PATHOLOGY - Equine Colic Flashcards
What is colic?
Colic is a generalised term for severe abdominal pain
Which history questions are useful to ask when investsigating colic?
- When were the clinical signs first noticed?
- Has there been any owner intervention and has this had any affect on the horse?
- Has there been any previous veterinary visits regarding colic?
- Has there been any changes in management?
- Has there been any changes in diet?
- Is the horse on any medications?
- What is the horse’s deworming history?
Which specific parameters are important to assess when doing a clinical examination on a horse with colic?
Overall demeanour and conditon of the horse
Assess pain levels
Assess cardiovascular parameters
Assess the abdomen
Palpate the scrotum and inguinal rings in males
Rectal examination
Assess for passage of faeces
Assess the horse’s response to analgesia
What can be indicated by marked pain and abdominal distension in colicing horses?
Marked pain and abdominal distension in colicing horses can indicate large colon volvulus
What can be indicated by marked pain that decreases as the colicing horse becomes more depressed?
Pain that decreases as the colicing horse becomes more depressed can indicate small intestinal disease
Which cardiovascular parameters should you assess in a horse with colic?
Heart rate and rhythm
Pulse rate, rhythm and quality
Hydration
Mucous membrane colour
Capillary refill time (CRT)
Palpate the extremities
Temperature
What is the normal heart rate for a horse at rest?
28 - 40 bpm
What should you do if a horse with colic has a heart rate of over 60bpm?
If a horse with colic has a heart rate of over 60bpm, you should pass a nasogastric tube as this can be a key signs of gastric dilatation and the nasogastric tube will decompress the stomach to prevent fatal rupture of the stomach
Describe how to pass a nasogastric tube in a horse
The alar fold needs to be elevated to displace the nasal diverticulum (‘false nostril’) in order to direct the nasogastric tube ventro-medially to enter the ventral meatus of the nasal cavity. When you begin to feel soft resistance you are in the pharynx. Make sure to flex the horses neck so the tube is more likely to enter the oesophagus rather than the trachea and allow the horse to swallow before gently advancing the tube. Administer water down to tube and assess for reflux of stomach contents to ensure the tube is in the stomach
What are some of the signs that the nasogastric tube is in the oesophagus rather than the trachea?
Negative pressure
Visualisation of the tube passing on the left hand side of the neck
Slight resistance to advancing the tube
No cough
Smell of stomach gas
What are the potential complications of passing a nasogastric tube?
Passing the tube into the middle or dorsal meatus
Epistaxis if you hit the echmoid conchae
Intubating the trachea
Trauma to the oesophagus
How do you assess hydration in the horse?
Skin tenting
Check the mucous membranes (should be pink and moist)
What should you be aware of when using skin tenting to assess hydration in a horse?
In order horses, the skin is less elastic so it may remain tented for longer even if the horse is not dehydrated
What is indicated by the appearance of these mucous membranes?
These mucous membranes are red/purple in colour with toxic lines, which are bright red/purple lines on the horse’s gums, right above the teeth. This discolouration of the mucous membranes and toxic lines are key signs of endotoxaemia and sepsis
What should you assess when palpating the extremities?
Palpate digital pulses
Assess temperature of the extremities (ears and limbs)
What is indicated by cold extremities in the horse?
Cold extremities can indicate shock
What can be indicated by pyrexia?
Pyrexia can indicate inflammation of the gastrointestinal tract (i.e. enteritis, colitis, enterocolitis etc.) or infection
Which factors should you assess when assessing th abdomen of a horse with colic?
Auscultate the abdomen
Assess abdominal shape for abdominal distension
How should you auscultate the equine abdomen?
Auscultate the abdomen in four quadrants, i.e. auscultate dorsally and ventrally on both sides of the abdomen
In which quadrant should you be able to auscultate the caecal flush in a horse?
You should be able to auscultate the caecal flush in the dorsal, right quadrant
How often should you hear the caecal flush when auscultating the abdomen?
The ceacal flush should occur every 90 - 180 seconds
What is associated with absent gut sounds in a horse with colic?
Absent gut sounds in a horse with colic is generally associated with more severe disease
Why is it so important to palpate the scrotum and inguinal rings in every male horse with colic?
It is imporatant to palpate the scrotum and inguinal rings in every male horse with colic as the small intestine can herniate through the inguinal rings and into the scrotum, causing colic
How do you prepare to do a rectal examination on a horse?
- Restrain the horse appropriately by using either a twitch, a crush or sedation
- Administer butylscopolamine (buscopan)
- Have lots of lubricant available
Why is it beneficial to administer butylscopolamine (buscopan) prior to doing a rectal examination on a horse?
Butylscopolamine (buscopan) is an anticholingergic so relaxes the gastrointestinal tract to allow for easier rectal examination
What is the duration of action for butylscopolamine (buscopan)?
15 to 20 minutes
What is one of the main side effects of butylscopolamine (buscopan) that you should be aware of?
Butylscopolamine (buscopan) causes tachycardia
Very important to measure the heart rate before administering buscopan to get an accurate heart rate
Which structures should you be able to palpate on rectal examination?
Aorta
Caudal aspect of the left kidney
Nephrosplenic ligament
Caudal aspect of the spleen
Pelvic flecture between the left dorsal and ventral colon
Bladder
Caecal band
Inguinal rings
Which factors should you assess when assessing the passage of faeces in colic cases?
Consistency of faeces
Quantity of faeces
Mucus in the faeces
Blood in the faeces
Assess for parasites in the faeces
What can be indicated by decreased faceal passage in colic cases?
Decreased faecal passage can cause gastrointestinal ileus
Which diagnostic tests can be useful to do when investigating colic cases?
Blood tests
Abdominocentesis
Abdominal ultrasound
Abdominal radiography
Which blood tests are beneficial when assessing a horse with colic?
