Caroline Spelta equine health Flashcards
GIT, Neuro, haemat, card, resp
(five observations in each categorie; mild, modertae and severe).
Describe signs of mild, moderate and severe signs of colic in the equine ?
Colic is not a disease but a syndrome (signs of colic)
Mild colic
- inappetence
- restlessness
- weight shifting
- flank watching
- stretching out
- posturing to urinate
- intermittent pawing
Moderate colic
- continuous pawing (front foot)
- head tossing
- penile protrusion
- yawning
- flehmening
- up and down
- dog sitting
- kicking at abdomen
Severe signs of colic
- violent pawing
- violent rolling
- collapsing / throwing themselves on the ground
- refusal to stand frim lateral recumbency
Identify a minimum of ten differentials for colic ?
Differentials for colic
(any condition which causes abdominal pain)
GIT
- stomach; ulcers, choke
- small intestine; endotoxaemia, hernia, volvulus, intussusception, IBD, ileus
- colon; sand impaction, right/left dorsal displacement, infarction, colitis
- distension, ischaemia and inflammation
Distension
- abnormal gas production / obstruction
- impaired motility / ileus
- extraluminal compression causing obstruction, neoplasia
- ischaemia, strangulation
extra-abdominal
- hepatic pain
- renal pain
- urinary system pain
- peritoneal pain
- reproductive system pain eg dystocia, testicular torsion
- laminitis
- cardiovascular; heart failure
- neurological; hendra, botulism
- metabolic hypocalcaemia
Describe why horses are predisposed to colic ?
Colic is the most common
Horses hind gut fermenter
Predisposition
Very large fermentative vat
- unable to reructate from fermentative vat
Domestication
- changed diet
- changed use / housing / management
Poor gastrointestinal design
- U turns, pelvic flexure
- Bottlenecks caecocolic valve
You identify colic; what follow up diagnostic tests could be utilised ?
Colic; Follow up diagnostic tests
- Baseline
- Baseline values can be used to measure the horses response to treatment
- Temperature 37-38.5
- HR 36 +/- 10
- Respiratory rate 12 +/- 4
- Gut sounds +<2sec, digital pulses +
- pressence of manure its volume and consistency
- abdominal contour
- auscultation, percussion and succussion (ping for gas on the right caecum)
- secondary complications - Nasogastric tubing
- Abdominal palpation per rectum
- Abdominocentesis - fluid analysis and cytology
- Abdominal ultrasound
- Gastroscopy
Describe the indication and safe technique for nasogastric intubation ?
Nasogastric intubation
Indication - pain
- primary indication is gastric decompression / comfort / effective pain relief
- horses stomach is only 10-15L
- evidence of apin
- tachycardia >60bpm pass stomach tube immediately
- provides an effective pain relief in cases of stomach distension
- if significant reflux returned, leave the tube in place with a one way valve (glove finger slit tip)
**
Procedure**
- Two bucket technique “in” and “out”
- use clean water in one bucket and put reflux into second bucket
- Total reflux = initial clean water - net reflux
- Significant reflux >4.5 L
Equine; Describe how you would carry out abdominocentesis ?
Abdominocentesis
Abdominocentesis of peritoneal fluid - changes in health of organs, especially intestine reflected as physical and cytological changes in fluid.
Can be used to differentiate
1. Intestinal injury (predominately small intestine); inflammation, ischaemia
2. Peritoneal cavity disease; - Peritonitis, bowel
Procedure
- lignocaine / local anaesthetic
- most ventral aspect of the linea alba, midline to slightly to the right (spleen located on the left)
- teat cannula or 18 guage needle
Sample collection
- Lithium heparin (green) = lactate, biochemistry
- EDTA; cytology
- Plain tube (red); bacterial culture
Describe your baseline for a physical examination of a horse ?
Physical exam - The key items
Temperature 37-38.5
Heart rate 36 +/- 10
Respirator 12 +/- 4
CRT <2 sec
Gut motility and digital pulses
- Demeanor
- Mucous membranes - colour, CRT
- GIT sounds = (borborygmi), absent vrs present, hypomotile, herpermotile, ileocaecal flush
- peripheral pulse qaulity
- Abdominal contour
- Abdominal auscultation, percussion and succussion (ping for gas distended viscus (caecum on the right).
- Always assess for secondary complications.
How can naso gastric intubation be useful diagnostically ?
Objective measurements and findings
- Pain relief
- reflux present or absent (gastric accumulation or retrograde flow from the small intestine).
- normal volume 1-2 L
- if significant reflux leave the tube in
Assess PH
- Acidic = gastric outflow obstruction
- Alkaline = small intestine - retrograde flow
- Clinical response alleviation of pain and resultant decrease in heart rate.
