PATHOLOGY - Equine Gastrointestinal Disease Flashcards

1
Q

What are the general clinical signs of dysphagia in horses?

A

Gagging
Neck stretching
Nasal regurgitation
Slow feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some of the causes of dysphagia in horses?

A

Epiglottic entrapement
Glossitis
Temporohyoid osteoanthropathy
Palatoschisis
Guttural pouch diseases
Equine grass sickness
Linear oesophageal ulceration
Choke
Secondary oesophageal obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is one of the most common forms of epiglottic entrapement?

A

Aryepiglottic fold entrapement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some of the common causes of glossitis in horses?

A

Tongue foreign body
Tongue neoplasia
Sialoliths

Can cause glossitis which can progress to abscesses and necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can you diagnose the cause of glossitis in the horse?

A

History
Clinical signs
Thorough oral examination
Probe any tracts detected at the tongue
Radiography/CT to determine the extent of damage
Biopsy and histopathology (to rule out neoplasia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you manage glossitis in the horse?

A

Debridement and lavage of any tracts to remove any foreign material
Topical and systemic antibiotics (inc. metronidazole)
Nutritional support
Fluid therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is temporohyoid osteoarthropathy?

A

Temporohyoid osteoarthropathy is where there is fusion of the temporohyoid joint (the joint between the hyoid apparatus and the skull). The hyoid apparatus is connected to the tongue and larynx and thus this can result in pain and reduced mobility of these structures. This can eventually result in fractures at the level of the temporohyoid joint which can cause damage to cranial nerves VII and VIII which run near this joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the clinical signs of temporohyoid osteoarthropathy?

A

Dysphagia
Head tilt (due to CN VII invvolvement)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you definitively diagnose temporohyoid osteoarthropathy?

A

Radiography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do you treat temporohyoid osteoarthropathy?

A

Ceratohyoidectomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a ceratohyoidectomy?

A

A ceratohyoidectomy is the surgical removal of the ceratohyoid bone which will reduce the force applied from the hyoid apparatus to the skull to reduce the risk of further fractures and to decrease pain and discomfort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is palatoschisis?

A

Palatoschisis is a term for a cleft palate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the clinical signs of palatoschisis in horses?

A

Difficulty nursing
Nasal regurgitation
Dysphagia
Clinical signs of aspiration pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you treat palatoschisis in horses?

A

If horses with palatoschisis survive to adulthood you can medically manage their condition and monitor carefully for any signs of aspiration pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the anatomy of the guttural pouches

A

The guttural pouches have medial and lateral regions seperated by the stylohyoid bone. The medial sections of the guttural pouches have CN IX, X, XI and XII running through them along with the internal carotid artery. The lateral sections of the guttural pouches have CN VII and the external carotid artery running through them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can disease within the guttural pouches cause dysphagia?

A

Disease within the guttural pouch can cause compression of CN IX (glossopharyngeal nerve) which can result in dysphagia

Guttural pouch mycosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can cause linear oesophageal ulceration?

A

Lineal oesophageal ulceration is caused by prolonged gastroesophageal reflux

This can be due to a gastric outflow obstructions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is one of the key signs of linear oesophaeal ulceration?

A

One of the key signs of linear oesophageal ulceration is extreme pain on passage of a nasogastric tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the most common oesophageal disease in horses?

A

Choke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is choke?

A

Choke is a simple oesophageal obstruction usually due to horses eating too fast or due to a foreign body obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the most common sites for a simple oesophegeal obstruction resulting in choke?

A

The most common sites for a simple oesophageal obstruction resulting in choke include the proximal oesophagus near the pharynx, the oesophagus as it runs through the thoracic inlet and the oesophagus as it runs into the cardia of the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the clinical signs of choke?

A

Dysphagia
Nasal regurgitation
Coughing
Clinical signs of aspiration pneumonia

Note the typical appearance of greenish, food containing nasal regurgitation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do you diagnose choke?

A

History
Clinical signs
Palpate the oesophagus (if the horse is resentful of this, it could indicate choke)
Pass a nasogastric tube (if you cannot pass the tube this can indicate oesophageal obstruction and choke)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When should you consider radiography when investigating choke?