Haematology
Biochemistry and electrolytes
Blood lactate
Why is PCV not an accurate way to assess dehydration in a horse?
While a high PCV can indicate dehydration, a high PCV can also be caused by splenic contraction which can occur when a horse is stressed, excited or has just exercised
What can be indicated by a high PCV and a low TS?
An increased PCV and decreased TS can indicate dehydration with a loss of plasma proteins into the intestinal lumnen, which can indicate gastrointestinal inflammation, or into the peritoneum which can indicate peritonitis
What can be indicated by high blood lactate levels in a horse with colic?
Lactate is a byproduct of anaerobic metabolism and thus can indicate poor tissue perfusion. In colic cases, this usually indicates poor perfusion of the gastrointestinal tract
Why can it be beneficial to do an abdominocentesis in colic cases?
Abdominocentesis will allow you to assess the peritoneal fluid which can indicate the health of the intestines as the composition of the peritoneal fluid can change if intestines are compromised
How do you carry out an abdominocentesis in a horse?
Insert a needle or a teat cannula into the right side of the linea alba at the most ventral point, or do ultrasound guided abdominocentesis and catch the fluid in an EDTA tube and a serum tube
What is the main risk of an abdominocentesis?
The main risk of an abdominocentesis is inserting the needle into the intestines, however if this happens it is not a disaster, just get new pair of sterile gloves and use a new abdominocentesis site
These is a much higher risk of inserting the needle into the intestines in foals
Why should you never use an needle bigger than 19 gauge to do an abdominocentesis in a foal?
If you use a needle bigger than 19 gauge in a foal, there is a risk of the omentum prolapsing through the puncture site
When should you not perform an abdominocentesis?
Foals with intestinal distension
Pregnant mares
How should normal peritoneal fluid appear?
Normal peritoneal fluid should be clear to yellow in colour and not cloudy
What can abdominal ultrasound allow you to assess in colic cases?
Free abdominal fluid (make sure to assess the cellularity)
Intestinal wall thickness
Intussusception
Nephrosplenic entrapement
What is the FLASH technique for abdominal ultrasound?
A TFAST is a systematic ultrasound examination technique which is used to assess seven key regions of the abdomen
When is abdominal radiography a useful diagnostic when investigating colic?
Abdominal radiography can be a useful diagnostic if you suspect sand accumulation or enteroliths in the gastrointestinal tract
Which analgesics and sedatives are commonly used in colic cases?
Detomidine
Xylazine
Butorphanol
Flunixin
Phenylbutazone
Butylscopalamine (Buscopan) compositum
Which two drugs make up butylscopalamine (buscopan) compositum?
Metamizol
Butylscopalamine (Buscopan)
What is the function of metamizol?
Metamizol is an analgesic drug
What should you be aware of when administering analgesia to colic cases?
It is usually best to start with a less potent analgesic such as phenylbutazone or metamizol + butylscopalamine (Buscopan) as more potent analgesics can potentially mask worsening colic pain which can be a key indicator that the colic is worsening and could require surgical intervention. If patients continue to colic despite pain medication, this can also indicate a more severe underlying disease process
(T/F) Referral of colic cases always means surgery is required
FALSE. Not all referrals of colic cases require surgery
What are the key indicators that a colic cause requires referral?
Refractory to pain
Sepsis/endotoxaemia
Refractory small or large intestinal obstruction
Evidence of devitalised intestine
Severe abdominal distension
If the owner is very concerned and wants referral
What is the average price of equine colic surgery?
£5,000 to £10,000
What will happen when the colic case arrives at the referral centre?
This is useful to know to inform the owners
- Fill out consent forms
- Referral practice will take a history and do a clinical examination
- Repeat blood testing
- Repeat nasogastric tubing if necessary
- Repeat abdominocentesis
- Repeat abdominal ultrasound
- Administer intravenous fluids if necessary
- Prepare the horse for colic surgery if indicated
What is another term for colic surgery?
Exploratory laparotomy
How do you prepare a horse for colic surgery?
- Administer NSAIDS (unless they have already been given NSAIDS recently) and antibiotics
- Check the tetanus status of the horse
- Clip and prepare the abdomen for surgery (preferably do this before the horse is anaesthetised to reduce anaesthetic time)
- Carry out normal induction preparation
What postoperative care should be carried out following colic surgery?
Administer NSAIDS
Administer antibiotics
Nasogastric tubing for gastric decompression if necessary
Gradually introduce good quality roughage (hay etc)
Keep the incision clean and dry
Very limited exercise
What are some of the post-operative complications of colic surgery?
Incisional swelling and infection
Incisional dehiscence
Herniation
Repeat colic
What are the potential causes of repeat colic following colic surgery?
Feed related
Post-operation ileus (POS)
Anastomotic complications
Abdominal haemorrhage
Septic peritonitis
Diarrhoea/colitis
Repeat of previous cause of colic
How do you manage post operative ileus?
Gastric decompression with nasogastric tubing
Intravenous fluid therapy
Colloid fluids
NSAIDS
Antibiotics
Prokinetics
When should you remove staples/sutures following colic surgery?
You should remove staples/sutures 10 to 14 days following colic surgery
How should you manage a horse’s exercise following colic surgery?
Horse’s should be on box rest for 8 weeks following colic surgery, with 20 to 30 minutes of in-hand grazing 2 to three times a day. After 8 weeks, they can be allowed in small paddock and after 14 weeks they can exercise under the saddle. Horse’s can be expected to return to normal exercise around 6 months post surgery
What should horse’s be fed following colic surgery?
