Alimentary System - Esophagus, Forestomachs, Stomach Flashcards
What causes congenital megaesophagus?
persistent right aortic arch (PRAA) - right aorta develops instead of the left one and forms a vascular ring with the ligamentum arteriosum that constricts the esophagus
How do animals with persistent right aortic arch typically die?
aspiration pneumonia
Congenital megaesophagus, puppy:
persistent right aortic arch (PRAA)
Where does esophageal dilatation occur in persistent right aortic arch?
cranial to the aorta - can be seen in radiographs
What are the 2 most common causes of acquired megaesophagus? How can it be differentiated from congenital megaesophagus from persistent right aortic arch?
- idiopathic
- manifestation of myasthenia gravis
whole esophagus will be dilatated, not just cranial to the aorta
What causes choke? Where does it most commonly occur? How does it present postmortem?
foreign bodies or food is swallowed and becomes stuck in the esophagus
dorsal to the larynx —> area cannot expand
focal compressive necrosis causing poor vascular supply and ischemia
What are 2 complications of choke?
- regurgitation
- bloat
What is reflux esophagitis? In what animals is it common?
damage to the esophagus due to leakage of acidic gastric contents, causing ulceration and thickened linear epithelium (heart burn)
pigs - more common to have gastric ulcers near the entrance to the stomach
What is a common cause ot erosive-ulcerative esophagitis?
BVD
What is the most common cause of parasitic esophagitis in dogs? How does it present?
Spirocerca lupi
chronic (granulomatous) inflammation in the distal esophagus with nodule formation and may occasionally lead to neoplastic transformation
What are the 2 most common neoplastic transformation in canine parasitic esophagitis?
- osteosarcoma
- fibrosarcoma
Esophageal osteosarcoma caused by Spirocerca lupi occupies space in the thorax. What can this lead to?
Marie’s disease - periosteal proliferation in distal limbs
What is ruminal tympany/bloat? What are the 2 types?
over-distention of the rumen and reticulum by gases produced during fermentation
- PRIMARY - new diets that promote the formation of stable foam (grain, alfalfa, clover)
- SECONDARY - physical or functional obstruction of the esophagus resulting in failure to eructate (vagus indigestion, esophageal papillomas, lymphosarcoma)
What are other names for ruminal tympany/bloat? How does it typically present?
frothy bloat (bubbles in ruminal content), free-gas bloat
assymetrically enlarged rumen causing distention of the paralumbar fossa
How can the cause of ruminal tympany be differentiated?
entire herd = primary due to diet in pasture
single individual = secondary due to physical or functional obstruction of the esophagus
Why is it important to know the time of death when investigating a case of ruminal tympany/bloat?
if bloat is thought to be the cause of death, the necropsy must occur close to the time of death, since all corpses will eventually bloat naturally after death due to the overgrowth of bacteria
Bloat, cow:
What is the most reliable postmortem indicator of antemortem bloat? What else can be used?
bloat line at the level of the thoracic inlet
ruminal pH —> acidic pH of <5.5 is indicative of primary bloat
What causes the discoloration after the bloat line?
bloat causes the diaphragm to push the heart and lungs cranially, causing cardiopulmonary failure and the push of venous blood to the head and neck
What are trichobezoars? Phytobezoars/phytotrichobezoars?
solid concretions of hairballs
hairballs composed mainly of plant material impregnated with some phosphate salts commonly found in the colon of horses
How do trichobezoars compare to enteroliths from the forestomach and abomasum?
not as heavy
What is traumatic reticulitis?
foreign body is swallowed and perforates the reticulum and may puncture lungs, diaphragm, and pericardium (tamponade)
What is hardware disease? What 2 things does it typically lead to?
traumatic reticuloperitonitis due to the ingestion of nails or wire (cattle have a hard time discriminating between hardware and grass)
- vagus indigestion
- ruminal atony
What is a common complication to hardware disease (traumatic reticuloperitonitis)?
chronic pericarditis and epicarditis
(pericardium is thick due to fibrosis)
What is the most common cause of chemical rumenitis? How does it present?
lactic acidosis from grain overload in cattle - grain decreases pH and damages the epithelium and keratinocytes)
green - normal
red = ulceration
What are 2 common complications with chemical rumenitis?
- bacteria and normal flora can reach portal circulation and lead to bacteremia, liver abscesses, and vena cava thrombosis
- opportunistic fungi can cause mycotic rumenitis
What are commonly indicative of old bouts of chemical rumenitis?
stellate ulcers —> focal scar formation from healed ulcers