Equine Gastrointestinal Disease Flashcards
What is colic?
Abdominal pain.
What are the signs of colic?
Rolling
Pawing
Flank watching
Lip curling
What should we clinically examine in a suspected colic patient?
Cardiovascular - heart rate/rhythm, resp. rate, PCV + TP, lactate
Abdominal - auscultation (4 quadrants), distension
Rectal - distension, impaction, displacement
Stomach tubing
Ultrasound - rectal/transabdominal
Abdominoparacentesis (belly tap) - intestinal damage, haemoperitoneum, rupture, inflammatory/neoplastic cells
Oral
Gastroscopy - ulceration, outflow obstruction, impaction
Radiography
What tests can we run on a suspected colic patient?
Blood - PCV, TP, lactate, haematology/biochemistry
Peritoneal fluid - gross appearance, cytology, protein
Faecal - egg count, culture
Glucose absorption test
Laparoscopy
Laparotomy
Describe dental disease in horses.
Eruption disorders Dental decay Periodontal disease Fractured tooth Diastema
How can we treat dental disease in horses?
Filling, widening
Rasp at least 1x a year
Removal has problems - opposite tooth has nothing to grind against (long-term management)
Or risk dysphagia, impaction from not chewing properly
How can we examine a horse’s mouth?
Watch horse eat Palpate Sedate Mouth gag Wash out Torch, mirror
What are the primary/secondary causes of oesophageal obstruction (choke) in horses?
Primary = bad luck, eating too fast, dry concentrate, poor dentition Secondary = rare, oesophageal damage, mass
What are the clinical signs of choke?
Neck extended, food/discharge from nose, cough, gag
Over time - dehydrated, acid-base imbalance, weight loss
Aspiration pneumonia
Risk acute oesophageal rupture / stricture or diverticulum long-term
How do we diagnose choke?
Auscultation Cardiovascular parameters Gastroscopy Stomach tube (Bloods, ultrasound, plain/contrast radiography)
How do we treat choke?
Sedate - low head carriage = reduced risk of aspiration
Stomach tube, lavage obstruction via tube
Check obstruction cleared, no damage to mucosa, no aspiration, underlying problems?
Rest from feeding, start with mash and grass
May need antibiotics and anti-inflammatories
What are the causes of gastroduodenal ulceration?
Imbalance between inciting and protective factors
Inciting = HCl, bile acids, pepsin
Protective = mucus-bicarbonate layer, mucosal blood flow, mucosal prostaglandin E, epidermal growth factor production, gastroduodenal motility
Risk factors = empty stomach exercise, diet, stress, NSAIDs, hospitalisation
What are the clinical signs of gastroduodenal ulcers?
Range from asymptomatic
Poor appetite, recurrent colic, tooth grinding, dog sitting, diarrhoea, poor performance
How do we diagnose gastroduodenal ulcers?
Gastroscopy (foals difficult as too small)
Remember ulcers are common, therefore presence does not mean significance/cause of clinical signs!
How do we treat gastroduodenal ulcers?
Depends on cause
Management
Adult = omeprazole (or misoprostal off licence)
Foals = sulcralfate
What are the primary causes of gastric dilation and rupture?
Gastric impaction (acute/chronic colic, difficult to treat)
Grain engorgement
Etc.
What are the secondary causes of gastric dilation and rupture?
More common
Small or large intestinal obstruction
Ileus (secondary, equine grass sickness)
What are the clinical signs of gastric dilation and rupture?
Overfilling of stomach Acute colic Tachycardia Fluid from nose (right before rupture!) Dehydration
How do we diagnose gastric dilation and rupture?
Clinical signs
Reflux
Colic work-up
Gastroscopy
How do we treat gastric dilation and rupture?
Stomach tube!! Treat underlying cause IV fluids Nil per os - IV nutrition Electrolytes
Describe anterior enteritis (SI).
Inflammatory condition affecting proximal small intestine
Most cases = underlying aetiology cannot be determined
Some = salmonella or clostridia cultured from gastric reflux
Recent diet change to high concentrate is a risk factor
What are the clinical signs of anterior enteritis?
Distended small intestine and stomach
Signs same as gastric dilation
Often pyrexic
How do we diagnose anterior enteritis?
Colic investigation:
Peritoneal fluid = raised protein but not serosanguinous
Reflux - culture
Often need ex-lap
How do we treat anterior enteritis?
Repeated gastric decompression (life-saving!)
Antibiotics - penicillin, gentamicin, metronidazole
IV fluids
Electrolytes
Nil per os - nutritional support
Analgesia
Ex-lap, SI decompression
What is the main clinical sign of SI malabsorption and maldigestion?
