GI 4, 5, 6 and Practical Flashcards
What is atresia?
Therefore what is intestinal atrasia?
What species does it most frequently occur?
What is anal and rectal atrasia?
Species?
Atresia- congenital absence, pathological closure, opening, passage or cavity
Intestinal atresia- usually ileum and colon
complete lack of some part or blind ends, but muscular and CT layers
Most frequent in calves
Anal and rectal atresia- failure in developing anal opening
Most frequent in piglets
What species can develop megacolon?
What are the two causes?
Dog, cat, horse, pig
1) aplasia of neurons in large intestine myenteric ganglion-
lack of peristalsis so fills up
2) idiopathic- old cats
recurrent and progressive episodes, intractable constipation
most common
What are the three types of intestinal displacement/misalignment can occur?
Herniation- protrusion of an organ/tissue through an opening in its surrounding
Intussusception- invagination- telescoping of segment into another
Volvulus- a torsion/twisting at root of mesenteric attachment
What are the two causes of hernias?
What are the three different types of hernias?
Hernias can be acquired or congenital
- Diaphragmatic- intestines into thorax
- Horse- SI into epiploic foramen
- Inguinal hernia- back end
This image shows potential herniation in a horse
What is the name of the condition?
With diaphragmatic herniation what can the compression lead to?
Epiploic foramen- small intestine can pass through
Compression of lungs with diaphragmatic herniation can lead to pulmonary atelectasis (collapsed lung)
What causes intussusception?
Therefore what diseases can cause intussusception?
What species is more commonly affected by volvulus and where?
Hyperactive bowel movement
Dog- mainly SI- parvovirus, distemper
Horse- mainly ileum into caecum- tapeworm
Horse-
jejunum, ileum- 180
pedunculated lipoma around the intestine
What are the consequences of intestinal misalignment/displacement?
- Misalignment leads to occlusion of veins
- Leads to persistence of arterial blood supply but not drainage
- Increased blood pressure and O2 deficit/hypoxic damage
- Causes capillary fragility- necrosis and haemorrhagic infarction or haemorrhage
What are the three alterations of the intestinal lumen?
Obstruction
Stenosis- narrowing
Functional paralysis
What can cause intestinal obstruction?
- Ingesta- large colon impaction/coprostasis (horse)
- Foreign bodies- enteroliths, corn cobs, string
- Parasites
- Bezoars- impacted hair
- Neoplasms
- Haematoma
- Abscesses
String (linear foreign body) causes ‘dislocation’
What can cause intestinal stenosis?
Compression/strangulation
e.g pedunculate lipoma
Fibrosis after ulceration surgery
What causes functional paralysis in horses?
What are the gross lesions?
What is the causative agent?
What horses are usually affected?
Grass sickness- primary dysautonomia
Gross lesions- stomach and SI filled with watery food contents, large intestine
Aetiology- clostridium botulinum
necrosis and loss of neurons in sympathetic ganglia
variable presentation
Frequent in UK, young horses kept on pasture
What is the name for intestinal inflammation?
What does intestinal inflammation lead to and why?
Enteritis
Enteritis leads to diarrhoea
Pathological mechanisms-
- Maldigestion- lack of enzymes for digestion, impaired villous epithelial cell functions (villous atrophy)
- Malabsorption- reduced resorptive area due to loss of villous epithelial cells
- Hypersecretion- secretion of electrolytes due to enterotoxins
- Increased motility
What agents can cause enteritis and diarrhoea from the following mechanisms?:
Maldigestion
Hypersecretion
Maldigestion- lack of enzymes, impaired villi
rotavirus, coronavirus, enteropathogenic E.coli
Hypersecretion- electrolytes due to enterotoxins
Enterotoxic E.coli, yersinia enteroclitica
How can catarrhal enteritis present differently?
What can cause it?
Either acute or chronic
With-
epithelial loss, hyperaemia, moderate lymphocytic infiltration of submucosa
Aetiologies
ID- viral, bacteria
Chemical- poisons
Who is more commonly affected by viral catarrhal enteritis?
What does it generally cause?
What are the common agents?
what do they cause specifically and what lesions do they cause?