What can a clinician detect upon rectal palpation in the horse ?
Abdominal palpation per rectum
Safety first - palpation of painful structures can elicit significant injury to the Veternarian.
What can we identify
- bowel distension; large vrs small
- pressence of tight bands (displacement or volvulus)
- large or small colon impactions
- masses or hernias
- ruptured viscus (bowel perforation) - loss of negative pressure and gritty serosa
Left dorsal quadrant
- caudal edge of the spleen
- nephrosplenic space
- nephrosplenic ligament
- left kidney
Identify potential issues with abdominal centesis ?
Complications of abdominocentesis
Enterocentesis
- seeding of bacteria into the peritoneal cavity (peritonitis)
- most commonly occurs in cases of large intestinal impaction
- broad spectrum antibiotic therapy - 5 days
Splenic tap
- sample PCV > systemic PCV
- unlikely to result in life threatening complication
- possible to induce splenic rupture
Omental evisceration
Haemorrhage
Describe what we should observe in a healthy patients peritoneal fluids ?
Normal peritoneal fluid
Colour
- normal; pale yellow / straw coloured
- blood may indicate; latrogenic contamination, splenic tap, diapedesis of RBCs
**
Transparency**
- normal is clear, should be able to read the news paper through sample
- Turbid; increased nucleated cells or inflammation
Protein
normal <20g/L
- high abdominal fluid protein - intestinal injury
Cytology
TNCC < 5 x 10^9 cells/L
normal; mononuclear (macrophages, some lymphocytes and non degenerate neutrophils
- peritoneal inflammation > 5 x 10^9 cells/L
- Bacterial peritonitis/ toxic change >25 x 10 ^ 9
- haemorrhage
Microbiology (red cap plan tube)
- bacterial culture and susceptability
Lactate (Ischaemia)
- Lactate is an indicator of tissue ichaemia normal <2m(mol/L
- Must compare plasma lactate to pertoneal lactate
- Plasma; reflects every body organ
- Peritoneal fluid; ultrafiltrate of plasma
- Peritoneal lactate >1.5x plasma lactate
- suggestive of local production of lactate within the abdominal cavity (ie tissue ischaemia)
Describe the indications and procedure procedure for gastroscopy / Duodenoscopy ?
Gastroscopy / Duodenoscopy
Indications
- recurrent colic
- poor performance
- notusually indicated in an acute colic episode
Procedure
- horses require 16 hours of fasting
- evaluation of stomach and proximal duodenum
- 3m scope required (adult horses)
- Detection of; gastric tumours, gastric emptying defects, impactions, equine gastric ulcer syndrome (EGUS)
Describe PCV / TP in the equine patient ?
PCV / TO
Simple and useful diagnostic test
PCV (Packed cell volume)
High indications
- haemoconcentration, splenic contraction (adrenaline) primary increase in red cell mass
- >54% at admission = increased mortality
- Low indications
- haemorrhage, haemolysis, failure of production
PCV must always be assessed in conjunction with total protein
- there may be multiple problems occuring in the same patient
- dehydration ^ PCV and TP
NSAIDS; Provide three examples, mechanism of actions, and dosgae in the equine patient ?
NSAIDS
MOA
- inhibition of the enzyme cycloxogenase COX, preventing the production of prostoglandins.
**
Flunixin meglumine**
- most effective NSAID for visceral and (occular pain)
- analgesic, anti-pyretic and anti-inflammatory
- reliable and predicatable analgesic effect
- onset: 15 mins
- duration 12 hours
- 1.1 mg/kg dose IV/PO q 12h
- never administer IM = clostridial myonecrosis
Meloxicam
- only licensed NSAID for use in foals
- no adverse effects at 2x dose for 7 days
- less inhibition of small intestinal mucosal repair after ischaemic injury than flunixin
- 0.6 mg/kg IV or PO (never IM)
Phenylbutazone
- most effective for musculoskeletal pain, fair soft tissue analgesia
- increasing dose does not increase analgesic effect (but will prolong duration until elimination)
- ideally no doses less then 12 hours apart
- 2.2-4.4 mg/Kg IV or PO (never IM)
More is not better - there is ceiling effect of analgesia (If your NSAID is not working, reconsider diagnosis +/- implement other analgesic protocol)
Provide examples of alpha-2 agonists and their indications, duration of action and potential contraindications ?
Alpha-2 Agonist (Treatment analgesia)
Sedatives, but effective short duration
- useful to give immediate control of signs of abdominal pain and allow diagnostic procedures to be performed safely.