Roughage (hay/haylage or fresh grass) using haynets to slow feeding
Small amounts of concentrates
Fresh water at all times
Probiotics
Any changes in feed management should be made slowly over 2 - 3 weeks
Describe the anatomical location of the equine large intestine
The caecum is located on the right side of the abdomen. The right ventral colon runs from the caecocolic orifice, cranially to the level of the xiphoid where it turns to form the ventral diaphragmatic flexure and runs caudally as the left ventral colon to the level of the pelvis, turns and narrows to form the pelvic flexure and runs dorsal and cranial as the left dorsal colon which turns at the diaphragm to form the dorsal diaphragmatic flexure and continues caudally as the right dorsal colon. The transverse colon runs cranially from right to left to the root of the mesentery (point of firm attachment at the dorsal body wall) and then turns caudally to become the small colon
What is the large colon?
The large colon is a term used to describe the portion of colon running between the caecum and the transverse colon
What are the main sites of celluose digestion and fermentation in the horse?
Caecum
Left and right ventral large colon
What are the different classifications of large intestinal colic?
Large intestinal simple obstructions
What are the possible causes of simple large intestinal obstructions?
Caecal impaction
Large colon impaction
Small colon impaction
Enteroliths
Sand colic
Small colon impaction
Colon displacement
What is a primary caecal impaction?
A primary caecal impaction is usually an accumulation of dry, relatively solid ingesta resulting in impaction
What is a secondary caecal impaction?
A secondary caecal impaction is usually an accumulation of fluid within the caecum. Secondary caecal impactions develop when horses are being treated for other conditions, very commonly in the post-operative period
What are the risk factors for secondary caecal impactions?
Pain
Stress
Change in management
Change in diet
Reduction in exercise
Dental abnormalities
Dehydration
Why is there often delyaed diagnosis of secondary caecal impactions?
Secondary caecal impactions occur when hoses are being treated for other conditions, commonly in the post-operative period so early signs may be missed due to being attributed to discomfort following surgery or the concurrent condition. The delayed diagnosis can result in imminent risk of caecal rupture
What are the clinical signs of caecal impactions?
Gradual onset of mild, intermittent colic
Gradual onset of signs of pain
Reduced faecal output
Dehydration
Will become more painful if impaction is unresolved
How do you diagnose caecal impactions?
Rectal examination
How does a primary caecal impaction typically feel on rectal examination?
The caecum can be identified by the ventral caecal band and will typically feel firm and enlarged
How does a secondary caecal impaction typically feel on rectal examination?
The caecum can be identified by the ventral caecal band and will typically feel semifluid filled and enlarged
How do you carry out medical management of caecal impactions?
Enteral fluid therapy
IV fluid therapy
Laxatives
NSAIDS
What is the function of enteral fluids for medical management of caecal impactions?
Enteral fluids are used to rehydrate and soften the impaction
What are the benefits of using enteral fluids over IV fluids for medical management of caecal impactions?
More cost effective
Reaches the impaction more rapidly
How do you administer enteral fluids in horses with caecal impactions?
Adminiser small but frequent boluses of enteral fluids via a nasogastric tube
How do you administer laxatives in horses with caecal impactions?
Add laxatives to enteral fluids and administer via a nasogastric tube
Which laxtative can you use in the medical management of caecal impactions?
Magnesium sulphate (MgSO4)
What dose of magnesium sulphate (MgSO4) is appropriate for impactions?
0.5 - 1g/kg
When is it appropriate to use IV fluid therapy when managing caecal impactions?
IV fluid therapy can be used to correct dehydration if clinically indicated and to supplement oral fluid therapy
Which surgical procedure can be done to treat caecal impactions refractory to medical management?
Typhlotomy (removal of the impacted content from the caecum)
Why is it so important not to delay surgical management of caecal impactions if necessary?
It is important not to delay surgical management of caecal impactions if necessary as there is a risk of caecal rupture - especially for secondary caecal impactions. Caecal ruptures have a very poor prognosis and require euthanasia
What is caecal tympany?
Caecal tympany is excessive gas accumulation within the caecum resulting in distension
What are the causes of primary caecal tympany?
- Excessive intake of fermentable carbohydrates such as lush grass or grains which can cause dysbiosis and excessive gas production
- Reduced caecal motility
- Dysbiosis
|Primary caecal tympany is rare
What are the causes of secondary caecal tympany?
Caecal tympany secondary to large colon impactions, displacements, volvulus or tympany
|Secondary caecal tympany is much more common
What are the clinical signs of caecal tympany?
Abdominal distension with ping sound on auscultation
Colic signs
Signs of pain
How do you diagnose caecal tympany?
Rectal examination
How does caecal tympany typically feel on rectal examination?
The ventral caecal band will feel very taut and and caecum will be distended
How do you treat caecal tympany?
Caecal trocarisation
Treat underlying cause
What is caecal trocarisation?
Caecal trocarisation is a technique that involves inserting a large bore catheter into the caecum to remove the gas and decompress the caecum
How do you carry out caecal trocarisation?
Clip and sterile prep a tympanic area of the right flank, in the region of the paralumbar fossa, and insert a large bore catheter to begin decompression. When the caecum begins to decompress, pull to catheter back slightly. Attach an extension cord to the catheter and place the extension cord in water to allow you to more easily assess when there is no more gas leaving the caecum. While you’re pulling out the catheter, apply some topical antibiotics to the site
What are the most common sites for large colon impactions?
Pelvic flexure
Right dorsal colon
What are the risk factors for large colon impactions?
Pain
Stress
Change in management
Change in diet
Reduction in exercise
Dental abnormalities
Dehydration
What are the clinical signs of a colon impaction?
Gradual onset of mild colic
Gradual onset of signs of pain
Reduced faecal output
Dehydration
Will become more painful if impaction is unresolved
How do faeces typically look with large colon impactions?
