Lecture 12: GI 3 (lower GI) Flashcards
How do the number of taniae change throughout the equine cecum/colon?
Cecum: 4
R ventral: 4
Sternal flexure: 4
L ventral: 4
Pelvic flexure: 1
L dorsal: 1
Diaphragmatic flexure: 2
R dorsal: 2
What is a common insignificant lesion in the equine intestine?
hemomelasma ilei which are dark and elevated hemorrhagic plaques in the ileum. This is due to strongyle migration
What is a common insignificant lesion in the pig intestine?
intestinal emphysema also known as pneumotosis cystoides intestinalis
What are 2 segmental congenital abnormalities of the intestinal tract and what is a common consequence?*
Stenosis, or the narrowing of a lumen or atresia which is the complete occlusion of the intestinal tract. This leads to ischemia and failure to pass feces at birth
A Holstein calf presents for necropsy with abnormal dilation and constriction of the spiral colon. What is a likely differential?*
Atresia coli is an autosomal recessive condition in which the colon does not develop. This is most common in Holstein calves in their spiral colon. it will appear as oral dilation (dilation before the obstruction) and aboral constriction. Often there will be an enlarged uterus that is backed up with feces.
This condition can also affect foals in their small and large colon
What species are associated with atresia ani?*
It is a hereditary condition affecting calves and pigs primarily
What is the most common GIT congenital defect?
atresia ani
What can cause atresia ani? What additional problems may occur?*
Vitamin A deficiency may cause it.
Animals with this condition may also have malformations in the distal spinal column, genitourinary tract, or intestinal atresia or agenesis
What are the 4 types of acquired intestinal abnormalities
They can be
-luminal
-mural
-external
-functional (due to neuro)
How do you compare acute and chronic intestinal obstruction?
Acute obstructions typically affect the upper or mid small intestine. It can result in vomiting, dehydration, hypochloremia, hypokalemia, and metabolic acidosis.
Chronic obstruction affects the ileum or large intestine. It does not involve vomiting or metabolic acidosis. It can cause necrosis, perforation, and peritonitis
A cat presents for necropsy and upon examination you see a pleated intestine, what is your top differential?*
Linear foreign body.
Peristalsis of the linear foreign body like a string will cause pleating of the intestine and mucosal damage
What are 6 types of intestinal luminal obstructions*
foreign body
trichobezoar
phytobezoar
enterolith
parasite
colonic impaction
What is an enterolith and why does it occur?
It is a mineralization of magnesium, ammonium, and phosphate. It can be caused due to diet, alkaline water, colonic pH, or a nidus.
A horse from Florida or California presents for necropsy and you find a mineralized intestinal rock-like thingy. What is it? Is it significant?
An enterolith (mineralization of magnesium, ammonium, and phosphate)
Usually and insignificant lesion
What is a common GI parasite that causes luminal intestinal obstruction?
Small colon nematodes
What is a common cause of colonic impaction in small animals? What is a secondary consequence of this?
obstipation (feces) which can cause megacolon
What is a common cause of colonic impaction in horses? What can cause it?*
It is usually caused by digesta, sand, or feces in the pelvic flexure or transverse colon
It is often secondary to reduced water intake, diet change, or poor dentition
What are 2 types of mural intestinal obstruction?*
jejunal hematoma
rectal stricture
What is another name for jejunal hematoma?*
hemorrhagic bowl syndrome (old name)
A dairy cow from North America that was in mid-lactation presents for necropsy after sudden death, she was anemic with pale MM and had segmental intramural and luminal hemorrhage, what is your top differential and why?*
Jejunal hematoma which is most common in dairy cows usually in mid-lactation. It presents with segmental intramural hemorrhage and potentially with luminal hemorrhage as well but not always (it can rupture from the wall into the lumen)
Clinically these cows present with hemorrhage and bloody feces, bloat, abdominal pain, and sudden death. Due to the hemorrhage there is anemia and pale MM
What is a common cause of jejunal hematoma?
The cause is unknown, there may a potential it is related to aflatoxin
What is a common cause of reduced fecal output and significant abdominal distension in pigs?*
Rectal stricture
What causes rectal strictures?*
It is secondary to Salmonella typhimurium infection in the intestines of pigs. It will cause necrotizing proctitis and ischemia resulting in scarring and contraction. It is most common at the junction of the caudal mesenteric and pudendal artery because there is no collateral flow
What are 3 common causes of extramural obstruction? Which is the most common?*
strangulating lipoma (most common in horses)
neoplasia
peritoneal adhesion
What is the pathogenesis of intestinal displacement? *
- The intestine is displaced into an abnormal position
- It will become incarcerated aka. stuck in a bad position
- It will become strangulated due to reduced blood flow resulting in edema, congestion, and hemorrhage
This results ischemia and ultimately necrosis
Define volvulus*
When the organ twists on the mesenteric axis
Define torsion*
When the organ twists on its long axis
What species/type of animal is predisposed to intussusception?*
It usually targets young dogs in their ileocolic area
What is an intussusception?
a telescoping intestine
How do you name an intussusception?*
The intussuscipiens recieves the intussusception
Describe what an ileocolic intussusception means?*
the ileum is the intussusceptum and it moves into the colon the intussuscipiens
What causes intussusceptions?
