Gastrointestinal Flashcards
what are the four mechanisms that cause weight loss?
reduced intake
reduced digestion, absorption or assimilation
increased losses
increased requirements
what are the three most common causes of weight loss?
dental disorder
parasitism
inadequate diet
what are some possible reasons for malabsorption and protein losing enteropathy?
idiopathic, parasites, infiltrative bowel disease, neoplasia
what % of body weight should a horse be consuming in hay?
2.5%
what is chronic colic?
colic signs of varying intensity lasting more than 48 hours
what is recurrent colic?
shorter periods of colic pain with recur at variable intervals
what are the four types of intestinal pain?
stretch
inflammation
ischaemia
muscle spasm
what are the two main locations colics can be split into?
GI or non-intestinal
what should be investigated/questioned in cases of colic?
number/nature of previous colics
faecal output
diet (water/feed access…)
worming history
dental disease and quidding
crib biting/wind sucking
sand??
what can running bloods help to rule in/out of chronic colic cases?
specific organ disease (enzymes, bile…)
inflammatory process (WBC, fibrinogen, globulins…)
protein loss (albumin…)
what causes verminous arteritis?
strongyles vulgaris (mesenteric artery)
what can mask a possible decrease in total protein?
concurrent dehydration
what are the four possible causes of hypoalbunminaemia?
protein losing nephropathy
protein losing enteropathy
effusions (peritoneal/pleural)
liver disease
how does albumin change in response to chronic inflammation?
goes down (negative acute phase protein)
what are the two main positive acute phase proteins?
fibrinogen
serum amyloid A
what are the three general causes of hyperfibrinogenaemia?
infection
inflammation
neoplasia
how should peritoneal fluid appear?
clear and light yellow
if peritoneal fluid appears red (serosanguinous) with acute colic present, what does this suggest?
diapedesis is occurring (blood moving into peritoneal cavity) which usually suggests a strangulating colic
what can neutrophils tell us about the nature of a peritonitis?
whether it is septic or not
if there are more degenerate neutrophils present in a peritonitis case, what can be suggested about the nature of this?
it is septic (caused by bacteria)
how do neutrophils appear in cases of non-septic peritonitis?
hyper-segmented mature nuclei
what can be assessed on intestinal ultrasound?
wall thickness
lumen diameter
motility
anatomy
what is the most common reason for increased wall thickness of the GI tract?
inflammation
what structures are found on the right hand side of the abdomen?
large intestine - caecum, right dorsal colon, right ventral colon
what part of the colon does the caecum empty into?
right ventral colon
what is the majority of the left side of the abdomen taken up by?
spleen
why is the pelvic flexure a common site for impaction?
it is a narrow bend
how many intercostal spaces should the stomach take up?
no more than 5 (suggests its enlarged/distended if its more than this)
where will small intestines be found if filled with fluid?
bottom of the abdomen
what can be done to test absorption of nutrients in horses?
glucose absorption test - give a set amount of glucose and see how much the small intestine absorbs (greater than 85%)
what parts of the GI tract can be biopsied rectally?
rectum and duodenum
what are the categories of inflammatory/infiltrative bowel disease?
granulomatous enteritis
lymphocytic-plasmacytic enteritis
eosinophilic enteritis
what is multi systemic eosinophilic epitheliotropic disease?
eosinophils attack anything with epithelial lining - coronary band, pancreas, skin, liver…
what neoplasia can be strongly associated with weight loss?
lymphoma
what are some paraneoplastic syndromes associated with lymphoma?
hypercalcaemia
haemolytic anaemia
cachexia
what is the treatment of inflammatory bowel disease?
prednisolone
dexamethasone
what needs to be monitored when giving dexamethasone to horses?
laminitis
what is a common cause of chronic bacterial colic?
bastard strangles (and other abscesses…)
what are the functions of the equine liver?
digestive/secretory (bile salts)
metabolic (CHO, protein, fat)
detoxification/excretory
synthetic (clotting factors, proteins)
storage (vitamins, minerals)
what is the first stage of testing when suspecting liver disease?
blood analysis (confirms liver disease/damage)
what is needed to determine the severity of pathology and prognosis of liver disease?
liver biopsy, blood analysis, clinical signs
how much of the liver function has to be lost for them to show signs of failure?
