Equine emergencies, injuries, colic, liver Flashcards
wounds, rectal tears, grass sickness, worms, analgesia, choke, dysphagia, rectal prolapse, weight loss, serum proteins, glucose absorption test, infiltrative bowel disease, lymphoma, GI ulcers, cholangiohepatitis, ragwort, hyperlipaemia
Initial treatment of stable fire - burnt horse?
Stop any burning - cool with lukewarm water and remove rugs
Sedation/anziolytics if required
Flunixin IV
+/- Oxygen
Severe cases may need IV catheter placement +/- tracheostomy (URT inflammation, burn shock)
Referral/euthanasia may need to be considered
Less severe cases - cool skin with cold water, clip hair and lavage with chlorhexidine solution, apply water based antimicrobial ointment e.g. silver sulfadiazine
How to assess the severity of burns in stable fire etc?
Full clinical exam - check for involvement of eyes and other structure e.g. joints/tendon sheaths
Assess extent of burns injury = percentage of total body surface area, correlated with mortality
Assess depth of burns injury - 1st to 4th degree, correlated with morbidity
Determine if referral/euthanasia should be considered
Initial advice to an owner about wounds in horses?
Control any profuse haemorrhage by placing a dressing/any clean, dry material over site and maintaining pressure - if possible
Do not move horse if it is very lame unless in imminent danger
May only need telephone advice if minor wounds in low risk area
For more severe cases, tell them not to apply anything to the wound before you have assessed it
Clinical exam, history and what to initially do for a wound of a horse?
Initial first aid: control haemorrhage, stabilise limb Full history about circumstances of injury and when occurred, tetanus status Full clinical exam: - Assess for shock - Assess stance ability to bear weight - Check vital parameters - Check amount of blood lost - Check for other wounds
What to do more detailed assessment of horse wounds after initial clinical exam?
Poss sedation
Assess age of wound/degree of contamination, location
Apply sterile gel to wound and clip and clean area around it
Remove gel and lavage site with sterile polytonic fluids/chlorhexidine/povidone iodine with 35/60ml syringe and 18/19G needle
Wear sterile gloves and use finger/sterile probe to determine:
- depth and direction of wound
- presence of any foreign material
- subcutaneous pockets
- bone/tendon exposure
Is wound near joint/tendon sheath
Involves penetration of thoracic/abdominal organs or other vital areas e.g. trachea/oesophagus
Which wounds should be sutured? Things needed?
<8h old and have healthy looking tissue a the wound margins
Wounds around eyelids, nostrils and lips (full thickness)
May need:
- sedation
- GA
- local nerve blocks: mepivacaine/lignocaine (not with adrenaline), regional nerve block, ring/L block
- suture materials and equipment
- staples may be appropriate in some cases
- drains
- protection/bandaging of site
To do:
- remove necrotic/non-viable tissue (preserve issue flaps if possible, eyelids/nostrils/lips good anatomic reconstruction v important)
- skin staples only where no tension
- 3-3.5 metric monofilament for skin e.g. polypropylene, absorbable, similar size subcutaneous tissue
- +/- stenting
Ongoing management of horse wounds?
Analgesia and anti-inflammatories (IV then oral course)
Antibiotics (IV/IM then oral course e.g. trimethoprim sulphonamides)
+/- tetanus toxoid/tetanus booster
+/- box rest (beware colic due to no exercise -> reduced motility -> impaction)
Suture/staple removal - usually 10-14 days
Frequency of bandage changes depends on amount of exudation
Secondary intention healing for horse wounds - what dressing etc?
Apply sterile hydrogel and non-adherent, absorbent dressing initially
Bandaging of distal limb important (+/- splint or cast bandage)
Ongoing wound management important - can take a long time and can be expensive
Some wounds may be suitable for delayed primary closure (tertiary healing) or skin grafting techniques
Complications of horse wounds?
Synovial sepsis/fracture (missed initially)
Bone sequestrum formation - where cortex of bone exposed
Wound dehiscence
Foreign material remains in situ - be careful if wood involved
Sores associated with bandaging - bandaging performed by the owner may not be appropriate
Types of skin grafts for horses?
Pedicle grafts - rarely used, equine skin relatively inelastic
Free grafts - usually autografts, pinch/punch/tunnel grafts, solid or meshed sheets, meek micro grafts
Timing of skin grafting?
