Horses 1 Flashcards
(100 cards)
1
Q
what are some clinical signs of teeth related conditions in horses
A
- Trouble eating
- Quidding (food falling out of mouth)
- Grain in manure
- Colic/Choke
- Slobbering
- Mouthing
- Not eating
- Weight loss
- Fighting bridle
- Throwing head
- Bad head carriage
- Off balance (lame)
- Facial swelling
- Lumps under jaw
- Draining fistula
- Bad breath
- Nasal discharge
2
Q
Dental examinations how often recommended at what age and why
A
- Recommended at least twice yearly
- Even more frequently in some younger and older horses
○ Younger -> caps (deciduous premolars) that when growing out could get food stuck in between -> born with 3 cheek teeth
§ Cups shed at following ages
□ 2.5 years - P2
□ 3 years - P3
□ 4 years - P4
§ Discomfort generally in 3 and 4 year old
○ Older -> malocclusion due to abnormal wear or loss of teeth
3
Q
Horse dentition what are the 5 main types of teeth and how many/function
A
1) Incisors -> 3 incisors
- From midline outwards called central, intermediate and corner incisors
2) Canines -> most males (fighting teeth) have and most females don’t (20% will get)
- Brachydont -> don’t continually erupt
3) Wolf teeth -> vestibule pre-molar 1, not always present, could be just one side
- Frequently removed as being blamed for interfering with bit when horse is ridden
4) Premolars -> 3 (not including wolf teeth)
5) Molars -> 3 - grinding food
4
Q
horse how many possible permanent teeth, what type of teeth and what do they have
A
36-44
- ALL permanent teeth are hypsodont (high crowned teeth) in horses with peripheral crown cementum (i.e. cementum on the outside of the crown of the tooth over the enamel) -> continue eruption
- They have a reserve crown, which accommodates continual wear.
○ As this reserve crown is within the alveolus, cementum covers the surface of the enamel to allow for attachment of the periodontal ligament.
5
Q
what leads to the discolouration of horses teeth and what occurs with the development of the cheek teeth
A
- The discolouration of horse teeth is due to food pigments staining the dead cementum of the crown.
○ This is not calculus as seen on the teeth of small animals.
○ The tooth of the horse is composed of enamel, cementum and dentine as with other species.
The development of the cheek teeth
○ During development, deep enamel infolding occurs forming enamel lakes (infundibulae) - filled with cementum
6
Q
What is the triadian system in horse and number important teeth
A
100 - upper right 200 - upper left 300 - lower left 400 - lower right 101-103 = incisors 104 = canine 105 = wolf tooth 106-108 = PM 109-111 = M Deciduous teeth -> 500,600,700,800
7
Q
in terms of aging foals up with 2 years old based on teeth what is involved
A
6 days: central incisors present
6 weeks: central and intermediate incisors present
6 months: all incisors present (corner incisors erupt)
12 months: dental star present in central incisors, corner incisors not in wear
18 months: corners in wear
24 months: dental star in all lower incisors, M2 present
8
Q
in terms of permanent dentition when central incisors, intermediates and corners erupt therefore when complete dentition
A
2.5 years: permanent central incisors erupted
3 years: centrals in wear
3.5 years: intermediates erupted
4 years: centrals and intermediates in wear
4.5 years: corners erupted
5 years: all incisors in wear (dentition complete at this age)
9
Q
what occurs in terms of dentition to 6,7 and 8 year old
A
6 years: cups disappear from centrals, oval shaped occlusal surface
7 years: small hook present on distal aspect of the upper corners. Cups present in corners only.
8 years: incisors oval, cups gone, dental star present in centrals - VERY HARD TO DEERMINE AFTER THIS
10
Q
what occurs in terms of dentition at 10 years, 15 years, 20 and 20+ years and what is important to remember
A
10 years: Galvayne’s groove at gum margin of corners, centrals and intermediates round, corners oval
15 years: Galvayne’s groove halfway down corner incisor, centrals triangular, corners round. Bite plane starts to become more angled.
○ Enamel ring goes lingually - disappears at 16 years in centre incisors
20 years: Galvayne’s groove extends full length of corner incisor. Lower incisors may be worn almost all the way to the gum - enamel ring
20+ years: Galvayne’s groove moves down the corner until it grows out.
