Lecture 5 - Esophagus, stomach, and rumen

What is achalasia?

Defective upper sphincter (difficult swallowing) or lower sphincter (persistent regurgitation)

What is ectasia?

Dilation of esophagus so it no longer contracts or propels normally (megaesophagus)

What are three potential causes of a megaesophagus?

1. Persistent right fourth aortic arch (PRFAA)

2. Congenital dilation of esophagus

3. Acquired megaesophagus (toxic or neuromuscular)

What are four areas where choke can occur?

1. Dorsal to the larynx

2. Thoracic inlet

3. Base of the heart

4. Diaphragmatic hiatus

What can gastric reflux cause? What can colonize as a result?

-Ulcerative esophagitis

-Candida albicans can colonize

What is the most common tumor type found with esophageal neoplasms?

Squamous cell carcinoma

What is tympany (bloat)?

Rumenal distension from accumulation of gas produced by microflora

What is the etiology of primary tympany (frothy bloat)?

Sudden change in diet to one rich in lecithins (ex. legumes, alfalfa, clover) produce a bubbly froth that traps rumenal gas so it cannot be eructated

What will you see on necropsy with a primary tympany (frothy bloat)? How does it occur?

Bloat line - increased pressure on pleural cavity causes impaired venous return, tissues cranial to pleural cavity become congested

What is secondary tympany? What are two causes?

-Inability to eructate correctly → defect in rumenal function

-Can be neurogenic or obstructive

What is the etiology of traumatic reticuloperitonitis?

Sharp foreign object penetrates through peritoneal cavity, diaphragm, and pericardium and causes severe fibrinopurulent inflammatory response

What is rumenitis associated with? When does this usually occur?

-Low pH due to lactic acid accumulation

-Occurs with sudden dietary shift

What is the etiology of a GDV?

-Stomach fills with gas causing it to rotate around its mesenteric root (towards the center of the body) bulling the spleen with it

-Veins are squeezed off causing engorgement of both organs

-If blood supply is cut off for long enough, the stomach can become hypoxic leading to necrosis

What does canine distemper virus cause if it infects gastric epithelium?

Causes apoptosis and mucosal atrophy, can find inclusion bodies

What is the HOT complex in ruminants?

-Haemonchus contortus

-Ostertagia ostertagii

-Trichhostrongylus axei

What is a gastrinoma?

Neoplasm from pancreatic islet that produce excessive gastrin

What are two common types of carcinomas found in the stomach?

1. Squamous cell carcinoma

2. Adenocarcinoma

What is a GIST? What does it develop from?

-Gastrointestinal stromal tumor

-Develops in the nerve cells of the digestive tract wall (myenteric plexus cells)

What gastric neoplasm is most common in species other than dogs?

Lymphoma