> 70%
what is jaundice?
retention of bilirubin (yellow staining of tissue)
what are the three main differentials for jaundice?
anorexia (usually mild)
haemolysis
liver failure
what are some clinical signs of liver disease?
jaundice
weight loss
depression/CNS signs
skin lesions
haemorrhage
colic (stretching of liver)
oedema
diarrhoea
bilateral laryngeal paralysis
what are some possible CNS signs of liver disease?
quiet/dull
yawning
somnolence (sleepy)
central blindness
head pressing
compulsive walking
sham chewing
why does liver disease cause CNS signs?
toxins build up
what is the most common skin lesion associated with liver disease?
photosensitisation
(can cause pruritus and coronitis)
what can cause hepatic photosensitisation?
phylloerythrin accumulation
primary - tetracyclines, st johns wart
immune mediated vasculitis
what are the most common sites of photosensitisation?
depigmented skin exposed to sunlight
why can liver disease cause bilateral laryngeal paralysis?
recurrent laryngeal nerve is very long (longest axon in body) - more susceptible to damage
what is tested for in blood to show liver damage?
liver enzymes
what liver enzymes are specific to the liver?
GGT, SDH, GLDH
what is the origin of GGT in the liver?
biliary
what is the origin of the SDH and GLDH in the liver?
hepatocellular
what liver enzymes are of biliary origin?
biliary
what are the other sources of ALP? (other than liver)
bone, intestine, kidney, placenta
what do liver enzymes in blood indicate?
degree of damage/disease not the function
what does increased GGT and ALP indicate about the type of liver disease?
biliary
what does increased AST, GLDH and LDH indicate about the type of liver disease?
hepatocellular
what is the most useful test to determine liver function?
bile acids
what happens to the majority of secreted bile acids?
reabsorbed in SI and return via enterohepatic circulation
what are the three forms bilirubin can be measured in?
total
conjugated
unconjugated
where does most bilirubin originate from?
RBC and haemoglobin breakdown
what produces unconjugated bilirubin?
macrophages breaking down RBCs
what does the liver do to bilirubin?
conjugate it which is then excreted into the intestine
what are some causes of increased unconjugated bilirubin?
liver failure, haemolysis, anorexia, intestinal obstruction, Gilberts syndrome
what can cause an increase in conjugated bilirubin?
cholestasis and hepatocellular failure
why is ammonia difficult to measure?
very volatile (evaporates rapidly from sample)
RBCs produce ammonia so will increase as sample stands
why does poor liver function cause an increase in ammonia?
liver turns ammonia to urea which is excreted, poor function means this doesn’t occur
what are some non-specific changes on blood analysis that points towards liver disease?
decreased urea
increased globulins
increased triglycerides
decreased protein synthesis
how should the liver appear compared to the spleen on ultrasound?
liver should be darker (hypoechoic)
if same greyness, liver has been infiltrated by fibrous tissue…
what are some possible complications of liver biopsy? (these are rare)
haemorrhage
inappropriate sample (focal lesions)
infection
what can liver biopsy be used to predict?
prognostic outcome
what is the toxin in ragwort?
pyrrolizidine alkaloid
what makes ragwort palatable?
when it is dried in hay (horses rarely eat when at pasture)
how does ragwort poisoning mainly present?
signs of liver failure (weight loss, behavioural change, anorexia)
should ragwort poisoning be treated?
not if bile acids >50 mol/L
how can ragwort be treated?
supportive - fluids, glucose, endotoxaemia treatment
low protein diet (reduce hepatic encephalopathy)
how does the liver usually present in cases of cholangiohepatitis and cholelithiasis?
swollen
what is the main treatment of chronic active hepatitis?