A

Radiography is indicated if the horse has had choke for over 12 hours to assess for any complications of choke and the degree of aspiration pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do you treat choke?

A

Heavily sedate the patient to allow their head to drop - this will help with drainage . Gently pass a nasogastric tube and gently lavage to try and clear the obstruction. You may have to repeat this several times to fully clear the obstruction. Make sure to remove any feed and bedding from the stable during this process and leave the horse with only access to water. Administer broad spectrum antibiotics for aspiration pneumonia and NSAIDs for analgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

When should you refer a choke case?

A

You should refer a choke case if you are unable to clear the obstruction after 24 hours or if there are significant complications

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the potential complications of choke?

A

Aspiration pneumonia
Oesophageal ulceration
Oesophagitis
Oesophageal strictures
Oesophageal perforation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What should you do if there are any indications of complications secondary to choke?

A

Endoscopy for further investiagtion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are the clinical signs of an oesophageal perforation?

A

Swelling at the site of rupture
Pain at the site of rupture
Subcutaneous emphysema
Cardiovascular collapse if there is mediastinitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do you diagnose oesophageal rupture?

A

Contrast radiography
Endoscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How do you treat an oesophageal rupture?

A

If the rupture is at the cervical oesophagus you can surgically debride any necrotic tissue, place a drain to try and prevent mediastinitis and an oesophagostomy tube distal to the rupture site for feeding the horse, and monitor for sepsis and endotoxaemia. However, be aware that most oesophageal rupture cases require euthanasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is secondary oesophageal obstruction?

A

A secondary oesophageal obstruction results from damage to the oesophagus (i.e. due to previous choke or injury to the neck) or due to congenital conditons (usually connective tissue disorders) which result in the formation of diverticula or strictures which will cause secondary oesophageal obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which breed of horse is predisposed to connective tissue disorders which can result in secondary oesophageal obstruction?

A

Friesian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the two forms of diverticula which can cause secondary oesopheal obstruction?

A

Pulsion diverticulum
Traction diverticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is a pulsion diverticulum?

A

A pulsion diverticulum is where there is increased intraluminal pressure within the oesophagus causing the oesophageal wall to protrude and form an outpouching known as a pulsion diverticulum. Feed can become trapped within this diverticulum and cause a secondary oesophageal obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is a traction diverticulum?

A

A traction diverticulum is where there is an increased pulling/stretching (traction) force exerted on the oesophagus causing the oesophageal wall to protrude and form an outpouching known as a traction diverticulum. Feed can become trapped within this diverticulum and cause a secondary oesophageal obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the clinical signs of oesophageal obstruction secondary to oesophageal diverticula?

A

Recurrent clinical signs of choke which worsen with age due to further weakening and outpouching of the oesophageal wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How do you diagnose oesophageal diverticula?

A

Endoscopy
Barium contrast radiography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How do you treat oesophageal diverticula and secondary oesophageal obstruction?

A

Surgical intervention can be considered for cervical oesophageal diverticula to remove the obstruction and correct the diverticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How do you diagnose an oesophageal stricture?

A

Endoscopy
Barium contrast radiography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

How do you treat oesophageal strictures?

A

Serial boughienage (balloon dilatation) unless it is a full thickness stricture which would require a oesophagomyotomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is an oesophagomyotomy?

A

An oesophagomyotomy is a longitudinal incision of the oesophageal muscle, whilst leaving the oesophageal mucosa intact, where the stricture is located to allow for widening of the oesophegeal lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are the most significant gastric parasites in horses?

A

Gastrophillus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How do you treat gastrophillus?

A

Ivermectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the risk factors for acute gastric dilatation in horses?

A

Excess feeding
Feed which triggers excessive fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the clinical signs of acute gastric dilatation?

A

Severe colic
Reflux
Tachycardia
Clinical signs of endotoxaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the clinical signs of endotoxaemia?

A

Toxic lines
Congested mucous membranes
Profound depression
Tachycardia
Initially brisk CRT then prolonged
Pyrexia then hypothermia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the main complication that can be seen with acute gastric dilatation?

A

Gastric rupture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How do you diagnose acute gastric dilatation?

