Salivary gland

Saliva

· Contains

— mucin, amylase and maltase

· Function

— Mediation of local immunity

— Protection of mucus membranes from dehydration and microbes

— Delivery of taste molecules to receptors

— Food moistening ® bolus

— Excretion of heavy metals etc in maintenance of fluid balance

· Parotid

— Predominantly serous

· Submandibular

— Mixed mucous and serous

· Sublingual

— Mucous

Anatomy

Parotid

Embryology

· Outward growth of buccal cavity

· Parotid bud visible @ 4/40

· Consists of endoderm advancing into mesenchyme of stomaderm

· Lies in close proximity to 1st and 2nd branchial arches

Anatomy

· Largest salivary gland

· Weight 15 –30g

· Irregular lobulated flattened pyramid

· Within gland

— Facial n. superficial

— retromandibular v. ¯

— ECA deep

· Parotid duct

— 5cm long, 5mm diameter

— Passes across masseter and round ant border to pierce buccinator

— Opens opp 2 upper molar

· Accessory parotid lies on masseter between duct and zygomatic arch

· Lymphoid tissue both anterior and within parotid gland (part of MALT)

— 23 LN …

Poles

· Upper concave against ext auditory meatus, TMJ

· Lower rounded inf and post angle of mandible, indented by mandible& SCM wraps round post belly digastric

Surfaces

· Lateral

— Skin, superficial fascia, superficial layer parotid fascia

· Anterior

— U shaped, clasps ramus of mandible with masseter ext and medial pterygoid muscle int

· Deep (posteromedial)

— Mastoid, styloid process and muscles, internal jugular vein, internal carotid artery, pharyngeal

wall

v Enclosed in parotid sheath (from investing layer of deep cervical fascia)

— Superficial layer attached to mastoid, esternal auditory meatus, zygomatic arch

— Deep layer attached onto mastoid, tympamic part of temporal bone, carotid sheath, styloid process and mandible - forms stylomandibular lig between stylid process and angle of mandible

Lobes

v Arbitarily seperated by facial N.

· Superficial

· Deep

Relations

Gt Auricular nerve

· Arises C2, 3

· Emerges midpoint post border SCM, passes vertically up deep to platysma, behind EJV

· Splits into anterior and posterior within parotid fascia

— Anterior Skin over parotid and ear lobe

— Posterior Retroauricular skin

Facial nerve

· Emerges through stylomastoid foramen @ base tympano-mastoid groove

® Post auricular branch to occipitalis

· Passes deep to superficial, lateral to styloid process above origin of stylohyoid muscle

® muscular branches to stylohyoid and post belly digastric

· Enters parotid @ post medial border

v Stylomastoid artery lies anterior (branch of post auricular a)

· Variable division within gland

— Commonest is division into temporozygomatic & cervicofacial

· 5 terminal branches commonly exit anterior surface

Blood supply

· ECA

· Retromandibular v

Innervation

· Post ganglionic parasympathetic secretomotor fibres from otic ganglion along auriculotemporal n

· Sympathetic (vasoconstrictor) from sup cervical ganglion via ECA

Submandibular gland

· Large superficial part and small deep around mylohyoid

Relations

Superficial

· Between mandible, mylohyoid and investing layer of deep cervical fascia

Lateral surface

— Submandibular fossa of mandible

— Overlaps anterior insertion med pterygoid

— Grooved post by facial a

Superficial (inferior)

— Skin, platysma, investing fascia

— Crossed by facial v and Cx branch VII ± marg mandib VII

Medial

— Ant mylohyoid

— posteriorly hyoglossus, lingual n, submandibular ganglion, hypoglossal n, deep lingual v

Deep

· Between mylohyoid and hyoglossus

Superior

— Lingual nerve

Inferior

— Submandibular duct, hypoglossal nerve

— Duct 5cm long emerges from deep part runs between mylohyoid and hyoglossus ® between sublingual gland and genioglossus

Blood supply

· Facial artery

· Facial vein

Innervation

· Secretomotor fibres from submandibular ganglion along lingual n

Sublingual

Anatomy

· Almond shaped

· Lies in front of ant border hyoglossus

· Between myoglossus and genioglossus

· Sublingual fossa of mandible laterally

· 15 ducts

— 1/2 open into submandibular dcut

— 1/2 directly on the sublingula fold

Blood supply

· lingual artery, submental artery

Innervation

· Submandibular ganglion

Infective lesions

Viral

Mumps

· Caused by paramyxoviruses

· Primarily affects children

· Prodromal maliase 21/7

· Contagious disease 10/7

Clinical

· Bilateral parotid swelling (uncommonly unilateral)