Weight loss!
How do we diagnose SI malabsorption and maldigestion?
Abdominoparacentesis
Ultrasound
Oral glucose tolerance test (not absorbed)
Laparoscopic biopsy
How do we treat SI malabsorption and maldigestion?
Method depends on diagnosis
Prognosis depends on diagnosis and response to treatment
Resection? Corticosteroids?
May be no treatment
Describe a simple SI obstruction.
Obstruction of lumen without direct obstruction of vascular flow
Food material - coarse, ileal hypertrophy (secondary to tapeworm)
Ascarid impaction
Adhesions
Describe a strangulation SI obstruction.
Simultaneous occlusion of intestinal lumen and its blood supply
Pedunculated lipoma, epiploic foramen entrapment, SI volvulus, mesenteric rent, inguinal/diaphragmatic hernia, intussusception
Results in gastric overfilling - risk rupture
Deterioration of intestinal mucosa
What are the clinical signs of SI obstruction?
Colic - severe as gut dies, eases when gut dead
Reflux
Tachycardia
Hypovolaemia
Rectal - distended small intestine
Peritoneal fluid - serosanguinous, increased protein/lactate
How do we treat SI obstruction?
Surgery/euthanasia
Rarely, ileal impaction can clear
Act fast!
What are the primary/secondary causes of caecal impaction?
Primary = ? underlying motility disorder Secondary = usually young horses after painful orthopaedic procedures (monitor faecal output/appetite/pain level after any surgery)
What are the clinical signs of caecal impaction?
Colic
Can just rupture - signs of severe shock, death
How do we diagnose caecal impaction?
Clinical signs and history
Rectal exam
Abdominoparacentesis
How do we treat caecal impaction?
Medical vs surgical
Oral and IV fluids
Surgery = typhlotomy / caecal bypass
Describe caecal intussusception.
Ileo-caecal or caeco-caecal
Young horses
Tapeworm
What is the main clinical sign of caecal intussusception?
Colic - varying severity, can be chronic
How do we diagnose caecal intussusception?
Rectal exam
Ultrasound
Peritoneal fluid unreliable!
How do we treat caecal intussusception?
Surgery
Then treat tapeworm
Describe impaction of the large intestine (LI).
Usually pelvic flexure
Food material
Poor teeth, long fibre, motility disorder, recent box rest, sand
What are the clinical signs of LI impaction?
Usually mild colic, can be chronic
Reduced faecal output
How do we diagnose LI impaction?
Rectal exam
Abdominoparacentesis
How do we treat LI impaction?
Oral fluids and cathartics Analgesia Paraffin? IV fluids? Eventually surgery
Describe LI displacement.
Right/left dorsal displacement
Nephrosplenic entrapment
Can: correct itself +/- medical treatment, remain displaced and become compromised (needs surgery), torsion (emergency surgery)
How do we diagnose LI displacement?
Rectal exam
Ultrasound - nephrosplenic entrapment
Abdominoparacentesis
How do we treat LI displacement?
Medical if not too painful and no evidence of gut damage - fluids oral/IV, analgesia, nephrosplenic entrapment = phenylephrine and lunging
Otherwise surgery, or if persistent
Describe LI torsion.
Strangulating lesion of LI
Extreme pain, violent horse
Distended abdomen
Respiratory compromise
How do we diagnose LI torsion?
Rectal exam
How do we treat LI torsion?
Immediate surgery
Prognosis depends on damage to LI
LI resection?
Risks recurrence
How do we diagnose LI diarrhoea?
Cardiovascular parameters Rectal exam Ultrasound Abdominoparacentesis Rectal biopsy Faecal egg count/cultures
How do we treat LI diarrhoea?
Hydration Electrolytes Anti-endotoxic Laminitis prevention Antibiotics? Plasma? Feeding Nursing care! - clean, treats, groom
Describe small colon impaction.
Quite rare
Foreign body (e.g. plastic bags), salmonella
Difficult to diagnose - intermittent diarrhoea and colic
Can try medical treatment
Many require surgery
Describe peritonitis.
Primary = pyrexia and mild colic, abdominoparacentesis, antibiotics, laparoscopy/laparotomy if persistent or recurrent Secondary = intestinal surgery contamination etc.
What colic findings would imply possibly surgical treatment?
