Weight Loss in Horses Flashcards
Why is weight loss in horses of importance?
•Common clinical presentation
–A challenging diagnostic approach potentially involving many body systems – weight loss is a very specific and general thing
–Multiple potential causes
–Often without a specific diagnosis – client may not have the money to spend and many other things!
•Highly emotive topic
–Weight loss can be related to neglect
What are the most common cause of weight loss in the horse?
Mark with * for the most common
–Dental disease *
–Renal disease
–Liver disease
–Intestinal disease in general *
–Malnutrition
–Neoplasia – more common in dogs and cats!
–GI Infection – moderately common
–Systemic infection
–Parasites * - a bit less common than they have been as owners getting better at monitoring
–For weight loss, usually thinking about something chronic
What can cause reduced intake as a mechanism of weight loss?
Inappropriate feeding, unable to obtain feed, competition for feed, dental disorders, dysphagia
What can cause reduced digetion, absorption or assimilation of nutrients as a mechanism of weight loss?
–dental disorders (horses doesn’t chew properly so first stop of digestive process is a problem), malabsorption syndromes (something specific to the intestine
–liver disease – will also have a role in digestive process
What can cause increased losses as a mechanism of weight loss?
–protein losing enteropathy or nephropathy
–sequestration to body cavity = peritonitis or pleuritis
What can cause increasedrequirements as a mechanism of weight loss?
pregnancy, lactation, sepsis, neoplasia, other systemic disease
What can cause anorexia (as part of reduced intake with weight loss)?
•Anorexia – decreased intake overall. Can be related to:
–Pain
•Intestinal pain
–Gastric ulcers – post prandial pain (only if severe)
–Adhesions - low grade recurrent colic
–Visceral pain – pleural / peritoneal disease
•Severe musculoskeletal pain
–E.g. Laminitis
–Dysphagia
- Pharyngeal / laryngeal dysfunction (Guttural pouch)
- Toxicity e.g. lead
- Botulism
- Chronic Grass sickness
What is Equine Grass Sickness?
What are the different levels and how long do they survive?
- A generalised dysautonomia affecting primarily the enteric nervous system, but other body systems as well
- Non GI effects aid in its diagnosis
- Mainly parasympathetic NS
- Acute : Die rapidly
- Sub acute : Survive > 2 days
- Chronic : Survive > 7 days
- A Clinical diagnosis
- decrease in GI motility from mouth of anus, with decrease in GI secretions
What do Equine Grass Sickness Horses often look like?
What does this look similar to?
- Grass sickness horse slightly underweight
- Very tucked up abdomen
- Often very weak
- Muscle fasciculations, esp around shoulder – indication of weakness
- Nasal discharge but bottom left pic shows spontaneous reflex – stomach will be full
- This presentation could also show similar to strangulation of SI
- EGS – high HR, same with strangulating lipoma, but with EGS once you have done the NGT – it will decrease, lipoma cases don’t stay decreased and will go back again
- EGS – belly tap normal, serosanguinous with lipoma
- Very difficult to differentiate between EGS and strangulating lipoma
- Usually will go to surgery to differentiate!
What are some diagnostic tests for equine grass sickness?
•Ileal biopsy (in vivo)
–Best diagnostic test
–Requires laporotomy (midline / flank)
- Laporotomy decreases survival
- Neuronal degeration within ganglia
- Depletion of ganglia
- Vacuolation
–Pathology localised to ileum in Chronic EGS
–Generalised intestinal pathology in acute disease
•Rectal biopsy - 71% sensitivity 100% specificity – the reality is that if you need to go to surgery and waiting for biopsy if you know you may need to go to surgery, not suitable to wait 3 days until results come back
–14 horses
Label the following arrows
What are some histological findings in a horse with equine grass sickness?
•Chromatolysis, vacuolation of cells within autonomic ganglia
–also affects other autonomic ganglia
•Not a straight forward diagnosis – might have 1 or 2 neurons that are affected
What is the Phenylephrine Test with regards to trying to diagnose equine grass sickness?
- Topical application of 0.5% phenylephrine to one eye
- examination 30 minutes later
- Positive test = reversal of the ptosis in that eye, increase in angle between the corneal surface and the eyelash.
- test useful in supporting of defective smooth muscle activity as an underlying cause of the ptosis
- BUT False positives seenà normal horses can show some response to this test
- Can also see false positive if been sedated with alpha 2 agonist
What would you see on oesophageal endoscopy with equine grass sickness?
What is the problem with using this test to diagnose?
- Linear oesophageal ulcers
- indicative of gastro-oesophageal reflux
- In absence of severe ileus and extensive gastric distension
- suggestive of lower oesophageal spincter dysfunction
- Many EGS horses do not have oesophageal ulcers
What is the treatment for equine grass sickness?
What is the prognosis?
- Nursing care is paramount for a successful outcome
- Useful website vets and owners
- Prognosis poor
- Is subacute and survive first few days, may become chronic and may be able to save them. If they come as chronic straight away, difficult to tell what it is
- Encourage to eat, a lot of TLC
- Symptomatic therapy for each individual problem
- Analgesia
–NSAIDs
–Promotes voluntary feeding - reduces pain associated with swallowing and abdominal pain
–Oesophageal / gastric ulceration - H2 blockers, sucralfate
What supportive care can you offer to horses with equine grass sickness?
•Feeding
–Small feeds every 30 - 60 minutes
–Hand feeding (don’t leave horse to eat)
–Hand grazing
–Varied diets
•Appetite stimulation – not necessarily very commonly used
–Diazepam 0.02mg/kg IV BID-TID
•Nursing
–Grooming
–Access to other horses
–Rhinitis - Steam, mucolytics – some horses gets very long crusts within their nasal passages, make resp noise when breathing
–Prokinetics - can try them but not likely to have a huge effect
–Cisapride has most data – no longer available
What is the long term prognosis for horses with equine grass sickness?
- Using the selection criteria detailed in the above article approx 80 % chronic equine grass sickness survive.
- Currently no accurate indicators in chronic cases at initial presentation that can be used to predict the duration of supportive or success of the outcome.
- (Milne and others 1994) àsurvival predictors
–Degree of dysphagia (closely associated with appetite)
– the severity of rhinitis
- Main problems encountered in the first 2 months post discharge from a hospital
- mild colic
- poor appetite,
- Dysphagia
- sweating and coat changes (areas of piloerection frequently affecting anatomical sites previouslyaffected by patchy sweating).
How can you CONFIRM your diagnosis of equine grass sickness?
- Cranial cervical ganglion
- Cranial mesenteric ganglia
–Ganglia is subrenal
- Remove spleen
- Raise kidney, remove suprarenal connective tissue - contains adrenal
–Obtain the cranial mesenteric ganglia
–Section extending from mid aorta, cranial pole of kidney to peritoneum
What is associated with liver disease?
•Maldigestion
–Rare in horses
- Anorexia
- Hypoalbuminaemia
–Rare in horses
- Increase energy consumption
- Infection / Sepsis
What is wrong here?
Equine Lymphoma
How do you perform an oral glucose tolerance test and what do the results mean?
–starve overnight
–1 gm/kg in a 10-20% solution administered by nasogastric tube
–keep horse calm
–Expect to have an increase of over 85% from baseline
–If between 25-95% - partial malabsorption
–Anything below 25 – complete absorption
–Means horse cannot absorb SUGARS, not necessarily fat or protein