A

You can diagnose acute gastric dilatation based on clinical signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How do you treat acute gastric dilatation?

A

Gastric decompression with a nasogastric tube
Intravenous fluid therapy
Management of endotoxaemia
Gastroprotectants (risk of ulceration)
Small frequent meals, Pelleted feed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What should you do following management of acute gastric dilatation?

A

Monitor the healing of the stomach using endoscopy (as there can be complications)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are the risk factors for acute gastric impaction in horses?

A

Older horses
Poor dendition
Inappropriate diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What are the clinical signs of acute gastric impactions in horses?

A

Severe colic
Reduced feed intake
Endotoxaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the main complication that can be seen with acute gastric impaction?

A

Gastric rupture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How do you diagnose acute gastric impaction?

A

Resistance to passage of the nasogastric tube into the stomach can be a key indication of gastric distention however you can do an ultrasound or endoscopy for a definitive diagnosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How do you treat acute gastric impactions?

A

Indwelling nasogastric tube
Continuous gastric lavage of 5 litres of water per hour until the impaction is cleared
Carbonated drinks can help to break up some of the material
Intravenous fluid therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Which horse breeds are at an increased risk of chronic gastric impactions?

A

Warmbloods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is the proposed underlying cause of chronic gastric impaction in horses?

A

The proposed underlying cause of chronic gastric impactions is that the nerves involved in gastric emptying are dysfunctional and thus feed will chronically accumulate within the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are the clinical signs of a chronic gastric impaction?

A

Chronic colic
Ventral oedema
Reduced feed intake
Weight loss
Changes in abdominal sillouette

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How do you diagnose chronic gastric impaction?

A

Resistance to passage of the nasogastric tube into the stomach can be a key indication of gastric distention however you can do an ultrasound or endoscopy for a definitive diagnosis

Note how enlarged the stomach is
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

How do you treat a chronic gastric impaction?

A

Indwelling nasogastric tube
Continuous gastric lavage of 5 litres of water per hour until the impaction is cleared
Feed management through permanent turnout so all the forage they have access to is grass or pelleted food as these are easier to pass through the pylorus (due to be a low fibre ration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is the prognosis for chronic gastric impaction?

A

Horses with chronic gastric impaction require diligent management and often only survive for 2 to 4 years after clinical presentation. They are also at increased risk of spontaneous stomach rupture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What are the risk factors for equine gastric ulceration syndrome (EGUS)?

A

High concentrate, low roughage diets
Decreased access to grazing
Prolonged periods without eating
Intense exercise
Concurrent gastrointestinal disease
Pregnancy
Stress (increased cortisol levels associated with gastric ulcers)
Crib-biting
NSAIDs

64
Q

Why do high concentrate, low roughage diets increase the risk of equine gastric ulceration syndrome (EGUS)?

A

Increased concentrate and low roughage diets are high in carbohydrates which will be fermented in the stomach and produce acidic byproducts which will make the stomach even more acidic and increase the risk of gastric ulceration

65
Q

Why does intense exercise increase the risk of equine gastric ulceration syndrome (EGUS)?

A

Intense exercise redirects blood flow from the gastrointestinal tract which reduces the mucosal blood flow, increasing the risk of developing gastric ulceration

66
Q

How does crib-biting increase the risk of equine gastric ulceration syndrome (EGUS)?

A

Crib-biting causes contraction of the abdominal muscles and increases intra-abdominal pressure which can push gastric acid from the glandular region of the stomach into the squamous portion of the stomach, causing gastric ulceration

67
Q

What are the early clinical signs of equine gastric ulceration syndrome (EGUS)?

A

Reduced feed intake
Reduced coat quality
Girthy
Subtle changes in athletic performance

68
Q

What are the later clinical signs of equine gastric ulceration syndrome (EGUS)?

A

Poor appetite
Signs of pain after eating
Poor performance
Refusal to move forward in the saddle
Weight loss
Chronic colic

69
Q

How do you diagnose equine gastric ulceration syndrome (EGUS)?

A

History
Clinical signs
Endoscopy (definitive)

70
Q

How would you grade this squamous mucosa for gastric ulceration

A

Grade 0 - this is healthy squamous mucosa

71
Q

How would you grade this squamous mucosa for gastric ulceration?

