Small intestine Flashcards
Small intestine
transit time - 3h
130L fluid secreted into small inetsestine/day
BV supple; jejunum, ileum
what are the attachements of the SI
mesentery
Duodenocolic ligament
hepatodudenal ligament
Ileoceal fold
what is the function of the Crypts of liberkuhn
Stem cells at base which divide & migrate up to villi tips in 3-6 days - adapted for secretion of fluid
what is the function of the vili
mature cells with absorptive function
Injury to villi disruption of absorption but secretion continues = hypersecretion
what are the function of SI
Digestion and absorption
Movement of water accross epithelium ion gradient
Ileum has specialised functiosn - absorbs bile acids & vit B12
what are the motility patterns of the SI
Peristalsis - wave of contraction = propels GIt contents aborally
Segmentation - non -propulsive, alternating contraction & relaxation of circular muscles = mixes digestive enzymes with ingesta and provides contact with epithelial cells for absorption
what is the neurohormonal control of the SI
Enteric nervous system
Enteric endocrine system
what are the normal parameters for a transabdominal evaluation of SI
SI wall thickness - normal <3mm SI diameter; normal <3cm motility - constant peristalsis SI contents - swirling fluid Abor normal - sedimentation/settling
what is a consequence of a strangulating lesion
obstruction lumen blockage & compromised BV blood supple of the affect intestine = intestinal ischaemia with eventually necrosis & perforation
Conditions resulting in simultaneous occlusion of intestinal lumen and blood supply
Not responsive to treatment prompt surgical intervention needed
Pedunculated lipoma
Most common cause of strangulation lesion
older horses ==> explorative laparotomy (hypomotile and distended)
mass on the end of a stalk ==> ties knot arround the intestine - occludes the blood supply
might not be the cause of colic - need to see if it actually strangulated a piece of intestine
Epiploic foramen entrapment
Displacement of segment of SI Through small hole (foramen) that separates omental bursa from the peritoneal cavity
where the epiploic foramen located
potential 4-5cm opening into the omental bursa (R cranial abdomen)
dorsal boundary - caudal VC & caudate process of the liver
Ventral boundary - portal vein, right lobe of the pancreas & hepatoduodenal ligament
what are the main two types of strangulating hernias / bowel entrapment
umbilical
Inguinal
intussusception
invagination adjacent to bowel segement (intessuscipient)
aetiology uncertain - lesion at leading edge
- small mass, Fb, parasites
Most common site = ileocaecal
Si volvulus
SI rotates > 180 degress along its mesenteric ais - initiated by change in local peristalsis
Foals - most common SI obstruction
Confirmed at surgery - twist at cranial mesenteric artery
intra-abdominal adhesions
Response to inflammation & injury - colic surgery, intraabdominal inflammation
Mostly asymptomatic - simple obstruction due to extraluminal compression, causing ‘kinking’ of SI
strangulating obstruction - incarcerates SI
==> an important complication of colic surgery
Non strangulating lesions
Conditions resulting in occlusion of intestinal lumen without initially/primarily compromising blood supply
Resulting distension can affect blood supply ==> PROGRESSIVE development of compromised mural integrity
what are the 3 types of simple obstrcution
MECHANICAL - ages are important
- intra-luminal masses (ascaric impaction + faecal)
- intraluminal compression - ileal hypertrophy
- Extraluminal compression - (intra abdominal adhesions, mass)
Ascarid impaction
Paracarius equorum
WEANING FOALS UNDER TWO YEARS OF AGE (4-24)
Cs: colic following the admin of anti-helmintic, SI obtsrcution +/- dead ascarid in reflux
how do you treat an ascarid impaction
surgery - enterotomy or manually evacuate ascarid into caecum
prognosis; poor to guarded
Ileal impact what are the risk factors, what age animals are most susceptible
adult horses
risk factors