11
Q
In terms of oral examination what are some important equipment
A
WEAR GLOVES - Full-mouth gag/speculum ○ Haussman/McPherson - Dental Halter - Flush mouth - Light source - torch - Consider Sedation/Local - Anaesthesia
12
Q
How to use a horse gag during dentals
A
Placed with ratchets facing DOWN
Plates at the front sit between the incisors
Strap behind ears firmly to prevent gag slippage
Gag opened gradually by one or two ratchets at each side
Mouth examined by inserting hand through the side of the mouth and feeling the teeth
AVOID placing hand between the cheek teeth rather insert along buccal or lingual sides
13
Q
visual and manual examination of the mouth during dental examination what are looking at
A
- Soft tissue ○ Ulcers ○ Foreign bodies ○ Tongue - Teeth/Gums ○ Visualize ○ Palpate (v. sensitive) § Determine mobility § Gingival margins § Periodontal pockets -clear -> probe and mirrors used to detect
14
Q
In terms of incisors what common pathology occur here
A
- Common site of trauma - fracture avulsions
- Malocclusions - generally not a problem
○ May indicate molars problems - Equine odontoclastic tooth resorption and hypercementosis (EOTRH)
○ Resorption of bone around incisor teeth -> radiograph to diagnosis
15
Q
in terms of premolars and molars how to examine, how much grow and main issue
A
- Teeth most often ‘floated’ (filed)
- Difficult to examine properly
- Erupt (not grow) at approx. 2-3(4)mm per year
- Reduce in rostro-caudal length with age
- May affect performance
16
Q
Eruption bumps what are they, where commonly occur and due to
A
- Eruption cysts: ○ Bilateral, non-painful ○ Mandible and, less commonly, maxilla ○ DDx: Periapical disease - Due to ‘frustrated’ permanent teeth -> permanent teeth continue to grow without deciduous teeth being removed yet
17
Q
what are the main pathology seen in the cheek teeth and where
A
- Malocclusions
○ Hooks, Ramps, Steps, Excessive transverse ridges (ETR), lateral edges, ulcers etc.
§ Hooks -> commonly develop on P2 upper arcade and M3 lower arcade - Fractured teeth, patent infundibulae
- Periapical Disease - around tooth
- Periodontal Disease - around the gum
18
Q
why do horses get sharp edges and where occur
A
- Anisognathic-different sizes and shapes
○ Maxillary aracade 30% broader and curved (compared to mandible) - THEREFORE will get Outside (buccal) of maxillary (upper arcade) and inside (lingual) of mandibular (lower arcade) will get sharp edges
○ Need circular grinding motion to avoid this
19
Q
periapical disease what is it, cause and diagnosis
A
- Inflammation, usually infection, of the apices of the teeth. (Upper M1, M2, PM4, Lower M1)
- Etiology:
○ Bacterial diapedesis (translocate from capillaries) through damaged gingiva
○ Haematogenous - Diagnosis:
○ Clinical signs
○ Oral examination
○ Radiographic examination (valuable, difficult to interpret)
§ See radiolucency, and draining fistula
○ Nuclear Scintigraphy, CT or MRI
20
Q
tooth removal (exodontia) what is the preferred way and what other way can do it, what need to beware of
A
- Intra-oral extraction-ideal but technical
- Surgical removal - anaesthesia
○ Repulsion with a bolt and hammer - cause trauma/damage and increase potential for bone infection
○ Lateral buccotomy -> cut the check and access tooth on the side - Complication rates approach 50% ** BEWARE
21
Q
What is the 2 main nerve block done during equine tooth removal and the 2 main brancches
A
1) trigeminal
- infraobital branch
- mental branch
2) local
22
Q
In terms of the infraorbital branch of the trigeminal branch for teeth extraction where done, what blocks and anatomical landmarks with size of needle and amount of anaesthetic
A
○ Maxillary foramen (entrance) - complications
○ Infraorbital foramen (exit) - more user friendly
○ Carefully infiltrate into foramen
○ Blocks - skin to muzzle, upper incisors to cheek teeth (cheek teeth depends on how far move up the infraornital sinus)
○ Anatomical Landmarks Infraorbital (foramen)nerve block
§ Thumb over - Naso-incisive notch
§ Finger on -> Facial Crest
§ Levator nasolabialis muscle over the infraorbital foremen
§ Index finger -> Infraorbital foramen
§ 22G-40mm needle
§ 8-10ml local anaesthetic and adequately sedate
23
Q
Mental branch of the trigeminal nerve for teeth extraction where can be done, what does it block and the anatmocial landmarks
A
○ Mandibular foramen (entrance)
○ Mental foramen (exit)
○ Blocks - Incisors and rostral mouth NOT CHEEK TEETH
○ Anatomical landmarks
§ Chin crease
§ Palpation -> rostral foramen, mental nerve
§ 22 G 40mm needle 8-10ml local anaesthetic
24
Q
Local anaesthesia for tooth extraction what useful for, limited to, where blocking and what need to avoid
A
- Useful for wolf tooth and incisor extraction
- Limited use for cheek tooth extraction
- Block medial and lateral to tooth
- Avoid major palatine artery
25
What are the mild, moderate and severe clinical signs of colic
```
mild
- Off feed (inappetence)
- Dull/quiet
- Flank watching
Moderate
- Lying down
- Pawing
Severe
- Rolling/crouching
- Uncontrollable/violet
```
26
what are the 3 causes of abdominal pain and what level of pain
- Dysmotility - mild
- Distention/tension on mesentery - moderate
- Ischemia - severe pain