They can be idiopathic but also due to
- linear foreign bodies
- a high parasite load
- previous surgery
- enteritis
- intramural mass
or it can be a perimortem change
A horse presents for a necropsy with an intestinal intussusception and a parasite load. What is the most likely parasite that you found?
High parasite loads of Anaplocephala perfoliata can cause intussusception in horses
What organs are usually entrapped in an abdominal hernia
Usually omentum and intestines. Other organs are rare to find
Compare an external and internal hernia?
An internal hernia will displace through a normal or pathologic hole in the abdomen without a hernial sac which is surrounding tissue
An external hernia displaces through an opening in the abdominal wall which forms a hernial sac and it may or may not have a hernial ring. This can be either natural or acquired.
What species are internal hernias most common? And what type of hernia(s)?*
Internal hernias are generally uncommon but usually target the horse - usually either an epiploic foramen or gastrosplenic ligament entrapment or omental/mesenteric hernia
What are 9 types of external hernias? Which are the most common*
umbilical and inguinal
diaphragmatic hernia (from trauma)
ventral hernia of the abdominal wall of pregnant mares
femoral hernias
perianal hernias
prepubic hernias
hiatal hernias
external hernias can be a post more artifact in horses so you should try and find hemorrhage, fibrin, and edema to confirm
these are common hernias
What is the most common congenital defect in Holstein cattle?
Umbilical hernias
Holsteins are genetically predisposed
In what species are umbilical hernias most common?*
pigs, foals, calves, dogs
Infection may predispose but it also may be hereditary
In what species are inguinal hernias most common? How does it form?*
They are heritable and are common in intact males because their inguinal ring is still intact. Also it can happen in females but much less common
In what species is rectal prolapse more common?
Swine, sheep, cattle and exotic species
Rectal prolapse is a common post mortem artifact so double check that
What causes rectal prolapse?
tenesmus (straining)
excessive coughing due to increased abdominal pressure
It may be due to colitis or UTI
What is inflammation of the small intestine?
enteritis
What is inflammation of the colon?
colitis
What is inflammation of the cecum?
typhlitis
What is inflammation of the rectum?
proctitis
How is GI inflammation classified?
It is classified by 2 factors;
gross factors like necrosis, hemorrhage, and fibrin
type of inflammation like neutrophilic, lymphoplasmacytic, eosinophilic, granulomatous or histiocytic
What does diphtheritic enteritis mean?*
It is enteritis that occurs with Salmonella infection it causes necrotic and sloughing mucosa forming a fibrin cast in the lumen and ulceration underneath
What are the common clinical signs of neonatal diarrhea?*
Signs depend on the age of the animal but commonly include dehydration which shows as sunken eyes and tacky MM, along with fecal staining also known as tag which is fancy for a poopy bum. The poop could be hemorrhagic (maybe not too) and stinky
What is the agent causing enterotoxigenic E. coli?
K99 E. coli, particularly the toxin it produces which causes secretory diarrhea
What is the common animal affected by enterotoxigenic E. coli?*
It usually targets very young calves (<5d)
What is the gross and histologic clinical signs of enterotoxigenic E. coli?*
Pineapple juice diarrhea grossly
On histo there are few changes and so you need to test for specific virulence factors and toxins
What are the 3 types of E. coli in calves?*
enterotoxigenic (in younger calves)
AEEC (in older calves)
neonatal sepsis (<3d old calves that have received very little colostrum)
What animals do rota and coronavirus infect?*
They infect a range of animals with an age range between 5d and 2wk
What are the histologic features of rota and coronavirus infection?
Histologic features include villus atrophy, lysis, exfoliation, blunting, and fusion
These features can be subtle and can occur due to autolysis and thus you need a fresh biopsy
Compare rotavirus and coronavirus infection*
Coronavirus will cause more severe crypt necrosis vs rotavirus. It can look similar to canine parvo and result in fibrin and necrosis in the small intestine.
Rotavirus is much less severe and is usually secondary to a primary problem. It rarely causes mortality EXCEPT in pigs.
What is the agent causing Cryptosporidium?*
C. parvum, andersoni, suis, and/or canis
It is a protozoa
What species does Cryptosporidium target?*
It targets lambs, pigs, calves and it zoonotic
It primarily target animals between 5-35d
It can infect other species if they are immunosuppressed like snakes in their stomach if they have gastritis
How is Cryptosporidium diagnosed?