A

Grade 1 - there is a yellowish pigment with hyperkeratosis

72
Q

How would you grade this squamous mucosa for gastric ulceration

A

Grade 2 - beginning to see some evidence of erosion and ulceration

73
Q

How would you grade this squamous mucosa for gastric ulceration

A

Grade 3 - Clear evidence of ulceration with areas of bleeding

74
Q

How would you grade this squamous mucosa for gastric ulceration

A

Grade 4 - More extensive, raised ulceration due to the body’s attempt to heal the ulcers

75
Q

Which squamous gastric ulceration grades are of clinical significance?

A

Grades 3 and 4 are of clinical significance

76
Q

How do you grade glandular mucosa for gastric ulceration?

A

Record the location and the gross appearance of the lesions as they can be very variable

77
Q

How do you treat gastric ulceration?

A

Omeprazole
Sucralfate
Increase access to forage and grazing
Decrease or stop concentrate feeding (put on high fat ration if require additional calories)
Decrease intensity of exercise
Avoid exercise on an empty stomach
Manage crib biting
Reduce stressors (increased cortisol levels associated with gastric ulcers)

78
Q

Which forage can be particularly good for managing equine gastric ulceration syndrome (EGUS)?

A

Alfalfa as it contains high levels of calcium which chelates gastric acid

79
Q

How can you try to manage crib biting?

A

Increase turnout and forage provisions

Be aware crib biting is hard to stop

80
Q

What are the general causes of weight loss in horses?

A

Decreased feed intake (e.g dental disease, oropharyngeal disease)
Parasitism
Malabsorption (e.g. inflammatory diseases)
Increased losses (e.g. diarrhoea, protein losing enteropathy, protein-losing nephropathy)
Malassimilation of nutrients (e.g. hepatic or metabolic disease)

81
Q

What is protein-losing enteropathy?

A

Protein-losing enteropathy is where serum proteins are lost excessively into the gastrointestinal lumen. Protein-losing enteropathy can be caused by multiple conditons which damage the gastrointestinal mucosa or impede lymphatic drainage (allows lymphatic fluid to leak into GI tract)

82
Q

What is chronic colic?

A

Chronic colic is subacute abdominal pain over a period of days, with or without weight loss

83
Q

How should you approach investigating chronic colic ± weight loss?

A

Detailed history
Clinical examination
Rectal examination
Dental examination
Faecal analysis
Biochemistry and haematology
Abdominocentesis
Referral diagnostics

84
Q

What can be indicated by increased gut sounds in horses?

A

Increased gut sounds indicates excessive fermentation in the large intestine which can indicate malabsorption potentially

85
Q

Which referral diagnostics can be done to investigate chronic colic ± weight loss?

A

Endoscopy ± biopsies
Ultrasound
Radiography
Gastrointestinal motility tets
Exploratory laparotomy ± biopsies

86
Q

What is the first thing you should do when investigating chronic colic?

A

Take a detailed history and clinical examination to assess if the chonic colic could be due to management, and give the owner advice on how to prevent managemental colic if applicable

87
Q

What can you advise owners to do to prevent managemental colic?

A
  1. Maintain a daily routine and minimise changes in diet, exercise, turnout etc.
  2. Feed 2 - 3% of the horse’s body weight in forage
  3. Provide daily access to grass
  4. Avoid feeding excess concentrates
  5. Provide constant access to clean water
  6. Anthelmintic protocol
  7. Provide six monthly dental care
  8. Keep a diary of any colic episodes to see if a pattern can be identified
88
Q

What are the differential diagnoses for chronic colic ± weight loss?

A

Gastric ulceration
Peritonitis
Impaction (inc. enteroliths, faecoliths and sand)
Ileum hypertrophy
Parasitism
Inflammatory bowel disease
Adhesions
Non-strangulating infarction
Right dorsal colitis
Chronic salmonellosis
Intussussception
Neoplasia
Peri-rectal abscesses
Chronic hepatitis
Cholelithiasis
Urolithiasis
Chronic cystitis
Pyelonephritis

89
Q

(T/F) Equine inflammatory bowel disease always presents with diarrhoea

A

FALSE. Equine inflammatory bowel disease does not present with diarrrhoea

Diarrhoea in horses is always due to large intestinal disease

90
Q

What are the clinical signs of inflammatory bowel disease in horses?