Moderate-severe pain
Persistent behavioural signs despite analgesia
Absence of faeces
Heart rate > 60 bpm
Poor MM colour
Reduced/no gut sounds on auscultation
Rectal - distension +/- displacement of S/L intestine
Increased PCV/TP/lactate
Positive reflux with nasogastric tubing (more than 2L)
Distended SI/displaced LI on ultrasound
Discoloured and turbid peritoneal fluid on abdominoparacentesis
What practicalities of surgery need to be considered?
Cost - unsuccessful cases likely to end in dead horse + big bill
Transport of horse to surgery
Prognosis - hard to be sure pre-surgery
Complications many/common - owner awareness from outset
How do we prep a horse for colic surgery?
Jugular IV catheter placement
Decompress stomach with nasogastric tube (‘refluxing’)
Administration of analgesia/antimicrobials
IV fluids to support circulation
Clip abdomen?
Shoe removal/tape feet
Wash out mouth
How can we carry out refluxing with nasogastric tubing?
Horse restrained - stock/twitch/sedation (xylazine)?
Tube passed into ventral nasal meatus
Head flexed to encourage passage into oesophagus not trachea
Horse swallows as tube advanced
Observe left-hand side of neck for end of tube advancing into oesophagus to confirm correct placement (critical!)
Pass down into stomach - if no spontaneous reflux establish syphon by attaching funnel to end of tube and pouring in measured amount of water from jug and then lowering end of tube into bucket, collect and measure what comes out
How do we prep a horse for laparotomy?
After induction
Move to table from recovery box - place in dorsal recumbency for ventral midline incision
Urinary catheter (suture prepuce in males)
Clip abdomen plus second fine clip
Cover legs and feet
Drape
Sterile skin prep
Surgical colic kit - different surgeons have different instrument preferences
Describe simple intestinal obstructions.
Lumen only obstructed (e.g. food), vasculature minimally compromised
Prognosis usually good
E.g. pelvic flexure impaction
Describe functional intestinal obstructions.
Peristalsis fails to propels ingesta (i.e. ileus) leading to distension
E.g. grass sickness/post-operative ileus secondary to distension
Describe strangulating intestinal onstructions.
Compromise of vasculature resulting in ischaemia of intestine
E.g. pedunculated lipoma/large colon volvulus
Veins obstructed first, causing oedematous thickening of gut wall
Release of endotoxins into circulation (endotoxaemia) - systemic compromise/shock
Prognosis increasingly poor after 6-8hrs
Later secondary problems e.g. laminitis - further worsen prognosis
Describe SI strangulating obstructions.
Strangulated section goes maroon/purple/black as blood supply compromised
Mucosa becomes permeable to endotoxins which leak into peritoneal cavity/circulation
Proximal = ‘simple obstruction’ with just distension as gas/fluid cannot pass obstruction
Distension will however cause ileus if protracted which can be hard to reverse
Distal = intestine appears relatively normal
Which specific conditions cause a SI strangulating obstruction?
Pedunculated lipomas
Herniation - epiploic foramen/inguinal/mesenteric defects
Intussusceptions
How do we resect and anastomose SI to treat a strangulating obstruction?
Isolate affected segment with bowel clamps
Ligate blood vessels supplying affected segment
Resect affected segment
Anastomose intestine with sutures/staples
Close defect in mesentery to prevent herniation
Check patency of lumen, integrity of anastomosis (no leaks) and mesentery (no holes)
Lavage and remove packing
Decompress remaining bowel
Replace bowel in abdomen
Describe SI simple/functional obstructions.
E.g. ileal impaction/enteritis
Decompression of SI +/- enterotomy to remove obstruction
Non-strangulating so blood supply not compromised
No resection or anastomosis required
What are the common LI obstructions?
Displacements (left dorsal/nephrosplenic entrapment, right dorsal)
Large colon torsion
Enteroliths (not common in UK)
How do we surgically manage colonic displacements?
Recognising nature of displacement
Decompression of distended bowel (needle/suction for gas)
Evacuation of colon via pelvic flexure enterotomy may be necessary if distension is with food/fluid
Correction of displacement
Resections rarely necessary and technically challenging
Colopexy (anchoring colon by suturing e.g. to body wall) occasionally performed in non-athletes to prevent recurrence of displacement
Describe large colon volvulus.
Commonly a strangulating obstruction with ischaemia of huge section of GI tract
May occur at sternal flexure or close to attachment of right ventral colon to cecum
Results in great deal of gas distension of affected colon
Usually affects larger horses and particularly seen in brood mares ~90 days after foaling
What are the clinical signs of large colon volvulus?
