PATHOLOGY - Equine Colic Flashcards
1
Q
What is colic?
A
Colic is a generalised term for severe abdominal pain
2
Q
Which history questions are useful to ask when investsigating colic?
A
- 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?
- What clinical signs is the horse exhibiting?
3
Q
Which items should you have in your car before travelling to a colic case?
A
Stethoscope
Thermometer
Analgesia
Sedation
Buscopan
Euthanasia drugs
Nasogastric tube
Rectal gloves and lubricant
Needles, syringes, and blood tubes (for bloods and abdominocentesis)
Ultrasound (if you have one)
Twitch
4
Q
Which specific parameters are important to assess when doing a clinical examination on a horse with colic?
A
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
5
Q
What can be indicated by marked pain and abdominal distension in colicing horses?
A
Marked pain and abdominal distension in colicing horses can indicate large colon volvulus
6
Q
What can be indicated by marked pain that decreases as the colicing horse becomes more depressed?
A
Pain that decreases as the colicing horse becomes more depressed can indicate small intestinal disease
7
Q
Which cardiovascular parameters should you assess in a horse with colic?
A
Heart rate and rhythm
Pulse rate, rhythm and quality
Hydration
Mucous membrane colour
Capillary refill time (CRT)
Palpate the extremities
Temperature
8
Q
What is the normal heart rate for a horse at rest?
A
28 - 40 bpm
9
Q
What should you do if a horse with colic has a heart rate of over 60bpm?
A
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
10
Q
Describe how to pass a nasogastric tube in a horse
A
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, siphon, and assess for reflux of stomach contents to ensure the tube is in the stomach
11
Q
What are some of the signs that the nasogastric tube is in the oesophagus rather than the trachea?
A
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
12
Q
What are the potential complications of passing a nasogastric tube?
A
Passing the tube into the middle or dorsal meatus
Epistaxis if you hit the echmoid conchae
Intubating the trachea
Trauma to the oesophagus
13
Q
How do you assess hydration in the horse?
A
Skin tenting
Check the mucous membranes (should be pink and moist)
14
Q
What should you be aware of when using skin tenting to assess hydration in a horse?
A
In order horses, the skin is less elastic so it may remain tented for longer even if the horse is not dehydrated
15
Q
What is indicated by the appearance of these mucous membranes?
A
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
16
Q
What should you assess when palpating the extremities?
A
Palpate digital pulses
Assess temperature of the extremities (ears and limbs)
17
Q
What is indicated by cold extremities in the horse?
A
Cold extremities can indicate shock
18
Q
What can be indicated by pyrexia?
A
Pyrexia can indicate inflammation of the gastrointestinal tract (i.e. enteritis, colitis, enterocolitis etc.) or infection
19
Q
Why is it important to take a temperature before doing a rectal palpation?
A
It is important to take a temperature before doing a rectal palpation as you can introduce a lot of air with a rectal palpation which can result in an inaccurate temperature
20
Q
Which factors should you assess when assessing the abdomen of a horse with colic?
A
Auscultate the abdomen
Assess abdominal shape for abdominal distension
21
Q
How should you auscultate the equine abdomen?
A
Auscultate the abdomen in four quadrants, i.e. auscultate dorsally and ventrally on both sides of the abdomen
22
Q
In which quadrant should you be able to auscultate the caecal flush in a horse?
A
You should be able to auscultate the caecal flush in the dorsal, right quadrant
23
Q
How often should you hear the caecal flush when auscultating the abdomen?
A
The ceacal flush should occur every 90 - 180 seconds
24
Q
What is associated with absent gut sounds in a horse with colic?
A
Absent gut sounds in a horse with colic is generally associated with more severe disease
25
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
26
How do you prepare to do a rectal examination on a horse?
1. Restrain the horse appropriately by using either a twitch, a crush/stocks or sedation
2. Administer butylscopolamine (buscopan)
3. Have lots of lubricant available
27
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
28
What is the duration of action for butylscopolamine (buscopan)?
15 to 20 minutes
29
What is one of the main side effects of butylscopolamine (buscopan) that you should be aware of?