A

Weight loss
Chronic colic
Hypoproteinaemia (due to PLE)
Thickened small intestinal wall on ultrasound

91
Q

How do you diagnose inflammatory bowel disease?

A

Endoscopy with small intestinal mucosal biopsies and histopathology

92
Q

Which test can you do in horses to assess for malabsorption?

A

Glucose absorption test

93
Q

How do you carry out a glucose absorption test?

A

Fast the horse for 12 hours, then administer glucose via a nasogastric tube (make sure the horse is NOT sedated). The plasma glucose should reach twice its basal concentration within 2 hours, if not, this can indicate malabsorption

94
Q

How do you treat inflammatory bowel disease in horses?

A

Immunosuppressive therapy
Increase nutrient and protein content in the diet

95
Q

Which drug do you use for immunosuppressive therapy in horses?

A

Prednisolone

96
Q

What is the prognosis for inflammatory bowel disease in horses?

A

Lymphocytic and plasmocytic inflammatory bowel disease typically have a prognosis of 6 to 12 months from first presentation, whereas eosinophilic and granulomatous inflammatory bowel diseas have a better prognosis and tend to respond better to immunosupporessive therapy

97
Q

Which disease can present in a very similar way to inflammatory bowel disease?

A

Lymphoma

Important to differentiate these on histopathology

98
Q

What is peritonitis?

A

Peritonitis is inflammation of the peritoneum

99
Q

What causes primary peritonitis?

A

Primary peritonitis is idiopathic

100
Q

What causes secondary peritonitis?

A

Secondary peritonitis can be caused by abdominal trauma, rupture of the gastrointestinal tract or abdominal surgery

101
Q

What are the clinical signs of peritonitis?

A

Colic
Pyrexia
Weight loss (if chronic peritonitis)

102
Q

How do you diagnose peritonitis in horses?

A

Abdominocentesis
Haematology
Bacterial culture
Rectal palpation
Ultrasound

103
Q

How does peritonitis typically present on abdominocentesis?

A

Abnormal appearance of peritoneal fluid
Increased leukocytes
Increased total proteins
Increased lactate (can be increased with just peritonitis but usually indicates septic peritonitis)
± Bacteria

104
Q

Which bacteria species is most commonly isolated in peritonitis cases?

A

Actinobacillus species

105
Q

How does haematology change with peritonitis?

A

Increased serum amyloid A
Increased fibrinogen

106
Q

How do you treat peritonitis in horses?

A

NSAIDS
Broad spectrum antibiotics
Fluid therapy (if indicated)
Treat endotoxaemia (if indicated)

107
Q

Which NSAID is best for treating peritonits?

A

Flunixin (remember peritonitis is very painful)

108
Q

How do you monitor that patients are responding to treatment of peritonitis?

A

To confirm patients are responding to treatment of peritonitis, repeat the abdominocentesis and assess the peritoneal fluid

109
Q

Why do horses not typically urinate when they are colicing?

A

Horses do not typically urinate when they are colicing as they require abdominal contraction to urinate

110
Q

How do you approach the investigation of diarrhoea in horses?

A

History and clinical signs
Clinical examination
Haematology and biochemistry
Faecal analysis and culture and sensitivity
Ultrasound

111
Q

Which history questions can be beneficial to ask when investigating diarrhoea in horses?

A
  1. Has there been any recent dietary changes?
  2. Has the horse been inappetent?
  3. Are there any systemic clinical signs?
  4. Has the horse been on any recent medications?
  5. Are any horses in the area affected by these clinical signs?
  6. What is the precise nature of the diarrhoea?
  7. Could the horse have had access to different feed, pasture or potential toxins
112
Q

Which medications can cause diarrhoea in horses?

A

Antibiotics
NSAIDS
Anthelmintics

113
Q

How can antibiotics cause diarrhoea in horses?