Can be applied to granulating wounds
Can also be applied to fresh injuries/surgically created defects
Wound bed requirements for a graft to be accepted in horses?
Vascularised
No necrotic tissue present
No evidence of overt infection
No evidence of delayed wound healing - sequestrum, foreign body
Acute wounds: rule out synovial involvement, bone/tendon/ligament pathology
Indications for skin grafts in horses?
Traumatic injuries Non- or slow healing granulating wounds Adjunct to management of skin neoplasia Extensive skin burns Deformity-causing scarring
How quick is epithelialisation of horse wounds?
<1mm/week
How to place grafts for horse wounds?
Start at the lowest site (prevents haemorrhage from obscuring sites) Make a pocket in the granulation bed No 15 scalpel blade Firmly tuck grafts into each pocket Non adhesive dressing, bandage Box rest Change bandage in 5-7 days
Full thickness graft donor site?
Pectoral region most commonly used
Complications with nasogastric intubation of horses? Tips to avoid this?
Haemorrhage - common
Oesophageal perforation - uncommon, poor prognosis
Inhalation pneumonia - uncommon
Tips:
- use appropriate size, plenty of lube and ensure not roughened/damaged
- ensure horse is suitably restrained
- pass down ventral meatus
- never force tube, ensure placed properly in oesophagus/stomach before administering fluids
Problem with liquid paraffin via nasogastric tube?
Associated with severe lipoid pneumonia
Can be life threatening and difficult to treat
Even if small amount gets into lungs
Which horses have an increased risk of rectal tears during examination? Tips to avoid it?
Arabs, stallions/colts, horses with colic, fractious horses
Tips:
- ensure properly restrained
- sedate if fractious
- never push against rectum if horse strains: sedate +/- butylscopolamine
Initial action if blood on rectal sleeve (possible rectal tear) for horse?
Inform owner Sedate horse Give butylscopolamine \+/- epidural anaesthesia Evaluare integrity of rectal mucosa Protoscopy useful if endoscope available Determine the location and grade of the tear
Classification of horse rectal tears?
Grade 1: mucosa and submucosa
Grade 2: muscularis
Grade 3a: mucosa, submucosa and musculis (not midline)
Grade 3b: mucosa, submucosa and muscularis (midline)
Grade 4: all layers
Treatment of rectal tears?
Depends on grade of tear, location (extra/intraperitoneal rectum) and owner factors (economics etc)
Grade 1 - medical management/no treatment required
Grade 2 - medical management
Grade 3 and 4: medical/surgical management
Broad spectrum antibiotics - penicillin
Flunixin meglumine
Check tetanus status
+/- epidural anaesthetic and packing of rectum
Surgery - direct suturing, placement of rectal liner, temporary diverting colostomy
Horse level risk factors for colic?
No clear age, breed or sex predilection overall, specific types of colic do have specific age or sex risk factors
Crib biting/wind sucking - risk factor for EFE, SCOD, recurrent colic
Weaving - risk factor for recurrent colic
(can modify pasture access and diet)
Management level risk factors for colic?
Geography - sand colic, enteroliths, EGS, IFEE
Seasonal - spring and autumn peaks, EGS peaks in May, large colon impactions and EFE peak in winter
Change in feed within 2 weeks (association with weight of feed/concentrate feed, shifts in gut microbiota) - especially LCV
Coastal bermuda hay (not UK) - ileal impaction
Increased stabling/reduced pasture turnout - general colic, SCOD, colic in horses with CBWS behaviour
Pasture associated with Equine Grass Sickness
Dental care - SCOD:horses who had teeth checked less frequently, LCV:horses with known dental problem/seen quidding, LC impactions:donkeys with dental disease
Parasites and anthelmintic administration - measures to minimise parasite burdens reduces risk, Anoplocephala perfoliata associated with spasmodic impaction/ileal impaction/caecal intussusception
Access to water
Transport
Exercise
Owner/carer
Risk factors for colic recurrence?
Known dental problem
CBWS
Weaving
Time at pasture
Epidemiology of pedunculated lipoma strangulation?
Older horses and ponies (>8yo) Ponies>>>horses Geldings>mares Small intestine most common Occasionally small colon and other sites
Epidemiology of large colon volvulus (LCV) in horses?
