Alimentary System, Part 3A, Intestine Flashcards
Are congenital anomalies common? Which types are we more likely to see in domestic animals?
Congenital anomalies are relatively common. Ones we are more likely to see are ones in the lumen of the intestine or lack of orifice like in the case of atresia ani.
Define atresia.
atresia: a passage is abnormally narrowed or completely absent.
Define stenosis
incomplete occlusion of the intestinal lumen
Define atresia coli.
Cases of atresi coli = intestine does not connect with the rectum or the anus.
Define atresia ani.
Case of atresi ani = colon is ok but we do not have an anal orifice. They are progressive and will result in fatality if nothing is done.
What is the most common segmental anomaly of the intestine of domestic animals?
Atresia coli
A pig farmer found one of his pigs, around 7 weeks of age, dead in the farm. He brings the body to the pathology lab and asks you what you think this pig died from. The owner says that when the pig was born, it seemed completely normal but then developed abdominal distension shortly after birth. What is your preliminary diagnosis?
Diagnosis: Segmental Anomaly
Pathogenesis: Ischemia of a segment of gut during fetal development?
Explanation: Segmental anomalies in the intestine are relatively common and can range from stenosis (incomplete occlusion of the intestinal lumen) to atresia (complete
occlusion/ obliteration of the intestinal lumen).
- It may be an autosomal recessive trait in Holstein calves.
A pig farmer found one of his pigs, around 7 weeks of age, dead in the farm. He brings the body to the pathology lab and asks you what you think this pig died from. The owner says that when the pig was born, it seemed completely normal other than being a little less developed than its litter mates. Shortly after birth, it then developed abdominal distension. What is your preliminary diagnosis?
Diagnosis: Segmental Anomaly
Pathogenesis: Ischemia of a segment of gut during fetal development?
Explanation: Segmental anomalies in the intestine are relatively common and can range from stenosis (incomplete occlusion of the intestinal lumen) to atresia (complete
occlusion/ obliteration of the intestinal lumen).
- It may be an autosomal recessive trait in Holstein calves.
How did this animal survive for 7 weeks without an anus? Abd distension, was not as developed as litter mates.
A horse ranch farmer, who specializes in breeding American Paint Horses, owns a mare that recently gave birth to a foal that was completely white. The farmer is puzzled, because she has never seen this before, but thinks that it’s just some weird coat color mutation. A few days later, the foal develops colic and she calls you immediately to come help her. What is your preliminary diagnosis?
Diagnosis: Lethal white syndrome in foals AKA congenital colonic aganglionosis
Pathogenesis: Colon is poorly developed due to the lack of development of the parasympathetic ganglia.
Explanation: This disease is an autosomal recessive genetic disorder that is most prevalent in the American Paint Horse. Usually (but not all) horses with a white-spotting pattern are carriers of this trait (heterozygous). Affected foals are
all (or mostly) white.
- PS system is important for GI motility. If don’t have that, there is no peristalsis –> impaction. Meconium is the first feces which needs to be eliminated in the first few hours of life. White foals develop colic after a couple of days because of these Meconium retention and impaction.
You perform a necropsy on the american paint horse foal that you brought in from the horse ranch farm down the road. Your preliminary diagnosis is colonic or ileocolonic aganglionosis, but you want to take a further look at your histologic samples. Microscopically, what would you see in a sample taken from the small and/or large intestine? What would this result in?
Microscopically there is absence of myenteric and submucosal
parasympathetic ganglia in the wall of the ileum, cecum and colon
leading to intestinal immobility and colic (colonic or ileocolonic aganglionosis).
- What can be seen in the image below?
- What is this classified as?
- What is this composed of?
- How does this form?
- What can this lead to?
- Enterolith
- Acquired intestinal obstruction
- Enteroliths are composed of concentric lamellae of magnesium, ammonium phosphate (struvite) deposit.
- These deposits are formed around a “nucleus”→ foreign body such as a nail, wire etc. Vary in size, some may weight up to 10 kg.
- Foreign body can not be digested –> impaction.
You are presented with a foal that, according to its owner, coughed up a “bunch of weird looking worms” a few months ago and was found dead earlier this morning. You perform a necropsy and find these in the intestine. What is your preliminary diagnosis? Why did this foal die?
- Diagnosis: Ascarids impaction, parascaris equorum
- Pathogenesis: Foal infected with parascaris equorum defecated in the barn and/or in the field. Feces contaminated with eggs –> contaminated feces ingested by healthy horse –> larvae burrow in bloodstream and migrate to lungs and liver –> obstructed intestines –> dilation of intestine CRANIAL to impaction –> colic, electrolyte loss –> death
This pig suffered from chronic salmonellosis.