Duration of action
- Xylazine; 20 mins
- Romifidine; 30 mins
- Detomidine; 30-45 mins
Disadvantages / Contraindications
- profound decrease in GIT motility as well as cardiovascular and respiratory depression
- ataxia
- increased sweating and urine production
- violent behaviour (RARE) = Alpha 2 angries
Provide an example, MOA and contraindication for the use of opiods in horses ?
Horses Opiods (treatment, analgesia)
Effective analgesics
Butorphanol 0.02-0.1 mg/kg IV q 4-12 hrs
Significant side effects
- agitation and hyperexcitability
- always administer in conjunction with an Alph-2 agonist (the only exemption is a really sick horse)
- inhibition of gastrointestinal motility - decreases faecal output.
Describe the MOA, action and contraindication of Lignocaine ?
Lignocaine
MOA; Na channel blocker
Administration / effect
Local anaesthetic; intrarectal (topical)
- 20ml of 2% solution, increases rectal wall
- compliance
- may aid abdominal palpation and reduce rectal tear
1.3 mg/kg IV bolus
- analgesic, antiinflammatory - prokinetic (small intestine)
- reduces factors that may inhibit intestinal motility
Contraindication (Toxicity)
- skeletal muscle tremors, ataxia, seizures, collapse, and cardiac arrest
- care to not overdose (especially hypoproteinaemic patients)
Describe the action and contraindication in the use of parafin oil ?
Parafin oil (mineral oil)
Actions
- measure of GIT gastrointestinal time
- 18hr, oil staining around the perineum
- 1-2 L
- takes up space where water could be administered
Contraindications
- hind leg dermatitis, cellultis if large volumes administered
- aspiration could cause a fatal pneumonia
Reccomned laxatives for use in the equine patient ?
Laxatives for use in the equine patient
Magnesium sulphate
- irritant cathartic
Dioctyl sodium succinate (DSS)
- surface active agent with wetting and emulsifying properties
- reduces surface tension and allows water and fat to penetrate ingesta
Never co administer with Parafin oil - will faciliatte absorption of parafin into the circulation !
Describe the component of a gram negative bacteria that results in endotoxaemia; and its structural components ?
Endotoxin - Lipopolysaccharide (LPS)
Endotoxin - is the structural components of the outer layer of gram negative bacteria (Lipopolysaccharide)
- which comprises 75% of the outer cell wall
- heat stable, in contrast to secreted toxins
- functions in the bacteria as a permeability barrier
Structural components
O specific chain
- highly variable between between different bacteria serotypes
- determines immunospecificity
Core polysaccaride region
- linking section conserved between strains
Lipid A
- highly conserved amongst all gram negative bacteria
- anchors LPS to the outer membrane
- is the toxic principle of LPS.
Describe the pathophysiology of endotoxaemia in horses ?
Pathophysiology of endotoxaemia in horses.
(Pressence of endotoxin in the blood stream)
- Endotoxin released
- rapid bacterial replication or death
- bacteraemia (gram-ve in circulation), localised infection, endogenous / exogenous from GIT, translocation - Endotoxin is absorbed across the gut barrier
- facilitated by damaged gut barrier function - Endotoxin becomes free in the blood stream
Innate immune response - pattern recognition
Sepsis
- systemic inflammatory response to bacterial infection
SIRS - Systemic inflammatory response **syndrome **
- A general systemic inflammatory process independant of cause
**MODS Multiple organ dysfunction syndrome **
- Insufficiency of two or more organ systems eg. azotaemia
**MOFS Multiple organ failure syndrome **
- Failure of 2 or more organ systems eg laminitis, DIC
Describe how an acute injury to the equine GIT may predispose to endotoxaemia ?
Endotoxin / LPS and the GIT
Acute gastrointestinal injury (colic) increases GIT permeability to LPS.
Permeability increased;
- GIT rupture
- local ischaemia; stangulating lipoma
- inflammation; anterior enteritis
- systemic acidosis
- LPS detected in up to 40% of colic cases at admission.
Describe the deleterious effects of endotoxin pressence in the blood stream ?
The deleterious effects of endotoxin in horses
- Interact with mononuclear phagocytes (monocytes and macrophages).
- cytokines
- Eicosanoids
- Tissue factor
- Kinins
- free radicals - Endotoxin contacts blood plasma
- endotoxin interacts with normal plasma and tissue proteins to initiate enzymatic reactions.
- important mediators of inflammatoionand haemostasis
- margination, activation and extravasation of neutrophils
- neutropenia
Inflammation = protective + destructive
Define and describe (CARS) the bodys response to endotoxaemia ?
Cars ( Compensatory anti-inflammatory response syndrome)
Most horses don’t die - CARS
- stimuli evoke with delayed kinetics anti-inflammatory molecules that rein in the inflammatory response and restore homeostasis.
- horses at this stage are susceptable to opportunistic infections