Butylscopolamine (buscopan) causes tachycardia
## Footnote
Very important to measure the heart rate before administering buscopan to get an accurate heart rate
30
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
31
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
Sand in the faeces
Assess for parasites in the faeces
Faecal egg count
32
What can be indicated by decreased faceal passage in colic cases?
Gastrointestinal ileus
Gastrointestinal obstruction
33
Which diagnostic tests can be useful to do when investigating colic cases?
Rectal palpation
Blood tests
Abdominocentesis
Abdominal ultrasound
Abdominal radiography
34
Which blood tests are beneficial when assessing a horse with colic?
Haematology
Biochemistry and electrolytes
Blood lactate
35
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
36
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 lumen, which can indicate gastrointestinal inflammation, or into the peritoneum which can indicate peritonitis
37
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
## Footnote
Be aware that lactate can also increase with dehydration and exercise, however this increase isn't usually as marked. Important to interpret this value considering your clinical signs
38
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 (i.e. lactate can increase, leukocytes can increase, total protein can increase, fluid volume can increase, bacteria present). Important to do cytology
39
What is the reference range for leukocytes in normal peritoneal fluid?
Less than 5000 cells/μl
40
What is the reference range for total protein in normal peritoneal fluid?
Less than or equal to 20g/l
41
What is the reference range for lactate in normal peritoneal fluid?
Less than 2mmol/l
42
How do you carry out an abdominocentesis in a horse?
Sterile prep the site, insert a needle or a teat cannula into the right side of the linea alba at the most ventral point (quickly through the skin then advance slowly), or do ultrasound guided abdominocentesis and catch the fluid in an EDTA tube and a serum tube
43
When is ultrasound guided abdominocentesis particularly useful?
Ultrasound guided abdominocentesis is particularly useful when you feel distended intestine on rectal palpation as ultrasound guided will allow you to identify a pocket of fluid to reduce the risk of inserting the needle into the intestines *(which is an increased risk with distension)*
44
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
## Footnote
These is a much higher risk of inserting the needle into the intestines in foals
45
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
46
When should you **not** perform an abdominocentesis?
Foals with intestinal distension
Pregnant mares
47
How should normal peritoneal fluid appear?
Normal peritoneal fluid should be clear to yellow in colour and not cloudy
48
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
49
What is the FLASH technique for abdominal ultrasound?
A FLASH is a systematic ultrasound examination technique which is used to assess seven key regions of the abdomen
50
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
51
Which analgesics and sedatives are commonly used in colic cases?
Detomidine
Xylazine
Butorphanol
Flunixin
Phenylbutazone
Butylscopalamine (Buscopan) compositum
52
How should you administer analgesia in colic cases?
Intravenous ideally
53
Which two drugs make up butylscopalamine (buscopan) compositum?
Metamizol
Butylscopalamine (Buscopan)
54
What is the function of metamizol?
Metamizol is an analgesic drug
55
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
56
(T/F) Referral of colic cases always means surgery is required
FALSE. Not all referrals of colic cases require surgery
57
What are the key indicators that a colic case requires referral?
Refractory to pain management
Sepsis/endotoxaemia (high lactate, blood in abdo tap, toxic lines, very high heart rate)
Lots of reflux with nasogastric tubing *(leave the tube in)*
Refractory small or large intestinal obstruction
Evidence of devitalised intestine
Severe abdominal distension
Thickened loops of small intestine on ultrasound
If the owner is very concerned and wants referral
58
What is the average price of equine colic surgery?
£5,000 to £10,000
59
What will happen when the colic case arrives at the referral centre?
| This is useful to know to inform the owners
1. Fill out consent forms
2. Referral practice will take a history and do a clinical examination
3. Repeat blood testing
4. Repeat nasogastric tubing if necessary
5. Repeat abdominocentesis
6. Repeat abdominal ultrasound
7. Administer intravenous fluids if necessary
8. Prepare the horse for colic surgery if indicated
## Footnote
Make owners aware if they go to surgery they may not receive an update for around 5 hours as they surgical team won't cell them until the horse is up and standing after surgery
60
What is another term for colic surgery?
Exploratory laparotomy
61
How do you prepare a horse for colic surgery?