corticosteroids (immunosuppressive medication)
what should the diet of a horse with liver disease consist of?
carbohydrate based
moderate amounts of high quality protein
fat soluble vitamin supplement
how will hyperlipaemia present in a blood tube?
dense, white, cloudy serum (looks like fat in severe cases)
what are the risk factors for hyperlipaemia?
breed
obesity
females
age (insulin sensitivity)
underlying disease
stress/transport
starvation
why does starvation cause hyperlipaemia?
horse in negative energy balance so begin breaking down fat into blood (horses can’t produce ketones)
what animal do we worry about hyperlipaemia most in?
donkeys
what are the clinical signs of hyperlipaemia?
non-specific (anorexia, lethargy, weakness) - not eating then makes the hyperlipaemia worse
what is done to treat hyperlipaemia?
treat underlying disease
get in positive energy balance
correct dehydration, electrolytes and acidosis
insulin therapy (laminitis risk)
what is the prognosis of hyperlipidaemia?
guarded (especially in donkeys) - worse in females
what is colic?
a clinical sign of abdominal pain
what are some horse level risk factors for colic?
some specific colic have a age/sex predilection
stereotypies - wind sucking…
what age horses are predisposed to pedunculate lipoma?
older horses
what types of colic do crib-biting/wind-sucking predispose to?
epiploic foramen entrapment
simple colonic obstruction
recurrent colic
what are some management level risk factors for colic?
geography - sand, grass sickness…
season - housing…
feed types/practices - concentrates, changes…
increased stabling
dental disease
parasites and anthelmintics
water access
transport
why is it important to provide advice to owners about colic when their animal has it?
reoccurrence is common so management may need to be altered
what is the most common site for a pedunculate lipoma?
small intestine
what are the predisposing factors for pedunculate lipoma strangulation?
older horses
more common in ponies than horses
more common in geldings than mares
what are the risk factors for large colon volvulus?
mares post foaling
larger horses
increased stabling
dental disease
changes in feed
what are the risk factors for large colon impaction?
stabling (autumn/winter) - box rest
straw bedding
what are some risk factors for epiploic foramen entrapment?
increased stabling (seasonal)
crib biting and wind sucking
what are good factors for predicting mortality in colic cases?
reaction length
PCV and heart rate
duration of surgery
post operative complications
what are some possible post-operative complications (and colic) for colic cases?
ileus, surgical site infection, jugular thrombosis
what is equine grass sickness also known as?
equine dysautonomia
what do clinical signs of equine grass sickness relate to?
neuronal degeneration of autonomic and enteric nervous system
what are the signs of acute equine grass sickness?
colic, reflux, tachycardia, SI distention, sweating, salivation, swallowing difficulty, ptosis
what is ptosis?
drooping of upper eyelid
what are the clinical signs of chronic equine grass sickness?
weight loss, dysphagia, tachycardia, patchy sweating, muscle fasciculation, rhinitis sicca
‘elephant on a barrel’ stance
what age horses is grass sickness most commonly seen in?
2-7 years old
what time of year is equine grass sickness seen?
spring (April/May)
also peaks in Autumn sometimes
what does space-time clustering o0f grass sickness mean?
when you see a case you are more likely to see another case close by at a similar time
what is the prognosis for grass sickness?
often fatal
what are the management risk factors for grass sickness?
access to grass
recent pasture change
pasture disturbance
what are the indications that a colic can be treated medically?
mild-moderate pain
good response to analgesia
HR <50
improving GI motility
no net reflux
resolving/no abdominal distention
normal peritoneal fluid
normal PCs and lactate
what are the two main principles of medically treating colic?
analgesia and fluids
what needs to be considered about an analgesic in colic cases?
potency
duration of action
other effects (wanted and unwanted)
what are the main categories of analgesics for colic?