Mainly young animals- loss of villous tip epithelial cells so villous atrophy, causes vomiting, diarrhoea, poor fluid intake/dehydration
Coronavirus- calves, piglets, puppies
Rotavirus- calves, lambs, foals, piglets, puppies- jejunum and ileum
Canine parvovirus type 2- replication in mitotic cells
oropharyngeal infection- viraemia- infection: lymphatic tissues, intestine, BM
Enteric form- acute catarrhal enteritis with crypt loss and secondary villous atrophy
Feline parvovirus infection
Lesions similar to canine
Enteric- acute fibrinous enteritis
Affinity for crypt epithelium- loss of crypt cells- lack of new, villous shortening, empty crypts, infection in dividing crypt epithelium
With each form of porcine proliferative enteropathy describe the lesion location and appearance
From the image which presentation is which?
Porcine proliferative enteropathy- lesions mainly in ileum, post-weaning pigs, mucosal hyperplasia
Proliferative haemorrhagic enteropathy- over 4mo, high mortality
Necrotic enteritis- due to mucosal necrosis, high mortality
Terminal ileitis- chronic, could be healing of necrotic enteritis
Image-
top left- terminal ileitis
top right- necrotic enteritis
bottom left- proliferative enteropathy
bottom right- haemorragic enteropathy
What bacterial agent caused this haemorrhagic enteritis?
Haemorrhagic enteritis- blood in the intestinal lumen
Anthrax- bacillus anthracis
Acute course
Notifiable
What does this image show?
What causes this disease?
Shows L3 induced granulomas in wall of colonic/caecum mucosa
Causes by cyathostomiasis
Give a gross description of this image
What is the morphological diagnosis?
GD- Ileum, diffusely the mucosa is thickened by approx 2cm thick and mucosal surface is corrugated, the ridges of the corrugated areas are pale tan, valleys reddish
MD- ileum, severe diffuse chronic histiocytic enteritis
[Johne’s disease]
The following image shows a high power section of an ileal lesion (cow)
What are the arrows pointing to?
A Ziehl-Neelsen stain is used and shows areas of pink
What does this mean and what disease/aetiology is likely?
Mostly macrophages
Arrows show epithelioid cells
Arrowheads show two large multinucleated giant cells
ZN stain shows acid-fast bacteria
Johne’s- paratuberculosis- mycobacterium avium subspecies paratuberculosis
What is abnormal about this histological slide of the jejunum?
What disease could this be in a dog?
- Superficial coagulative necrosis of villi
- Extensive necrosis and loss of epithelial lining in intestinal crypts
- Lymphocytes, plasma cells and macrophages expanding lamina propria
Canine parvovirus 2
This image shows a lesion that was multifocally affecting caudal aspect of the tongue, pharynx, larynx with pale to tan masses
Give a histological description of the lesion
What is the morphological diagnosis
What is the aetiology
HD- focally there is exophytic, well-demarcated, non-encapsulated neoplasm,
Papillary fronds composed of thickened keratinising squamous epithelium
neoplastic cells in cords of keratinising squamous epithelium, cells are polygonal with distinct cell borders, mitotic figures are rare
MD- tongue papilloma
A- bovine papillomavirus 4
These two slides are from a 4 month old female goat with profuse watery diarrhoea and death- several others in the herd are affected
The left slide shows a villi of the jejunum
The right side shows the higher power
What can you identify
What are the arrows pointing to?
What disease can cause this?
The jejunum has mucosal hyperplasia
Coccidial parasites
Macrogametocytes- arrows
Microgametes- arrow heads
A german shepherd dog was euthanised due to severe respiratory problems
The right tonsil is diffusely enlarged red to the pale mottled surface with an irregular large mass
What is the black line showing?
What do the black stars and white starts show?
What type of neoplasm is this?
Tonsil, the basal membrane (black line) is multifocally interrupted and infiltrated by chords and nests of neoplastic cells that deepen in the lymphoid tissue
Tonsil neoplastic epithelium (black stars)
Infiltrating/replacing normal lymphoid tissue (white stars)
Squamous cell carcinoma
The image shows a 4 year old holstein cow tongue with an incidental finding
Give a gross description
What causes this?
Tongue, in musculature there are multiple, well demarcated, pale tan to yellow, up to 5mm diameter soft pyogranulomas
Also multifocally to coalescing through out are pale tan to white, firm, irregular streaks (fibrosis)
Wooden tongue
Actinobacillus ligniersii