27
clinical approach to colic with mild pain
- dysmotility/mild distension
○ Physical exam/history
○ CV compromise
§ NO -> NGT (nasogastric tube), rectal exam (abnormal -> NO then likely medical treatment and recovery 3-4 hours), ultrasound, abdominal tap
28
Clinical approach to colic with moderate pain
```
dysmotility, distension, ischemia
○ Physical exam/history
○ CV compromise
§ No -> NGT, rectal exam (abnormal)
□ NO -> ultrasound, abdominal tap -> treat and recovery 2-3 hours
□ YES -> likely surgical
§ Yes -> likely surgical
```
29
Clinical approach to colic with severe pain and what is respond and don't respond
significant distension, ischemia
○ TREAT PAIN and NGT (if yes to this then likely surgical) -> need to relieve the distention
§ Response -> physical exam/brief history, CV compromise
□ NO -> rectal exam, ultrasound, abdominal tap -> abnormal
® NO - reassess 2-3 hours
® YES -> likely surgical
□ YES -> likely surgical
§ Doesn't respond -> need more sedative and then move to response
30
In terms of history for colic case what are the horse and management factors need to consider and the 2 critical things to as
- Horse factors:
○ Duration /severity of pain – is it escalating? - CRITICAL
○ Any drugs given, dose/route and how long ago? - CRITICAL
○ Previous colic (surgery) - CRITICAL
○ Manure passed today (mild-moderate)
○ Age of horse /purpose /(insurance status)
- Management factors:
○ Change in feed/ management past few weeks
○ Previous episodes of colic
○ (Recent worming) - if have a high burden when dewormed then possible inflammatory response to the dying worms - not common
31
What properties for NSAIDS, apha-2 agonists and ketamine
- NSAIDS are anti-inflammatory with analgesic properties
○ Flunixin/phenylbutazone - pick one
- Alpha 2 agonists are sedatives with analgesic properties
○ Detomidine/xylazine
- Effects are complemented with opiates
○ Butorphanol (morphine/methadone (avoid in colic due to ileus)
- Ketamine is an anaesthetic with analgesic properties - not appropriate for analgesia
32
in terms of interpretation of pain for colic what is involved
- Duration /severity of pain –is it escalating?
○ Severity determines possible lesions
○ Lesions can progress
○ Longer duration (hours) suggests more likely to need intensive treatment /surgical- correlate with CV status
○ Finite duration of ischaemia before CV collapse and death
33
what are the 2 main short-term visceral analgesics, their onset and duration, and when to use
○ Alpha 2 agonists: rapid onset, variable durations
§ xylazine: 20-30 minutes (200-250mg /500 kg IV)
§ detomidine: 40-60 minutes (0.5ml /500 kg IV)
○ Opiates: rapid onset, augments sedation
§ butorphanol: 30-40 minutes (0.5-1ml /500kg IV)
§ morphine: hours (avoided in colic: ileus)
- Use detomidine and butorphanol for severe pain
- Use xylazine alone for lower grade pain or procedures
34
what type of drug used for longer term pain relief with colic, the 3 main drugs, duration and potency
NSAIDS
1) Flunixin: 0.5 -1.1mg/kg IV - most common
§ Duration 12-24 hours, onset 40 minutes
§ Potent visceral analgesic at high dose
§ Improves appearance of mmbs - keep in mind when reassessing horses
2) PBZ: 2.2- 4.4mg/kg IV
§ Duration 12-24 hours, onset approx 40mins
§ Less potent than flunixin for visceral pain - debatable
§ Oral phenylbutazone: 2 hours for effect
3) Buscopan: ‘Antispasmodic’ + weak NSAID -> not for significant GIT pain
§ Relatively poor analgesic compared with others
35
Sedatives for colic cases what is the main type and 2 drugs and duration used
○ Strong visceral analgesics - short acting analgesics - important to know duration
§ Alpha 2 agonists: rapid onset
□ Xylazine: 30 mins duration
□ Detomidine: 60min duration
36
what are 3 main risk factors for colic and why within
1) Change in feed/ routine past few weeks
○ Large amount of grain- fermented in large intestine
○ Lucerne hay- gas production
2) Previous episodes of colic
○ Management influential
3) Recent worming
○ Colic 1-2 days after worming
○ Presumed disruption of motility
○ Can be severe and surgical
○ Intestinal inflammation when worms are killed
○ Worm ‘injury’ uncommon these days
37
Physical examination for a horse with colic what is the 8 main things to do
1) assess level of pain
2) cardiovascular status
3) temperature
4) mucous membrane colour
5) abdominal distention
6) gut sounds - very subjective
7) nasogastric intubation (NGT)
8) rectal examination
38
placing a stomach tube in a horse what should you do
- Ensure tube remains ventral and central (within the ventral meatus)
- Once get to larynx will have resistance and then twist 180degrees
- Ensure the head is flexed for this
39
in terms of cardiovascular and temperature for physical examination of colic horse what is involved and what does this indicate
- Cardiovascular status
○ Ischaemia/endotoxaemia: hypovol +CV compromise
§ HR >60, RR >20, delayed crt, poor peripheral pulses - surgical lesion
§ injected/congested/toxic mmbs
§ Early ischaemic lesions can have normal CV
- Temperature
○ See febrile causes: rarely surgical
○ May still need intensive treatment
40
Abdominal distention detection during colic physical exam what generally represent and significance