Reduced heard/dry faeces which may be covered in mucus
How do you diagnose large colon impactions?
Rectal examination
How does a large colon impaction typically feel on rectal examination?
When doing rectal examination, the pelvic flexure is the first portion of the colon that is palpated. It will often feel doughy or firm and enlarged and can move caudally into the pelvic cavity if impacted
How do you carry out medical management of large colon impactions?
Enteral fluid therapy
IV fluid therapy
Laxatives
NSAIDS
What is the function of enteral fluids for medical management of large colon impactions?
Enteral fluids are used to rehydrate and soften the impaction
How do you administer enteral fluids in horses with large colon impactions?
Adminiser small but frequent boluses of enteral fluids via a nasogastric tube
How do you administer laxatives in horses with large colon impactions?
Add laxatives to enteral fluids and administer via a nasogastric tube
Which laxtative can you use in the medical management of large colon impactions?
Magnesium sulphate (MgSO4)
When is it appropriate to use IV fluid therapy when managing large colon impactions?
IV fluid therapy can be used to correct dehydration if clinically indicated and to supplement oral fluid therapy
Why is mineral oil no longer recommended for enteral administration when managing impactions?
Though mineral oil is a marker of gastrointestinal transit, it does not soften the impaction, instread it hinders water penetration. Furthermore, one of the main risks of enteral fluid administration is aspiration and aspiration of mineral oil into the lungs can be fatal
Which surgical procedure can be done to treat large colon impactions refractory to medical management?
Laparotomy with enterotomy at the site of large colon impaction
What are enteroliths?
Enteroliths are mineral accumulations within the gastrointestinal tract which can cause obstructions resulting in distension proximal to the obstruction
What are the most common sites for enterolith obstruction?
Right dorsal colon
Transverse colon
What are the clinical signs of enteroliths and enterolith obstruction?
Mild to moderal intermittent colic which can progress and become more severe with distension proximal to the enterolith obstruction
How do you diagnose enterolith obstructions?
Radiography
How do you treat enterolith obstructions?
Surgical removal of the enteroliths, making sure to look for any more in the colon
What is sand colic?
Sand colic is where sand accumulates within the large colon, with fine sand tending to accumulate in the ventral colon and coarse sand tending to accumulate in the dorsal colon
What are the potential consequences of sand accumulation in the large colon?
Sand accumulation can cause an impaction, however, sand can also cause damage to the epithelium of the colon through friction, resulting in signs of diarrhoea
How do you diagnose sand colic?
History (do the horses have access to sandy ground etc)
Faecal flotation
Radiography
How do you medically manage sand colic?
Administer psyllium fibre and magnesium sulfate (MgSO4) in enteral fluids via nasogastric tube, at least twice a day over five to ten days
How do you surgically manage sand colic?
Laparotomy and enterotomy to remove the sand
What are the potential causes of small colon impactions?
Enteroliths
Faecaliths
Foreign bodies
What can predispose horse’s to small colon impactions?
Colitis
What are the clinical signs of small colon impactions?
Mild colic with progressive colic pain
Progressive abdominal distension
Reduced faecal output
How do you diagnose small colon impactions?
Rectal examination
Ultrasound
Radiography
How do small colon impactions typically feel on rectal examination?
Typically you will feel loops of tubular, firm intestine
How does a small colon impaction typically present on ultrasound?
Typically a small colon impaction will appear as a distended, amoltile small colon with a thickened wall
What can radiography be used to detect when investigating small colon impactions?
Enteroliths in the small colon
Foreign bodies in the small colon
How do you carry out medical management of small colon impactions
Enteral fluid therapy
IV fluid therapy
Laxatives
NSAIDS
Enema
Which surgical procedure can be done to treat small colon impactions refractory to medical management?
Intraluminal lavage to break down the impaction
Possible enterotomy to remove the impaction
What are the two classifications of large colon displacement?
Left dorsal displacement
Right dorsal displacement
What is another term used to describe left dorsal displacement?
Nephrosplenic entrapement
What is a left dorsal displacement?
A left dorsal displacement is where the left ventral and dorsal colon become displaced and entrapped by the spleen laterally, the left kidney medially and the nephrosplenic ligament ventrally, resulting in simple large colon obstruction and gas distension
How does left dorsal displacement typically feel on rectal examination?
To diagnose left dorsal displacement on rectal examination, you will feel the pelvic flexure over the nephrosplenic ligament and be able to feel that the spleen is displaced medially from the body wall
How do you diagnose left dorsal displacement?
Rectal examination
Ultrasound
What is the typical appearance of left dorsal displacement on ultrasound?
You will be able to visualise the colon between the spleen and the left kidney
How do you medically manage left dorsal displacement?
Prokinetics
Intravenous phenylephrine
Enteral fluid therapy
IV fluid therapy
Exercise
Why are prokinetics administered to help medically manage left dorsal displacement?
Prokinetics increase gastrointestinal motility and thus can potentially help to move the colon back to it normal position
Why do you administer phenylephrine to medically manage left dorsal displacement?
Phenylephrine is a vasoconstrictor which triggers splenic contraction, reducing the size of the spleen to potentially allow the colon to return to it’s normal position
Why is exercising the horse beneificial for medicial management of left dorsal displacement?
Exercise can help to mobilise the colon as well as triggers splenic contract, reducing the size of the spleen to potentially allow the colon to return to it’s normal position
What surgical management can be used to treat left dorsal displacement?
Laparotomy to remove any gas from the colon and migrate it back to its normal position
Rolling the horse under general anaesthetic
What is the prognosis for left dorsal displacement?
Good prognosis as the tissue remains viable with left dorsal displacements
What is right dorsal displacement?
