIALOCHEMISTRY

13. SIALOMETRY

14. SIALOENDOSCOPY

DIAGNOSTIC MODALITIES FOR SALIVARY GLANDS

HISTORY TAKING & CLINICAL / PHYSICAL EXAMINATION

information gathered from the patient & clinical / physical examination will serve as a guide to categorize the problem (which may be developmental, obstructive, infectious, functional, traumatic, etc.) in order to determine the appropriate diagnostic test/s to be done

PLAIN-FILM RADIOGRAPHS

two-dimensional radiocraphs that can be used to detect salivary gland stones (calculi), but only 80-85% of salivary aland stones are radiopaque (light/white area that is visible radiographically)

• PERIAPICAL RADIOGRAPH

• PANORAMIC RADIOGRAPH

• OCCLUSAL RADIOGRAPHS

PLAIN-FILM RADIOGRAPHS

PERIAPICAL RADIOGRAPH

reveals salivary gland stones in a duct or aland of either a major or minor salivary gland (but correct film placement must be considered)

PANORAMIC RADIOGRAPHS

shows salivary gland stones in the parotid gland & submandibular gland (for cases when the salivary gland stone is posteriorly located)

OCCLUSAL RADIOGRAPHS

mandibular occlusal radiographs for identifying salivary gland stones in the sublingual gland & submandibular gland (but with high false-negative rates due to the presence of mucous plugs)

ULTRASONOGRAPHY (USG)

• utilizes high-frequency sound waves (ultrasound waves) to produce images of structures within the body without the use of radiation

• indications:

1. biopsy guidance

2. detection or assessment of mass lesions and/or salivary stones (≥ 2mm)

3. monitors recovery following treatment

• contraindications: none (but should not be performed if it delays definitive treatment in an emergent situation)

COMPUTED TOMOGRAPHY (CT) SCAN

uses several x-ray images that can show in detail the different levels of bone density including the muscles, fat, & tissues inside a solid organ

INDICATIONS FOR CT SCAN

A) rules out calcified structures

B) demonstrates salivary gland stones & chronic inflammation

C) detects the presence of a tumor

CONTRAINDICATIONS FOR CT SCAN

1. pregnant women (especially during the 1st trimester due to radiation)

2. Obese patients (attributed to the weight limit & fixed diameter of the gantry of the scanner)

3. patients with history of iodine sensitivity or severe allergic reactions to iodine that is present in high concentrations of about 25 - 40% in the contrast media (which may be given orally, rectally, through inhalation, or via an intravenous route)

The use of a non-contrast CT scan or a contrast CT scan

Will depend on the medical circumstances for a given case

CONTRAST MEDIA / CONTRAST AGENT / CONTRAST MATERIAL

• Is a special dye that may appear either:

  • radiolucent / negative (i.e., low atomic numbers that include carbon dioxide, nitrous oxide, oxygen, & air)

  • radiopaque / positive (i.e., high atomic numbers such as iodine, bromine, & barium).

• it is utilized to target specific organs & tissues to increase visibility

MAGNETIC RESONANCE IMAGING (MRI) SCAN

• utilizes magnetic fields & radio waves to generate a detailed image of the body’s bones, organs, and tissues without the use of radiation

INDICATIONS FOR MRI SCAN

• rules out soft tissue lesions

• Demonstrates salivary gland stones & chronic inflammation

• Detects the presence of a tumor

CONTRAINDICATIONS FOR MRI SCAN

• pregnant women (especially during the 1st trimester due to the contrast agent)

• Claustrophobic patients (using an open MRI machine may be a better option)

• Presence of any metallic foreign object or substance inside the body/on the surface of the body (e.g., pacemaker, metallic plates/screws/pins, body piercings or modifications, nicotine/dermal patches with foil backing, tattoos, bullets/shrapnel, stents, aneurysm clips, cochlear implants, dental crowns & bridges, orthodontic appliances, dowel posts, dental implants, magnetic dentures, & amalgam restorations)

FERROMAGNETIC MATERIALS (e.g., iron, cobalt, & nickel)

Cause major distortion of the magnetic field and the resulting image

PARAMAGNETIC MATERIALS (e.g., titanium, platinum, zirconium, aluminum, & tantalum)

Produce very little distortion of the magnetic field

DIAMAGNETIC MATERIALS (e.g., gold, silver, copper, mercury, & zinc)

Have the least effect

POSITRON EMISSION TOMOGRAPHY (PET) SCAN

Uses radioactive positrons (i.e., radiotracer) to detect cellular level changes in the metabolic & chemical activity of the body

INDICATIONS FOR PET SCAN

• identifies regional salivary gland functional alterations & inflammations

• Measures tumor metabolism

• Evaluates tumor proliferation rates

CONTRAINDICATIONS OF PET SCAN

• pregnant women & breastfeeding mothers (due to the use of radiotracers)

• Obese patients (attributed to the weight limit & fixed diameter of the gantry of the scanner)