1. Administer NSAIDS *(unless they have already been given NSAIDS recently)* and antibiotics
2. Check the tetanus status of the horse
3. Clip and prepare the abdomen for surgery *(preferably do this before the horse is anaesthetised to reduce anaesthetic time)*
4. Carry out normal induction preparation
62
What postoperative care should be carried out following colic surgery?
Administer NSAIDS
Administer antibiotics
Nasogastric tubing for gastric decompression *(due to post op ileus)*
Gradually introduce good quality roughage *(hay etc)*
Keep the incision clean and dry
Very limited exercise
63
How do you know when it is sutiable to stop antibiotics following colic surgery?
Assess the incision
Bloods to assess white blood cell count and serum amyloid A
64
What are some of the post-operative complications of colic surgery?
Incisional swelling and infection
Incisional dehiscence
Herniation *(increased risk with healing by second intention as the muscles will be weaker)*
Repeat colic
65
How should you manage incisional infection post colic surgery?
Saline lavage
Culture and sensitivity for antibiotics
Regular bandage changes
Topical antiseptics
| Confer with the surgeons
66
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
67
How do you manage post operative ileus?
Gastric decompression with nasogastric tubing
Intravenous fluid therapy
Colloid fluids
NSAIDS
Antibiotics
Prokinetics
68
When should you remove staples/sutures following colic surgery?
You should remove staples/sutures 10 to 14 days following colic surgery
69
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 walking 2 to 3 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
70
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
71
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
72
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
73
What are the main sites of celluose digestion and fermentation in the horse?
Caecum
Right and left ventral large colon
74
What is a primary caecal impaction?
A primary caecal impaction is usually an accumulation of dry, relatively solid ingesta resulting in impaction
75
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
76
What are the risk factors for secondary caecal impactions?
Pain
Stress
Change in management
Change in diet
Alteration in exercise
Dental abnormalities
Dehydration
77
Why is there often delayed 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
78
What are the clinical signs of caecal impactions?
Gradual onset of mild, intermittent colic
Reduced faecal output
Dehydration
Will become more painful if impaction is unresolved
79
How do you diagnose caecal impactions?
Rectal examination
80
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
81
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
82
How do you carry out medical management of caecal impactions?
Enteral fluid therapy *(isotonic electrolytes)*
IV fluid therapy
Laxatives
NSAIDS
83
What is the function of enteral fluids for medical management of caecal impactions?
Enteral fluids are used to rehydrate and soften the impaction
84
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
85
How do you administer enteral fluids in horses with caecal impactions?
Adminiser small but frequent boluses of enteral fluids via a nasogastric tube
86
What should you check before you administer more enteral fluids?
Check if the fluids have been absorbed through passing a nasogastric tube and measuring the reflux
87
How do you administer laxatives in horses with caecal impactions?
Add laxatives to enteral fluids and administer via a nasogastric tube
88
Which laxtative can you use in the medical management of caecal impactions?
Magnesium sulphate (MgSO4)
89
What dose of magnesium sulphate (MgSO4) is appropriate for impactions?
0.5 - 1g/kg
90
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
91
Which surgical procedure can be done to treat caecal impactions refractory to medical management?
Typhlotomy *(removal of the impacted content from the caecum)*
92
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
93
What is caecal tympany?
Caecal tympany is excessive gas accumulation within the caecum resulting in distension
94
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
| Primary caecal tympany is rare
95
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
96
What are the clinical signs of caecal tympany?
Abdominal distension
Ping on auscultation
Colic
Pain *(high heart rate and resp rate)*
97
How do you diagnose caecal tympany?
Rectal examination
98
How does caecal tympany typically feel on rectal examination?
The ventral caecal band will feel very taut and and caecum will be distended
99
How do you treat caecal tympany?
Caecal trocarisation
Treat underlying cause
## Footnote
Caecal trocar is very important as the gas distended caecum can compress the caudal vena cava, reduce venous return and cardiac output and result in cardiovascular collapse
100
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
101
What are the most common sites for large colon impactions?
Pelvic flexure
Right dorsal colon
102
What are the risk factors for large colon impactions?
Pain
Stress
Change in management
Change in diet
Alteration in exercise
Dental abnormalities
Dehydration
103
What are the clinical signs of a colon impaction?