- feeding coastal bermuda hey or any fine hay
failing to deworm with anthelmintic against tapeworms (A. perfoliata) ( praziquantel)
where does a functional obstruction occur
Ileus
Disruption of normal propulsive GI motor activity from non-mechanical mechanism
causes/mechanism
- primary - inflammatory SI disease, ishcaemic injury
- secondary - electrolyte disorders, pain, systemic disease
Anterior enteritis clinical syndrome
Inflammation & oedema of duodenum & proximal jejenum
Excess fluid & electrolyte secretion of SI
Intestinal hypersecretion & impaired motility = large volume of enterogastric reflux
what are the main Cs associated with anterior enteritis
mod to severe pain oftem relieed with gastric decompression
tachycardia, tachypnoea
low grade fever
dilated SI+/- intestinal wall thicknes
what does a peritoneal fluid analysis show in anterior enteritis
colour: yellow, turbid (incrrase protein and cell count) serosanguineous if severe
mild/ mod > total nucelated cell count with moderate/marked > TP conc
Higher the total protein the worst the prognosis
what does the clinical path show in anterior enteritis
increased PCV/TP
normal or increased or decrease WCC
electrolyte and acid base inbalances common
secondary hepatopathy (increase liver enzymes)
SIRS (systemic inflammatory respinse syndrome
what is the tx for anterior enteritis
Frequent gastric decompression
fluid/electrolyte replacement
Ab therapy - typically not recommended unless treating endotoxaemia, aspiration pneumonia or immunocomprimisedd
Anti-endotoxic therapy
Prognosis will be good with adequate supportive care
Equine proliferative enteropathy - Lawsonia intracellularis - aetiology
obligate intraccellula bacteria in cytoplasm crypt epithelial cells of jejunum and ileum Older foals (3-8 months) - weaning (risk factors)
What are the clinical signs associated with equine proliferative enteropathy
colic, weight loss, oedema, variable faecal consitency
panhypoproteinaemia
increase SI mural thickness
How do you diagnose equine proliferative enteropathy
faecal PCR - highly specific (lacks sensitivity)
ileal PCR
serum Ab
Silver staining tissue
Inflammatory bowel disease what are the specific types
Granulomatous enteritis
Lymphocytic-plasmacytic enterocolitis
Mutli-systemic, esonophilic
Eosinophilic enterocolitis
CS of Inflammatory bowel disease
weight loss, recureent/severe colic, oedema
+/- diarrhoea
+/- dermatitis
pathophysiolgy - interaction of multiple immune functions, lack of immunity to normal flora
How do you treat inflammatory bowel disease
corticosteroid
Immune suppressants
exploratory laporotomy
How do you diagnose inflammatory bowel disease
biopsy
Carbohydrate absortion test - oral glucose tolerance test (OGTT)
Alimentary lymphosarcoma
neoplasia of GALT
+ progressive involvement of SI & associated LNs
minimal LI or systemic involvement
young horses (2-4 years)
what is the clinical pathology associated with alimentary lymphosarcoma
Anaemia
neutrophila or neutropaenia
lymphocytosis = rare
Hypoalbuminaemia + hyperglobulinaemia
You are presented with a weanling foal 6 months of age who has colic 3 days after the administration of an anthelmintic. The weanling has a poor deworming history
What is the most likely cause, how would you come to a diagnosis
what are your treatment options
Paracaris equrum impaction
dx: US
Txm - surgery ==> enterotomy or manually evacutae ascarids from caecum
You are presented with a 7 month old foals that has just been weaned who is showing signs of colic, wieght loss, oedema and variable faecal consitency, Panhypoprotaeineam and increase SI mural thickness
What disease are you suspicous off?
what steps would you take to diagnose
Equine proliferative enteropathy - lawsonia intracellularis
Faecal PCR
Ileal PCR
silver staining tissue
How would you treat a weanling with Equine proliferative enteropathy
A/B 2-4 weeks erythromycin, Rifampicin, chlorampenicol
supportive therapy - colloids, supportive Iv fluid therapy good nutrition