Right dorsal displacement is where the left dorsal and ventral colons move laterally and become displaced between the caecum and the right body wall, and the pelvic flexure ends up positioned near the diaphragm. Often this displacement results in a degree of volvulus, resulting in a large colon obstruction and gas distension
Which signalement is more prone to right dorsal displacement?
Large breed horses are more prone to right dorsal displacement
How do you diagnose right dorsal displacement?
Rectal examination
Ultrasound
How do you medically manage right dorsal displacement?
Prokinetics
Enteral fluid therapy
IV fluid therapy
Caecal trocarisation (if indicated)
Exercise
(T/F) Right dorsal displacements rarely require surgical intervention
FALSE. Right dorsal displacement commonly requires surgical intervention
What is the prognosis for right dorsal displacement?
Good prognosis as the tissue remains viable with right dorsal displacements
What is large intestinal volvulus?
Large intestinal volvulus is where the large intestine rotates on its long axis. A rotation of 180° is usually physiological or due to displacements, rotation of 270° will cause large intestinal obstruction, and rotation of 360° or more will cause strangulation of the blood supply, ischaemia and necrosis and the translocation of bacteria and endotoxins into the blood stream resulting in sepsis and endotoxaemia
Which signalement is at the greatest risk of large intestinal volvulus/torsion?
Post-parturition mares
What are the clinical signs of large intestinal volvulus of over 360°?
Moderate to severe colic
Only intermittent response to analgesia
Abdominal distension
Clinical signs of endotoxaemia and sepsis
Dehydration
What are the key signs of sepsis/endotoxaemia?
Toxic lines
Congested mucous membranes
Profound depression
Tachycardia
CRT more than 2 secs
How do you diagnose large intestinal volvulus of over 360°?
If the horse is very painful with very severe colic and not responsing to analgesia, they should be sent for surgical referral as there is a high risk they have large intestinal volvulus of over 360°
What is the prognosis for large intestinal volvulus of over 360°?
Poor prognosis
What is the prognosis for large intestinal volvulus of less than 360°?
Good prognosis
What is a rectal prolapse?
A rectal prolopse is the extrusion of the rectum and possibly the small colon beyond the anal sphincter
What is a type I rectal prolapse?
A type I rectal prolapse is the prolapse of the rectal mucosa beyond the anal sphincter
What is a type II rectal prolapse?
A type II rectal prolapse is the complete prolapse of the rectal ampulla beyond the anal sphincter
What is a type III rectal prolapse?
A type III rectal prolapse is the complete prolapse of the rectal ampulla with intusussception of a portion of the small colon beyond the anal sphincter
What is a type IV rectal prolapse?
A type IV rectal prolapse is complete prolapse of the rectum and small colon beyond the anal sphincter
What causes a rectal prolpase?
Straining
How can you treat a type I or II rectal rectal prolpase?
- Push the tissue back into the rectum
- Reduce oedema
- Epidural to reduce straining
- Do not feed for 12 - 24 hours
- Treat the underlying cause of the straining
- Perform a submucosal resection if any partial thickness damage of the tissue or rectal prolpase amputation if full thickness damage to the tissue
What can you use to reduce oedema when treating a rectal prolpase?
Topical glycerin, sugar and/or magnesium sulfate (MgSO4)
What can be done to prevent recurrence of a rectal prolpase while treating the underlying cause of straining?
The prevent recurrence of a rectal prolpase, place a loose purse-string suture using umbilical tape. If this is well tolerated, leave it in place for 24 - 48 hours, making sure to open the purse string suture every 2 - 4 hours to allow for defaecation
How do you treat a type III or IV rectal prolpase?
Unfortunately type III or IV rectal prolpases result in a loss of blood supply to the small colon and require euthanasia
How do you determine the prognosis of a rectal prolapse?
The prognosis directly correlates with the quantity of tissue that has been prolapsed
What is one of the most common causes of rectal tears in horses?
Rectal examination
Which signalements are at increases risks of rectal tears due to rectal examination?
Minature horses
Young stallions
Geriatric horses
Why are young stallions at an increased risk of rectal tears due to rectal examination?
Young stallions are more likely to rear during rectal examination, making them at increased risk of rectal tears
Why are geriatric horses at an increased risk of rectal tears due to rectal examination?
Geriatric horses have thinner rectal walls and are thus at an increased risk of rectal tears due to rectal examination
Where anatomically do most rectal tears occur?
Rectal tears occur most commonly dorsally along the long axis of the rectum
What is a grade I rectal tear?
A grade I rectal tear involves the mucosa and submucosa
What is a grade II rectal tear?
A grade II rectal tear involves just the muscular layer and the submucosa and muscosa prolpase through the tear
What is a grade IIIa rectal tear?
A grade IIIa rectal tear involves all of the layers except the serosa
What is a grade IIIb rectal tear?
A grade IIIb rectal tear is a dorsal rectal tear involving all layers except the mesorectum (remember the dorsal aspect of the rectum does not have a layer of serosa and is instead attached to the dorsum of the body wall by the mesorectum)
What is a grade IV rectal tear?
A grade IV rectal tear involves all layers of the rectal wall
How do you initially diagnose a rectal tear?
If fresh blood is observed on the rectal sleeve this is a key sign of a rectal tear and is enough to warrant emergency care
How can you get a definitive diagnosis of a rectal tear?
Endoscopy
Bare arm palpation to feel the defect
Abdominocentesis showing abdominal contamination
What can cause partial thickness rectal tears to progress to to full thickness rectal tears?
Partial thickness tears can progress to full thickness tears rapidly when faeces passes the tear
What emergency treatment should you provide when there is evidence of a rectal tear?
