Lec 2 - Pathology of the Esophagus & Stomach

Exam 1

T/F: The majority of the esophagus does not have a serosal layer.

TRUE

What are the 2 routes of infection of the esophagus?

1. ingestion

2. penetration

What is achalasia?

esophageal motility disorder → failure of sphincters to relax

What is cricopharyngeal achalasia?

congential disorder of upper esophageal (cricopharyngeal) sphincter

When are you most likely to see congential cricopharyngeal achalasia?

young, small breed dogs (terriers, cockers, mini poodles)

postweaning dysphagia (regurg of solid food, gagging, choking)

T/F: Acquired achalasia is fairly common.

FALSE - typically associated with abnormalilities in cricopharyngeal muscle (fibrosis, muscular hypertrophy or atrophy, myositis

What is megaesophagus and what does it result in?

dilation of the esophagus → insufficient, absent, or uncoordinated peristalsis

What 3 things cause megaesophagus?

1. innervation/denervation disorders

2. partial physical obstruction/ stenosis

3. idopathic

When is megaesophagus usually suspected clinically?

regurgitation after ingestion of solid food → malnutrition, rhinitis & aspiration pneumonia

What is regurgitation?

contents of the mouth, pharynx, or esophagus are expelled

What happens during regurgitation?

gagging, coughing, NO ABDOMINAL EFFORT

What does regurgitation look like?

food undigested ± covered with mucus

often tubular

What is vomiting?

contents of the stomach & upper intestine are forcefully ejected

What happens during vomiting?

ptyalism, nervous behavior, borborygmi, ABDOMINAL EFFORT, heaving retching

What does vomit look like?

food may contain bile, usually digested

What are the 2 forms of congenital megaesophagus?

1. persistent right 4th aortic arch

2. congenital idiopathic megaesophagus

A persistent right fourth aortic arch is formed by what structures?

vascular ring of aorta, pulmonary artery, & ductus arteriosus

Dilation of the esophagus due to a persisent right fourth aortic arch occurs ________ to the heart.

cranial

What breeds are genetically predisposed to a persisten right fourth aortic arch?

GSD, Irish Setters, German Pinscher, Boston Terrier, Greyhounds

T/F: A persistent right fourth aortic arch may be incomplete & diagnosed before 1 year of age.

FALSE - may be diagnosed after one year of age

What is thought to be responsible for congenital idiopathic megaesophagus?

idiopathic denervation

Which breeds are associated with congenital idiopathic megaesophagus?

Great Danes, Irish Setters, Mini Schnuazers, Labs

Can megaesophagus be acquired? Is this common?

yes

no

What is the major form of acquired megaesophagus?

esophageal achalasia → failure of relaxation of the distal esophageal (cardic) sphincter

Dilation of the esophagus secondary to esophageal achalasia occurs _________ to the stomach.

cranial

What are the 5 main causes of esophageal achalasia?

1. idopathic → GSD, Goldens, Irish Setters

2. secondary to polymyositis or inflammation

3. myasthenia gravis → NM Ach receptors

4. hypothyroidism

5. lead & thallium toxicity

What are the 2 main causes of esophagitis?

1. gastric reflux → anesthesia, chronic vomiting

2. viral esophagitis → erosive/ulcerative, feline calicivirus

Inflammation and ulceration of the esophagus may lead to _______.

strictures

most common 2^o to anesthesia

What are 2 less common causes of esophagitis?

1. parasites → Spirocerca lupi form cystic granuloma

2. fungal → Candida albicans (thrush)

What are the 4 main neoplasms that can affect the esophagus?

1. papillomas

2. squamous cell carcinoma (very rare)

3. fibroma, fibrosarcoma, osteosarcoma (Spirocerca lupi)

4. leiomyoma/sarcoma, lymphoma (rare)

What are 2 causes of gastric dilation?

1. young puppies after overeating

2. source of distending gas (aerophagia), fluid, or food → obstruction of cardia & pylorus

What types of dogs are at risk of developing GDV?

large, deep chested breeds (Danes, St. Bernards, Irish Setters, Wolfhounds, etc)

What is the “formula” of events that leads to a GDV?

lax gastrohepatic ligament + overfeeding, postprandial exercise + other predisposing factors

The stomach rotates ________ on the __________ axis when view from the _______ surface.

clockwise

ventrodorsal

ventral

Rotation of the stomach during a GDV is about _______ degrees.

180-360

What other organs can be affected by a GDV?

twisted esophagus

vascular compression → HYPOXIA

What are the chain of events following an unresolved GDV?

gastric hypoxia, acid-base imbalance, antiperistaltic waves → atony, cardiovascular ischemia, arrythmia, shock

pancreatic ischemia → myocardial depressant factor → cardiovascular collapse → DEATH

Gastritis is associated clinically with what signs?

vomiting, dehyrdation, metabolic acidosis

What are the 2 main causes of gastritis?

1. dietary indiscretion

2. generalized gastrointestinal inflammatory diseases (food allergies, idiopathic IBD)

What types of pathogens can lead to gastritis?

1. Bacterial → Heliobacter spp maybe

2. Fungal → Histoplasma capsulatum, Pythium insidiosum

3. Parasitic → T. canis, Physaloptera spp, Gnathostoma, Cylicospirura felineus, Ollulanus tricupsis (cats)

4. Idopathic → scirrhous eosinophilic gastritis of dogs and cats

T/F: Chronic gastric ulcers have fibrosis/ regeneration.

TRUE

What clinical signs are associated with stomach ulcers?

vomiting (hematemesis), inappetence, abdominal pain, anemia, melena

What are some causes of gastric ulcers seen in small animals?

local disturbances in mucosal epithelial barrier, gastric acidity (hypersecretion), blood flow

What are some specific causes of gastric ulcers?

steroids & NSAIDs, Helicobacter spp. (unclear), 2^o to mast cell tumors (histamine release), gastrin secreting tumors (Zollinger-Ellison syndrome), idopathic

Uremic gastropathy is also known as ___________.

uremic gastritis

Uremic gastropathy is secondary to what disease?

chronic renal disease

can also see mineralization w 2^o renal hyperparathyroidism

Uremic gastropathy is characterized by what?

mineralization of the glands, vessels (endothelium), & lamina propria of the gastric mucosa w/ thrombosis, hemorrhage, necrosis ± ulceration

What clinical signs are associated with uremic gastropathy?

hemorrhage → hematemesis & melena