○ Large intestine in an adult
○ Large or small intestine in immature animal
○ Always significant
○ Often surgical
41
Nasogastric intubation for colic what does reflex and lack of reflux man as well as nose bleed
○ Any volume should be considered significant -> may be spontaneous or may need to create a syphon
§ SI obstruction****
§ Large intestinal distension; Impedes gastric outflow -> rare, only If large intestines are VERY distended
○ Lack of reflux? - what does it mean
§ Relative to duration
§ 16 hrs to back up
○ Nose bleed - when pass a tube -> common complicated
§ Raise head, cover nose, put frozen peas on the head
§ Reassure client
42
If feel distention during rectal exam for colic what does it suggest and the two main types with causes
```
○ Distension occurs due obstruction
§ Non strangulating
□ Physical blockage of lumen
□ Impacted /dehydrated luminal content
□ Displacement: think hosepipe with a kink
§ Strangulating
□ Displacement with a 360 dg twist
```
43
In terms of rectal examination what structures can you feel where
§ Caudal abdomen only**
□ Large intestine: Pelvic flexure (6. left ventral and dorsal colon)
® Displacement identified by taenial band orientation
§ Caecum: right caudal abdomen, fixed in position (2)
§ Small intestine: - midline
□ Midline
□ Only palpable if distended
§ Small colon: faecal balls (1)
§ Nephrosplenic space - left
□ Spleen (3)
□ Left kidney (4)
44
What are important safety considerations of rectal examination
§ Sedate - cannot make it too safe
§ +/- muscle relaxant
□ Propan B** (1.5-2ml /500kg horse IV)
□ Buscopan (3-5ml /500kg horse IV) - 2nd choice
□ Both can increase HR for up to 3 hrs
□ Not appreciable with buscopan in my experience
§ Against Stocks / stable door
§ Capable handler
§ Lignocaine per rectum (20ml) -> does help some horses
§ Lube
§ Do not push against peristalsis - wait for it to pass, less tolerant than cows
45
In terms of distention in large colon, caecum and small intestines felt via rectum what are likely causes
```
§ Large colon distension
□ Gas: Mild-moderate is springy
® Severe is tight (think inflated balloon)
□ Ingesta: Feed material is ‘doughy’
® Very firm is severe impaction of dry feed
§ Caecum
□ Gas more common
□ Impactions have to be severe to palpate clearly
§ Small intestinal distension
□ Feed impactions rare in Australia
□ Fluid/gas due to obstruction is common
□ Stacked tubes in midline
```
46
Rectal tear during rectal exam what generally feel like, what need to do immediately and high risk horses
```
§ Sudden release of pressure against hand
§ Blood on rectal sleeve
□ Sedate if not already
□ Notify client
□ Check severity
® Ungloved hand, water based lube
® Mucosa only full thickness
® Usually dorsal
○ Higher risk
§ May be unwise /unnecessary:
□ Severe colic (risky for you and horse)
□ Unhandled horse
□ Miniature horse
□ Inadequate facilities or handler not competent
□ Young colts and Arabs: increased risk
□ Obvious surgical lesions - not going to change anything
```
47
Rectal tear during rectal exam what are the 2 main situations and treatment needed
□ Mucosa only
® Not normally a problem
® No further rectal exams
® Soften manure- enteral fluids
□ Mucosa + submucosa + muscular +/- serosa
® Needs definitive management
® Pen /gent/ flunixin/ propan B (decrease rectal movement) - OR give epidural
® Pack off rectum oral to tear - use damp cotton wool
◊ Damp cotton wool in stockinette 20cm oral to tear
® Broad spectrum antibiotics
® Get definitive treatment and communicate with the client
48
Analyse scenario, what to do next
- A horse that was consistently laying down and intermittently rolling, give dose of detomidine/butorphanol and full dose of flunixin, horse looked brighter for 20 mins, now 1 hour later laying down, flank watches , HR 48, no reflux and mucous membrane looks normal
intermittently rolling - moderate pain
40mins for butorphanol
1 hour later less painful BUT flunixin should be working at this point and is potent and so there is a large amount of drugs and still not response
LOOK FOR SURGICAL REASONS
49
Analyse scenario, what to do next
- A horse that was consistency laying down and intermittently rolling, dose of xylazine and client give full dose of PZB orally, brighter for 20 mins, 1 hour later horse is still flank watching , HR 48, no reflux, mmmbs normal
brighter for 20mins due to xyalzine short duration so consistent
1 hour later still flank watching - PZB not on board yet, showing lower pain then before wait for PZB to come in - not getting worse
NEXT - ensure pain getting better, rectal exam and another dose of short acting anagesia
50
What are the 2 main further investigation techniques for colic
1) ultrasound
| 2) abdominocentesis
51
Ultrasound for colic what examine, what can find and determine
```
○ SI distension
§ Ventral abdomen
§ Clip hair, alcohol/gel
§ Inguinal region**
§ Maximum penetration
§ Minimum frequency
○ Finding -> Round loops -> (Lack of motility)
§ +/- sedimentation
○ Surgical
```
52
Abdominocentesis how to perform
```
§ Most ventral part of abdomen
§ 2-3cm right of midline
§ Clip, prep, +/- local bleb/ stab incision (teat cannula) - ASEPTIC
§ 18G needle
□ faster, cheaper,
□ risk enterocentesis
§ Teat cannula- safer ?
