Horses Flashcards
The ability to extend the hock while flexing the stifle is characteristic diagnostic feature of what condition?
Peroneus tertius rupture disrupts the stay apparatus- when intact, this muscle prevents this motion,. Also mentioned: jerking movement as leg moved forward
Horse % dry matter protein
12% (1.3 g/kg, 40g/1000kcal)
Most common cause of maxillary sinusitis
Tooth root abscess (first molars)
Strangulating lipoma signalment
15-20, gelding, obese
Enterolith formation food, type of lith
Alfalfa hay in California; mg ammonium phosphate
Findings: fiddleneck consumption
megalocytosis, bridging portal fibrosis, biliary hyperplasia of liver. (pyrrolizidine alkaloid)
Findings: yellow star thistle
nigropalladial enecephalomalacia- loss of upper motor gnglia leading to loss of inhibition and dystonia (impossible to eat)
Shaker foal syndrome- infectious agent
Clostridium bolulinum pre-formed toxin ingestion only
Shake foal syndrome pathophys
spore toxin blocks acetylcholine at NMJ+ flaccid paresis/paralysis
Shaker foal syndrome CS
weak tongue, weakness, flaccid paralysis, resp depression that cna lead to death
Cerebellum- responsible for
coordination (range, rate, strength of movement), balance, posture
CP deficits are on the ____ side of a brain lesion
Same
Brain region w/ CS: intention tremor, hypermetria, hypometria, ataxia; normal mentation
Cerebellum
What side is the lesion on compared to fast-phase of nystagmus
Fast phase away from lesion
Lesion/head tilt association
Same side
Name two ddx for symmetric ataxia, weakness, limb spasicity, toe dragging
EDM or CVM (wobblers)
Dx EDM
no definitive test, low Vit E suggestive
Club foot pathophys
(flexural deformity of DIPj) - d/t DDF tendon contracture
Most common cuase of bacterial keratitis in horse
Psuedomonas- gram negative (less: e. coli, staph- gram +)
Cantharadin tox- effect
Endotoxic shock and renal failure (blister beetle toxicity)
Agent in Tyzzers Dz
Clostridium piliforme (aka bacillus piliformis)- (the only gram - clostridium!)
Cause of Theiler’s Dz
4-10 weeks post Tetanus antitoxin most commonly (plasma blood)
What is bog spavin
Chronic synovitiswith bilateral effusion of tibio-tarsal joints
What is bone spavin
osteoarthritis of the hock
What important structures are in the guttural pouch
Internal and external carotids, cranial sympathetic trunk, CN 9, CN 7
Blocked by palmar digital
50-70% of the palmar surface of the foot including most of DIPj (except proximodorsal)
Blocked by abaxial sesamoid
Foot and PIPj, skin over palmar pastern and distal dorsal pastern
Blocked by low four point
entire MCPj (fetlock) and distal
Blocked by high four point
metacarpal region, entiere MCPj and digit structures
Tx keratitis with typical agent
Tx with aminoglycoside like tobramycin (Gram neg- Pseudomonas)
What agent/disease is most likely to cause pulmonary abscess, what age is this common
Rhodococcus Equi pneumonia- foals 2-6 months
Dx: Increasing forelimb lameness and short, choppy gait, swelling over fetlock, pain on flexion
Osselets
What are osselets, cause
Inflammation of the periosteum on dostal distal epiphyseal surface of MC3 and fetlock (usually bilateral), chronic stress injury from running
CS, pathophys purpura hemorrhagica
Type III (Ag-Ab complex) usually from strep equi equi, S. e. e. vax or resp pathogens; aseptic necrotizing vasculitis –> hemorrhage, edema, sloughing
Breed predilection- equine night blindness and recurrent uveitis
Apaloosa
Fescue toxicity
prolactin suppresion, thickened placenta, dystocia, agalactica
Red maple tox
heinz body anemia
St John’s Wort tox
Photosensitization, hepatotoxicity
CS EHV-3
papules, pustules, ulcers to external genitalia (including balanoposthitis- prepuce)
Pathophys of all EE’s
mosquito –> lymph spread–> 5d
How can you artificially start breeding season
16 hours of light, 60 days before breeding
What causes sheared heels, tx
heel asymmetry from foot/gait imbalance; corrective shoeing and supportive bar shoes
Ataxic/hypermetric 5-10 d post turnout: MOA, Px
GABA receptor de-inhibition - resolve within days of removing from rye/bermuda grass
Stringhalt agent
sweet pea, dandelion- when both hind affected (trauma cause of unilateral)
Cauda equina syndrome- MOA
Autoimmune
Breed: OA malformation
Arabians
Breed: cerebellar abitrophy
Arabians
Meningitis- age, agent
neonates, secondary to bacteremia
Most common CNS tumor
Lymphoma
Most common tumor in greys
Melanoma
Transmission, breed, signalment of Recurrent Exertional Rhabdomyolysis (RER)
Autosomal dominant with variable expression in nervous 2-3y TB- a degenerative change in myofibers
Tx Recurrent Exertional Rhabdomyolysis
Low carb, high fat - NO high grain- predisposes; less stress
HYPP (hyperkalemic periodic paralysis) breed, transmission, MOA
Fancy QH (paint/appaloosa)autosomal dominant, muscle membrane sodium channels–> weakness, collapse, fascic THIRD EYELID
Chronic mgmt of HYPP
Acetazolamide K-wasting diuretic; genetic test!
