Salivary Glands Flashcards
Discuss the Parotid gland and Facial nerve and their arrangement
Parotid gland:
- divided into superficial and deep lobe
- is located in narrow space between the posterior part of the mandible
- Enlarges when inflamed and can be palpated
The facial nerve:
- originates from the stylomastoid foramen
- Travels inbetween the superficial and deep lobes of the parotid gland
- Divides into 2 trunks: the temporo-facial and the cervico-facial, and then into little branches. Occasionally one of these branches can be palsied e.g. resulting in the external part of the lip being paralysed (marginalis mandibulae)
Which 2 fascie are in relation with parotid gland?
Discuss the parapharyngeal space
Superfical fascia with a fibrous platysma aponeurosis
Deep facia
Pathologies of the parapharyngeal space affect the deep lobe. REMEMBER THAT PAROTID GLAND HAS STRICT CONNECTION WITH LATERAL WALL OF THE PHARYNX
Discuss the vascularisation of the facial nerve
- posterior auricular artery
- stylomastoid artery
Both are branches of external carotid artery
Veins
- posterior facial vein –> empties into jugular vein
Describe the submandibular gland and the nerves it intimately connects with
Submandibular gland is in close relation with inf. mandible, deep muscles of oral cavity and tongue.
Three important nerves are the lingual nerve, hypoglossal nerve and marginalis mandibulae
Note: This is level 1 of the neck - where many oral cavity tumours have lymphatic drainage
Describe the scretory unit of a salivary gland (microanatomy)
The acinus (serous/mucous/mixed) Myoepithelial cells Intercalated duct Striated duct Excretory duct
Fully describe the duct of the parotid gland and the duct of the submanibular gland
Stensen’s duct - parotid gland
Wharton’s duct - submandibular gland
Stensen’s is straight in a horizontal direction to the cheek. Wharton’s has a sharp bend (curved) therefore more vulnerable to inflammatory disease / stone production
Detail how the saliva is modified as it moves through the duct - and its composition in various glands
Striated duct (serous): HCO3 into lumen, Cl out of lumen Intercalated ducts (serous): K+ into lumen, Na+ out of lumen Excretory ducts: DO NOT MODIFY SALIVA
Parotid: Serous and fatty
Submandibular: Mixed serous
Sublingual: Miixed mucous
Minour glands: Mucous
Detail the functions of saliva
- Moistens oral mucosa
- Moistens and cools food
- Medium for dissolved food
- Buffer (HCO3)
- Digestion (amylase and lipase)
- Antibacterial and defensive (IgA, proteases, cathepsins)
Describe the innervation of salivary glands and the saliva flow in different states
Autonomic innervation: Sym. and Para sym. are not antagonistic!!!
Parasympathetic: Abundant and watery saliva. Amylase and other proteins decrease
Sympathetic: Scant and viscous saliva. Amylase and other proteins increase.
Parasympathetic
CN 9 -> Parotid
chorda tympani nerve -> submandibular
sublingual nerve -> sublingual gland
Sympathetic
- superior cervical ganglion
- external carotid artery
- lingual artery
- facial artery
FLOW
1 - 1.5L / day
Unstimulated : submanibular background secretion
Stimulated: parotid
Give a full description of xerostomy as well as its causes and its treatments
A severe reduction in the volume of saliva - causes tongue pain. Tongue looks muscular
Causes:
- alteration of salivary function by psychotropic drugs and diabetes
- Irradiation for carcinomas of head and neck
- Graft vs Host disease
- Rare systemic disseases
- Candidiasis
Treatment:
- Muscarinic agonists
- Hydration
- Oral Hygiene
- Saliva surrogates
- Lubrifying agents
Fully describe sialorrhea, causes and treatments
Increased in the quantity of saliva. Quite rare. Usually psychogenic / neurological / hormonal causes
May be treated with injection of botulinum into the major salivary glands (depending on the underlying cause)
List the main pathologies of the salivary gland
Benign tumours Malignant tumours Inflammatory diseases Infectious diseases Granulomatous diseases Autoimmune diseases
Describe the diagnostic tools used for glandular enlargement
History Physical examination (inspection, palpation)
1st level exam: ULTRASOUND - we can see if nodule/benign/malignant and request FNA
2nd level exam: MRI (Not CT) - able to detect lesions in the deep space
Discuss the inflammatory and non-inflammatory diseases of salivary glands (non neoplastic)
Skin appears red and painful.
