Equine Weight Loss and Chronic Colic Flashcards
What are the 4 mechanisms of weight loss?
- Reduced intake
- Reduced digestion, absorption or assimilation of nutrients
- Increased losses
- Increased requirements
How does reduced intake occur?
Inappropriate feeding
Unable to obtain feed
Competition for feed
Dental disorders
Dysphagia,
How does weight loss occur due to increased losses?
Protein losing enteropathy (nephropathy, sequestration to body cavity = peritonitis or pleuritis)
Which increased requirements lead to weight loss
Pregnancy
Lactation
Sepsis
Neoplasia
Systemic disease
List some common causes of weight loss
Dental disease
Parasites
Inadequate diet
PPID
Liver disease
Malabsorption and protein losing enteropathy
What are the daily feed requirements for a horse?
2-2.5% BW
What is the daily requirement of a racehorse?
1.5% BW
List some less common causes of weight loss in horses
Chronic diarrhoea
Abdominal abscess
Renal disease
Cardiac disease
Chronic thoracic disease
Non-GI neoplasia
Grass sickness
Define chronic colic
Colic of variable intensity that last longer than 48hrs
Define recurrent colic
Shorter periods of colic pain which recur at variable intervals
List 4 GIT related causes of recurrent colic
Intermittent partial/complete obstruction
Inflammation
Motility disorder
Mesenteric traction
Define colic
Behaviour manifestation of visceral pain
Colic normally refers to which 4 types of intestinal pain?
Stretch
Inflammation
Ischaemia
Muscle spasm
What information needs to be gathered on the history of recurrent colic cases?
- Number/ nature of previous colics / abdominal sx
- Faecal output / diarrhoea / wgt. loss /medical conditions
- Diet esp. recent changes
- Worming
- Dental problems, quidding?
- Crib biting/windsucking?
- Sand pastures?
Describe the clinical exam for recurrent colic cases
- Exam as for acute colic:
- Clinical examination
- Nasogastric intubation (usually only during an acute episode)
- Rectal examination
Also observe for concurrent/associated signs: - Weight loss
- Diarrhoea
Describe the history and initial clinical exam for chronic GIT disease
- Rule out obvious simple causes e.g. recent diet change, dental disorders etc
- Assess exposure to infectious causes e.g. worming history, environment, drug history
- Determine if in “ACUTE” or “CHRONIC” categories
- Diarrhoea?
- Rule out other causes - pregnancy , heart disease, PPID, others
Why would you want to perform a preliminary clinical pathology for chronic GIT disease?
Will help to rule in or out:
- Specific organ disease: enzymes, bile acids etc.
- Inflammatory processes: WCC, fibrinogen, globulins
- Protein loss: esp. albumin into the lumen of the bowel
- Occasionally indicators of malignancy e.g hypercalcaemia
- Faecal egg count: for mature parasites
Why must you be cautious when interpreting clinical pathology?
If the first set of bloods don’t give you a diagnosis, repeating the same tests more than once more rarely will
Reference ranges are calculated to include 95% of the normal population -i.e. in any give horse, 1 in 20 results will be “abnormal”
Solution: chose specific tests and avoid extensive and expensive panels
Decreases in total protein may be masked by?
Concurrent dehydration
How should you interpret hypoalbuminaemia
GI loss more common than renal
Effusions: peritoneal/pleural
Liver disease (rare)
How should you interpret hypoglobinaemia
GI loss
How should you interpret hyperglobinaemia
Chronic inflammatory disease (including cyathostomiosis)
How should you interpret hyperfibrinogenaemia?
Infection
Inflammation
Neoplasia
Verminous arteritis is caused by?
Strongylus vulgaris - migrating to the mesenteric artery cause loss of blood supply to certain areas of the colon
Following clinical pathology tests, what is the next step in diagnosing chronic GIT disease?
Monitor temperature several times a day over several days - consider abscess and neoplasia if intermittently febrile
Perform peritoneal fluid analysis
How should normal peritoneal fluid appear
Clear and light yellow
Cloudy peritoneal fluid = …?
Increased protein and WBCs
Red peritoneal fluid = … ?
RBCs - may indicate a strangulating colic
Name the 3 types of ultrasound that can be used to diagnosed chronic GIT disease
Transabdominal
Transrectal
Intestinal
What does an increased in intestinal wall thickness on US indicate?
Inflammation
What does an increase in intestinal lumen diameter indicate on US?
Obstruction
What are the visible structures on the right side of a horse?
Liver
Duodenum
Caecum
RDC
What are the visible structures on the left side of a horse?