You must use a fresh biopsy
Use a fecal float/smear or a mucosal smear to identify. Especially if you use an acid fast stain the crypto will stain pink
It can occur in other locations. It can occur at any entrance to the body especially in birds
What are the histologic features of Cryptosporidium?*
Histologically you look for villus atrophy, blunting, and fusion.
You will see the crypto on the brush border.
How do you compare Cryptosporidium and attaching and effacing E. coli
attaching and effacing E.coli will look the same but is smaller
What are the causative agents of coccidiosis?*
Eimeria primarily in herbivores
Isospora primarily in carnivores
They are protozoa
What animals are primarily affected by coccidiosis?*
Typically targeting calves between the age of 2 weeks and 6 months
It is common in dairy calves around 1 month old (when they get moved to group housing)
What are the clinical signs of coccidiosis infection?*
It has high morbidity and low mortality
Malabsorptive diarrhea (it can have mucus or prolapse)
It can also cause anemia due to hemorrhage, hypoproteinemia, and dehydration.
A unique feature that can occur is nervous coccidiosis (caused by an unidentified neurotoxin)
What are the gross features of coccidiosis?*
hemorrhagic or fibrinohemorrhagic typhlicolitis in the large intestine and potentially in the ileum too.
It causes cerebriform thickening in the intestine
In small ruminants it can cause multifocal white, raised nodules
What is a unique gross lesion of coccidiosis in small ruminants?
In small ruminants it can cause multifocal white, raised nodules
What disease does the intestine of coccidiosis look similar to?*
It looks like Johnes disease because of the cerebriform thickening
What are the histologic features of coccidiosis infection?
It destroys colonic glands due to the intracellular gamonts
How is coccidiosis diagnosed?
The oocytes are identified on mucosal scraping or a fecal smear
What is the causative agent of attaching and effacing E. coli?
enteropathic E. coli
What animals do attaching and effacing E. coli infect?*
Calves between 5d and 6 months old. Usually in the large intestine and distal rectum
What are the gross and histologic features of attaching and effacing E. coli?*
Grossly it presents as diarrhea and colon necrosis with or without hemorrhage
Histologically it looks like Cryptosporidium but smaller but it required a fresh biopsy
What is the causative type of Clostridium perfringens?*
Clostridium perfringens type C because it makes beta toxin
What animals does Clostridium perfringens affect?*
Lambs, calves, piglets, foals, kids between the ages of 5 - 10d
It is rare up to 2 months
What are the clinical signs of Clostridium perfringens?*
Clinically it causes bloody diarrhea and death
Usually they are found dead without clinical signs because they die fast
What are the gross features of Clostridium perfringens infection?
It causes a small intestine full of watery bloody diarrhea and it may have fibrin.
How is Clostridium perfringens diagnosed?*
It is important to collect lots of samples for testing because the bacteria is anaerobic. You also have to type the bacteria because it must be type C that expresses beta toxin. Clostridium perfringens species are commonly commensal in the GI
What animals are targeted by Rhodococcus equi?*
It commonly targets foals between the age of 2 weeks and 6 months
What are the gross features of Rhodococcus equi infection?*
It forms crateriform ulcers in the small and large intestine which are commonly formed over the peyers patches. This, along with lymphadenopathy are the characteristic lesions of infection
It also causes suppurative bronchopneumonia and 50% of cases have abdominal lesions
What are the histologic features of Rhodococcus equi infection?*
Pyogranulomatous enterotyphlocolitis and lymphadenitis
There may also be gram positive intracellular bacteria in macrophages
What is the causative agent of parvoviral enteritis?*
canine parvovirus 2 and feline panleukopenia
CPV2 evolved from panleuk.
What species are targeted by parvoviral enteritis
many
What is the pathogenesis of parvoviral enteritis?*
It targets rapidly dividing tissue, primarily…
- crypt enterocytes
- hematopoietic bone marrow
- lymphoid tissue
- cardiac myocytes in young puppies
- cerebellum in young animals causing cerebellar hypoplasia
What are the clinical signs of parvoviral enteritis?*
diarrhea with or without hemorrhage
anemia
dehydration
hypoproteinemia
leukopenia
What are the gross features of parvoviral enteritis?*
It causes widespread serosal hemorrhage that can extend through the wall of the intestine.
On the serosa there is fibrin deposition creating a ground glass appearance.
The intestines will be full of mucoid, tomato soup-like contents
This primarily affects the small intestine rather than the colon or the stomach
What is the histologic features of parvoviral enteritis?*
crypt necrosis
intranuclear inclusions are rare