NSAIDs
alpha 2 agonists
opiates
what NSAIDs are available for colic cases?
phenylbutazone
flunixin meglumine
metimazole
ketoprofen
meloxicam
how potent is phenylbutazone when treating colic?
moderate (12 hour duration)
what pain severity colic would phenylbutazone be used for?
mild/moderate (good first line)
why should care betaken when giving flunixin meglumine to treat mild/moderate colic pain?
can mask increased HR caused by SIRS (endotoxaemia) - horse could be developing a strangulation etc.
how strong of an analgesic is flunixin meglumine?
very potent
what are the alpha 2 agonists available for analgesia of colic?
xylazine
romifidine
detomidine
what colic cases is xylazine useful for?
very painful when wanting to assess patient (short duration of action)
what is romifidine usually combined with in colic cases?
butorphanol (opiate)
what colic cases would romifidine be a useful analgesic?
if horse is needle shy (IM administration)
moderate-severe pain
what is detomidine usually combined with in colic cases?
butorphanol (opiate)
what opiates are available for colic cases?
butorphanol
pethidine
morphine
what colic pain is butorphanol used to treat?
moderate-severe
when should morphine not be used in colic cases?
in first opinion practice
what is the effect of butylscopolamine?
smooth muscle relaxant
what types of colic is butylscopolamine indicated for?
spasmodic colic with mild pain
(useful when performing rectal - minimise risk of tear)
why may the use of flunixin for colic cases not be recommended?
it masks colic pain and the effects of SIRS making assessment of colic difficult (if has got SIRS want to treat ASAP)
when is flunixin use for colic cases acceptable?
referral not an option and horse has moderate/severe pain (otherwise euthanised)
when exact diagnosis is known
how much water/electrolyte should be administered orally to a horse with colic?
4-6L (500kg horse) every 4 hours
what type of colic can oral fluid aid to assist the resolution of?
large colon impaction (hydrate ingesta)
when are IV fluids indicated for colic?
reflux obtained on nasogastric intubation
severe systemic compromise
what is used to effectively treat most cases of spasmodic colic?
butylscopolamine and NSAID (metimazole)
what causes the pain in spasmodic colic cases?
intestinal spasm
how severe is pain associated with large colon impaction?
mild/moderate
what is the classical finding when rectalling a horse with large colon impaction?
doughy, firm structure on left of caudal abdomen
what is the classic epidemiological clue that the horse presenting with colic has large colon impaction?
recent increase in stabling (injury, weather…)
how are large colon impactions treated?
oral fluids every 4 hours until faeces are passed (magnesium sulphate)
analgesia - flunixin meglumine
can require surgery - clinical parameters, progress…
how can gastric impaction be confirmed?
gastroscopy
how are gastric impactions treated?
medically or surgically depending on severity and clinical presentation
IV fluids and carbonated drinks
when can a large intestinal displacement/distention be managed medically?
normal CV parameters
mild/moderate pain
no marked gaseous distention of large colon
what is the initial medical therapy used to treat large intestinal displacement/distention?
analgesia
light walk/trot
oral fluid
feed withheld until passing faeces
what is left dorsal displacement of the large intestine also known as?
nephrosplenic entrapment
how can nephrosplenic entrapment be diagnosed?
rectal
ultrasound - failure to image left kidney/spleen due to gas
what is usually the initial treatment for nephrosplenic entrapment? and why?
phenylephrine infusion - shrinks spleen to try get gut to move
how can sand cause colic?
irritation of colon mucosa (diarrhoea and mild recurrent colic)
colonic impaction
how can sand colic be diagnosed?
sand in faeces
seashore sound on auscultation
ultrasound/radiography
what is not a good way of differentiating if a neonatal colic is medical or surgical?
pain (foals are wimps)
what are the most likely causes of neonatal colic?
meconium impaction
enteritis
SI volvulus
congenital abnormalities
how is meconium impaction colic treated?
enema
what are the most common colics associated with donkeys?
colonic impaction
what advice would you give to an owner after you have been to look/treat a horse with colic?
remove feed and provide water
ask for update in 2 hours (unless signs worsen)
offer small amounts of feed once faeces passed
what advice would you give to an owner regarding colic prevention?