§ Collect in EDTA + plain
```
53
Abdominocentesis findings what is no fluid, clear, sanguineous, turbid yellow and brown
```
§ No fluid
□ No help
§ Clear –light yellow
□ Normal
§ Sanguineous
□ Ischaemia - strangulation? - SURGERY
§ Turbid yellow
□ Peritonitis (see febrile colic)
§ Brown, large volume +/- feed
□ Ddx rupture/ enterocentesis
□ Clinical signs: enterocentesis generally not problematic
```
54
what are the 4 main treatment options for colic
```
1. Sedative
○ Short acting for procedures
○ Long acting for pain relief /travel
2. Analgesia
○ Flunixin /PBZ/ (buscopan)
3. Enteral fluids
○ Promote motility, soften ingesta
○ Not if reflux, otherwise ok
4. Must reassess every colic
○ Phone contact or revisit
```
55
In terms of referral and euthanasia for colic what is important, what need to do and when to euthansia
- Estimate of costs important
- Refer early: this is the key to a good outcome
- Make safe for travel
○ Pass NGT before if small intestinal
○ Detomidine +/- butorphanol
- Truck better than float for violent colic: transport co/
- No people to travel with horse
- Do not leave clients with responsibility for re-sedating during the truck ride
- Euthanase if surgery not an option
56
Medical colic what percentage the main cuase and cuases within
- 90% are resolved without surgery
Dysmotility:
1) hypermotile/overactive -
○ Cause often not identified (consider colic risk factors)
2) hypomotile: infrequent, quiet or absent gut sounds
○ Causes
§ Stress, pain, change in routine/feeding
§ Drugs (sedatives -> alpha 2 and butorphanol repetitive)
§ Withholding feed
§ No identifiable cause
57
hypermotile colic what physical exam findings, a common cause, and treatment
○ Continuous/loud gut sounds
○ Mild to moderate or intermittent pain
○ “Spasmodic colic”
§ Difficult to prove if truly gut ‘spasm’
○ Cause often not identified (consider colic risk factors)
○ NAD on further investigation, CV normal
○ Buscopan (anti-spasmodic) (or NSAID) +/- sedative
○ Ddx impending colitis (febrile)
58
Hypomotile colic main what generally occurs, what impacts and general diagnosis
§ Lack of propulsive motility (functional obstruction)
§ Luminal contents accumulates
§ Feed/gas (large intestine), fluid (small intestines)
□ Large intestine -> rectal exam - large colon impaction
□ Small intestine -> ultrasound and NG reflux -> is it a functional or obstruction
59
large colon impaction leading to colic presentation/PE findings and causes
- Presentation
○ Reduced fecal output
§ approx 12 piles manure /day is normal
- Rectal exam- pelvic flexure
- Doughy ingesta (moderate severity)
- Firm ingesta (severe impaction)
- Causes
○ May be:
§ Diet related - if not proper digestion then can impact on pelvic flexure
§ High starch/ low fibre diet (dehydrates ingesta)
§ Lack of pasture access
○ Reduced fluid intake (fluid drawn from lumen)
○ Fibrous/poor quality feed / poor dentition
60
What are the 3 main treatments that need to occur in large colon impaction
1) Management
§ Pain relief: Flunixin or PBZ
□ Repeat doses not required unless severe
§ Soften ingesta
§ Promote motility
2) Enteral fluids: most effective - stomach tubes
3) IV fluids in severe cases, systemic dehydration, or unable to tolerate enteral fluids
61
for large colon impaction enteral fluids what are the 2 main positives and the 3 main options for fluids and when use
```
§ Increases luminal fluid
§ Stimulates gastrocolic reflex
Enteral fluid options
□ Isotonic fluid softens manure
® Na bicarb /KCl
□ Oil lubricates it
® Marker of transit
□ MgSO4 (‘epsom salts’) 24hrs
® If don't have good access to the horse
® Osmotic laxitive
® Most aggressive
® Max dose 1g/kg/24hrs
® Must be hydrated
◊ Free access to water
```
62
Volume of enteral fluids for large colon impaction, what can be tolerated, what if too much, what is needed to resolve the impaction
```
□ 6-8L / 500kg horse well tolerated
□ Larger volumes can cause colic
® Pain immediately after tubed
® Removing fluid unproductive
® Sedate- xylazine
□ To resolve an impaction:
® Depends on severity
® Maint: 25L/day/500kg - NEED TO BE ABOVE MAINTENANCE
® Many resolve with less than this
◊ Severe ones require much more
```
63
Large colon impaction what are the expected outcomes, when start feeding again and prognosis
```
○ Single dose of NSAID sufficient
○ Gut sounds/ demeanor improve
○ Softening of impaction on rectal
○ Manure passed within a few hours
○ Start feeding again when manure passage consistent
§ Monitor until drugs have worn off
§ Excellent prognosis unless severe
§ Address possible risk factors
○ Good prognosis generally
```
64
Large colon impaction unexpected outcomes and what to do in these situations
○ Continued or recurrence of abdominal pain
○ No manure or only small amounts of fluid/mucus
○ Abdominal distension
What to do in this situation
§ Re-evaluate
§ Repeat rectal
□ gas build up oral to obstruction
□ movement of colon to abnormal position: displaced?