Mares - post foaling Larger horses Increased stabling Dental disease Feed - especially changes
Epidemiology of large colon impaction in horses?
Change in management - stabling
Autumn/winter
Box rest e.g. hospitalised - motility, water balance
Straw bedding
Good prognosis (poss worse in donkeys and older animals)
Epidemiology of epiploic foramen entrapment?
Seasonal - Dec, Jan, Feb: increased stabling, feed
Crib biting/wind sucking behaviour
Predictors of whether a colic case is critical or not?
Pain
Cardiovascular signs
Absence of gut sounds
Post colic surgery survival?
High mortality in first few days after surgery
Slower rate of death in first 100 days
And then rate is constant
Risk factors for mortality after colic surgery?
Resection length
PCV
Duration of surgery
Potential postoperative complications of colic surgery?
Post-operative ileus (POI) Thrombophlebitis Post operative colic - SI strangulation, large colon torsion Diarrhoea Laminitis Incisional infection/dehiscence
What is grass sickness?
= Equine dysautonomia
Polyneuropathy affecting central and peripheral nervous systems of horses
Clinical signs related to neuronal degeneration in the autonomic and enteric nervous systems (severity depends on extent of degeneration)
Diagnosis of grass sickness?
Clinical signs
Histology - ileal biopsy (surgery), PM exam
Acute/subacute clinical presentation of grass sickness?
Colic Reflux Tachycardia SI distension Patchy sweating Salivation Difficulty swallowing Ptosis
Chronic clinical presentation of grass sickness?
Weight loss Dysphagia Tachycardia Patchy sweating Muscle fasciculations Rhinitis sicca (crusting around nares) 'Elephant on a barrel' stance
Epidemiology of grass sickness?
Previous outbreaks on premises increases risk
Regional - more common in North, Scotland
Young horses 2-7yo (particularly 3-5)
At pasture
Spring - especially April/May
Also peak in Autumn in certain years
Spatial clustering
Management risk factors for grass sickness?
Access to grass - longer time at pasture
Recent change in pasture (e.g. changed fields previous 2-4 weeks)
Pasture disturbances e.g. mechanical removal of droppings
Element levels in soil
Avoid turning out young horses to a pasture that has previously had GS in spring time, supplement with hay/haylage
Theory for cause of grass sickness?
Toxico-infection with C botulinum type C
Present in GIT, combination of risk factors triggers toxin production
Type C toxin found in ileum and faeces of GS cases
EGS cases have lower Ab to Clostridium type C than controls
Vaccination possibility?
How are parasites/anthelmintics a risk factor for colic?
No association with anthelmintic type/programme
Increased risk if not on a worming programme
Decreased risk if on a regular worming programme
Increased risk after anthelmintic administration
How can Strongylus vulgaris cause colic?
Thrombosis of the cranial mesenteric artery
Non strangulating infarction
Once was responsible for up to 90% of all colic cases - rarely seen since modern anthelmintic use
What causes post-worming colic?
Follows anthelmintic treatment of horses known to have high worm burdens
Inflammation of GIT subsequent to death of large numbers of parasites
Concurrent treatment with steroids sometimes undertaken in Cyathostominosis cases
Clinical signs of Cyathostominosis in horses?
Weight loss, hypoalbuminea
Diarrhoea
Intussusceptions - caecocaecal, caecocolic
Can be associated with high mortality
Colic from large burdens of Parascaris equorum - why? other signs? Which age affected?
Small intestinal impaction -> poss rupture
Weight loss/unthriftiness
Can be associated with high mortality despite surgical intervention
Relatively common in horses in first year of life
Strong acquired immunity
Pasture management for parasite management in horses?
Poo picking - twice weekly
Co-grazing with ruminants
Rotating pasture
Anthelmintics used for: - Anaoplocephala perfoliata - Strongylus vulgaris and Cyathostomins - Parascaris equorum - Fasiola hepatica? Resistance?
Anoplocephala perfoliata - pyrantel x 2 or praziquantel
Strongylus vulgaris and Cyathostomins - resistant to BZs, 50% resistant to pyrantel, MLs effective (ivermectin, moxidectin)
Parascaris equorum - resistant to ivermectin and moxidectin and some to pyrantel, use pyrantel or BZs
Fasciola hepatica - BZs?
