Pathology of the oral cavity

Question 1

Developmental abnormalities of the oral cavity

Answer 1

Palatoschisis (cleft palate)

Cheiloschisis (cleft lip or hare lip)

Prognathia

Brachynathia (micromandible or hypognathia)

Agnathia

Question 1

Palatoschisis and cheiloschisis

Answer 1

Cleft palate and clept lip

Among most common developmental abnormalities

Genetic or toxin in origin

Can mean an inability to create a negative pressure in the oral cavity

Many die due to starvation or aspiration pneumonia

Question 2

Treatment of Palatoschisis (cleft palate) and cheiloschisis (cleft lip or hare lip)

Answer 2

If small defect: may be corrected surgically

If large defect: surgery will be costly and difficult, may not be compatible with life

Question 3

Prognathia

Answer 3

refers to the characteristic of having projecting jaws, in some dog breeds is part of their phenotype (Brachycephalics).

Question 4

Brachynathia (micromandible or hypognathia)

Answer 4

An abnormal shortness of the mandible, rarely seen

Can cause abnormal wearing of the teat

Question 5

Agnathia

Answer 5

A congenital abscence of all or a major proportion of the jaw

Question 6

Anatomy of the tooth

Answer 6

Crown - above gum
Root

3 parts:
- enamel
- dentine
- pulp cavity

Question 7

Abnormalities of the teeth

Answer 7

Malocclusions

Discolouration of teeth

Discolouration of the oral cavity

Odontodystrophy

Infection of teeth

Question 8

Malocclusions of the teeth

Answer 8

failure of the upper and lower incisors to interdigitate properly leading to uneven wear and in some species e.g. rodents - difficulty in prehension and mastication.

Can be caused by polydontia/oligodontia.

Question 9

Discolouration of teeth - Congenital porphyria, congenital pink tooth or erythropoietic porphyria

Answer 9

Teeth are pink due to congenital inability to metabolise haemoglobin pigments. Porphyrins are incorporated into dentin and fluoresce, easily demonstrated under ultraviolet light.

These pigments also produce photosensitivity in skin. This results in severe sunburn if animal exposed to normal levels of sunlight, especially in light skin or hypopigmented areas.

Question 10

Discolouration of teeth by drugs

Answer 10

Some drugs are also photosensitising agents e.g. phenothiazine which was used as an anthelmintic and tetracycline antibiotics. If you inject bitches with tetracycline when pregnant, produces puppies with brown teeth, which fluoresce under UV light.

Question 11

Discolouration of teeth by haemosiderin

Answer 11

Haemosiderin may also produce pinky / brown colour to teeth usually due to damage and haemorrhage into tooth.

Question 12

Discolouration of teeth by pus

Answer 12

-Pus in tooth results in discolouring of tooth (N.B. single tooth rather than all teeth as in porphyria).

Question 13

Anaemia of the oral cavity

Answer 13

Very pale, confirm with blood sample

Question 14

Jaundice of oral cavity

Answer 14

yellow, icterus.

Main 3 pathogenesis of jaundice in an animal are:
- pre-hepatic (haemolysis),
- hepatic (hepatitis - viral, bacterial, parasitic, immune mediated, toxic etc.),
-post-hepatic/obstructive (obstructions or compressions of the biliary system - neoplasia (e.g. of duodenum))

Question 15

Cyanosis of oral cavity

Answer 15

Cardiac insufficiency or toxic

Question 16

Discolouration of the oral cavity

Answer 16

Anaemia

Jaundice

Cyanosis

Congestion

Petechial haemorrhages

Question 17

Odontodystrophy

Answer 17

Caused by toxic, nutritional, and metabolic insults.

Damage to ameloblasts (which form enamel) in utero upsets permanent incisor formation.

Enamel is marked by pits, lines, etc.

In canines:
* Segmental enamel hypoplasia occurs as a result of hyperthermia and viral infections (distemper virus).
* Infection of ameloblasts must occur before 6 months of age or in utero.

Question 18

Infection of teeth

Answer 18

1. direct infeciton of pulp cavity
2. Gingival crevice inflammation

Question 19

Direct infection of pulp cavity

Answer 19

e.g. in a dog whose canine tooth has been snapped off while biting stones etc. to expose pulp.

