Medical treatment of colic Flashcards
Why is colic so important in practice?
One of the most common emergencies in first opinion equine practice
List some risk factors for critical colic cases
- Pain score
- Heart rate
- CRT
- Weak pulse
- Absence of gut sounds in one or more quadrants
Describe the steps involved in approaching a colic case
- History taking
- Observation
- Clinical exam
- Assessment
- Plan
How is the plan for colic cases devised?
Results of clinical exam and further tests
-> medical or surgical colic?
- Medical = analgesia and repeat examination
- Surgical = contact referral facility asap
List the indications/clinical signs that show colic can be managed medically
- Mild/moderate pain
- Good response to analgesia
- HR <50bpm
- GI motility continuing
- No net reflux
- Resolving/no abdominal distention
- Normal peritoneal fluid
- Normal PCV/TP and systemic lactate
Why should you keep your mind open during colic cases
A diagnosis may not always be possible on the initial examination
Response to initial medical treatment and results of repeat clinical examination are key
Which diagnostic finding is always an indication for the possible need for surgery in colic cases
Non-response to analgesia
What are the key components of medical treatment for colic?
- Analgesia
- +/- oral fluids
- +/- other specific therapies based on initial diagnosis: IV fluids, Phenylephrine, psyllium
What needs to be considered when providing horses with analgesia for colic?
Potency
Duration of action
Sedative / other effects e.g. smooth muscle relaxation
Potential side effects
The 3 main analgesia agents used in colic cases are?
NSAIDs
Alpha 2 agonists
Opiates
Name 5 NSAIDs that can be used for colic cases
Phenylbutazone
Flunixin
Metimazole - Buscopan compositum
Ketoprofen
Meloxicam
Describe the features of phenylbutazone for use in colic cases
- Moderate potency
- 12 hours duration
- Beware perivascular administration
- Good first line analgesic for the colic case with mild/moderate pain
Describe the features of flunixin for use in colic cases
- Potent analgesia
- 12 hours duration
- Very effective in masking increase in HR with SIRS (endotoxaemia)
- Should be used with caution in cases of colic showing mild/ moderate pain where cause is unknown
Name 3 alpha 2 agonists that could be used in colic cases
Xylazine
Romifidine
Detomidine
Describe the features of xylazine for use in colic cases
Good analgesia
Short acting ~ up to 30 mins duration in painful colic cases
Very useful in assessment of the painful colic case
Describe the features of romifidine for use in colic cases
Around 2-4 hours analgesia in colic cases
Usually combined with butorphanol
Can also be administered IM
Useful in colic cases showing moderate – severe signs of pain
Describe the features of detomidine for use in colic cases
Potent analgesia for around 2-4 hours in colic cases
Usually combined with butorphanol
Useful in colic cases showing moderate – severe signs of pain
Name 3 opiates used in colic cases
Butorphanol
Pethidine
Morphine
Describe the features of butorphanol for use in colic cases
Usually combined with alpha 2 agonist
Can be used on its own
Useful in colic cases that are moderately / severely painful
What is the action of Butylscopolamine/Hyoscine?
Smooth muscle relaxant
What is Buscopan compositum?
Muscle relaxant combined with Metimazole (NSAID)
When is butylscopolamine indicated/useful?
- Indicated in spasmodic colic cases / mild colic pain
- Useful when performing rectal examination where horses are straining: reduces the risk of a rectal tear occurring
Why is the use of flunixin debated?
- Its a potent analgesic
- Signs of colic masked: owners may not appreciate the severity of the situation
- Masks the effects of SIRS (endotoxaemia): increases in HR and PCV are delayed
When is it acceptable to give flunixin? (3 scenarios)
- When referral is not an option & horse is exhibiting moderate / severe pain (if no response seen euthanasia is appropriate)
- When an exact diagnosis is known & medical treatment is appropriate (e.g. pelvic flexure impaction)
- When the decision to refer has already been made
In which situation would you be cautious to give flunixin?
Mild / moderate pain of unknown cause & where referral is an option
Describe the administration and uses of oral fluids
- Easy and inexpensive
- 4-6 litres water (500kg horse) / electrolytes administered q.4h by nasogastric intubation -> stimulates gastrocolic reflex
- Can place an indwelling stomach tube for continuous administration of fluids
- Provides hydration provided the horse is not refluxing
- Hydrates ingesta assisting resolution of large colon impactions
Describe the administration of IV fluids
Expensive
Does not directly hydrate ingesta – excess fluids lost by urination
Difficult to administer and monitor safely outside clinic facilities
When are IV fluids indicated?
Reflux obtained on nasogastric intubation (is there a surgical lesion?)
Severe systemic compromise & immediate systemic support needed
Describe the features and signs of spasmodic colic
- Pain due to intestinal spasm
- Undiagnosed / spasmodic colic is the most frequent diagnosis in first opinion veterinary practice
- Mild pain
- Normal cardiovascular parameters
How is spasmodic colic treated in most cases?
Butylscopolamine +/- NSAID (metimazole / phenylbutazone)
Describe the features and signs of large colon impaction
Mild / moderate signs of pain
Classic findings on rectal examination: doughy, firm structure on LHS of caudal abdomen
What is a common epidemiological clue for large colon impaction?
Recent increase in stabling due to weather/injury
How can you make sure not to confuse a large colon impaction with secondary large colon impaction?