Sudden and sever abdominal pain
Colon extremely enlarged, very evident on rectal exam
Mucosal ischaemia leads to endotoxinaemia and systemic status deteriorates rapidly
High heart rate, poor peripheral perfusion
How do we treat large colon volvulus?
Surgery to correct the problem and remove ischaemic colon if necessary
What is the prognosis for large colon volvulus patients?
Directly related to time that elapses between onset of condition and surgery
As a result, survival rates much higher for veterinary facilities located near e.g. brood mare farms
What post-op care can we provide for equine GI patients?
'Colic check' every 2-4hrs Analgesia Antimicrobials IV fluid therapy Belly bandage Monitoring for complications Regular blood sampling - PCV, TP, lactate Nasogastric intubation
What are the potential post-op complications?
Endotoxinaemia Ileus Jugular thrombophlebitis Incisional infection Further obstruction Anastomosis leakage Peritonitis Adhesions
What should we be monitoring post-operatively?
Pain - behavioural signs, HR, specific e.g. peritoneal/incisional/MSK
Pyrexia (rectal temp.)
GI system - reflux through NG tube, faecal output, gut sounds, appetite
Cardiovascular - HR, MM colour/CRT, PCV/TP/lactate/electrolytes
Incision - swelling, pain, discharge
Catheter - swelling, pain, jugular patency
Feet - mobility, digital pulses, heat
Respiratory - auscultation, rate, nasal discharge/cough
How do we provide post-op feeding?
If significant reflux on passing NG tube - nil by mouth, IV fluid therapy, muzzle to prevent horse eating bedding
Once reflux ceased/parameters improving, start with 5cm depth water in bucket (gradually increase)
Grass = good first solid food
Small wet mashes of concentrates, less appetising
Hay reintroduced in handfuls, gradually increased
Return to normal volumes over ~3 days
What post-op exercise is allowed?
Initially box rest for 6 weeks, maybe very short walks in hand to allow grazing/promote GI motility
Check no incisional problems (e.g. breakdown of underlying abdominal wall) - may require prolonged restriction
At 6 weeks can turn out into small paddock for further convalescence
Ridden exercise may resume after 3 months if abdominal repair sound
What are the potential post-op complications?
Immediate = endotoxaemia, ileus Short-term = laminitis, jugular thrombophlebitis, peritonitis, colitis, incisional infection Longer-term = adhesions
What are the clinical signs of endotoxaemia?
Tachycardia, tachypnoea
Pyrexia leading to hypothermia
Hyperaemic MMs leading to dark purple/brown
Colic signs, dullness
How do we treat endotoxaemia?
IV fluid therapy
Flunixin
Polymixin B
Hyperimmune plasma
How do we treat ileus?
Nasogastric intubation, refluxing - gastric decompression to relieve gastric distension
Fluid IV - maintenance + dehydration correction + 80% net reflux losses
Supplement electrolytes if needed
Prokinetics? - lidocaine infusion/erythrocytes/metoclopramide
Describe laminitis.
Inflammation of laminae
Endotoxic horses at greatest risk
Prevention attempted - ice boots on at-risk patients
Clinical signs = increased/bounding digital pulses, heat, foot pain
Treatment = frog support/deep bedding, analgesia
How do we treat jugular thrombophlebitis?
Remove catheter
Local anti-inflammatory treatment
Can consider thrombolytics such as aspirin
Antibiotics?
Catheter not placed in other jugular - alternative site if IV access still required
Describe signs and treatment of peritonitis.
Clinical signs = colic, inappetence, pyrexia
Antibiotics (broad spectrum, often penicillin/gentamycin/metronidazole)
Abdominal drainage/lavage?
What are the clinical signs of colitis?
Clinical signs = pyrexia, colic, diarrhoea
After colon torsion/displacement, where colon has been compromised
From antibiotics and NSAID usage plus sudden change in management
How do we treat colitis?
Can require intensive nursing IV fluid therapy Analgesia - may need to avoid NSAIDs Misoprostal and sucralfate may help Probiotics?
Describe incisional infection.
Occurs in 10-15% of cases, more common after 2nd laparotomy
Local oedema around incision is normal
Palpate for focus of pain
Look for drainage of purulent material
How do we treat an incisional infection?
Antibiotics if horse systemically affected, e.g. pyrexia
Culture for sensitivity
Encourage drainage
Tends to persist until suture material resorbs (~6 weeks)
Describe adhesions.
Consequent on surgery/general handling of intestines at surgery
May result in further obstruction and colic
Recurrence of significant colic often ends in euthanasia, as owners reluctant to put horse through further surgery for which prognosis likely to be guarded at best
