GI Disease in Foals Flashcards
Why is the Gi tract of foals different to that of in adults and why?
- Oral – view the dentistry lecture – teeth change quite a lot in these years
- Predominantly liquid diet until weaned!
- Hindgut underdeveloped and smaller compared to adults horses, due to this diet
- Stomach and small intestine relatively larger
- Diet is very rich in sugars (lactose)
- Maternal passive transfer provides humoral immunity
–Foals rely heavily on acquired or passive immunity, they acquire all
What are some oral congenital abnormalities in foals?
–Cleft palate
–Campylorhinus lateralis (wry nose)
–Subepiglottic cysts
–Brachygnatisms (parrot mouth)
Look closely at this picture - what is wrong with this foal?
Milk splashing out from nose, probably with cleft palate
What is wrong here?
Cleft palate
What is wrong here?
Rye nose, malformation of nasal passages – might not be able to get colostrum that they need in first few days of life!
What are some oesophageal congenital abnormalities?
–Stenosis
–Persistent right aortic branch
–Vascular abnormalities
–Duplication cysts
–Idiopathic megaoesophagus
ALL VERY RARE
What are some hindgut congenital abnormalities?
–Atresia (dead end), can affect:
- Coli
- Recti
- Ani
- Foals from 2-48h old
- No meconium passed
- Fermentation from milk that has accumulated – get colicky
What is the diagnosis for a hindgut congenital abnormality?
- Digital palpation (ani) – use the finger, introduce into rectum and see whether you can identify if it’s a dead end – only for distal atresia, if anything further forward wont be able to feel it
- Contrast Rx
- US/colonoscopy – helpful if distal one
What are some GI disorders that can cause colic in foals?
–Meconium impactions
•Meconium is the first faeces the foal will produce, accumulates when in the uterus. Should be passed through within a few hours. Can obstruct
–Gastric ulceration
•Similar to adults
–Parasitism (Parascaris equorum)
•1 that causes colic
–Intestinal obstruction (REFERRAL)
What are some GI disorders that can cause diarrhoea in foals?
•Diarrhoea (includes colic as a clinical sign)
–Viral (Rotavirus, Coronavirus, Adenovirus) R
–Bacterial (Clostridial, Salmonella, E.coli, Rhodococcal, lawsonia i., etc) R
–Parasitism (Cryptosporidium, Strongyloides westerii) R
–Foal heat
–Prenatal Asphyxia Syndrome R
– R is for conditions that will probably warrant referral
What are clinical signs of colic in foals?
- Foals more demonstrative of abdominal pain than adults
- Wide array of clinical signs
–Aspecific
•Tachycardia, tachypnoea, anorexia, tooth-grinding – remember the different reference ranges for their age range!
–Abdominal distension
–Flank watching
–Rolling
–Lying in dorsal recumbency
–Tail flagging (tenesmus) – stand as if they are trying to go to the loo and move their tail at the same time – probably a sign of tenesmus
What are some means of diagnosis of colic in foals?
- History (foaling, feeding, meconium etc.) – was foaling okay, any issue? Did it drink its colostrum? Has it passed meconium yet? Even if foal has passed meconium, doesn’t mean it has passed it all!
- Physical examination
- Abdominal palpation – similar to small animals as smaller abdomen, can actually feel things!
- Digital rectal (= with finger)
- Pass NGT – if young one, might want to use urinary catheter – the bigger you can pass, the better as getting reflux out of a foal is a bit more difficult than in adults!
- Abdominal ultrasonography – usually get good pics as not a lot of fat!
- Abdominal radiography ± contrast
- Haematology/biochemistry
- ±Abdominocentesis
ALWAYS CONSIDER REFERRAL AS AN OPTION
Important not to waste time – foals are delicate!
How can you use the physical exam to help aid a diagnosis of colic in a foal?
–Vitals different from adults and are age specific
–Look out for signs of sepsis
•Pyrexia, depression (sometimes sleepiness and lethargy, they should try to run away!), petechiae (look at oral and vaginal mucosa etc.), synovitis (any swollen joints? Can be one or more), uveitis (haematogenous spread maybe), diarrhoea
–Critically ill foals may not display signs of abdominal pain even with serious GI disease
–Tachypnoea and tachycardia are not unusual without significant disease – they are very reactive! The problem is when the foal looks calm and there is still tachycardia!
•Persistent tachycardia (>120bpm) likely indicates need for surgery
How can you use abdominal palpation to help aid a diagnosis of colic in a foal?
–Palpate to feel gas distension (obstruction)
–Hard masses (intussusception, meconium)
–Percussion
–Ballottement: presence of free fluid (bladder rupture – especially common in male foals as their urethra is quite long?)
–Hernias (umbilical and inguinal)
–Detect pain
How can you use digital rectal and NGT to help aid a diagnosis of colic in a foal?
•Digital rectal
–Use lots of lubricant – their rectum is very thin
•NGT
–Use stallion urinary catheter
–Hard to obtain reflux
–Muzzle if refluxing – they will go and feed, prevent them from feeding! Same with adults, don’t want to feed them as if they are reflucing – there is a problem and don’t want to exacerbate it!
What is wrong here?
Abdo adhesions – prevents intestines from moving properly
What is wrong here?
Thickened SI
What is wrong here?
Intussusception
What is wrong here?
Distended SI
What is wrong here?
Meconium impaction – can sometimes see on US
What is wrong here?
Distended SI with fluid in it – black arrows = horizontal fluid lines
Probably all visible also on US
What is wrong here?
White arrovs indicate stricture of SI, likeli a site of torsion – foal had a volvulus
Can see obstruction
Volvulus
What is wrong here?
Obstruction of large or small colon – foal in the end had meconium impaction – what we see if the gas distension cumulated in the large colon
Have LI gas distention so can see colon filled with gas
What is wrong here?
Very sensitive with contrast to identify atresia coli or recti – this is a case of atresia coli
Can see stricture
Doesn’t progress anywhere – atresia coli
How can you use haematology to help diagnose colic?
–Hypovolaemia
- PCV/TPP – make sure the foal is well hydrated, esp if they are not eating as they rely so much on milk
- Lactate – make sure we are perfusing everything adequately
–Inflammatory profile
- Neutropenia – usually bad thing! Means they are not coping well with inflammatory response!
- Acute phase proteins
–Serum Amyloid A – only takes a few hours to increase
–Fibrinogen is another one but doesn’t change as quickly – takes 3-6 days to increase
What would you use biochemistry to assess with colic?
Renal function
How can you use abdominocentesis to help diagnose colic?
–Lower TNCC in peritoneal fluid than adult values, changes slightly within first 7 days and 1 month:
- 7do: 0-2x109cells/L
- 1mo: 0-1.5x109cells/L
–Total protein: <25g/L
–Colour important
- Serosanguineous (orangey) suggestive need for surgery
- Normal – pale yellow and be able to read through it
–If concerned of uroperitoneum
•PFcreatinine : Serumcreatinine à normal <2
What is going on here?
Intussusception
What is this parasite?
How does it infect foals?
What does it cause?
What is it responsive to?
Strongyloides westeri
Infection via the trans-mammary route
Causes diarrhoea only if in very high numbers
Generally good response to ivermectin