- Reduce rectal activity using atropine, butylscopolamine (buscopan) or an epidural
- Gently remove the faeces from the rectum and the tear
- Start treatment for septic shock and periotnitis using broad spectum bacteriacidal antibiotics (penicillin or gentamicin) and metronidazole, flunixin and intravenous fluids
- Pack the rectum from proximal to the tear to the anus
- Hospitalise the patient for continuous monitoring
How do you determine to prognosis of rectal tears?
The prognosis of rectal tears correlates with the number of layers of the rectal wall that have been damaged, with full thickness rectal tears being rapidly fatal in most cases
How can you minimise the risk of rectal tears?
Properly restrain the horse
Properly sedate the horse
Use sufficient lubrication
Do not try to force against straining or periastalsis
Do not try to palpate structures ahead of your hand, go past the structure and then palpate
What is spasmodic colic?
Spasmodic colic are colic signs as a result of dysmotility and spasms which result in cramping
This is the most common cause of colic
What are the clinical signs of spasmodic colic?
Mild to moderate colic
What causes spasmodic colic?
The cause of spasmodic colic is unknown
How do you diagnose spasmodic colic?
Spasmodic colic is diagnosed based on the mild to moderate clinical signs with no other abnormalities on clinical examination, no findings on rectal palpation, normal blood tests, no reflux with nasogastric tubing and normal peritoneal fluid
How do you treat spasmodic colic?
NSAIDS
Spasmolytic drugs
Which spasmolytic drug can you to treat spasmodic colic?
Butylscopolamine (buscopan)
Why do small intestinal obstructions cause reflux?
Usually, fluid within the small intestine will be transported to the colon where it will be absorbed into the bloodstream. However, if there is a small intestinal obstruction, this normal flow of fluid is disrupted and the fluid from the obstructed small intestines with accumulate in the lumen of the stomach, allowing for retrieval of excess gastric reflux on passage of a nasogastric tube
What is the maximum amount of nasogastric reflux that would be considered normal in a horse?
Up to 2 litres, not including any water that had been put into the stomach tube is considered to be normal reflux
What are the possible causes of simple small intestinal obstructions?
Ascarid impactions
Ileal impactions
Small intestinal adhesions
Which helminths most commonly causes ascarid impactions of the small intestine?
Parascaris equorum
Which signalement is affected by parascaris equorum impactions?
Parascaris equorum affects young horses such as foals, weanlings and yearlings. Adult horses develop resistance against parascaris equorum
How does parascaris equorum cause colic?
Adults parascaris equorum reside in the small intestine where they can cause small intestinal impactions and colic. Furthermore, administration of pyrantel or ivermectin can cause rapid paralysis of the parascaris equorum which can also cause a small intestinal impaction
How do you prevent ascarid impactions?
To prevent ascarid impactions, implement an effective deworming programme
What is the prognosis for ascarid impactions?
Severe ascarid impactions have a guarded prognosis
Why is the ileum prone to impactions?
The ileum has a thicker muscularis layer than the rest of the small intestine and thus has a more narrow lumen, making this region prone to impactions
What are the potential causes of ileal impactions?
Feeding thin fibre hay with low fibre content
Cestode infections
Which cestodes can cause ileal impactions?
Anoplocephala perfoliata as the adults reside mainly at the ileocaecocolic junction, resulting in ileal impactions
What are the clinical signs of ileal impactions?
Moderate to severe colic
Reflux develops later in the disease (as the ileum is the terminal end of the small intestine)
Dehydration
How do ileal impactions feel on rectal examination?
The ileal impaction itself is rarely palpable on rectal examination, however you can palpate dilated loops of small intestine
How do you medically manage ileal impactions?
Enteral fluid therapy (via nasogastric tube)
IV fluid therapy (if clinically indicated)
Laxatives
NSAIDS
Nasogastric tubing to manage reflux
How do you surgically treat ileal impactions?
Ileal impaction can be manually broken up and massaged into the caecum or an enterotomy can be performed to remove the impaction
What are small intestinal adhesions?
Small intestinal adhesions are bands of fibrous tissue that form between the loops of small intestine, or between the small intestine and other structures in the abdomen such as the body wall or other organs which can result in small intestinal obstruction
Which signalement is at a higher risk of developing small intestinal adhesions?
Foals are at a greater risk of developing small intestinal adhesions
What is one of the main causes of small intestinal adhesions?
One of the main causes of small intestinal adhesions is due to the inflammation, trauma and handling of small intestines during abdominal surgery
How do you prevent the formation of adhesions due to abdominal surgery?
Early surgical intervention
Good surgical technique
Antiinflammatory drugs
How does early surgical intervention help to prevent the formation of adhesions due to abdominal surgery?
Surgical intervention earlier into a disease process is going to reduce the degree of inflammation of the small intestines which can reduce the risk of developing post-operative small intestinal adhesions
Describe the pathophysiology of small intestinal strangulations
Small intestinal stangulations are where this is simultaneous occlusion of the small intestinal lumen resulting in obstruction and occlusion of the small intestinal blood supply. This results in ischeamia, necrosis and the translocation of bacteria and endotoxins into the blood stream resulting in sepsis and endotoxaemia.
What are the two forms of small intestinal strangulation?
Haemorrhagic small intestinal strangulation
Ischaemic small intestinal stangulation
What is a haemorrhagic small intestinal strangulation?
A haemorrhagic small intestinal strangulation is when the veins are occluded before the arteries, resulting in a dark red lesion
What is an ischaemic small intestinal stangulation?
An ischaemic small intestinal strangulation is when the veins and arteries and occluded simultaneously, resulting in a pale lesion
What are the clinical signs of a small intestinal strangulation?
Moderate to severe colic
Only intermittent response to analgesia
Abdominal distension
Clinical signs of endotoxaemia and sepsis
Reflux
Dehydration
What are the clinical signs of sepsis/endotoxaemia?