Gradual onset of mild colic
Reduced faecal output
Hard/dry faeces ± mucus
Progressive dehydration
Progressive pain if impaction is unresolved
104
How do you diagnose large colon impactions?
Rectal examination
105
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
106
How do you carry out medical management of large colon impactions?
Enteral fluid therapy
IV fluid therapy *(if dehydrated or to supplement oral fluids)*
Laxatives
NSAIDS
107
Which laxtative can you use in the medical management of large colon impactions?
Magnesium sulphate (MgSO4)
108
(T/F) Large colon impactions can occur secondary to small intestinal disease
TRUE. Make sure to consider your clinical signs, clinical examination and results from diagnostics to ensure there is no additional pathology
109
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, instead 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
110
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
| Usually indicated if horse does not respond after 2 doses of fluids
111
What are enteroliths?
Enteroliths are mineral accumulations within the gastrointestinal tract which can cause obstructions resulting in distension proximal to the obstruction
112
What are the most common sites for enterolith obstruction?
Right dorsal colon
Transverse colon
113
What are the clinical signs of enteroliths and enterolith obstruction?
Mild to moderate intermittent colic which can progress and become more severe with distension proximal to the enterolith obstruction
114
How do you diagnose enterolith obstructions?
Radiography
115
How do you treat enterolith obstructions?
Surgical removal of the enteroliths, making sure to look for any more in the colon
116
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
117
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
118
How do you diagnose sand colic?
History *(do the horses have access to sandy ground etc)*
Faecal flotation
Radiography
119
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
120
How do you surgically manage sand colic?
Laparotomy and incise into the colon to remove the sand
121
What are the potential causes of small colon impactions?
Enteroliths
Faecaliths
Foreign bodies
122
What can predispose horse's to small colon impactions?
Colitis
123
What are the clinical signs of small colon impactions?
Mild colic with progressive colic pain
Progressive abdominal distension
Reduced faecal output
124
How do you diagnose small colon impactions?
Rectal examination
Ultrasound
Radiography
125
How do small colon impactions typically feel on rectal examination?
Typically you will feel loops of tubular, firm intestine
126
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
127
What can radiography be used to detect when investigating small colon impactions?
Enteroliths in the small colon
Foreign bodies in the small colon
128
How do you carry out medical management of small colon impactions
Enteral fluid therapy
IV fluid therapy
Laxatives
NSAIDS
Enema
129
Which surgical procedure can be done to treat small colon impactions refractory to medical management?
Intraluminal lavage to break down the impaction
Possible surgical removal of the impaction
130
What are the two classifications of large colon displacement?
Left dorsal displacement
Right dorsal displacement
131
Which horses are at increased risk of large colon displacements?
Horses on high concentrate/fermentable diets are at increased risk of large colon displacements
Large breed horses
132
What is another term used to describe left dorsal displacement?
Nephrosplenic entrapement
133
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 obstruction and often 180° twists
134
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
135
How do you diagnose left dorsal displacement?
Rectal examination
Ultrasound
136
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
137
How do you medically manage left dorsal displacement?
Prokinetics
Intravenous phenylephrine
Enteral fluid therapy *(stimulates GI motility)*
IV fluid therapy
Exercise
NSAIDs
138
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
139
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
140
What is the main risk of phenylephrine you should discuss with owners?
Hypertension and haemorrhage
141
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
142
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
143
What is the prognosis for left dorsal displacement?
Good prognosis as the tissue remains viable with left dorsal displacements
144
Which procedure can be done to prevent recurrence of left dorsal displacement?
Nephrosplenic space ablation
145
What is right dorsal displacement?
Right dorsal displacement is where the left dorsal and ventral colons 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 180° volvulus, large colon obstruction and gas distension
146
Which signalement is more prone to right dorsal displacement?
Large breed horses are more prone to right dorsal displacement
147
How do you diagnose right dorsal displacement?
Ultrasound
148
What can you identify on ultrasound of a right dorsal displacement?
With right dorsal displacement, you may be able to visualise the colonic mesenteric vasculature on the right side of the abdomen
149
How do you medically manage right dorsal displacement?