§ Check for reflux
□ Severe impactions don’t tolerate oral fluids well
□ Re-visit diagnosis: ddx ‘impaction’ secondary to SI obstruction may be occurring
65
What is the difference between colon and caecal impaction
- Caecum on the right
- Firm impactions on the right - mid ventral abdomen
○ Harder to rectal and feel all of the caecum
- Often severe when horse presents
- Often minimal abdominal pain
- May rupture with minimal preceding signs!
- Surgical emergency
66
Caecal impactions how common, key risk factors and typical history
- Uncommon
- Key risk factors
○ Management change in previous 2 weeks
○ Hospitalisation for orthopaedic problems
- Typical history:
○ Horse usually lives out
○ Stabled for orthopedic dx
○ Low grade colic 24hrs +
○ Pass manure but smaller amounts
Ileocaecal gut sounds can still be present
67
What are the 7 main risk factors for medical colic
1) dietary manipulation
2) intesive or no excercise
3) parasitism
4) stable management
5) sereotypic behaviour/stress
6) higher risk populations - high level competition/TB racehorses
7) nutritional factors
68
what is the main nutritional factor that is a risk factor for medical colic and what aim for
○ Dietary intake influences the ingesta
§ Balance of slowly fermented fibre (hay, haylage, sugar beet pulp)
§ And rapidly fermentable non-structural carbohydrates (cereal starches)
○ May result in obstruction
§ Directly (impaction) or indirectly: mucosal inflammation leading to dysmotility
○ Aim for >70% fibre <30% cereal
69
What is the main nutritional risk factor for colic, why and prevention
Higher quantities concentrate -> SI has limited capacity to absorb starch -> excess into LI -> disruption to caeco-colic microbial population (especially in TB racehorses)
Prevention
- pasture access - reduces the risk (exception sand colic)
- make changes gradually (7-10 days)
-> Proportion of hay vs concentrates
-> Source of hay /concentrates
-> Amount or frequency of feeding
-> Risk lasts 2 weeks (Fermentation during adaption can cause ‘gas colic’ /loose manure)
70
Gi ulcerations what lead to, clinical relevance and what generally present as
- Colic or poor performance
- Clinical relevance debated - consider cause of medical colic
○ >90% racehorses have gastric ulcers
○ Few have (obvious) clinical signs
- Very low grade colic/off feed+/- teeth grinding
○ Associated with feeding
○ May have picky appetite
71
GI ulcerations as a cause of colic what is the main cause, pathogenesis and where in the stomach
○ High concentrate /low roughage diet
§ Acidification of gastric contents
§ Protective ‘mat’ of roughage is lost - job is to keep acid in glandular portion and away from squamous portion (squamous portion doesn't have the right barriers to protect against acid)
□ Leads to ulceration
® Squamous or glandular ulcers
® Squamous (area in the stomach) more significant: above margo plicatus
72
GI ulcerations as a cause of colic diagnosis
○ Diagnosed with gastroscopy (3m scope, 12 hrs off feed)
○ Blood work non specific
○ Alternately use response to treatment to confirm diagnosis
§ Some horses are poor responders to treatment -> false negatives
73
GI ulcerations what are the 2 main things in the treatment and certain drugs
○ Reduce acid load:
§ Proton pump inhibitors: omeprazole SID PO
§ Histamine (H2) antagonist (H2 promotes HCl secretion from parietal cells): ranitidine TIDBID PO
§ Sucralfate: ‘band-aid’ on ulcerated mucosa, stimulates mucus secretion, incr prostaglandin E synthesis
○ Increase roughage/ grass turnout
74
NSAID induced ulceration how occurs, when more likely, how common, when to avoid
- NSAIDS decrease local blood flow to GIT- stomach and right dorsal colon
- Concerns over causing ulceration very common
○ Clinical disease more likely if colonic ulceration - NOT STOMACH LIKE ABOVE
§ Inappetance, colic, small volume dxa, protein loss, can be febrile
§ (ddx infectious colitis: history of exposure)
- Rarely occurs at appropriate NSAID dosages
- Low roughage diet, avoid NSAID use!!