Toxic lines
Congested mucous membranes
Profound depression
Tachycardia
Initially the CRT is brisk and then is will progress to more than 2 secs
What does a small intestinal strangulation feel on rectal examination?
On rectal examination, you can usually palpate distended loops of small intestine
What changes can be seen in the peritoneal fluid in patients with small intestinal strangulation?
Serosanguinous
Increased total proteins
Increased lactate
Increased white blood cell count
How does small intestinal strangulation appear on ultrasound?
Bunched up, dilated loops of small intestines which can have oedematous walls
(T/F) All small intestinal strangulations require surgery
TRUE. All small intestinal strangulations require surgery as the necrotic, devitalised tissue will need to be removed via an enterectomy
Which key complication should you be aware of following a small intestinal strangulation enterectomy?
Reperfusion injury
What is the prognosis for small intestinal strangulations?
Long term survival following surgery is less than 70% due to complications
What are the potential causes of small intestinal strangulations?
Epiploic foramen entrapment
Pedunculated mesenteric lipoma
Small intestinal volvulus
Mesenteric or ligamentous rents
Inguinal hernia
Umbilical hernia
Intussusception
Diaphragmatic hernia
What are the anatomical borders of the epiploic foramen?
Ventrally, there is the hepatoduodenal ligament, the liver and the pancreas. Dorsally there is the portal vein and caudal vena cava
What are the risk factors for epiploic foramen entrapment?
Crib biting
Wind sucking
How do you diagnose epiploic foramen entrapement?
Epiploic foramen entrapement can only be definitively diagnosed at surgery
Why is surgery to correct epiploic foramen entrapement so challenging?
Surgery to correct epiploic foramen entrapement is challenging due to the risk of damaging the portal vein and caudal vena cava which lie dorsal to the epiploic foramen. Furthermore, the entrapped intestine will often be devitalised and require an enterectomy, however it is important to be aware you should not remove more than 50% of the intestine as this will result in malnutrition, and it is important to not remove the ileum if possible
How do pedunculated mesenteric lipomas cause small intestinal strangulations?
Pedunculated lipomas are suspended from the mesentery by a stalk which can become wrapped around a segment of small intestine, occluding the lumen and the blood supply resulting in a small intestinal obstruction and strangulation
Which signalement is at increased risk of pedunculated mesenteric lipomas?
Obese horses over 12 years old
How do you diagnose pedunculated mesenteric lipomas?
Pedunculated mesenteric lipomas can only be definitively diagnosed at surgery
What is small intestinal vovulus?
Small intestinal volvulus is where the small intestine rotates on its long axis, causing occlusion of the lumen and the blood supply resulting in a small intestinal obstruction and strangulation
Which signalement is at increased risk of small intestinal volvulus?
Foals
How do you diagnose small intestinal volvulus?
Small intestinal volvulus can only be definitively diagnosed at surgery
What are mesenteric or ligamentous rents and how can they cause small intestinal strangulations?
Mesenteric rents are defects in the small intestinal mesentery and ligamentous rents are defects in ligaments within the abdomen(such as the gastrosplenic ligament). Portions of the small intestine can become entrapped within these rents resulting in occlusion of the lumen and blood vessen resulting in obstruction and strangulation
(T/F) The prognosis for mesenteric and ligamentous rents is much better than for other small intestinal strangulations
FALSE. The prognosis for mesenteric and ligamentous rents is lower than other small intestinal strangulations, however, it is unknown as to why this is the case
How can an inguinal hernia cause a small intestinal strangulation?
An inguinal hernia is where a portion of the small intestine passes through the inguinal ring into the vaginal tunic, resulting in occlusion of the lumen and the blood vessles, resulting in small intestinal obstruction and strangulation
What is the term used to describe an inguinal hernia following castration?
Evisceration
Which signalement is at increased risk of inguinal hernias?
Stallions, espically post breeding
What are the clinical signs of an inguinal hernia?
Clinical signs of small intestinal strangulation
Cool, painful and enlarged testicle(s)
How do you diagnose inguinal hernias?
Testicular palpation
Rectal examination
Ultrasound of the scrotum
How does an inguinal hernia typically feel on rectal palpation?
You will typically be able to feel small intestine entering the inguinal canal on rectal palpation if there is an inguinal hernia
How do you treat an inguinal hernia?
Surgery to carry out an enterectomy on the devitalised intestine and to castrate the affected testicle due to vascular compromise to the spermatic cord
|Breeding stallions can still breed with one testicle
How do you treat congenital inguinal hernias in foals?
Congenital inguinal hernias in foals can be treated through manual manipulation and bandaging to maneuver the small intestine back into the abdomen
What is the prognosis for inguinal hernias?
Good prognosis
(T/F) Umbilical hernias commonly cause small intestinal strangulations
FALSE. While umbilical hernias are common, they rarelt cause small intestinal strangulations
Which signalement is at an increased risk of an umbilical hernia?
Foals
What are the clinical signs of a strangulating umbilical hernia?
Clinical signs of small intestinal strangulation
Warm, swollen, firm and painful hernial sac
How do you treat a strangulating umbilical hernia?
Surgery to do an enterectomy for any devitalised small intestine and to close the hernia
Which signalement is more prone to intussusception?
Young horses (less than 1 year old)
Where anatomically does intussusception most commonly occur in horses?
Ileocaecal intusussception
How do you diagnose intussusception?
Ultrasound
Why can the peritoneal fluid analysis be very variable in patients with intusussception?
For intussusception cases there is not always evidence of devitalised tissue within the peritoneal fluid as the devitalised tissue will not be as exposed to the peritoneal cavity due to being invaginated within another portion of small intestine
How do you treat intusussception?
Surgery involving enterectomy of the devitalised small intestine
(T/F) Diaphragmatic hernias are very rare in horses
TRUE.