parasite testing/control
dental exam/treatment
general management - feed, stabling…
when would euthanasia be considered an option in colic cases?
uncontrollable pain
severe CV compromise (HR> 90, PCV >60, purple MM)
GI rupture - brown/red ingesta in peritoneal fluid
what are the signs of GI rupture in horses?
marked increase in HR, PCV and MM deterioration
dark red/brown peritoneal fluid with ingesta in
what are the indications for surgery in colic cases?
severe, unrelenting pain
recurrance of pain even with moderate/potent analgesia (most important)
HR >60bpm
net reflux >2L
deteriorating CV parameters
reduced intestinal motility
increased abdominal distention
deteriorating peritoneal fluid values
what are the indications for surgery in colic cases?
severe, unrelenting pain
recurrence of pain even with moderate/potent analgesia (most important)
HR >60bpm
net reflux >2L
deteriorating CV parameters
reduced intestinal motility
increased abdominal distention
deteriorating peritoneal fluid values
what are common types of small intestinal surgical colics?
pedunculated lipoma
epiploic foramen entrapment
what are common types of large intestinal surgical colics?
large colon displacement
large colon torsion
what is the order of doing initial exploration for colic using a midline abdominal excision?
exteriorise caecum then trace to ileum
exteriorise SI
exteriorise large colon (palpate RVC and RDC)
exteriorise small colon (palpate down to rectum)
what are some possible complications of small intestinal resection?
leakage
mesenteric rent
lumen too narrow
does a jejuna-caecostomy have a better or worse prognosis than small intestinal anastomosis?
worse
what is a common cause of cecal colic?
high tapeworm burden causing ileal impaction and caecal intussusception
how is caecal intussusception treated?
surgical resection of caecum
what are common primary colic lesions of the large colon?
impaction, displacement, torsion, enteroliths
what is the most common site for enterotomy?
pelvic flexure
why is pelvic flexure enterotomy useful?
assists correction of torsions/displacement and can confirm sand colic
where is the incision for pelvic flexure enterotomy made?
immediately cranial to flexure (minimise lumen narrowing at the flexure)
what is the most commonly used analgesia for post-operative colic management?
flunixin meglumine
why is passing a stomach tube in post-operative colic cases important?
they can’t vomit - will rupture
what is the nutritional management of large intestinal displacements post operatively?
offer water within 3 hours
offer feed from 6-12 hours
what is an extremely important part of post-operative colic management?
walking horse (exercise and grass)
what are some possible post-operative complications of colic surgery?
surgical site infection, dehiscence, colic, adhesions, SIRS…
what is a common place for calculus build up in horses?
canines and corner incisors
who can perform category one dental procedures?
anyone (includes examination, rasping, removing calculus…)
who can perform category two dental procedures?
equine dentists (includes extraction of poorly attached teeth, wolf teeth (with vet supervision)…)
what is the most likely cause of quidding (balling up)?
periodontal disease due to diastema
what is the peridontium?
attachments of the tooth, gum and periodontal ligament
what is periodontal disease most commonly caused by?
food trapping in diastema
what age horse will typically have some caps coming loose and possibly causing periodontal disease?
2-4 years old
what is oesophageal obstruction also known as?
choke
what is the most common place for feed to become impacted in the oesophagus?
proximal cervical region
distal cervical region (thoracic inlet)
what side of the neck does the oesophagus usually sit on?
left
what are the clinical signs of choke?
sudden onset
coughing
ptyalism
dysphagia
extension/flexion of the neck
what is ptyalism?
overproduction of saliva
how is choke treated?
most will clear spontaneously (take all feed and water away)
if needed sedate (alpha 2) and pass a nasogastric tube to lavage the oesophagus
what aftercare may be required in choke cases?
antimicrobials if risk of inhalation pneumonia
water and gradual reintroduce soft feed
check for underlying conditions
endoscope if recurrent
what is done if an oesophageal food obstruction cannot be cleared?