- Ulcer medications do not effect RDC
75
Surgical colic what are the 3 main differential diagnosis
- Incorrect place - mainly small intestine and large colon
- Obstructed
- Strangulated
76
Clinical findings for strangulating vs non-strangulating colic CV compromise?
```
Strangulating
- YES - depending on duration
- HR increased, mmbs injected-toxic
- Poor peripheral pulses
- Increased PCV/TP/lactate
Non strangulating
- Not typical
- Pain may increase HR marginally BUT would then expect to improve when monitor the pain
```
77
Clinical findings for strangulating vs non-strangulating colic abdominocentesis
```
strangulating
- Serosanguinous
- WCC (increased)
- TP (increased)
- Lactate (increased 2x)
non-strangulating
- Clear yellow
- WCC 10x10^9
- TP <25g/dL
- Lactate <2mmol/L (except AE)
```
78
Clinical findings for strangulating vs non-strangulating colic NG reflux and ultrasound results
strangulating
- Yes - depending on duration and site
- Dilated loops up to 5cm
- Hypomotile - amotile
non-strangulating
- Not typical - unless so distended that obstruction of outflow (will know that large intestine as will see distention grossly)
- Colon obscuring view of left kidney (NSE)
- Thickened colon wall (volvulus differential colitis)
79
Clinical findings for strangulating vs non-strangulating colic NG reflux and ultrasound results
strangulating
- Yes - depending on duration and site
- Dilated loops up to 5cm
- Hypomotile - amotile
non-strangulating
- Not typical - unless so distended that obstruction of outflow (will know that large intestine as will see distention grossly)
- Colon obscuring view of left kidney (NSE)
- Thickened colon wall (volvulus differential colitis)
80
Clinical findings for strangulating vs non-strangulating colic rectal exam and pain
```
strangulating
- Stacked tubes in midline: fluid filled
- Moderate-marked
Beware stoic horses
non-strangulating
- Large viscus: gas or hard ingesta
Taenial bands/sacculated colon in dorsal abdomen
- Moderate-marked
```
81
Non-strangulating lesions what are the 2 main displacements, what occurs, and treatment needed
○ Right dorsal displacement:
- colon doges from right to left
§ Require surgery
§ And can progress to large colon volvulus
○ Left dorsal displacements
- nephrogenic entrapment of the colon (left kidney not seen in ultrasound)
- may respond to medical management:
§ Phenylephrine (contract spleen - decrease size of spleen)
§ Lunging exercise - move colon back into place
§ Rolling UGA - move colon back into place -> opposite to the displacement
§ Risk of fatal haemorrhage from phenylephrine in horses increases with age (>15 years)
82
Anterior enteritis what is it, results in, associated with, possible risk factors and what find with abdominocentesis
○ Anterior enteritis = Inflammation of proximal SI
§ Hypomotility: fluid accumulates - true ileus - distention of small intestine -> produce reflux
§ May be associated with Clostridial infection - debated
§ High concentrate diet may be a risk factor
§ Abdominocentesis:
□ Can be inflammatory
□ (overlap early ischaemic)
83
Anterior enteritis hallmarks
□ Large volumes reflux soon after onset of colic**
® Proximal lesion
® Other causes usually more distal: reflux hours after onset
□ Pain relieved when refluxed
□ May be febrile**
□ Dull**
84
Anterior enteritis treatment
□ Some ex lap: (unclear diagnosis or surgical decompression) - DON'T WANT TO MISS STRANGULATION so in doubt ex lap
□ Intensive medical management
□ Principles: address inflammation, decompress, support CV
® Anti-inflammatories
® IV fluid support: maint + losses in reflux
® Nil per os
® Reflux to decompress stomach
® +/- metronidazole - if worried about clostridial
® Monitor with ultrasound
® Duration of reflux unpredictable
® Electrolyte supplementation may be required
85
surgical procedures for non strangulating and strangulating lesions
- Non strangulating lesions: correct displacement +/- decompress intestine
○ Decompression of gas (needle suction)
○ Evacuation of contents (pelvic flexure enterotomy)
○ Reposition in correct location
- Strangulating lesions: correct vascular obstruction
○ Repositioning, untwisting, removal from foramen etc
○ Decompress
○ Assess viability
○ Resect (generally 30cm of intestines) and anastomose if necessary
86
resection and anastomosis for small intestines what limited to and complications
○ Limited to 50- 60% of total length (total 15-21m long)
○ Limited access to duodenum and distal ileum
○ Ability to resect depends on location
§ Resection can heavily influence prognosis
○ Complications:
i. Post-operative ileus
ii. adhesions
iii. anastomosis breakdown
iv. stricture
v. colic
87
resection and anastomosis of large intestines where generally done, what can happen, what is the goal and complications
○ Volvulus: base of caecum and colon
○ Deep in the abdomen