What are the clinical signs of diaphragmatic hernias?
Clinical signs of small intestinal strangulation
Dyspnoea (rare)
Dull ventral lung sounds
Borborigmi on thoracic auscultation
How do you diagnose diaphragmatic hernias?
Radiography
Ultrasound
How do you treat diaphragmatic hernias?
Surgery to do an enterectomy to remove any devitalised small intestine and to correct the defect in the diaphragm
Which disease has a very similar clinical presentation to small intestinal strangulations?
Anterior enteritis
What is the pathophysiology of anterior enteritis?
Anterior enteritis is endotoxin mediated acute inflammation of the proximal portion of the small intestine and subsequent ileus and hypersecretion of the small intestine. This results in a physiological obstruction and the accumulation of ingesta and fluid proximal to the affected portion of intestine. The inflammation and damage to the protective barriers within the small intestine also allow for the translocation of endotoxins and bacteria into the bloodstream, resulting in endotoxaemia and sepsis
Which bacteria can cause anterioir enteritis?
Clostridium perfringens
Clostridium difficile
Salmonella
What are the clinical signs of acute enterits?
Moderate to severe colic
Only intermittent response to analgesia
Abdominal distension
Clinical signs of endotoxaemia and sepsis
Pyrexia
Reflux which may be red/brown and putrid smelling
Dehydration
What changes can be seen on haematology and biochemistry in patients with acute enteritis?
Leukocytosis or leukopenia
Azotaemia
Increased lactate (can indicate metabolic acidosis)
Increased total proteins
Decreased bicarbonate (can indicate metabolic acidosis)
Hypochloraemia (can indicate metabolic acidosis)
What changes can be seen in the peritoneal fluid in patients with acute enteritis?
Serosanguinous
Increased total proteins
Increased lactate
Increased white blood cell count
How can you differentiate between small intestinal strangulation and anterior enteritis?
Clinical signs of anterior enteritis will usually improve following gastric decompression, anterioir enteritis often presents with a fever and can sometimes have a leukopenia. Furthermore, anterioir enteritis often results in red/brown putrid reflux
How do you diagnose anterior enteritis?
Anterioir enteritis can only be definitively diagnosed at surgery
How do you medically manage anterioir enteritis?
Gastric decompression with nasogastric tubing
Intravenous fluid therapy
Colloid fluids
NSAIDS
Antibiotics
Prokinetics
Gastroprotectants
Parenteral nutrition
What is the purpose of intravenous fluid therapy when treating anterior enteritis?
Restore circulating blood volume
Correct the acid-base balance
Correct electrolyte abnormalities
What is the purpose of NSAIDS when treating anterior enteritis?
Analgesia
Anti-inflammatory
Anti-endotoxic
Which NSAIDs should be used when treating anterior enteritis?
Flunixin
Fibrocoxib
When are antibiotics indicated when treating anterior enteritis?
Antibiotics are only indicated in the treatment of anterior enteritis if the patient is severely compromised - i.e. has systemic signs of sepsis or severe leukopenia - as there is a risk of dysbiosis with antibiotics which could worsen the patient’s condition
Which prokinetics can be used in the treatment of anterior enteritis?
Metoclopramide
Lidocaine
What is the route of administration for prokinetics in patients with anterior enteritis?
Continuous rate infusion (CRI)
How can lidocaine potentially act as a prokinetic?
Lidocaine provides analgesia for visceral pain and thus can potentially allow for the resumption of normal gastrointestinal motility
|Note the effectiveness of lidocaine as a prokinetic is controversial
When is parenteral nutrition indicated when treating anterior enteritis?
Parenteral nutrition is indicated in the treatment of anterior enteritis if there has been prolonged reflux or anorexia
When is surgical intervention indicated in patients with anterior enteritis?
Persistent tachycardia
Persistent colic
What surgical intervention can help to manage anterior enteritis?
Surgical decompression of the small intestine can help to resume normal gastrointestinal motility
What is equine grass sickness?
Equine grass sickness is a neurodegenerative disease which affects the enteric and autonomic nervous system
Which signalement is at increased risk of equine grass sickness?
Young grazing horses, especially in the UK during the spring
What are the three forms of equine grass sickness?
Acute
Subacute
Chronic
What are the clinical signs of acute and subacute equine grass sickness?
Dull demeanour
Tachycardia
Drooling saliva
Mild to moderate colic
Reflux
Muscle tremors
Patchy sweating
Bilateral ptosis
Why do patients with equine grass sickness present with colic and reflux?
Equine grass sickness affects the enteric nervous system as well as the autonomic nervous system, resulting in functional ileus which causes accumulations and ingesta and fluid which will accumulate in the stomach which will result in abdominal pain and reflux on passage of a nasogastric tube
What is bilateral ptosis?
Bilateral ptosis a term used to describe the drooping of both upper eyelids
What test can be done to determine if a horse has bilateral ptosis secondary to equine grass sickness?
Bilateral ptosis secondary to equine grass sickness should usually reverse 20 to 30 minutes following topical application of phenylephrine
What is the prognosis for acute equine grass sickness?
Fatal
What is the prognosis for subacute equine grass sickness?
Fatal
What are the clinical signs of chronic equine grass sickness?
Marked weight loss
Dysphagia
Rhinitis sicca
Bilateral ptosis
Diffuse weakness
What is rhinitis sicca?
Rhinitis sicca is a term used to describe dry nose
What are some of the key signs of diffuse weakness in horses with chronic equine grass sickness?
Low head carriage
Muscle tremors
‘Elephant on a ball’ stance
What is the prognosis for chronic equine grass sickness?
50% survival with prolonged supportive care
How do you diagnose equine grass sickness?
Equine grass sickness is diagnosed based on clinical signs and elimination of other differential diagnoses