SEROLOGIC EVALUATION

Various laboratory techniques that focuses on blood serum for evidence of infection by evaluating antigen-antibody reactions

INDICATIONS FOR SEROLOGIC EVALUATION

• aids in the evaluation of xerostomia

• Determines congenital and/or recent infections

• Detects the presence of non-specific markers of auto-immunity

CONTRAINDICATIONS FOR SEROLOGIC EVALUATION

none; its usefulness is dependent on sensitivity & specificity

SENSITIVITY

High sensitivity prevents false negatives that occur when there is no reaction

SPECIFICITY

High specificity prevents false positives that take place when there is a cross reaction

• Fine needle aspiration biopsy (FNAB) / fine needle aspiration cytology (FNAC)

• Frozen section

• Salivary gland biopsy (incisional biopsy or excisional biopsy)

HISTOPATHOLOGY

FINE NEEDLE ASPIRATION BIOSPY (FNAB) / FINE NEEDLE ASPIRATION CYTOLOGY (FNAC)

Refers to the use of a thin, hollow needle (21-25g) that is inserted into the mass to collect material for cytologic diagnosis

FROZEN SECTION

Intraoperative procedure that differentiates between benign & malignant tumors, evaluates tissue margins for involvement by malignancy, and determines the type of tissue involved

SALIVARY GLAND BIOPSY (INCISIONAL BIOPSY OR EXCISIONAL BIOPSY)

May be utilized in the diagnosis of major salivary gland lesions, but it is commonly used as an aid in the diagnosis of Sjögren’s syndrome

ANGIOGRAPHY / ARTERIOGRAPHY

possesses the ability to localize and catheterize arterial channels supplying the salivary gland structures

INDICATIONS FOR ANGIOGRAPHY / ARTERIOGRAPHY

• define the vasculature of a tumor

• Delineate the origin of the vascular supply

• Guide the surgical treatment of a damaged artery for traumatic cases

CONTRAINDICATIONS FOR ANGIOGRAPHY / ARTERIOGRAPHY

• pregnant women

• Obese patients (exceeding the limit of the angiography table can pose technical safety concerns)

• Patients with history of iodine sensitivity or severe allergic reactions to iodine that is present in high concentrations of about 25-40% in the contrast media

• Renal impairment or dehydration

• Diabetic patients taking metformin hydrochloride (acts by lowering the amount of sugar produced by the liver & it is eliminated by the kidneys) with pre-existing renal impairment

• Coagulopathy (from liver diseae, hematological disease, or chemotherapy)

• Patients under antiplatelet medications or blood thinners

SIALOGRAPHY / PTYALOGRAPHY

Gold standard in obtaining radiographic evaluation & demonstration of the salivary glands as routine x-ray projections are taken after radiopaque contrast media is introduced into the ductal systems of the salivary glands

INDICATIONS FOR SIALOGRAPHY / PTYALOGRAPHY

• detects size, position, and mobility of mucous plugs & salivary gland stones that may either be radiopaque or radiolucent (15-20% of cases with salivary gland stones)

• Provides information on the number and shape of strictures (narrowing of any tubular structure, canal, or passage)

• Evaluate the extent of destruction of salivary duct and/or gland parenchyma as a result of inflammatory, traumatic, obstructive, or neoplastic diseases

• Rules out auto-immune or radiation-induced sialadenitis

• Form of therapy that removes or flushes out small mucous plugs & necrotic debris (ductal system is dilated when the contrast medium is injected into the ductal systems)

CONTRAINDICATIONS FOR SIALOGRAPHY / PTYALOGRAPHY

• acute salivary gland infections may allow the extravasation of contrast media into the soft tissue which may result in extreme pain & possible foreign body reaction

• Patients with history of iodine sensitivity or severe allergic reactions to iodine that is present in high concentrations of about 25-40% in the contrast media

• Preceding a thyroid gland study because retained iodine in the salivary gland or ductal system may interfere with the scan of the thyroid gland

• DUCTAL PHASE

• ACINAR PHASE

• EVACUATION PHASE

THREE DISTINCT PHASES IN A COMPLETE SIALOGRAM

DUCTAL PHASE

Immediately after introduction of the contrast media which allows visualization of the major ducts

ACINAR PHASE

Occurs minutes after the ductal system is fully opacified with contrast media and the gland parenchyma (functional tissue of an organ) is filled with contrast

EVACUATION PHASE

Assesses the normal secretory clearance function of the gland and accentuates any ductal pathology that is not detected in the other phases

SIALOGRAPHY

Act or process of recording

SIALOGRAPH

Instrument that is used to make a record

SIALOGRAM

Actual result of the recording

SALIVARY SCINTIGRAPHY / SIALOSCINTIGRAPHY / RADIONUCLIDE IMAGING / RADIOACTIVE ISOTOPE SCANNING

Provides information on the functional capabilities of the salivary gland by assessing abnormalities in salivary gland uptake & excretion through the intravenous injection of a radioactive isotope called technetium-99m (99mmTC) pertechnetate which is a pure gamma ray emitting nucleotide

