Equine Top 20 Diseases - Part 1

Question 1

what is the classic case presentation of a corneal ulcer in a horse?

Answer 1

acute onset of unilateral blepharospasm, photophobia, miosis, epiphora, & corneal edema

Question 2

how is a corneal ulcer diagnosed?

Answer 2

thorough ophthalmic exam with ophthalmoscope & fluorescein staining positive

Question 3

what surgery can be done for severe corneal ulcer cases in a horse?

Answer 3

conjunctval grafts

Question 4

what treatment can be used for a corneal ulcer on a horse that is difficult to handle or has a severe ulcer?

Answer 4

subpalpebral lavage system

Question 5

what drug should never be used if a corneal ulcer is present?

Answer 5

steroids

Question 6

what is the main differential for a corneal ulcer in a horse? how do you rule it out? how do you treat it?

Answer 6

recurrent uveitis - has similar clinical signs but no fluorescein uptake that is treated with topical steroids

Question 7

what are 2 conditions that are sequelae to corneal ulcers? why might they be missed?

Answer 7

desmetoceles & stromal abscesses - they have no stain uptake because all endothelium is gone or covered over

Question 8

what drugs are used to treat corneal ulcers?

Answer 8

topical antimicrobials, atropine to decrease iridocyclospasm/improve drainage, & anti-collagenases

Question 9

what is the classic case presentation of a horse with sinusitis?

Answer 9

mucopurulent unilateral nasal discharge +/- facial swelling, epiphora & often malodorous

Question 10

how is sinusitis in a horse diagnosed?

Answer 10

radiographs to identify sinus or tooth pathology, upper airway endoscopy to evaluate drainage angles/rule out other causes of discharge, & thorough dental exam

Question 11

how is sinusitis treated in a horse?

Answer 11

sinus trephination/flap/lavage, +/- removal of offending tooth or mass, & long-term antibiotics

Question 12

what is the typical cause of primary sinusitis?

Answer 12

upper respiratory infection

Question 13

what is more common: primary or secondary sinusitis?

Answer 13

secondary

Question 14

what are the main causes of secondary sinusitis in a horse?

Answer 14

dental disease, sinus cyst, ethmoid hematoma, or neoplasia

Question 15

T/F: chronic sinusitis in a horse has a guarded prognosis for resolution

Answer 15

TRUE

Question 16

what is another name for equine cushing’s disease?

Answer 16

pituitary pars intermedia dysfunction

Question 17

what is the classic case presentation of a horse with cushing’s disease?

Answer 17

horse/pony over 15 years old with chronic laminitis, hypertrichosis, recurrent infections (hoof abscesses & sinusitis), loss of topline musculature, lethargy, abnormal fat deposition (supraorbital fat pads), & PU/PD/PP

Question 18

how is equine cushing’s disease diagnosed?

Answer 18

increased resting plasma ACTH, positive thyrotropin-releasing hormone stimulation test, & measure fasting insulin/insulin sensitivity because most horses with PPID also have insulin dysregulation

Question 19

how is equine cushing’s disease treated?

Answer 19

daily pergolide (dopamine agonist) may have to increase dose over time as disease progresses

Question 20

what is the pathogenesis of equine cushing’s disease?

Answer 20

lack of dopaminergic inhibition of the pituitary pars intermedia by the hypothalmus which leads to the development of functional adenoma in pituitary pars intermedia (will see increased ACTH, alpha-MSH, beta-endorphin, & cortisol levels)

Question 21

T/F: younger horses with regional adiposity, laminitis, & insulin dysregulation are usually considered to have equine metabolic syndrome & not equine cushing’s

Answer 21

TRUE

Question 22

what is the classic case presentation of a horse with colitis?

Answer 22

depression, inappetance, variable colic, decreased or hypermotile gi sounds, fever, variable degrees of shock/hypopefusion, +/- watery hemorrhagic diarrhea

Question 23

what does a fecal PCR test for in a horse with colitis?

Answer 23

salmonella, clostridium perfringens, c. difficile, potomac horses fever

Question 24

why do an abdominal ultrasound on a horse with colitis?

Answer 24

assess colon wall thickness - especially right dorsal colon because it is associated with NSAID causes

Question 25

why do abdominal radiographs on a horse with colitis?

Answer 25

look for sand

Question 26

what may be seen on labwork from a horse with colitis?

Answer 26

dehydration, abnormal electrolytes, usually neutropenic, & hypoalbuminemic

Question 27

what treatment is used for a horse with colitis?

Answer 27

biosecurity, supportive care (iv fluids), anti-endotoxemics & anti-inflammatories, antidiarrheals, & cryotherapy to prevent laminitis

Question 28

T/F: for over 50% of colitis cases, there is no definitive diagnosis made

Answer 28

TRUE

Question 29

what is colitis x?

Answer 29

idiopathic colitis - sometimes called antibiotic or stress associated

Question 30

what antibiotics are used for certain causes of colitis?

Answer 30

oxytetracycline for potomac horse fever & metronidazole for clostridosis

Question 31

what is the classic case presentation of a septic foal?

Answer 31

foal less than 14 days old with lethargy, decreased nursing, +/- obvious septic foci (joint effusion, omphalophlebitis, diarrhea, or pneumonia)

Question 32

what is the goal standard for diagnosising sepsis in a foal? what is the disadvantage?

Answer 32

gold standard - takes 4-7 days to get results

Question 33

how is sepsis diagnosed in a foal?

Answer 33

look for increased or decreased neutrophils with bands, increased lactate, ultrasound/radiography, & check blood IgG to assess for failure of passive transfer

Question 34

how is sepsis treated in a foal?

Answer 34

broad spectrum antibiotics, IV fluids/plasma, anti-endotoxin therapies, nutritional support, lavage joints for septic joints, anti-diarrheals, & nebulization for pneumonia

Question 35

T/F: for septic foals, the prognosis is good when treated at referral centers with aggressive therapy

Answer 35

TRUE

Question 36

what must be done for all foals at 12-24 hours of age? why?

Answer 36

check all foals for adequate passive transfer at 12-24 hours of age!!! help to decrease the risk of sepsis!!!

Question 37

T/F: gram negative pathogens are the most common bacterial causes of sepsis in foals

Answer 37

TRUE

Question 38

T/F: foals will deteriorate rapidly, so any decrease in nursing or activity is an emergency

Answer 38

TRUE