Prokinetics
Enteral fluid therapy
IV fluid therapy
Caecal trocarisation *(if indicated)*
Exercise
NSAIDs
150
(T/F) Right dorsal displacements rarely require surgical intervention
FALSE. Right dorsal displacement commonly requires surgical intervention
151
What is the prognosis for right dorsal displacement?
Good prognosis as the tissue remains viable with right dorsal displacements
152
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
153
Which signalement is at the greatest risk of large intestinal volvulus/torsion?
Large breed horses
Post-parturition mares
154
What are the clinical signs of large intestinal volvulus of over 360°?
Severe colic
Refractory to analgesia
Abdominal distension *(due to gas distension of the colon)*
Endotoxaemia/sepsis
Dehydration
155
What are the key signs of sepsis/endotoxaemia?
Toxic lines
Congested mucous membranes
Profound depression
Tachycardia
Brisk then prolonged CRT
156
How do you diagnose large intestinal volvulus of over 360°?
If the horse is very painful with very severe colic and refractory to analgesia, they should be sent for surgical referral as there is a high risk they have large intestinal volvulus of over 360°
157
What is the prognosis for large intestinal volvulus of over 360°?
Poor prognosis
158
What is a type I rectal prolapse?
A type I rectal prolapse is the prolapse of the rectal mucosa beyond the anal sphincter
159
What is a type II rectal prolapse?
A type II rectal prolapse is the complete prolapse of the rectal ampulla beyond the anal sphincter
160
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
161
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
162
What causes a rectal prolpase?
Straining
163
How can you treat a type I or II rectal rectal prolpase?
1. Clean, lubricate, reduce tissue oedema with sugar or topical glycerine and push the tissue back into the rectum
2. Epidural to reduce straining
3. Do not feed for 12 - 24 hours
4. Treat the underlying cause of the straining
5. Perform a submucosal resection if any partial thickness damage of the tissue or rectal prolpase amputation if full thickness damage to the tissue
164
What can you use to reduce oedema when treating a rectal prolpase?
Topical glycerin, sugar and/or magnesium sulfate (MgSO4)
165
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
166
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
167
How do you determine the prognosis of a rectal prolapse?
The prognosis directly correlates with the quantity of tissue that has been prolapsed
168
What is one of the most common causes of rectal tears in horses?
Rectal examination
169
Which signalements are at increases risks of rectal tears due to rectal examination?
Minature horses
Young stallions
Geriatric horses
170
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
171
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
172
Where anatomically do most rectal tears occur?
Rectal tears occur most commonly dorsally along the long axis of the rectum
173
What is a grade I rectal tear?
A grade I rectal tear involves the mucosa and submucosa
174
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
175
What is a grade IIIa rectal tear?
A grade IIIa rectal tear involves all of the layers except the serosa
176
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)*
177
What is a grade IV rectal tear?
A grade IV rectal tear involves all layers of the rectal wall
178
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
179
How can you get a definitive diagnosis of a rectal tear?
Endoscopy
Bare arm palpation to feel the defect
Abdominocentesis showing abdominal contamination
180
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
181
What emergency treatment should you provide when there is evidence of a rectal tear?
1. Reduce rectal activity using atropine, butylscopolamine (buscopan) or an epidural
2. Gently remove the faeces from the rectum and the tear
3. Start treatment for septic shock and peritonitis using broad spectrum bacteriacidal antibiotics, flunixin and intravenous fluids
4. Pack the rectum from proximal to the tear to the anus
5. Hospitalise the patient for continuous monitoring
182
How do you determine the 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
183
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
184
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
185
What are the clinical signs of spasmodic colic?
Mild to moderate colic
186
What causes spasmodic colic?
The cause of spasmodic colic is unknown
187
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
188
How do you treat spasmodic colic?
NSAIDS
Spasmolytic drugs
Spasmodic colics are self limiting
189
Which spasmolytic drug can you to treat spasmodic colic?
Butylscopolamine (buscopan)
190
Why do small intestinal obstructions cause reflux?
Usually, fluid within the small intestine will be transported to the caecum and colon where it will be absorbed into the intravascular space. However, if there is a small intestinal obstruction, this normal flow of fluid is disrupted and the fluid from the obstructed small intestines will accumulate in the lumen of the stomach, allowing for retrieval of excess gastric reflux on passage of a nasogastric tube. Furthermore, this will result in dehydration
191
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
192
What are the possible causes of simple small intestinal obstructions?