leave alone for a bit and repeat lavage 8 hours later
what is the prognosis of oesophageal tears/perforations?
poor/guarded
what is essential to the treatment of carbohydrate overload?
early and aggressive treatment (not allowing fermentations and endotoxin absorption)
what are two possible causes of disease associated with horses breaking into feed stores?
carbohydrate overload
additives (poultry - monensin…)
what can be done to treat the early stages of carbohydrate overload?
lavage gastric content (within 2 hours of ingestion)
activated charcoal
flunixin
cryotherapy/ice feet (prevent laminitis)
what can carbohydrate overload lead to that requires intense treatment?
SIRS
what is dysphagia?
difficulty swallowing (or eating)
what are the three main groups causing dysphagia?
pain, neurology, obstructive
what are some causes of dysphagia relating to pain?
abscess, dental pathology, trauma, foreign body, masseter myositis…
what are some causes of dysphagia relating to neurology?
lead, pharyngeal paralysis, head trauma, botulism, equine viral encephalitis…
why do lip lacerations often heal very well?
very good blood supply (but can dehisce)
what is the best way of suturing lip lacerations?
using multiple layers of sutures (at least 2)
how are mandibular fractures treated?
sedate, nerve block and wire
what are some possible causes of rectal prolapses?
diarrhoea, colic, heavy parasite burden, mass in rectum, dystocia…
how are grade I, II or III rectal prolapses treated?
reduce prolpase and address underlying cause
how are grade IV rectal prolapses treated?
surgical management
what can cause haemabdomen?
abdominal trauma - splenic rupture/tears…
what is the initial treatment used for incisional hernias?
conservative - prolonged box rest and hernia belt
why are horses at increased risk of colic after anthelmintic administration?
high parasite burden being killed causing inflammation of mucosa (can give steroids in some cases to help with this)
what colics can cyanthostominosis cause?
intussusceptions (caecocaecal or caecocolic) - due to altered motility
what colics is anoplocephala perfoliata associated with?
spasmodic colic
ileal impaction
caecal intussusceptions
what type of parasite is Anoplocephala perfoliata?
tapeworm
why do ascarids cause colic?
large worms that cause blockages
what is the name for pinworm?
Oxyuris equi
how clinically significant are Gasterophilus intestinalis?
very little (usually)
why is control of parasites to prevent risk of disease important in horses?
they tolerate worm burdens very well and often only show signs with very high burdens when disease is imminent
what is the aim of parasite control strategies?
reduce transmission of parasites to prevent high levels of infection and hence the incidence of disease
what are the four drugs used for worming horses?
fenbendazole, pyrantel, ivermectin, moxidectin
how can pasture be managed to reduce worm burden?
correct stocking density
faecal collection (>twice a week)
dung heaps away from grazing area
rotate and graze with ruminants
what age horses are effected by ascarids?
foals (first few months of grazing)
what is the ascarid of horses?
Parascaris equorum
what can the migration of Parascaris equorum cause in foals?
respiratory disease - coughing
how can Strongyle infection be diagnosed?
FEC
what can be used and when to treat Strongyles in foals?
moxidectin in autumn/winter
what is used to treat tapeworm in horses?
praziquantel
what can be used to treat ascarids in foals?
fenbendazole and pyrantel
what worm do you not need to worry about in older horses?
ascarids (immunity develops)
how do FEC of youngstock compare to adult horses?
almost always higher
what diagnostic tool is recommended for cyathostomins?
FEC for adults
small red worm blood test - inform on whether moxidectin treatment is worth it
what diagnostic tools are available for tapeworm?
FEC
ELISA - good for studs/herds
saliva antigen test (ELISA)
what should be the quarantine procedure for horses in terms of worm control?
FEC and diagnostics
moxidectin and praziquantel usually recommended
house for 3 days to eliminate shedding post treatment
what anthelmintic is Parascaris equorum most commonly resistant to?
ivermectin
what drugs are strongyles resistant to?
benzimadazoles (pyrantel to lesser extent)