May have infection in pulp cavity from circulating pyaemia producing pulpitis.

Question 20

Gingival crevice inflammation

Answer 20

mostly in carnivores (dogs and cats), may occur in horses.

Gingival inflammation starts because of dental calculus (tartar – subgingival plaque).

Question 21

Formation of dental calculus

Answer 21

Dental plaque becomes calcified and whole crown may become covered in brown chalky material.

Dental calculus forms more common from diets high in minerals and diets consisting of soft rather than hard crunchy food.

Calculus gives brittle dirty brown covering to tooth. May not affect enamel at all but may produce mild gingivitis round edge and gum starts to recede. This exposes more of crown, may reach level of dentine and infection may enter the alveolus and loosen ligaments holding tooth in. Tooth will become loose and fall out.

A more virulent infection into the alveolus produces alveolar periostitis. Infection spreads from pulp or from gingivitis to produce alveolar periostitis. May break out of alveolus into bone causing osteomyelitis.w

Question 22

Stomatitis

Answer 22

Generalised inflammation throughout the mouth

common in animals and can be related with infectious and non-infectious (physical trauma, chemicals, uraemia, autoimmune diseases) causes.

Erosions, ulcerations and necrosis are commonly seen as the final result of mild stomatitis as ingested substances move around the oral cavity leading to more damage to mucosa.

Question 23

Cheilitis

Answer 23

Inflammation of the lips

Question 24

Glossitis

Answer 24

Inflammation of the tongue

Question 25

Palatitis

Answer 25

Inflammation of the palate

Question 26

Gingivitis

Answer 26

Inflammation of the gingiva

Question 27

Tonsilitis

Answer 27

Inflammation of the tonsils

Question 28

Pharyngitis

Answer 28

Inflammation of the pharynx

Question 29

Classification of types of inflammation of mucosa: (any mucosal surface) From mildest to most severe

Answer 29

Catarrhal
Vesicular / erosive
Ulcerative
Diptheritic / fibrinous
Haemorrhagic

Question 30

Catarrhal stomatitis

Answer 30

Non-specific, general stomatitis. May produce bad smell

Question 31

Pathogenesis of catarrhal stomatitis

Answer 31

low grade streptococcal infection

ingestion of toxins

result of other more systemic diseases

Question 32

Pathology of catarrhal stomatitis

Answer 32

Starts as hyperaemia and oedema of tongue or pharynx with mucoid exudate on surface.

Lymphoid follicles on soft palate may enlarge and proliferate (hyperplasia), often seen as white spots.

There is an increased mucous secretion (can be scraped off to leave ordinary mucosa underneath).

Resolves normally if not secondarily infected.

Question 33

Vesicular / Erosive stomatitis

Answer 33

Damage to prickle cells (stratum spinosum) with hydropic degeneration leads to vesiculation (fluid within epithelium).

Lesion quickly erodes leaving hyperaemic stratum germinativum, which heals by proliferation of new cells, so long as infection does not continue.

Question 34

Pathogenesis of vesicular/erosive stomatitis

Answer 34

Ingestion of hot food (corrosive liquids)

autoimmune disease (pemphigus vulgaris, bullous pemphigoid, mucous membrane phemphigoid)

Question 35

Vesicular stomatitis pathology

Answer 35

The macroscopic lesions in vesicular stomatitides are epitheliotrophic, mostly in the mouth and are associated with viruses.

Vesiculation or blistering is present early in the course of diseases in this type of stomatitis.

Erosions, ulceration, necrosis, and secondary bacterial or fungal infection occurs later.

Question 36

Vesicles in dogs

Answer 36

Vesicles in mouth are often caused by hot food - especially in dogs.

Can produce quite big vesicles, but will heal.

No major problems associated with vesicles on tongue in dogs (except if due to drinking battery acid, but this also produces vomiting).

Occasionally see vesicles with autoimmune disease (pemphigus) in mouth or on lips of dog.

“True ulcer” occurs when connective tissue under epithelium is exposed i.e. stratum germinativum is breached and then lesion takes much longer to heal.

Secondary bacterial invaders of these lesions may result in more severe stomatitis.

Question 37

Erosive and ulcerative stomatitis

Answer 37

Erosions are loss of part of the surface epithelium, whereas ulcers are full epithelium loss exposing the basement membrane or tissues beneath the basement membrane.