Can be Ranula’s - traumatic lesions of the minor salivary gland which close the excretory gland - saliva accumulates
MUMPS AND ANIMAL SCRATCH DISEASE are the main ones. Others can be recurrent parotiditis, sarcoidosis, Sjogren’s Syndrome etc
2 swollen parotids could be HIV associated sialoadenitis
Fully describe sialolithiasis , it’s diagnosis and treatment
Stones of the salivary glands. 80% found in sub. M gland (majority are radiopaque), 20% in parotid (majority are radiolucent). Usually just 1 stone.
PAINFUL - worsens with eating
Complications include ductal atresia, sialadenitis and stricture
Diagnosis: SIALOENDOSCOPY - which is minimally invasive, both diagnostic AND THERAPEUTIC. Local anesthetic. Alternatively US performed (in past)
Therapy: Above. Only for parotid and sub M. gland. If stone is >4mm, it must be fragmented with endoscopic laser lithotripsy. also ANTIBIOTICS
Limit: only proximal stones
Pros: High sensitivity and specificity, can also be used to dilate the duct (if stenotic)
Cons: Pricey, long term results unknnown
Describe sialadenosis
Non-neoplastic, non-inflammatory enlargement of salivary glands associated with systemic disorders Usually asymptomatic • Causes: Obesity Malnutrition Malabsorption alcoholic cirrhosis
State the distribution of salivary gland neoplasms
2% of all head and neck neoplasms
Distribution
Parotid: 80% overall; 80% benign
Submandibular: 15% overall; 50% benign
Sublingual/Minor: 5% overall; 40% benign
Discuss minor salivary gland neoplasms
They are frequently malignant. The most common is the adenoid cystic carcinoma (ACC). Can arise from any subsite of head and neck mucosa
Distribution (most frequent)
Cheek
Palate
tongue
Commonly present as a nodule
Fully describe pleomorphic adenoma, its treatments and complications
THE MOST IMPORTANT BENIGN LESION
- Slow-growing, painless mass
- Parotid: 90% in superficial lobe, most in tail of gland
- Minor salivary gland: lateral palate, submucosal mass
- Solitary vs. synchronous/metachronous neoplasms
- Has a pseudocapsule
Pathology:
Smooth, Well demarcated, Solid, cystic changes, myxoid stroma
Treatment
Complete surgical excision:
- Parotidectomy with facial nerve preservation
- Submandibular gland excision
- Wide local excision of minor salivary gland
COMPLICATIONS
Can be multifocal (requires excision of all the tissue around the tumor)
Reoccuring - makes therapy challenging, adhesions mask the facial nerve and risk of palsy is high
Evolution into a squamous cell carcinoma in 15% of untreated cases
Fully describe Warthin’s Tumour
aka papillary cystadenoma lymphomatosum
Presents as a slow-growing, painless mass. Makes up 6-10% of parotid neoplasms.
Largely affects older, Caucasian, males
- normally very big mass
- if bilateral, remove 1 at a time with a few months in between to avoid double sided facial paly
- may also affect submandibular gland
- 10% bilateral or multicentric
- 3% with associated neoplasms
Treatment: Complete surgical excision. Superficial parotidectomy (save the facial nerve)
Compare 2 groups of salivary malignant tumours
Mucoepidermoid tumour and acinic cell tumour
(slow growing, local invasion, rarely metastasize, variably malignant)
vs
Adenoid cystic, adenocarcinoma, epidermoid, undifferentiated and malignant mixed
(high malignancy, both slow and fast growing, early local invasion, frequently metastatic)
Describe the mucoepidermoid carcinoma
Most common salivary gland malignancy
- 5-9% of salivary neoplasms
45-70% of cases involve parotid gland
Palate 18%
Affects people in 3rd-8th decades, peak in 5th decade
F>M
Treatment: Influenced by site, stage, grade
1. Stage I & II
• Wide local excision
- Stage III & IV
• Radical excision
• +/- neck dissection
• +/- postoperative radiation therapy
Describe the acinic cell carcinoma
2nd most common parotid and pediatric malignancy. Presents as solitary, slow-growing, often painless mass
- Peaks in 5th decade
- F>M
- Bilateral parotid disease in 3%
Treatment: complete local excision and postoperative radiation
5year survival is 82%
Fully describe the adenoid cystic carcinoma
Overall 2nd most common malignancy
Most common in submandibular, sublingual and minor salivary glands
- M = F
- 5th decade
Presentation:
Asymptomatic enlarging mass
Pain, paresthesia, facial weakness/paralysis
Treatment:
- Complete excision
- Tendency for perineural invasion - requires sacrifice of the facial nerve
- Postoperative radiation
- Neck dissection
Frequently recurs
5 year survival is 75%