○ Cannot remove all of affected intestine
○ If truly non-viable anastamosis will dehisce
○ Resection to reduce endotoxin absorption not to remove non-viable tissue
○ High complication rate
i. Peritonitis
ii. diarrhoea
iii. haemorrhage
iv. Post-operative pain
88
post operative management after colic surgery what is occurring in intestines, how to support and how long hospitalized
- Intestinal injury disrupts absorption and barrier mechanisms
- Normal intestinal propulsive activity - need to be careful with feeding
- Support
○ Fluids +/- electrolytes +/- energetic support
○ Protection against bacterial endotoxin
§ IV fluids
§ Electrolytes
§ Antiinflammatories
§ Clean contaminated surgery: broad spectrum antibiotics
§ Gradual return to feeding (approx 4 days)
- Hospitalised 5-7 days without complications
89
what are the 5 main early post operative complications of colic surgery
```
Consequences of inflammation
○ Ileus, laminitis, adhesions
1. Disruption of normal motility
○ ‘Ileus’
2. Disruption of barrier function
○ Endotoxaemia
§ End organ damage
§ Laminitis
3. Ileus
4) endotoxaemia
5) adhesions
```
90
Ileus as a early post operative complication of colic surgery what is it, where located, what needed, onset, duration and monitoring
○ Functional obstruction due to dysmotility (inflammation)
○ Most typical after small intest R&A
○ Colic (pooling intestinal fluid: distension)
○ Reflux, CV support (fluids), antiinflammatories
○ Onset 1-3 days
○ Duration unpredictable
○ Monitor with ultrasound
91
Endotoxaemia as a early post operative complication of colic surgery, what results, clinical signs and treatment
```
○ Bacterial absorption across damaged mucosa
○ Injected/congested mmbs
○ Incr HR, colic, +/-fever
○ Laminitis
○ Treatment
§ IV fluids /CV support
§ Hyperimmune plasma ($$$)
§ Polymixin B (care nephrotoxic)
§ Laminitis prophylaxis: Sole support/ ice boots
```
92
adhesions as a early post operative complication of colic surgery, what formed from, where least tolerate, results and how to minimse the risk
```
○ Inflammation, -gut, foreign material, excess handling etc
○ Small intestine least tolerant
§ 5 days to years after surgery
§ Obstructs lumen
§ Axis for volvulus
□ Present as colic
§ Can resect some
○ Minimise the risk
§ Good surgical technique
§ Early intervention all colics
```
93
Post operative management after discharge of colic surgery what need to allow for, how long to reduce excercise and what else need to do
- Allow time for healing of linea alba
○ 12 weeks to reach full strength
○ Minimise strain on linea for this time
- Ref vet guides client on appropriateness of turnout
- Confine 4-6 weeks, box 4-6 weeks, small yard 4-6 weeks
○ (Exercise increases strain)
94
what are the 2 main discharge complications
1) incisional infection
| 2) recurrence
95
incisional infection after colic surgery how presents and treatment
```
○ Purulent discharge
§ anytime in first month
○ Sub-cutaneous +/- linea
○ Pain on palpation +/- fever
○ Treatment
§ Establish draining
§ (remove skin sutures)
§ Culture and sensitivity
§ NSAID, local wound care
§ Antibiotics not always required
```
96
Incisional infection after colic surgery possible results, what need to do
```
§ Infection delays healing
§ Strain before healing is compete
□ Acute dehiscence (hospitalised horses)
□ Hernia formation (weeks-months)
§ Prolong duration in a box
□ Because healing is slower with Infection
§ Manage the infection
§ +/- Supportive bandage, possible hernia belt if needed
```
97
Recurrence of surgical colic after surgery how common for large intestinal vs small intestinal
```
○ Large intestinal: displacement/volvulus
§ Up to 15% following initial lesion
§ >50% following second
○ Small intestinal
§ Rate not well established
§ EFE <5%
```
98
prognosis for small intestinal resections during colic surgery
○ 60-70% survival
○ Post operative complications very influential
○ Early intervention is very important
○ Many colic at least once after discharge
○ Greater risk of death for a year after discharge
§ $ may influence this
○ $12-15K +
99
Prognosis for large intestinal volvulus and displacement
```
- Large intestinal volvulus
○ 50% survival
○ Early intervention determine life or death
○ Fatal ischaemia can occur within 4hrs
○ $12-15K +
- Large intestinal displacements
○ Non ischaemic so do better: 80% +
○ Prolonged duration has ‘ischaemic like’ effects on colon and therefore horse
○ $10-12K
```
100
in terms of surgical colic is a diagnosis needed and what plays the vital role for survival
- Definitive diagnosis is not necessary to recommend surgery but differentiate between small from large intestinal and strangulating and non-strangulating lesions is important for prognosis and cost
- PRIMARY VETERINARIAN plays a vital role in optimising survival with pre and post op management
