60- GI System, Teeth, Salv Glands, Peritoneum, Esophagus

enamel hypoplasia occurs before eruption of perm teeth secondary to what

hyperthermia and viral infection

most common cause of enamel hypoplasia in dogs

distemper virus

when must the virus infect the ambeloblasts for enamel hypoplasia? what does it cause?

during enamel formation before 6 months of age

causes necrosis and enamel disorganization

what can cause enamel discoloration

chemicals ingested during enamel mineralization like congenital porphyria causing pink teeth as well as tetracycline

salv glands: mycotoxicosis in cattle and horses

rhizoctonia leguminicola has a wide geographic distribution and infestation of legumes is associated with slobbers syndrome

neuro intoxication and slafarmine/swainsonine both can affect what body part

salv glands

describe salv gland foreign bodies

-can occur due to plant awns/fiber

-parotid duct more affected

-causes inflamm or secondary infection if the duct epithelium is destroyed, localized cellulitis occurs

describe salv gland salivary caliculi

SIALOLITHS

• can cause obstruction and inflamm

• more common in horses

• parotid duct more affected

describe salv gland microliths

formed and removed routinely

secretory inactivity can cause microliths to accumulate leading to large calculi causing obstruction

horses- usually single, hard, white, laminated structures composed of calcium carbonate. whats this describe?

horse microliths

what is a ranula

a smooth rounded fluctuant cystic distention of the duct in the floor of the mouth

what occurs after a rupture of a duct or gland (like with a ranula)

result in a permanent fistula due to continued flow of saliva prevents normal restoration and the duct epithelium eventually fuses with the surface

what can cause dilation of an oral duct

stagnation of flow, foreign bodies, calculi, inflamm strictures

what is an accumulation of salv secretions in a single or multiloculated cavities not lined by secreteory epitheliym

salivary mucocele

where are salv mucoceles present ? due to?

in soft tissues of neck or mouth most commonly on ventrolateral midline

due to duct trauma

sialadenitis

inflam of salv glands

although uncommon what are causes of salv gland inflamm

rabies, horse strangles, dog distemper

what age and type of cancer is most common in salv gland

aged animals, carcinoma

is salv gland carcinoma unilateral or bilateral? what gland is most affected?

unilateral

parotid and mandibular glands most common

____ tend to have more aggressive dz at the time of diagnosis with metastasis to regional LN and distant sites, esp lungs

cats

what neoplasm of salv gland has worse prognosis

adenocarcinomas that have metastasized to nodes or beyond

what causes pyogranulomatous glossitis aka wooden tongue

actinobacillus lignieresii

describe pyogranulomatous glossitis

• normal inhabitant of oral cavity aka an opportunistic invader

  • most common in cattle

• infection from sharp object that penetrate oral mucosa

what causes the wooden tongue characteristic

inflamm and fibrosis that cause increased firmness and enlargement of the tongue giving it the name wooden tongue

horses are rarely affected by wooden tongue but when they are they tend to be

cutaneous or LN abscesses

mastitis

occasional glossitis

common causes of ascites

• hypoproteinemia

• PLE like johne’s dz

• lymphangiectasia

• hypoalbuminemia from malnutriotion or parasitism

why can increased hydrostatic pressure cause ascites

it overwhelms the oncotic pressure and forces fluid out of the lymphatics and into the abdomen

what is the most common cause of increased hydrostatic pressure leading to ascites

right sided heart failure

what is nutritional fat necrosis caused by

high lipid, low vit e diet

why does the high lipid low vit e diet cause fat necrosis

low in free radical scavengers that then results in lipid peroxidation

appearance of nutritional fat necrosis

damaged and necrotic adipose tissue freq have white chalky appearance and gritty texture

most common species for nutritional fat necrosis

cats and those that favor a fist diet

what is pancreatic fat necrosis caused by

caused by pancreatic enzyme (lipase) release during pancreatitis / pancreatic necrosis

how do fatty acids lead to the white deposits with pancreatic fat necrosis

the FA combine with calcium, magnesium, sodium ions to form soaps resultign in chalky white deposits