A

Antibiotics can induce diarrhoea in horses through disrupting the normal gastrointestinal microbiome resulting in dysbiosis which can result in diarrhoea

114
Q

Which pathogen is the most common cause of post-antibiotic diarrhoea?

A

Clostridium difficile

115
Q

How can NSAIDS cause diarrhoea in horses?

A

NSAIDS can cause right dorsal colitis in horses, resulting in diarrhoea

116
Q

How can anthelmintics cause diarrhoea in horses?

A

Treatment with anthelmintics in horses with a high parasite burden can result in diarrhoea

117
Q

Which toxins can cause diarrhoea in horses?

A

Tannins (components of some plants)

118
Q

What should you particularly assess during the clinical examination of a horse with diarrhoea?

A

Assess if there is evidence of diarrhoea? How much is there etc
Assess for signs of systemic disease
Assess the vital physiological parameters
Abdominal auscultation
Assess for dehydration

119
Q

What is the main thing you should determine on clinical examination of a horse with diarrhoea?

A

The main thing you should determine on clinical examination of a horse with diarrhoea is the patient status and if they require referral

120
Q

What is the main cause of nutritional diarrhoea?

A

Recent dietary change

121
Q

What are the key signs of nutritional diarrhoea?

A

No systemic clinical signs
Normal vital physiological parameters
No evidence of dehydration
Normal haematology and biochemistry results (check serum protein levels especially)

122
Q

How do you treat nutritional diarrhoea?

A

You can switch the horse to a simple soaked hay feed and the diarrhoea should resolve itself over a few days

123
Q

Describe the pathophysiology of colitis/typhlitis?

A

Pathophysiological changes in colitis and typhlitis include widespread mucosal inflammation (with sloughing and necrosis in severe disease). Inflammation will cause vasodilation and increased vascular permeability which allows for the passage of fluid and serum proteins from the intravascular space into the intestinal lumen, resulting in a protein-losing enteropathy (which can result in oedema due to loss of oncotic pressure) . The damage to the mucosa also results in decreased absorption of water and electrolytes which contribute to dehydration which can progress to hypovolaemia, and electrolyte imbalances. Mucosal damage also allows for the translocation of bacteria and endotoxins into the bloodstream which will contribute to, hypovolaemia, decreased cardiac output (resulting in tachycardia) and eventual cardiovascular collapse.This can also progress to systemic inflammatory response syndrome (SIRS) and disseminated intravascular coagulation (DIC)

124
Q

What are some of the potential complications of colitis/typhlitis in horses?

A

Acute renal failure (due to hypovolaemia)
Laminitis (due to hypovolaemia)
Thrombophlebitis
Disseminated intravascular coagulation (DIC)

125
Q

What are some of the most common infectious causes of colitis/typhlitis in foals?

A

Clostridium perfringens C
Clostridium piliforme (Tyzzer’s disease)
Rhodococcus equi
Lawsonia intracellularis
Rotavirus

126
Q

What are some of the most common infectious causes of colitis/typhlitis in adult horses?

A

Clostridium difficile (most common in the UK)
Salmonella
Coronavirus

127
Q

What are some of the parasitis causes of colitis/typhlitis in adult horses?

A

Strongylus vulgaris
Cyathostomins

128
Q

What are some of the other possible causes of colitis/typhlitis in adults horses?

A

NSAIDs
Antibiotics
Sand impactions

129
Q

What are the ‘warning signs’ of severe colitis/typhlitis in horses with diarrhoea on clinical examination?

A

Clinical signs of endotoxaemia
Dehydration and hypovolaemia
Pyrexia
Colic
Intestinal hyper- or hypomotility
Taut taenial bands on rectal palpation

130
Q

What are the clinical signs of endotoxaemia?

A

Tachycardia
Toxic lines
Congested mucous membranes
Brisk CRT which can progress to a prolonged CRT
Profound depression
Initial pyrexia followed by hypothermia

131
Q

What is indicated by taut taenial bands on rectal examination?

A

Taut taenial bands indicates the large colon is very fluid filled

132
Q

What are the ‘warning signs’ of colitis/typhlitis in horses with diarrhoea on haematology and biochemistry?