Conclusions from horse parasite study?
Prevalence of strongyles and P equorum presence similar
Horses 1yo or less have high P equorum FEC
Youngstock <3yo have higher FEC
No evidence of increased prevalence or intensity of infection with S vulgaris
Poss increased prevalence of A perfoliata
Greater surveillance of parasitic infection is required
Timechart for when parasites in horses need to be controlled/treated?
May-Nov: P equorum when young, then Strongyles and tapeworm as matures
June-Nov: FEC monitoring/tapeworm ELISA
Nov-April: Larval cyathostome (+bot control)
Diagnosis of parasite burden in horses?
Cyathostomins: FEC for adult stages, larval stage ELISA
Large strongyles: FEC (indistinguishable from cyathostomins), larval culture and morphological identification is time consuming/needs specialist skills, ELISA
P equorum: FEC detection of spherical thick shelled eggs
A perfoliata: FEC (centrifugation flotation 60% se), ELISA, saliva based test
Oxyuris: adults in faeces, eggs in perianal region
Oxyuris equi?
Relatively common
Causes severe irritation
Wash peri-anal region and environment - power cleaning
Resistance/poor drug efficacy
Diagnose with adults in faeces/eggs in perianal region
Indications for medical treatment of colic (in general)?
Mild – moderate pain Good response to analgesia HR <50 bpm GI motility continuing / improving No net reflux Resolving / no abdominal distension Normal peritoneal fluid Normal PCV/TP and systemic lactate
Principles of medical treatment for colic?
Analgesia
+/- oral fluids (not if net reflux due to SI obstruction etc)
+/- IV fluids/phenylephrine/psyllium/epsom salts dependent on initial diagnosis
What to consider when choosing an analgesic for colic in horses? Groups to choose from?
Potency Duration of action Sedative/other effects e.g. smooth muscle relaxation Potential side effects NSAIDs, A2 agonists, Opiates
NSAIDs as analgesia for colic in horses - options? Potency? Duration of action? Cautions?
Phenylbutazone:
- moderate potency (good as won’t mask what’s going on)
- 12h duration
- beware perivascular administration (can cause irritation, sloughing etc)
- good first line analgesic for colic cases with mild/moderate pain
Flunixin meglumine
- potent analgesia
- 12h duration
- very effective in masking increase in HR with SIRS
- should be used with caution in colic cases showing mild/moderate pain where cause is unknown
Metimazole (Buscopan compositum)
Ketoprofen
Meloxicam
A2 agonists as analgesia for colic in horses - options? Potency? Duration of action? etc
Xylazine - good analgesia - short acting up to 30 mins duration - very useful in assessment of a painful colic case Romifidine - 2-4h duration - usually combined with butorphanol - can be administered IM - useful in colic cases showing moderate-severe pain Detomidine - potent analgesia for 2-4h - usually combined with butorphanol - useful in colic cases with moderate-severe pain
Opiates as analgesia for colic in horses - options?
Butorphanol
- usually combined with a2 agonist
- an be used on its own
- useful in colic cases that are moderately/severely painful
Pethidine
- preparation licenced for use in horses with colic but uncommonly used
Morphine
- potent analgesia but not appropriate for use in colic cases seen in first opinion practice (other analgesics are available and are more suitable)
Butylscopolamine/hyoscine for colic in horses? When used?
Smooth muscle relaxant
Buscopan and Buscopan composites (combined with metimazole)
Indicated in spasmodic colic/mild colic pain
Useful when performing rectal examination where horses are strain - reduces risk of rectal tears
Why must flunixin meglumine be used with caution for colic?
Potent analgesia so signs of colic pain masked - owners may not appreciate severity of situation/may delay contacting vet again
Masks effects of SIRS (endotoxaemia) - increases in HR and PCR are delayed
Makes decision making in early stages of strangulating lesions difficult
When is flunixin acceptable for colic? When to be cautious?
Acceptable:
- when referral is not an option and horse is exhibiting moderate/severe pain (if no response seen euthanasia is appropriate)
- when an exact diagnosis is known and medical treatment is appropriate (e.g. pelvic flexure impaction)
- when the decision to refer has already been made
Be cautious:
- mild/moderate pain of unknown cause and where referral is an option