- Corrugated feel: not smooth and large ‘vacuum packed’
- Usually a primary small intestinal lesion
- Results of initial +/- repeat assessments indicative of need for surgical management
How is a large colon impaction treated?
Oral fluid therapy via nasogastric intubation q.4h until faeces passed
Analgesia – IV flunixin meglumine appropriate
Surgery may be required in some cases
What can be added to oral fluids in large colon impaction cases? Why?
Magnesium sulphate as an osmotic laxative agent to increase hydration of ingesta
Caecal impactions may occur in horses secondary to treatment for which conditions?
Important to monitor faecal output in hospitalized horses that have been treated for a painful ocular / orthopaedic condition and received NSAIDs
Describe gastric impaction as a cause of colic
- Uncommon cause
- Variable history and presenting signs
- Medical / surgical management depends on severity of findings
- May be suspected on ultrasonographic assessment – gastric distention
How is a gastric impaction colic diagnosed?
Gastroscopy
How is gastric impaction treated?
IV fluid therapy
Repeat gastric lavage important
+/- use of carbonated drinks
Describe the medical therapy needed for large intestinal displacement/distention
- Analgesia – careful monitoring if using potent analgesia
- Light walking / trotting exercise
- Oral fluid therapy – bolus fluids as for primary large colon impaction
- Withhold feed until faeces start to be passed
When can large intestinal displacement/distention be managed medically?
Horses CV parameters normal
Degree of pain not severe
Marked gaseous distention of the large colon is absent
When is surgical intervention indicated for large intestinal displacement/distention?
Severe pain / marked or increasing gas distention of colon
Deteriorating CV parameters
Non-response to treatment
How is nephrosplenic ligament entrapment diagnosed?
Rectal examination
Ultrasonography
How does nephrosplenic ligament entrapment appear on ultrasound?
Failure to image left kidney and spleen – gas distended large colon visualised
Medical vs surgical management of nephrosplenic ligament entrapment depends on?
Initial evaluation
Medical therapy indicated if systemic status good, pain can be controlled and mild degree of gaseous distention
Describe how to medically treat nephrosplenic ligament entrapment
Phenylephrine infusion
Horse lunged for 15 mins
Repeat rectal examination to assess if LC has repositioned itself
* increased risk of haemorrhage in older horses (>15 y.o 64 x the risk) – owners should be made aware of this
When does sand colic occur?
More common in certain geographic regions
Potential to ingest sand
- Sandy soil
- Poor grazing
- Turnout on sand arenas
Why does sand cause colic?
Irritation of the colonic mucosa by sand can result in diarrhoea / recurrent mild colic
Can cause colonic impactions and colon displacement / torsion
How is sand colic diagnosed?
Sand in the faeces
Classic ‘seashore’ sound on auscultation
Sand retrieved on abdominocentesis
Ultrasonography
Abdominal radiography
Medical/surgical management of sand colic depends on?
Presenting signs of colic
How can you treat mild cases of sand colic?
Remove source of sand
Provide plenty forage
+/- psyllium added to feed intermittently
How is a medical sand colic treated?
Intensive medical treatment with Magnesium sulphate and psyllium sulphate
Monitoring of clearance using radiography
Describe the features of colic in neonatal foals
Degree of pain is less useful to assess need for potential surgery - Enteritis can present as severe abdominal pain
Ultrasound particularly valuable (+/- radiography occasionally indicated)
List the most likely causes of colic in the neonatal foal?
Meconium impaction
(Ruptured bladder)
Enteritis
SI volvulus
Congenital anomalies
How does colic in donkeys most commonly present?
Signs of dullness – uncommon to show marked signs of colic
Degree of pain less useful
Which type of colic is most common in donkeys?
Colonic impactions
What should be assessed when colic is suspected in donkeys?
Always check for dental abnormalities
May be due to ingestion of foreign materials in working equid populations
What is the main advice to give to the owners in colic cases?
- Remove feed & leave water with the horse
- Ask owners to provide an update in 2 hours, sooner if signs of colic recur
- If the horse responds to treatment: offer small amounts of food once faeces passed (and increase back to normal over around 24h)
- If the horse does not respond to treatment perform repeat visit
How can recurrence of colic be prevented?
Important to consider the potential cause of any medical episode of colic and advise the owner regarding prevention of future episodes
- Parasite testing / discussion about parasite control
- Dental examination / treatment
- General management (irregular turnout / poor feeding management)
Name 4 risk factors for recurrence of colic
Known dental problem
Crib-biting / windsucking behaviour
Weaving
Time at pasture
When should euthanasia be considered in colic cases?
- Uncontrollable pain despite potent analgesia
- Severe CV compromise: HR >90bpm
- PCV >60%: purple mucous membranes
- Gastrointestinal rupture: brown / red ingesta contaminated peritoneal fluid. Profuse sweating, sudden reduction in pain
How can you confirm gastrointestinal rupture has occurred?
- Marked, progressive increase in HR, PCV and deterioration in mucous membranes
- ‘Boarding’ of the abdomen
- Dark red / brown peritoneal fluid containing ingesta (differentiate from accidental enterocentesis)
Why does gastrointestinal rupture occur?
Frequently due to rupture of the stomach (usually along the greater curvature)
This is why nasogastric intubation can be life- saving
Hopeless prognosis even if surgery attempted