A

Increased PCV and TP
Increased PCV and decreased TP
Increased lactate
Leukopenia
Neutropenia

133
Q

What is indicated by an increased PCV and TP in a patient with diarrhoea?

A

An increased PCV and TP in a patient with diarrhoea indicates dehydration and hypovolaemia

134
Q

What is indicated by increased PCV and a decreased TP in a patient with diarrhoea?

A

An increased PCV and decreased TP indicates dehydration and hypovolaemia with a loss of serum proteins into the intestinal lumen (protein losing enteropathy) or into the abdomen (peritonitis)

135
Q

What is indicated by increased lactate in a patient with diarrhoea?

A

Increased lactate indicates hypoperfusion and anaerobic metabolism

136
Q

What is a key sign of colitis/typhlitis on ultrasound?

A

Thickening of the colon/caecal wall is a key sign of colitis/typhlitis on ultrasound

137
Q

What is the normal thickness for the colon wall on ultrasound?

138
Q

What is the normal thickness for the caecal wall on ultrasound?

139
Q

When should horses be admitted to the isolation unit?

A

All horses presenting with diarrhoea are submitted to the isolation unit. Horses presenting without diarrhoea but intestinal hypermotility, pyrexia, leukopenia and/or neutropenia should be admitted to isolation as there is a high risk of infectious disease. Barrier nursing is also required as these pathogens are zoonotic

140
Q

How do you diagnose clostridium difficile in horses?

A

Faecal ELISA

141
Q

How do you diagnose salmonella in horses?

A

Faecal ELISA
Faecal PCR

142
Q

When diagnosing salmonella in horses, how many tests are required for a confirmatory diagnosis?

A

When diagnosing salmonella in horses, three sequential tests should be taken and submitted for culture, if one comes back positive, five subsequent sequential negative tests are required to determine cessation of shedding

143
Q

How do you diagnose coronavirus in horses?

A

Faecal PCR
Immunohistochemistry

144
Q

What is the main cause of right dorsal colitis in horses?

145
Q

How do NSAIDS cause right dorsal colitis in horses?

A

NSAIDS inhibit cyclooxygenase-1 (COX) and thus prostaglandin production which results in reduced mucosal blood flow to the gastrointestinal tract. The right dorsal colon is particularly sensitive to changes in blood flow and mucosal integrity which increases the risk of gastrointestinal ulceration and inflammation

146
Q

What should owners be advised when being prescribed NSAIDS?

A

Owners should be advised that there is a risk of right dorsal colitis with NSAIDs and to monitor for soft faeces. If they notice soft faeces, they should stop the NSAIDs immediately and seek veterinary advice

147
Q

How do you manage acute colitis/typhlitis?

A

Prevent further endotoxin absorption
Anti-endotoxic drugs
Fluid therapy (enteric and IV)
Antibiotics (in some cases)
Transfaunation?

Make sure to continuously monitor clinical signs and clinical parameters

148
Q

What can be used to prevent further endotoxin absorption?

A

Activated charcoal
Biosponge (Smectite)

149
Q

What can be used to try and reduce endotoxin mediated inflammation?

A

NSAIDs (low dose to prevent the risk of right dorsal colitis)
Plasma

150
Q

What are the aims of fluid therapy when managing colitis/typhlitis?

A

Replace fluid deficits and restore circulatory volume
Provide maintenance fluids
Manage ongoing losses
Correct electrolyte imbalances
Correct acid bases imbalances
Maintain oncotic pressure

151
Q

Which fluids are ideal for managing colitis/typhlitis?

A

Isotonic crystalloids

152
Q

What can be used to maintain oncotic pressure in horses with colitis/typhlitis?

153
Q

What is the main risk of antibiotics in the management of colitis/typhlitis?

A

Antibiotics can cause further dysbiosis and exacerbate the clinical signs of colitis/typhlitis

154
Q

When are antibiotics indicated in the management of colitis/typhlitis?

A

Metronidazole can be used if clostridium difficile has been diagnosed

As clostridia is an anaerobe

155
Q

What can be done to try and reduce the risk of laminitis secondary to colitis/typhlitis?

A

Continuous icing on the hooves can reduce the risk of laminitis