Stomach
Spleen
Left ventral colon
Pelvic flexure
Small colon
Small intestine
Where does the stomach lie in the horse
8th - 13th ICS
Medial to spleen
Visible over ≥ 5 rib spaces = distension
Describe nephrosplenic entrapment
Colon migrates through the body wall of the spleen – hooks into the space between the kidney and the spleen
Which 3 tests are used when there is weight loss
Oral glucose absorption test
Rectal Biopsy
Duodenal biopsy
What is the oral glucose absorption test?
Absorption test vs. tolerance
Small intestinal only
Fast overnight
1 gm/kg in a 20% solution administered by nasogastric tube
Keep horse calm (do not sedate with alpha 2’s)
Describe a normal result following a normal oral glucose absorption test
NORMAL: >85% increase in blood glucose concentration at two hours
Describe the two abnormal results following a normal oral glucose absorption test
PARTIAL: 15 - 85% increase in blood glucose concentration at two hours
COMPLETE: < 15% increase in blood glucose concentration at two hours
= small intestinal disease
Describe how to perform a rectal biopsy
- Easy to perform
- 20 - 30 cm inside rectum
- Small piece of mucosa from floor at around 4 or 8 o’clock
- Submit for histology (in formalin) and culture
- Antibiotics and tetanus prophylaxis
Name 3 inflammatory/infiltrative bowel diseases
- Granulomatous enteritis
- Lymphocytic-plasmacytic enteritis
- Eosinophilic enteritis
-> Presence of inflammatory cells in intestinal wall leading to malabsorption and protein-loss
List the DDx of inflammatory bowel disease
Cyathostomosis
Mixed strongyle infection
Idiopathic
Infiltrative bowel diseases
Neoplasia
Lawsonia (foals 3- 11 months)
Multisystemic eosinophilic epitheliotropic disease often involves which parts of the body?
GIT, skin, particularly around coronary bands, pancreas, liver
How is Multisystemic eosinophilic epitheliotropic disease treated?
Dexamethasone
What are the clinical clues/signs that indicate lymphoma or other forms of disseminated neoplasia
Fever
Weight loss
Peritonitis
Pleural effusion
Abdominal distension
Intra-abdominal mass palpable per rectum
Hypercalcaemia/haemolysis/cachexia of malignancy
Other than lymphoma, name 4 other intestinal neoplasias
Leiomyoma
Myxosarcoma
Gastric or Adenocarcinoma
Melanoma
Describe how to treat inflammatory bowel disease
Non-specific
Prednisolone
Dexamethosone
Anthelmintics
Name 2 common causes of chronic GIT bacterial infections
S.equi
R.equi
How are chronic bacterial infections diagnosed?
Inflammatory haemogram - Neutrophillia, hyperfibrinogenaemia, anaemia
What are the two main GIT consequences of large strongyles?
- Verminous arteritis
- Thromboembolic colic
What is the main GIT consequences of small Strongyles?
Submucosal infection
Describe the haematological changes for parasitism in horses
Neutrophilia, hypoalbuminaemia, and hyperglobulinaemia, NOT eosinophillia
Describe equine gastric ulcer syndrome
- Common and widespread problem in horses in training (70%)
- Potential cause of poor athletic performance
Equine gastric ulcer syndrome is divided into which 2 conditions?
Equine glandular gastric disease
Equine squamous gastric disease
What are the important implications for risk factors and treatment in the two conditions of equine gastric ulcer syndrome?
Equine glandular gastric disease: risk factors not well known - possibly stress, NSAIDS
Equine squamous gastric disease: risk factors related to acid injury
What are the clinical signs of equine gastric ulcer syndrome?
Vague e.g. weight loss, poor performance
Selective appetite, slow eating, eat roughage in preference for grain
Bad/cranky behaviour
Why are horses so susceptible to equine gastric ulcer syndrome?
Horses are herbivores evolved to:
- Digest fibre,
- Graze continuously and maintain a full stomach
Stomach anatomy
- Poor mixing
- Grain portion rapidly fermentable
- Production of acids
Which portion of the stomach is prime to acid injury?
Squamous portion - pH 5.4
List the predisposing factors for acid injury in horses
- Intermittent feeding vs trickle feeding over 18+ hours
- High concentrate diets: VFAs, low fibre concs -> reduced saliva production (buffer)
- Exercise: gastrin production
- Stress: transport, confinement, stabling
How is equine gastric ulcer syndrome diagnosed?
Gastroscopy: ≥3 m endoscope
Faecal occult blood is not reliable
How is equine gastric ulcer syndrome treated?
- Proton pump inhibitor omeprazole
- ESGD more responsive clinically at lower doses e.g. 2 mg/kg daily for 3 – 4 weeks
- EGGD less responsive and requires higher doses e.g. 4 mg/kg daily for 4 – 6 weeks
- Reduce exposure to risk factors: diet, exercise, stress (modern management)
- Long term dietary supplements may help