INDICATIONS FOR SALIVARY SCINTIGRAPHY / SIALOSCINTIGRAPHY / RADIONUCLIDE IMAGING / RADIOACTIVE ISOTOPE SCANNING

• rules out auto-immune sialadenitis

• Differentiated between acute obstructive & non-obstructive sialadenitis

• Detects sialosis and tumors

• Performed when sialogrpahy is contraindicated

CONTRAINDICATIONS FOR SALIVARY SCINTIGRAPHY / SIALOSCINTIGRAPHY / RADIONUCLIDE IMAGING / RADIOACTIVE ISOTOPE SCANNING

• pregnant women & breastfeeding mothers (due to the radioactive isotope)

• Patients with history of iodine sensitivity or severe allergic reactions to iodine

• Severe case of Graves’ ophthalmopathy (thyroid eye disease / TED)

SIALOCHEMISTRY

examination of the electrolyte composition of saliva, particularly sodium & potassium

INDICATIONS FOR SIALOCHEMISTRY

• gathers data regarding salivary gland diseases & its effect on the entire oral cavity

• Supplies clues to homeostatic fluctuations from innervation, circulatory, or hormonal adjustments

• Aids in the diagnosis of infections

• Allows drug monitoring

• Identifies environmental, atmospheric, & occupational pollutants (e.g., heavy metals)

• Follow-up studies

CONTRAINDICATIONS FOR SIALOCHEMISTRY

None; but it can be time-consuming and very sensitive (due to the variable composition of saliva)

SIALOMETRY

Evaluates the function of the salivary glands by measuring the amount of saliva production which is usually carried out during day time & on an empty stomach (or at least 2 hours after a meal, drinking, smoking, oral care regimen, etc.)

SIALOENDOSCOPY

Endoscopic transluminal visualization of the ductal systems of major salivary glands as it provides a mechanism for the diagnosis & treatment of inflammatory and/or obstructive pathology related to ductal systems

INDICATIONS FOR SIALOENDOSCOPY

• Treatment option for sialolithiasis / salivary stones / salivary calculi

• Serves as a guide when sialolithotomy (surgical removal of a stone from the salivary gland) is necessary

• AIDS in evaluation and optimal intervention of ductal strictures & stenosis

CONTRAINDICATIONS FOR SIALOENDOSCOPY

• acute sialadenitis (inflammation of the salivary gland) since it may exacerbate the pain and swelling

• Inability to access the duct (e.g., difficult oral anatomy or angulation of the ducts)

I. DEVELOPMENTAL ANOMALIES OF THE SALIVARY GLANDS

II. INFECTIOUS DISEASES OF THE SALIVARY GLANDS

III. ASYMPTOMATIC ENLARGEMENT OF THE SALIVARY GLANDS

IV. OBSTRUCTIVE DISEASES OF THE SALIVARY GLANDS

V. CYSTS OF THE SALIVARY GLANDS

VI. AUTO-IMMUNE DISEASES THAT AFEFCT THE SALIVARY GLANDS

VII. TUMORS OF SALIVARY GLANDS

VIII. FUNCTIONAL DISORDERS OF THE SALIVARY GLANDS

IX. OTHER SALIVARY GLAND DISEASES / DISORDERS

CLASSIFICATIONS OF SALIVARY GLAND DISEASES

• DUCT ATRESIA

• HETEROTOPIA/ABERRANCY

• APLASIA & AGENESIS

• HYPOPLASIA

• HYPERPLASIA

• ACCESSORY DUCTS & LOBES

• CONGENITAL FISTULA

• DIVERTICULI

DEVELOPMENTAL ANOMALIES OF THE SALIVARY GLANDS

• VIRAL DISEASES

  • MUMPS/ ACUTE VIRAL PAROTITIS / EPIDEMIC PAROTITIS

  • CYTOMEGALIC INCLUSION DISEASE / SALIVARY GLAND INCLUSION DISEASE

  • HUMAN IMMUNODEFICIENCY VIRUS-ASSOCIATED SALIVARY GLAND DISEASE (HIV-SGD)

  • HEPATITIS C VIRUS INFECTION

• BACTERIAL DISEASES

  • BACTERIAL SIALADENITIS

    • ACUTE BACTERIAL SIALADENITIS / ACUTE SUPPURATIVE PAROTITIS

    • CHRONIC BACTERIAL SIALADENITIS

  • CHRONIC SCLEROSING SIALADENITIS / KUTTNER’S TUMOR

  
  

INFECTIOUS DISEASES OF THE SALIVARY GLANDS

• SIALOSIS / SIALADENOSIS

• ALLERGIC SIALADENITIS

• ASSOCIATED WITH MALNUTRITION OR ALCOHOLISM

ASYMPTOMATIC ENLARGEMENT OF THE SALIVARY GLANDS