Top 20 Equine Flashcards
equine
Pituitary Pars Intermedia dysfunction
MC sig? Path? CS? Dx? Tx?
aka Equine Cushings
Signalment
* MC in horses >15; ponies and Morgans - occurs in all breeds
Pathology
* Lack of dopamine inhibition of pituitary pars intermedia by hypothalamus → functional adenoma formation in pituitary pars intermedia → elevated ACTH, alpha-MSH, beta-endorphin, and cortisol
Clinical signs
* Hirsutism
* Chronic lamnitis
* Hirsutism/hypertrichosis
* Recurrent infections
* Loss of muscle mass
* Lethargy
* Regional adiposity
* PU/PD/PP
* Inappropriate lactation
* Hyperhidrosis
Diagnosis
Endogenous Baseline Plasma ACTH (must compare to seasonal reference intervals): elevated
* Most readily available
TRH (thyrotropin stimulating hormone); give and measure ACTH = high in PPID horses
* Not super available but more sensitive
Common supportive lab values - HypERglycemia, low USG (due to PU/PD), stress leukogram
Treatment
Management only (decrease clinical signs)
Pergolide (Prascend)- Dopamine agonist; suppresses pituitary ACTH secretion
* Often have to increase dose over time as dz progresses to maintain control
Cyproheptadine - Serotonin antagonist, old treatment
Trilostane? - 3-beta hydroxysteroid dehydrogenase inhibitor
Also measure fasting insulin or do insulin sensitivity testing because many have concurrent insulin dysregulation
If younger horse + insulin dysregulation → likely metabolic syndrome
equine
atrial fibrillation
et? CS? Dx? Tx? Prognosis?
Normal horses predisposed due to high vagal tone and large atria
Clinical signs
* Athletic horses: exercise intolerance, exercise-induced epistaxis
* Pleasure or idle horses: incidental finding
* Irregularly irregular heartbeat
Diagnosis
ECG
* Absence of P waves
* f waves with relatively normal QRS complexes
* Irregular R-R interva
Treatment
* Do not treat if underlying dz → won’t fix it, increase risk of fatality due to arrythmias
* Do not treat if retired or not causing issues
* Only treat if “lone AF” = no underlying dz and need better athleticism
Medical cardioversion = Quinidine IV or pO
* Class IA sodium channel blocker, has vagolytic properties that prolong the refractory period of the myocardium.
* Side effects: oral ulcers, hypotension, allergic reactions
Electrical cardioversion (TVEC) - requires GA
Prognosis good for lone AF
* Poor for athletic performance if secondary to underlying cardiac dz
equine
Gastric ulcer syndrome
CS? Location? Dx? Tx? Prognosis?
Clinical signs
* None
* Colic, inappetence
* Weight loss, ill thrift
* Girthy
Location
* Squamous (MC overall) MC @mucosa of lesser curvature just proximal to margo plicatus
* Glandular - usually at pylorus
Diagnosis
Definitive = fasting gastroscopy
* Graded on number and severity
Treatment
* Proton-pump inhibitors - Omeprazole
* H2 blockers - Cimetidine, Ranitidine, Famotidine
* Sucralfate - binds ulcers and protects mucosa
* Misoprostol - PGE1 analog - increase gastric bloodflow, decrease gastric acid secretion, increase mucous/bicarb secretion
* Small, frequent meals, more turnout, less stress, more roughage
Prognosis excellent with appropriate treatment and management
Glandular harder to treat
equine
esophageal obstruction
Predisposed? CS? Dx? Tx? Complications? Prognosis
“choke”
Predisposed
* Common in horses with dental problems
* Choke common in Friesians due to possible genetic megaesophagus
Clinical signs
* Ptyalism
* feed/saliva from nostrils
* retching/coughing
* palpable lump in esophagus
Diagnosis
* CS
* unable to pass NG tube
* endoscopy or ultrasound if complicated (or recurrent)
Treatment
* Remove feed/water
* Sedate, NSAIDs, +/- antispasmodic (Buscopan)
* Pass NG tube to obstruction → lavage with head down
* Prophylactic Abx for aspiration pneumonia
* If severe, prolonged → IVF, anesthesia, esophagotomy
Complications: structure, aspiration, diverticulum, rupture
Excellent prognosis for 1st-time offenders and uncomplicated cases
equine
Colitis
Et? CS? Dx? Tx?
Clinical signs
* Depression, inappetence
* colic
* decreased/hypOmotile GI sounds
* ariable degrees of shock/hypotension
* +/- watery or hemorrhagic diarrhea
Diagnosis
Fecal PCR panel - Salmonella, C. perfringens, C. difficile, Potomac Horse fever
* Over 50% cannot diagnose the cause = “Colitis X” - may be antibiotic or stress-associated
* Clostridium and Salmonella zoonotic
FEC for cyathostomes
AUS - look at colon wall thickness, especially right dorsal for NSAID-associated
AXR - for sand
CBC/Chem - dehydration, neutropenia, hypoproteinemia (hypoalbuminemia)
Treatment
* Isolate
* IVF, electrolytes, colloids
* Anti-endotoxic agents and antiinflammatories - banamine, pentoxyifylline, polymyxin B, hyperimmune plasma
* Antidiarrheals - bismuth subsalicylate, biosponge
* +/- Abx - metronidazole for Clostridium or oxtetracycline for PHF
* Prevent laminitis with ice
Can be mild to life-threatening