Ascarid impactions
Ileal impactions
Small intestinal adhesions
193
Which helminths most commonly causes ascarid impactions of the small intestine?
Parascaris equorum
194
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
195
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
196
How do you prevent ascarid impactions?
To prevent ascarid impactions, implement an effective deworming programme
197
What is the prognosis for ascarid impactions?
Severe ascarid impactions have a guarded prognosis
198
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
199
What are the potential causes of ileal impactions?
Feeding thin fibre hay with low fibre content
Cestode infections
200
Which cestodes can cause ileal impactions?
Anoplocephala perfoliata as the adults reside mainly at the ileocaecocolic junction, resulting in ileal impactions
201
What are the clinical signs of small intestinal impactions?
Moderate to severe colic
Reflux
Dehydration
202
How do small intestinal impactions feel on rectal examination?
The impaction itself is rarely palpable on rectal examination, however you can palpate dilated loops of small intestine
203
How do you medically manage small intestinal impactions?
Nasogastric tubing to manage reflux
Enteral fluid therapy *(via nasogastric tube)*
IV fluid therapy *(these patients are going to be dehydrated as they are refluxing fluid)*
Laxatives
Analgesia *(NSAIDs)*
204
How do you surgically treat small intestinal impactions?
Small intestinal impactions can be manually broken up and massaged into the caecum or an enterotomy can be performed to remove the impaction
205
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
206
Which signalement is at a higher risk of developing small intestinal adhesions?
Foals are at a greater risk of developing small intestinal adhesions
207
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
208
How do you prevent the formation of adhesions due to abdominal surgery?
Early surgical intervention
Good surgical technique
Anti-inflammatory drugs
Resume motility as soon as possible
209
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
210
Describe the pathophysiology of small intestinal strangulations
Small intestinal stangulations are where there 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.
211
What are the two forms of small intestinal strangulation?
Haemorrhagic small intestinal strangulation
Ischaemic small intestinal stangulation
212
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
213
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
214
What are the clinical signs of a small intestinal strangulation?
Severe colic
Refractory to analgesia
Abdominal distension *(due to gas distension of the small intestine)*
Endotoxaemia and sepsis
Reflux
Dehydration
215
What are the clinical signs of sepsis/endotoxaemia?
Toxic lines
Congested mucous membranes
Profound depression
Tachycardia
Initially the CRT is brisk and then be prolonged
Pyrexia to hypothermia
216
What does a small intestinal strangulation feel on rectal examination?
On rectal examination, you can usually palpate distended loops of small intestine
217
What changes can be seen in the peritoneal fluid in patients with small intestinal strangulation?
Serosanguinous
Increased volume
Increased total proteins
Increased lactate
Increased white blood cell count
218
How does small intestinal strangulation appear on ultrasound?
Bunched up, dilated loops of small intestines which can have oedematous walls
219
(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
220
Which key complication should you be aware of following a small intestinal strangulation enterectomy?
Reperfusion injury
221
What is the prognosis for small intestinal strangulations?
Long term survival following surgery is less than 70% due to complications
222
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
223
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
224
What are the risk factors for epiploic foramen entrapment?
Crib biting
Wind sucking
225
How do you diagnose epiploic foramen entrapement?
Epiploic foramen entrapement can only be definitively diagnosed at surgery
226
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
227
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
228
Which signalement is at increased risk of pedunculated mesenteric lipomas?
Obese horses over 12 years old
229
How do you diagnose pedunculated mesenteric lipomas?
Pedunculated mesenteric lipomas can only be definitively diagnosed at surgery
230
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
231
Which signalement is at increased risk of small intestinal volvulus?
Foals
232
How do you diagnose small intestinal volvulus?
Small intestinal volvulus can only be definitively diagnosed at surgery
233
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
234
(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
235
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
236
What is the term used to describe an inguinal hernia following castration?
Evisceration/eventration
237
Which signalement is at increased risk of inguinal hernias?
Stallions, especially post breeding
238
What are the clinical signs of an inguinal hernia?
Clinical signs of small intestinal strangulation
Cool, painful and enlarged testicle(s)
239
How do you diagnose inguinal hernias?