· Fever

· Chills

· Joint pain

· Trismus

· Encephalitis

· Nephritis

· Myalgia

· Uncommon

— Epididymitis

— Orchitis: 20% of males after puberty, but sterility rarely develops

— Meningoencephalitis

— Pancreatitis

— Thyroiditis

— Unilateral hearing loss

Coxsackie, HIV and echovirus also cause sialoadenitis in teenagers and adults

Acute bacterial sialoadenitis

· Parotid > sub mandibular

Risk factors

· Dehydration

· Poor dental hygiene / dental, periodontal disease

· ¯ salivary excretion: dehydration, oral sepsis, septicaemia, radiotheraphy

· Drugs which reduce salivary flow: Tricyclics, phenothiazines

· Duct obstruction by stone

· neonate

· elderly

· postsurgical

Clinical

· Progressive unilateral painful (parotid) swelling

· Fever & chills

· Trismus

· Dysphagia

· Erythema

Micro

· Staph aureus

· Strep viridans

· E coli

· Anaerobes

Treatment

· Broad spectrum antibiotics

· Rehydration

· ± I&D, removal of calculus if present

Chronic sialoadenitis

· Recurrent acute attacks

· Sialography normal

· Gland ®fibrotic®resolution

Treatment

· No active treatment required, sialogogues, massage, rehydration and sialoadenectomy in refractory cases.

Granulomatous sialoadenitis

Causes of granulomatous disease in salivary glands include:

            Wegener’s granulomatosis.

            Sarcoidosis

                        (6% develop salivary dx with anterior uveitis- diagnosis by labial biopsy)

            Mycobaterial disease (M tuberculosis or M avis (AIDS))

            Syphilis

            Cat scratch disease

Clinicopathological

· Granulomatous inflammatory disease of parotid or submandibular

· Retrograde or haematogenous route

Diagnosis

· FNA

· Skin test

· CT/MRI

Treatment

· Anti TB (M TB)

· Excision for atypical infections (M avis)

Actinomycosis

· Filamentous rod shaped anaerobes

· Assoc with spread from dental/peridontal or GI disease

· Granulomatous inflammation with abscess and fistulae

· Treat with long term penicillin

Cat scratch disease

· intracellular bacterium Bartonella (Gram neg organism)

            The organism in the cat’s blood stream

            Cat flea, also acting like the vector, then causes intradermal inoculation of this organism

            The disease transmits could transmit via cat scratch or bite; or via flea faece into the human wound

most commonly in children 1-2 weeks following a scratch or bite from a cat

Classic cat scratch disease

            tender and swollen regional lymph nodes (may last 2-4 months) proximal to bite

                        suppurative and granulomatous lymph node

            papule at the site of initial infection.

            fever and other systemic symptoms

                        headache, chills, backache and abdominal pain

            It may take 7 to 14 days, or as long as two months, before symptoms appear.

            usually resolves spontaneously, with or without treatment, in one month.

Atypical cat scratch disease takes several different forms depending on organ systems, commonly in immunocomprised patients

Parinaud's oculoglandular syndrome is a granulomatous conjunctivitis with concurrent swelling of the lymph node near the ear. Optic neuritis, involvement of the retina, and neuropathy can also occur.

Bacillary angiomatosis is caused by Bartonella henselae, the causative organism of cat scratch disease. It is primarily a vascular skin lesion that may extend to bone or be present in other areas of the body. In the typical scenario, the patient has HIV or another cause of severe immune dysfunction.

Bacillary peliosis is a condition that most-often affects patients with HIV and other conditions causing severe immune compromise. The liver and spleen are primarily affected, with findings of blood-filled cystic spaces on pathology ^[9]

Acute encephalopathy (generalized dysfunction of the brain) can occur. The New York Times Magazine described a case, presenting as a meningitis, with fever, headache, and impaired vision (due to swelling of the optic nerves).^[10] Despite the severity of initial presentation, patient outcome can be favorable.

Enlarged spleen and sore throat can also occur in rare cases

HistoPathology

the skin lesion demonstrates a circumscribed focus of necrosis, surround by histiocytes, often accompanied by multinucleated giant cells, lymphocytes, and eosinophils. The regional lymph nodes demonstrate follicular hyperplasia with central stellate necrosis with neutrophils, surrounded by palisading histiocytes (suppurative granulomas) and sinuses packed with monocytoid B cells, usually without perifollicular and intrafollicular epithelioid cells. Organism could be seen in the necrotic centre with Warthin-Starry stain or the Brown-Hopp modification of the Gram stain.

Investigations:

            Serology:

                        ELISA or IFA on antibody of Bartonella IgM (88-98%) or IgG(50-62%)

            Biopsy:

                        Lymph node Excisional Biopsy is discouraged

                        Consider LN FNA if in doubt for malignancy – sent for PCR

                        Liver and Spleen FNA: for bacillary peliosis

                        Skin biopsy for papule

            CT:     

                        Only perform in the disseminated case

· Treatment

Rehydration

Antibiotics for 2° infection

            Azithromycin, ciprofloxacin, doxycycline

            Azithromycin is especially used in pregnancy, to avoid the side-effects of doxycycline

Obstructive

Stricture

· Congenital abnormality

· Repeated infection

· Compression by tumour

· Iatrogenic injury

· Trauma

Investigation

· Sialogram (CT)

Treatment

Orifice stenosis

· Dilatation

· Stenotomy, cannulation / marsupilisation

— Failed dilatation

· Re-implantation/ligation

— Very occasional

Proximal

· Gland excision

· Duct ligation

— elderly

Kussmaul’s disease

· Mucinous plugs obstruciting duct

· Same risk factors and treatment as for bacterial sialoadenitis

Sialolithiasis

· Primary or secondary (?)