what can traumatic fat necrosis result from

direct blunt trauma to adipose tissue but is uncommon

describe massive idiopathic fat necrosis in cattle

hard masses of dense necrotic fat that envelops intestinal loops, resulting in stricture and functional blockage of ingesta

idiopathic fat necrosis occurs most likely In

large animal species

what is peritonitis

inflammation of the peritoneum and is caused by a variety of agents

species stoicism with peritonitis

horses show most pain and intolerance

cattle and cats are stoic and can live a long time with severe dz

what is crucial in determining a cause of peritonitis

cytologic examination and bacterial culture

gross appearance of thrush

thick plaque like lesions on mucosal surface thats tan to yellow and friable

can be easy to remove depending on thickness and chronicity

why does thrush occur? examples?

from altered normal oral cavity microflora

examples are antibiotic use and high BG concentrations

species that thrush is most commonly seen in

avian species

what is esophagitis

erosive and ulcerative esophagitis associated with viral dz with similar lesions in the oropharynx or reticulorumen

what are diseases that are associated with esophagitis

bovine viral diarrhea, rinderpest, bovine papular stomatitis, feline calicivirus

differentials that are not illnesses for esophagitis

irritant chemicals, reflux esophagitis, electrochemical reactions from batteries

describe mild acute esophagitis

results in mucosa reddening

severe esophagitis

deep esophageal ulceration and sloughing of mucosa

how does ulcerated mucosa in esophagitis heal

via granulation tissue and raised islands of surviving proliferative epithelium

fibrosis and scarring may cause stricture or stenosis

esophagitis lesions

generally obvious like material occluding the esophageal lumen, lumen stricture from fibrous connective tissue, full wall thickness defect

what will the esophagus look like proximal to the stenotic area with obstruction

dilated, contain retained ingesta, evidence of erosion, ulceration, inflammation

what are the complications of esophageal obstruction

• pressure necrosis and ulceration of mucosa

• progression to perforation

• development in esophageal diverticular or fistulae

most common sequelae of esophagitis obstruction

fibrosis and scarring of large ulcers causing narrowing of lumen, stricture, or stenosis

most common example of intrinsic esophageal obstruction? hows it occur?

esophageal impaction aka choke

occurs when large amg of unchewed food or grain masses lodge in esophagus lumen

esophageal impaction most common in

horses

what makes some sites more likely for esophagus impaction

where esophagus deviates or is slightly restricted like overlying larynx, thoracic inlet, base of heart, cranial to diaphragmatic hiatus

what is dilation from insufficient, absent or uncoordinated peristalsis in the mid cervical esophagus

megaesophagus

what can cause megaesophagus

innervation disorders

partial physical obstructions

secondary to inflamm diseases of esophageal musculature

persistence of right aortic arch

what is congenital megaesophagus caused by

partial blockage of the lumen of esophagus by a persistent right fourth aortic arch. wh

what is the ring of congenital megaesophagus made from

aorta, pulm artery, ductus arteriosus

congenital megaesophagus location

dilation occurs cranial to the heart bc of location of the obstructing vascular ring

all other forms of megaesophagus, besides congenital megaesophagus, occurs where

dilation cranial to the stomach

what is failure of relaxation of the distal esophageal cardiac sphincter of the stomach called

acquired megaesophagus

causes of secondary megaesopgagus

either idiopathic or secondary to a variety of conditions like

• polymyositis

• myasthenia gravis

• hypothyroidism

• more

describe acquired megaesophagus in adult horses

• caused by primary or secondary esophageal obstruction

• short duration bc dilation is reversible but if obstruction is long can cause perm damage

describe acquired megaesophagus in foals

• secondary to esophagitis from gastric outlet or duodenal obstruction

what can esophageal perforation in horses result in

a draining tract

tonsilitis and lymphoid hyperplasia are often lesions associated with?

bacterial and viral infections

why dont tonsils serve as lymph filters

they do not contain afferent lymphatic vessels

what kind of neoplasms occur in tonsils

primary neoplasms like lymphoma and squamous cell carcinoma