Testicular palpation
Rectal examination
Ultrasound of the scrotum
240
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
241
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
242
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
243
What is the prognosis for inguinal hernias?
Good prognosis
244
(T/F) Umbilical hernias commonly cause small intestinal strangulations
FALSE. While umbilical hernias are common, they rarely cause small intestinal strangulations
245
Which signalement is at an increased risk of an umbilical hernia?
Foals
246
What are the clinical signs of a strangulating umbilical hernia?
Clinical signs of small intestinal strangulation
Warm, swollen, firm and painful hernial sac
247
How do you treat a strangulating umbilical hernia?
Surgery to do an enterectomy for any devitalised small intestine and to close the hernia
248
Which signalement is more prone to intussusception?
Young horses (less than 1 year old)
249
Where anatomically does intussusception most commonly occur in horses?
Ileocaecal intusussception
250
How do you diagnose intussusception?
Ultrasound
251
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
252
How do you treat intusussception?
Surgery involving reduction and enterectomy of the devitalised small intestine
253
(T/F) Diaphragmatic hernias are very rare in horses
TRUE.
254
What are the clinical signs of diaphragmatic hernias?
Clinical signs of small intestinal strangulation
Dyspnoea *(rare)*
Dull ventral lung sounds
Borborigmi on thoracic auscultation
255
How do you diagnose diaphragmatic hernias?
Radiography
Ultrasound
256
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
257
Which disease has a very similar clinical presentation to small intestinal strangulations?
Anterior enteritis
258
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
259
Which bacteria can cause anterioir enteritis?
Clostridium perfringens
Clostridium difficile
Salmonella
260
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
261
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)*
262
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
263
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
| However be aware you cannot make a definitive diagnosis based on this
264
How do you diagnose anterior enteritis?
Anterioir enteritis can only be definitively diagnosed at surgery
265
How do you medically manage anterioir enteritis?
Gastric decompression with nasogastric tubing
Intravenous fluid therapy *(they will be very dehydrated)*
Plasma/colloids *(due to PLE)*
NSAIDs
Treat endotoxaemia
Prokinetics
Gastroprotectants *(give IM NOT oral)*
Parenteral nutrition
± Antibiotics
266
What is the purpose of intravenous fluid therapy when treating anterior enteritis?
Restore circulating blood volume
Correct the acid-base balance
Correct electrolyte abnormalities
267
What is the purpose of NSAIDS when treating anterior enteritis?
Analgesia
Anti-inflammatory
Anti-endotoxic
268
Which NSAIDs should be used when treating anterior enteritis?
Flunixin
Fibrocoxib
269
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
270
Which prokinetics can be used in the treatment of anterior enteritis?
Metoclopramide
Lidocaine
271
What is the route of administration for prokinetics in patients with anterior enteritis?
Continuous rate infusion (CRI)
272
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
273
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
274
When is surgical intervention indicated in patients with anterior enteritis?
Persistent tachycardia
Persistent colic
275
What surgical intervention can help to manage anterior enteritis?
Surgical decompression of the small intestine can help to resume normal gastrointestinal motility
276
What is equine grass sickness?
Equine grass sickness is a neurodegenerative disease which affects the enteric and autonomic nervous system
277
Which signalement is at increased risk of equine grass sickness?
Young grazing horses, especially in the UK during the spring
278
What are the three forms of equine grass sickness?
Acute
Subacute
Chronic
279
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
280
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
281
What is bilateral ptosis?
Bilateral ptosis a term used to describe the drooping of both upper eyelids
282
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
283
What is the prognosis for acute equine grass sickness?
Fatal
284
What is the prognosis for subacute equine grass sickness?
Fatal
285
What are the clinical signs of chronic equine grass sickness?
Marked weight loss
Dysphagia
Rhinitis sicca
Bilateral ptosis
Diffuse weakness
286
What is rhinitis sicca?
Rhinitis sicca is a term used to describe dry nose
287
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
288
What is the prognosis for chronic equine grass sickness?
50% survival with prolonged supportive care
289
How do you diagnose equine grass sickness?
Equine grass sickness is diagnosed based on clinical signs and elimination of other differential diagnoses