1. Name the specific etiologic agent.
2. What is your preliminary diagnosis?
3. What can also cause this condition?
4. What do you see morphologically?
5. What is a common consequence of this condition?
- Pig, chronic salmonellosis, (Salmonella typhimurium)
- Rectal stricture due to Acquired stenosis (decrease in size of lumen of a tubular organ). Salmonella produces vasculitis in intestine. in cranial hemorrhoidal artery which supplies this part of the rectum.
- Penetrating wounds (foreign bodies etc..) will form an area of a lesion –> produce a scar and the CT that contracts will
result in stenosis of the intestine. - Anus on left most part of picture. Chronic focal area of ulceration and fibrosis that resulted in narrowing of the lumen.
- Lumen of rectum is narrow. Relatively common in pigs. Can have distended abdomen due to megacolon associated with this. These lesions are usually a sequel of salmonellosis in pigs. Esp. salmonella typhimurium is supposedly responsible for this.
Define the term hernia.
Hernia: The protrusion of an organ or part of an organ/tissue through an abnormal opening
Define the term internal hernia. Give examples.
Internal hernia: Displacement of intestine through a normal or abnormal foramina within the abdominal cavity (rare).
Examples: incarceration (entrapment) of loops of the intestine within the slit-like epiploic foramen, or a rent (tear) in the omentum or mesentery
Epiploic foramen is part of the omental bursa. This bursa communicates with peritoneal cavity. Sometimes, a piece of intestine esp the small intestine can enter through this foramen –> severe colic assciated with that because the intestine can get strangled. Compression of intestine through this foramen –> venous infarction of that segment of the intestine.
Define the term external hernia. Give examples.
External hernia: Displacement of loops of intestine, omentum and
occasionally other viscera (hernial contents) outside the abdominal
cavity. Displaced contents are inside of a pouch (hernial sac, formed by
the peritoneum and the skin) which protrudes through the hernial ring
- an opening in the abdominal wall which could be acquired or natural
(e.g.: vaginal ring of the inguinal canal). Examples: Inguinal, umbilical,
diaphragmatic hernias.
Trauma: HBC dog –> rupture of diaphragm and parts of intestine, the liver, stomach, can enter throacic cavity –> diaphragmatic hernia which is an exampke of an external hernia.
Define the term Hernial contents.
viscera that is displaced and the hernial sac that is covering that piece of tissue (could be part of the peritoneum).
Define the term Hernial ring
The hernial ring is an opening in abdominal wall in which displacement will occur.
Define the term eventration.
If the displaced abdominal contents are not covered by parietal peritoneum or skin the lesion is referred to as “eventration”
You are presented with a mare who, according to her owner, was rolling around in field. At this time she had a mild case of colic, but was otherwise fine. While she was rolling around in the field, a piece of a bush perforated the abdominal cavity. She unfortunately was too sick and was euthanized. What is your preliminary diagnosis? Explain your reasoning.
- Eventration of the cecum secondary to trauma
- Characterized as eventration b/c not covered by peritoneum or skin.
You are presented with a mare who, according to her owner, was rolling around in field. At this time she had a mild case of colic, but was otherwise fine. While she was rolling around in the field, a piece of a bush perforated the abdominal cavity. She unfortunately was too sick and was euthanized. Why does this segment of her intestine look this way?
This portion of the intestine (cecum) is swollen and red b/c it was undergoing strangulation.
You are presented with a mare who, according to her owner, was rolling around in field. At this time she had a mild case of colic, but was otherwise fine. While she was rolling around in the field, a piece of a bush perforated the abdominal cavity. She unfortunately was too sick and was euthanized. Why does this segment of her intestine look this way?
Serosal surface is dark red. Compression of intestine or mesentery –> venous infarction.
You are working a shift at the emergency hospital when an owner runs in stating that her cat was just hit by a car. The cat was unfortunately already deceased upon arrival. The owner permits you to perform a necropsy and you see this. What is your preliminary diagnosis? What is another cause of this condition?
- Diagnosis: Diaphragmatic hernia due to trauma.
- It can also be congenital. Herniation of the liver and loops of the small intestine are more common. Congenital anomalies in diaphragm, like it does not close properly during development, and these animals have a larger opening where the esophagus enters into the stomach –> congenital diaphragmatic hernia.
You are presented with a patient whose routine castration procedure went…horribly wrong. The owner of this pig thought the procedure went smoothly until he found his pig dead in the enclosure a few days later.
1. What is your preliminary diagnosis?
2. Is this a common or uncommon consequence?
3. Explain the pathogenesis of this condition.
- Scrotal (inguinal) hernia - pig due to castration complication.