These lesions can be related to infectious and non-infectious causes.

Feline calicivirus.

Foreign bodies, uraemia, feline eosinophilic granuloma complex, autoimmune diseases.

Question 38

Aetiology of ulcerative glossitis in cats

Answer 38

Calicivurs (7-80%), picornavirus and feline immunodeficiency virus (FIV)

Question 39

Animals affected by Ulcerative glossitis in cats

Answer 39

Youngish to middle age

Question 40

Clinical and pathology of Ulcerative glossitis in cats

Answer 40

Whole back of mouth with ulcerative granulation tissue

Question 41

Aetiolofy of Eosinophilic granuloma complex

Answer 41

Not known

Autoimmune?

Question 42

Animals affected by Eosinophilic granuloma complex

Answer 42

Any age, usually young adult cats

Question 43

Clinical and pathology of Eosinophilic granuloma complex

Answer 43

Skin and oral cavity affected

Stomatitis and infiltrative eosinophilic stomatitis

Question 44

Ulcerative glossitis (cat)

Answer 44

Unable to eat although wants to.

Hurts to open mouth.

Chronic, tends to start at angle of jaw (bilateral), progression quite slow but over weeks affects whole of back of mouth.

May also affect tongue.

Question 45

Pathology of ulcerative glossitis in cats

Answer 45

Epithelium lost over whole of mucosa, lots of macrophages, lymphocytes, and proliferating fibrous response at base.

Question 46

Pathogenesis of ulcerative glossitis (cat)

Answer 46

Probably viral.

Calicivirus found in 7-80%, also often find picornavirus and feline immunodeficiency virus (FIV). Probably calicivirus that starts it.

Feline calicivirus causes mainly a respiratory infection. The infection may be followed by autoimmune / exaggerated immune response which produces lesions.

Also owners often claim develops after ‘having cold’ prior to it.

Will heal eventually, but takes time and cat loses lots of condition.

Question 47

Eosinophilic ulcer

Answer 47

Or eosinophilic granuloma, lick granuloma, labial ulcer, rodent ulcer. In cats of all ages.

Mainly affects mucocutaneous junctions of the lips, may also occasionally affect frenulum of tongue and skin.

Inflammatory disease but is progressive and destructive. In worst cases may erode away whole nose.

Question 48

Pathogenesis of eosinophilic ulcers

Answer 48

Histologically lots of eosinophils, neutrophils.
Exaggerated eosinophilic response.

Question 49

Treatment of eosinophilic ulcers

Answer 49

corticosteroids if confirmed

Question 50

Uraemia

Answer 50

In terminal renal failure (chronic renal disease) animal may present with fetid ulcerative stomatitis, painful ulcers in mouth, which become secondarily infected with bacteria.

Most commonly seen in dog sometimes in cat.

Ulcers on lateral elements on tongue.

Vasculitis.

Question 51

Physical causes of ulcerative stomatitis

Answer 51

any animal that is exposed to coarse feed or sharp things in food can suffer from ulcers in mouth.

They often become secondarily infected with production of metastatic infection that may result in large abscess on point of jaw. i.e. trauma on tongue may lead to secondary infection that may lead to abscess in drainage lymph node.

Question 52

Fibrinous/diphtheric stomatitis

Answer 52

Severe damage to epithelium produces exudation of fibrin -with formation of dry white fibrinous deposit - diphtheritic membrane.

Deep ulcers may occur due to trauma and produce a fibrin-covered ulcer.

Usually associated with organism Fusobacterium necrophorum found everywhere in environment (but N.B.- strict anaerobe).

Produces lesions that damage epithelium due to toxin that damages vessels.

Often a secondary invader but can be a primary pathogen.

Question 53

Haemorrhagic inflammation

Answer 53

Complete loss of integrity of epithelium leading to haemorrhage.

Uncommon.

Epithelium lost and haemorrhage produces blue / black discoloration of the tongue, hence the name.

Question 54

Proliferative stomatitis

Answer 54

Stick injuries in dog

Sticks may damage to pharynx with oedema and swelling in pharynx and secondary infection.

Can kill dog.

Pieces of wood may remain embedded in back of throat resulting in chronic inflammation.