GI disorders in the foal Flashcards
What is the toxic principle in box elder tree seed pods?
- Hyperglycine A
Differentials for nasal regurgitation of milk
- Cleft palate
- Pharyngeal dysfunction
- Megaesophagus
- Botulism - usually older foals
Cleft palate in foals diagnosis
- Should be a part of the neonatal exam - digital palpation of the hard palate
Which is more common: cleft soft palate or cleft hard palate?
- Soft palate
Common consequence of cleft palate
- Aspiration pneumonia
Treatment of cleft palate
- Surgical repair or euthanasia
- If they live long enough to consume
- Solid feed may survive
Dfdx for colic in neonates that are infectious
- Enteritis/sepsis
- Neonatal septicemia
- Salmonella
- Clostridium perfringens
Dfdx for colic in neonates that are non-infectious
- Meconium impaction
- Birth asphyxia related
- Congenital disorders
Older foals infectious dfdx
- Rotavirus (1 week to 2 weeks up to 3-4 months)
- Lawsonia intracellularis
- Parascaris equorum (couple of months)
Older foals non-infectious dfdx
- Gastroduodenal ulcer syndrome
- Sand
- motility issues in the colon
Aspects to diagnose colic in a neonate
- Palpate thorax and abdomen
- Neonates can have rib fractures
- Abdominal distension
- Clinical evidence or suspicion of sepsis
- Lab data showing neutropenia or leukopenia
- Ultrasound (do you see a lot of fluid?)
- Radiography
- Nasogastric tube and reflux
- Abdominocentesis
Normal abdominocentesis
WBC Count
Protein
Lactate
- White blood cell count (<5,000 cells/mL)
- TP <2.5
- Lactate <2 mmol
Differentials for small intestinal distension in foals
- ileus (asphyxia or sepsis)
- Enteritis (often origin of systemic sepsis)***
- Small intestinal strangulation or obstruction
Differentials for colonic tympany in foals
- Secondary to meconium impaction**
- Secondary to ileus +/- colitis
- Congenital conditions
Differentials for Peritoneal effusions in foals
- Uroperitoneum***
- Peritonitis
Clinical signs of a foal with meconium impaction
- 6 hour old foal
- Progressive abdominal distension
- Recurrent colic, rolling
- Non-productive soapy water enema
- Cannot palpate meconium in the rectum with your finger
What is different about the colic exam in the neonatal foal from the adult?
- Unable to perform extensive rectal examination
Other things to consider on a neonatal colic exam
- Observe
- Degree of frequency and pain
- Abdominal distension
- Auscult
- Digital rectal exam and check for feces**
- Check inguinal area for hernia
- Costochondral junction to detect rib fractures
- Ultrasound is more helpful in foals
Pain behavior in foals
- Rolling on the ground
- They look like they are dying
What is the most common cause of colic in neonates?
- Meconium impaction
What causes meconium impactions
- Immature colonic pacemaker neurons?
- Interstitial cells of Cajal are immature in the neonate even full-term
How long does it take meconium impaction signs to occur?
- 12-24 hours
Other clinical signs of meconium impaction
- Decreased suckling
- Depression
- Variable pain (straining to defecate; rolling)
- Abdominal distension
- Colonic tympany
Differentiate posture to urinate from posture to defecate
- make sure you can do it
What is meconium?
- First fecal excretion of the newborn
What is meconium composed of?
- Bile
- Epithelial cells
- Mucus
Diagnosis of meconium impaction
- Physical exam
- Digital rectal
- Ultrasound
- Gas distended colon
- meconium?
- Abdominal radiographs
Colonic tympany in meconium impaction
- Abdomen is filled
- Large viscus that contains multiple parallel horizontal echogenic lines and gas
Abdominal radiographs in foals with meconium impaction
- Differentiate large vs small intestinal gas
- meconium
- Abundant gas
Medical management of meconium impaction overview
- Oral laxative
- Enemas: Soapy water enemas, acetylcysteine enema, Fleet enema
- IV fluids
- Pain control
- +/- Prokinetic
Fleet enemas for Meconium Impaction
- Phosphate
- Often requires multiple doses
- Risk of hyperphosphatemia
- Not enough by the time the foal is colicky
Oral laxatives for Meconium Impaction
- Mineral oil (not for adult horses; the goal here is to actually help it slide out)
- Milk of magnesia
Soapy water enemas
- Ivory soap in water
- Harris flush tube
- Enema bucket
- Occluding anus can provide some hydropropulsion effect
Cautions with enemas in foals
- Delicate rectal mucosa
- Use of abundant sterile lubricant jelly
- Do not force the catheter
Acetylcysteine retention enema
- Intended to aid in breaking down the disulfide bonds in mucus component of meconium
- Acetylcysteine solution and warm water with sodium bicarbonate to help adjust the pH
- Technique is soft flexible Foley catheter with an inflatable cuff
- Insert into rectum 6-10 inches
- Inflate cuff with water
- Apply clamp to Foley catheter once in place and leave for 30-45 minutes
- Repet several times if necessary
IV fluid goals in meconium impaction
- Restore circulating fluid volume
- Hyperhydration of the luminal material
Pain control for meconium impactions with foals
- Flunixin meglumine
- Butorphanol
- Buscopan
Prokinetics for meconium impaction with colonic tympany
- Neostigmine (cholinesterase inhibitor)
- She does not use this, but it may help
Meconium impaction feeding recommendations
- Hold them off of the mare
Monitoring for meconium impactions
- Serial ultrasounds
- can determine if ileus and or gastric distension present before administration of laxatives via NG tube
Indications for referral in meconium impaction
- Profound abdominal distention and unrelenting pain
- Indications for referral +/- surgery
What is the risk of surgery in foals that is more than normal?