- This can be a complication of castration in both dogs/cats, cattle, stallion.
- The inguinal canal communicates with the peritoneal cavity. Sometimes pieces of intestine can enter inguinal canal –> hernias –> can come and go. intestine contains ingesta which contains bacterial –> entrapment of piece of gut –> incarceration of piece of intestine –> venous infarction, septic shock, etc.
A pig named Willie was ready for market but was found dead in his enclosure, he was only 5 or 6 months old :( The owner brings you the body and you see this.
1. What is your preliminary diagnosis?
2. What is this an example of?
3. What is a common consequence of this condition?
- Umbilical hernia, pig,
- Example of external hernia
- Had this problem since birth. In many cases, people notice presence of this and say that they come and go so they did not do anything and this could be a consequence (strangulation).
A pig named Willie was ready for market but was found dead in his enclosure, he was only 5 or 6 months old :( The owner brings you the body and you see this.
1. What is your preliminary diagnosis?
Strangulated loop of small intestine - umbilical hernia, pig,
This would be the hernial sac (composed of skin) and peritonium. Hernial contents are the piece of intesinte that went through into the hole. The hernail ring would be inside.
Dark reddish appearance of intestine. Friable due to venous infarction.
- What condition is pictured below?
- Explain the pathogenesis.
- Is this a pre-mortem or post-mortem occurrence?
- Torsion of the left colon -horse
- Left colon is suscopeible to torsion because it is not fixed by the mesentery. Not difficult for the left colon to develop this.
- In post mortem room., need to check to see if this is something that happened post mortem since you are moving horse around and hanging it. How can you tell if it is a real lesion? Different coloration between pre and post mortem. If veins appear prominent and dilated = this happened pre-mortem. Darkish blue/;red discoloration which is the accumulation of non-oxygenated ?blood –> infarction.
What condition is pictured below?
Colonic torsion - horse
You are presented with a horse experiencing severe abdominal pain. You are thinking that this is most likely a straight forward case, such as colic, and treat it as such. However, a few days later in the hospital the horse dies. On necropsy you find this.
1. What is your preliminary diagnosis?
2. What is the pathogenesis?
3. What do you have to do during your post-mortem exam and why?
- Intestinal volvulus - Torsion of piece of intestine along mesentery axis.
- Diagnosis is not complicated b/c often we have history of animal being in severe abdominal pain, maybe colic. Unable to manage pain clinically and animal may have presented clinical signs of toxicity already, endotoxemia, septic shock etc. Animal may be euthanized or die naturally.
- Look to figure out if this is a clockwise or counter clockwise torsion. 90 degree, 180 degree, 380, etc. Surgeons want to know the exact site of torsion or volvulus so document it.
What condition is pictured below? Explain the pathogenesis
Herniation of small intestine through the epiploic foramen (internal hernia) – horse
Piece of duodenum went through epipolic foramen and resulted in segmental venous infarction of the piece of duodenum. Veins are markedly distended, engorged with venous blood.
What condition is pictured below? Explain the pathogenesis
Intestinal strangulation by pedunculated lipomas
Lipomas: common tumors, esp in aging horses, in the mesentery. Many of these ar epedunculated (stock of mesentery in there) and can become very large, sometimes they can twist around mesenteric attachment and become necrotic. When they become nectrotic they may develop dystrophic mineralization and become very heacvy. They can twist around piece of intestine, esp. the small intestine, and result in intesintla strngulation and venous infarction. Twist around mesenteric axia dand induce the foration of volvulous and venous infarction.
is pictured below? Explain the pathogenesis
Pedunculated lipomas, horse,
Sometimes they can be very large.
Lipoma became necrotic b.c attachment to lipoma went around. This attachment contains BV and nutrients to lipoma.
Lipoma = benign tumor of adipose tissue.
Necrotic tissue can sometimes undergo mineralization(dystrophic)
Become heavier and greater risk of producing strangulation of piece of intestine?
Label accordingly.
What condition is pictured below?
Intestinal intussusception, foal
wrinkled, which is not normal. look closely to see there was tearing of mesenteric attachment (yellow bit) and it seems that it is going inside on the left. Is this post mortem or pre mortem? immediatley afte death: relaxation of SM, one piece of intestine can fold and produce post mortem intussception.
What condition is pictured below?
Intestinal intussusception, Foal,
Focal areas of discoloration, ulceration, hemorrhagic maybe covered with some fibri. All of this indicate that this is real (pre).
In many cases, when we see this, We don’t find an etiology in many cases.
CAses of coccidiosis see this b./c if you have an inflamamtory, parasitic condition –> increases perstaltic activity in the intetine due to diarrhea. The intestne may be more active because of this process –> intusussception.
Trauma?