— Primary more common with submandibular (80%)

· Stasis usually associated with predisposing factor

— Anatomical duct alteration

— Damaged duct epithelium: trauma, infection

— Stricture

—   Systemic disease: Hyperparathyroidism, hyperuricaemia, hypercalcaemia

—   80% of stones affect the submandibular gland; 80% of submandibular stones are radio-opaque

—   Submandibular stones are more common because of a higher pH, more calcium, phosphate and mucus.

—   A salivary stone consists of a core of mucoprotein and micro-organisms and an outer layer calcium and phosphate with some magnesium, carbonate and urate.

Clinical

· Recurrent glandular swelling

· Initially associated with meals

· Most common in middle-aged men.

Investigation

· Palpation

— Bimanual

· Plain Xray

· Sialogram

Treatment

· Distal

— Excision of stone

· Proximal

— Excision of duct and gland

If a stone is detected, the goal of treatment is to remove it. For small stones, stimulating saliva flow by sucking on a lemon or sour candies may cause the stone to pass spontaneously. In other cases where stones are small, the doctor or dentist may massage or push the stone out of the duct.

For larger, harder-to-remove stones, doctors usually make a small incision in the mouth to remove the stone.

More and more, doctors are using a newer and less invasive technique called sialendoscopy to remove salivary gland stones. Developed and used successfully in Europe for a decade, sialendoscopy uses tiny lighted scopes, inserted into the gland's opening in the mouth, to visualize the salivary duct system and locate the stone. Then, using micro instruments, the surgeon can remove the stone to relieve the blockage. The procedure is performed under local or light general anesthesia, which allows the patient to go home right after the procedure.

For people with recurrent stones or irreversible damage to the salivary gland, surgical removal of the gland is necessary.

In addition, antibiotics are prescribed if salivary stones have caused infection.

Lymphoepithelial lesions

Mass of lymphoid tissue within a salivary gland containing foci of epithelial cells of ductal origin. The incidence of lymphoma with benign lyphoepithelial lesions is 20%. NHL B cell.

Primary

· Autoimmune mediated atrophy of salivary ± lacrimal glands – Sicca syndrome

Secondary

· Associated with Connective Tissue disease - Sjögrens

— SLE, RA, polymyositis, polyarteritis, waldenstroms

Clinical

· Female

· Median age 50

· Dry eyes with chronic pruritus

· Xerostomia (dry mouth)

· Oesophageal webs

· Bronchial sicca

· Arthritis

· Multiorgan vasculitis

· Raynoud’s

· Thyroiditis

· Anaemia, purpura, macroglubulinaemia

· NHL

Investigation

· Biopsy of lip salivary glands

Treatment

· Symptomatic

· Monitor for development of lympoma ± ca oesophagus

· HIV associated salivary gland disease

· Parotid enlargement and variable xerostomia associated multiple lymphoepithelial cysts. · Infiltrate of CD8+ lymphocytes, anti-Ro and anti-La negative. Occurs in 20% of HIV positive children.

Sialectasis

· Recurrent and chronic sialadenitis of parotid gland

· Destruction of alveoli and parenchyma of salivary gland with stenosis of duct and cyst formation due to ductal obstruction and dilatation.

· Calculi may be found in duct

· May be a history of recurrent swelling after eating

· Sialogram will show sialectasis

· The definitive treatment is usually total parotidecomy

Parotid gland enlargement

Pseudo-parotomegaly

· Winged mandible, mandibular tumour, dental cyst, branchial cyst, Lipoma, sabecous cyst, pre-auricular lymph node.

· Sialosis – recurrent swelling of salivary glands not caused by neoplasia or inflammation. Due to swelling of acini

· Diabetes, gout, cushings, myxoedmea

· Medications: Detropropoxyphene, clonidine, COCP, thiouracil, phenylbutazone

· Alcoholism, cirrhosis

· Chronic liver disease

· Bulimia, anorexia

Investigation of sialosis

· Full ENT and general examination to exclude malignancy

· FBC, ESR, HIV test, anti-Ro/La, RhF, ANA, LFT, X-ray, sialogram, TFT, MRI, CT

· Sublabial Biopsy for evidence of Sjorgren’s syndrome

· Avoid True cut or incisional biopsy of salivary gland to avoid seeding malignancy

· FNA may be useful to exclude malignancy