- They are little adhesion machines
- They adhese a LOT
Two possible complications with meconium impaction
- Sepsis
- Urinary bladder or urachal leak
Sepsis complication of meconium leak
- Inadequate nursing due to pain and straining
- Possible mucosal injury leads to translocation of bacteria
- Occasionally transmural necrosis of the intestine
Urinary bladder or urachal leak in a horse with meconium impaction
- Straining
- Over hydration with fluids
Age period for meconium impaction
- 1-2 days usually
Dfdx for meconium impaction
- Sepsis
- Infectious diarrhea
- GI ulcer
- Volvulus, intussusception
- Peritonitis
Other differential that can cause gas distension of the small or large intestine in a 1-2 day old foal?
- Atresia ani
Other differential that can cause meconium impaction in a 1-2 day old foal?
- Aganglionosis or lethal white foal syndrome
Atresia coli timeline
- first 1-2 days
Atresia coli - how common?
- SUPER RARE
Atresia coli what will you feel on rectal?
- No feces
Other signs with atresia coli
- Abdominal distension
How do you diagnose atresia coli?
- Radiographs
- Endoscopy
What is the pattern of inheritance of Lethal white syndrome or aganglionosis
- Autosomal recessive
What is the mutation in lethal white syndrome?
- Mutation in the endothelin B receptor gene
What is the fundamental pathologic problem with lethal white syndrome?
- Lack of submucosal and myenteric ganglia
- Small intestine to colon
Which breeding cross is at risk for offspring with lethal white syndrome?
- Overo paint x Overo paint
Clinical signs of Lethal white overo
- No meconium production
- Colic soon after birth
Enteritis in foal diagnosis
- Ultrasound - rapid
- Thick walls
- Fluid distended
- Variable SI motility
- May be primary site for bacterial sepsis
Clinical signs of foal diarrhea
- Vague signs of illness
- Fever, obtundation, colic, decreased nursing
- Signs will start prior to nursing
How can you help differentiate surgical lesions from enteritis?
- Physical exam and ultrasound findings
General diagnostics for foal diarrhea
- Observation/clinical history
- Assessment of systemic effects
- Hematology/Biochemistry panel
- Fecal PCR
- Fecal cytology/bacterial culture
- Bacterial toxin assay (C. difficile toxin A and C. perfringens enterotoxin)
- parasitology
- Electron microscopy
What is the infectious agent in Potomac horse fever?
- Neorickettsia risticii
What changes often occur on the biochemistry panel?
- Sodium and chloride often drop
Infectious causes of foal diarrhea
- Rotavirus
- Systemic bacterial sepsis
- Salmonella
- Clostridium perfringens A, B, and C
- Clostridium dificile
- Coronavirus
- Parascaris equorum
- Strongyloides westeri
- Cryptosporidium
Foal diarrhea treatment decisions - what’s the first question you should answer?
- Does it need intervention?
Questions to answer to determine if the foal needs treatment
- Is it still nursing the mare?
- Signs of colic
- Estimated volume of fecal fluid loss
- Signs of systemic illness
- How critical?
- Referral?
What are differentials for abdominal ultrasound SI distension?
- Ileus and Enteritis
How can you differentiate ileus and enteritis in a foal with SI abdominal distension on ultrasound?
- WBC count could be low with either
- But enteritis is more likely to be low, whereas ileus isn’t normally
When is there an indication in a foal to pass an NG tube?
- High heart rate (>80 BPM) in a foal
- Indication to pass the tube
- First priority with any colic
Overview of enteritis treatment
- Culture (feces or blood)
- Broad spectrum antibiotics
- Anti-endotoxin medications
- IV fluids
- Intestinal protectants
- Nutritional management too
What to culture for enteritis?
- Blood
- Feces
Anti-endotoxin medications for use in foals with enteritis
- Flunixin meglumine
- Polymixin B (nephrotoxic)
IV fluids to use in foals with enteritis
- Crystalloids
- Plasma
- Hetastarch
Intestinal protectants to use with enteritis
- Bismuth subsalicylate (Pepto)
- Biosponge (Smectite)
- Sacchromyces boulardii
Nutritional management of enteritis foals
- Most foals require milk or enteral nutrition
- Parenteral nutrition possible but not ideal
How can you promote suckling behavior in a foal on parenteral nutrition?
- Gradually wean off parenteral nutrition to intermittent suckling
- Start allowing foal to nurse for 1-2 minutes to start every 2 hours
Target sign
- Small intestinal intussusception
- Can see on ultrasound the loops of bowel inside of the other loops of bowel
Clinical signs of intussusception
- Decreased suckling
- Dehydration
- Diarrhea
- PROGRESSIVE colicking
- Slightly distended abdomen
- May not be febrile
Treatment for intussusception
- Surgery
What is the most common cause of diarrhea in foals?
- Foal Heat Diarrhea
When does foal heat diarrhea occur?
- 7-12 days post partum
- Same time as post-foaling estrus for a mare
- Occurs in orphan foals as well
Mechanism of foal heat diarrhea
- Hypersecretion into the small intestine overwhelming the capacity of immature colon
- Normal physiologic mechanism
- Likely due to changing of the microbiome (eating mom’s feces and solid feed
How do you treat foal heat diarrhea?
- Self-limiting and normal