Ddx RER; dx, tx
Polysaccharide Storage Myopathy (PSSM)- mm. biopsy- necrosis/atrophy, increased glycogen; reduce stall rest, train gradually, increase fat/decrease soluble carbs
Agent- pigeon fever; tx
Pectoral abscesses! corynebacterium pseudoTB - penicillin or TMS, establish drainage
Cause of imm=med myositis
S. equi, influenza
Tx clostridial myositis
Make abscess aerobic by opening, systemic penicillin
Breeds- GBED
Glycogen branching enzyme deficiency- auto recess in QH, paint; foals die in a few months bc cant store sugar
Transm, breed malignant hyperthermia
Auto dom, QH
Induce 2nd deg AV block
alpha 2 agonist sedation
Tx afib
quinidine- but high SE; conversion under anesthesia only
When does PDA close
1st day/week
T of Fallot-
overriding aorta, VSD, hypoplastic pulmonary a, RV hyperplasia (+ PDA = pentalogy
Most common site, cause- endocarditis
Ao = mitral strep
Most common site of degeneration
Ao > mitral
Systolic left murmur: valve, cause
mitral- exercise intolerance
Systolic right murmur: valve, cause
tricuspid- athletic, physiologic
Diastolic left murmur: valve, cause
Ao, older horse
Ddx dependent edema
hypoalb, intrathoracic dz (mediastinal masses, pleuritis), vasculitis (purpura, EVA, EIA, ana), urticaria, CHF
Bacterial cause of hemolysis
Lepto
Parasitic cause of hemolysis
Anaplasma, babesia
Three heinz body anemia causes
Phenothiazine tox, wild onion, red maple
Reportable ddx for hemolysis
EIA
MOA, CS, Tx- purpura hemorrhagica
Type III HS post- S. equi equi (or strangles vax); ventral/peripheral painful vasculitis/edema, petechiation of MM; steroids
EIA- transm, agent, MOA
Retrovirus, biting flies; HS vasculitis, imm-med hemolysis- virus attaches to RBC
Dx, Tx EIA
Coggins! isolation, slaughter, report
Agent, transm: equine granulocytic erlichiosis;
A. phagocytophila via Ixodes (morulae in neuts, eos!)
Dx/Tx equine granulocytic erlichiosis
Oxytetracycline
what does Ixodes carry
anaplasma phago (equine granulocytic erlichiossi) babesia caballi, theileria equi (eq piroplasmosis)
CS, tx- equine piroplasmosis
anemia, monocytosis, icterus, Hgb’uria, lethargy, eyelid swelling; FAD- iso, euth
Most sen renal measure
Creat
three nephrotoxic Abx
ATP- aminoglycosides, tetracyclines, polymixin B
Effect of aminoglycosides; how to lower risk
renal tubular necrosis; SID»_space; TID
tendon calcification lameness, great vessel calcification: dz, cause, clip path findings
cestrum diurnum- Vit D tox (D3>D2); HyperCa, hyperPhos, azo, isosthenuria with
Cause of imm-med GN
EIA, post-strangles/lepto/herpes
Dx uroperitoneum
HypoNaCl, hyperK, Ab tab creat 2x serum
Young acute diarrhea (2)
C. dif/perf, sepsis, rota
Post-op or performance horse actue D
Right dorsal colitis
Widespread acute D
Salmonella, rota
Post-Abx D
Salm, C. dif
Dx salm
5 cultures q 12 h
Dx coronoa vs rota D
Corona PCR, Rota ELISA (think: CP, RE)
Dx PHF agent
N. risticii PCR of buddy coat
Fluids for acute D
Avoid acidifying NaCl- plasma, hetastarch colloids
Tx endotoxin in D
Flunixin
Which D Abx to use in adult horses
ONLY in- PHF: oxytetra; Clostridium: metro (or vanco in Ca resistance); luekopenia
Most common Salm serogroup
B, C, E (A-I pathogenic)
What % horses with GI dz shed Salm
60% (1-5% are subclin shedders)
Transm: PHF
snail or mayfly ingestion (has trematode or metacercariae)
CS: PHF
laminitis, fever, +/- D
C. perf enterotoxin type severity
C worse than A (C.P-CA)
C. dif toxins, targets
A- entero, B- cyto (think consonant/vowel) (C.D-AB)
What is DTO-smectite
BioSponge toxin binder in clostridium
CS- cantharidin
Sloughing/necrosis of oral, GI, urinary mucosa; hypoCa, Mg, prot
Bute- SE and SE-MOA
Right dorsal colitis- mild colic, weight loss, hypoAlb if colon leaky d/t decreased mucosal protection from prostaglandins
Tx RDC
complete pelleted food
Weanling diarrhea and PLE - agent
(age- 6-9m) Lawsonia intracellularis (gram- rod)
Dx, Tx lawsonia
IMPA serology AND fecal PCR; oxytetra
DPJ findings, MOA
Duod-prox jejunitis: ++ reflux, pain (mod-sev)- d/t hypersecretion of SI = dec. motility ((28% get laminitis)
2 forms of gastric ulcers and causes; Tx
Squamous (TB, pastured broodmare; stress, meal feed) > glandular (NSAID); omeprazole
Lawsonia sig/presentation, dx findings:
6-9m weanling with D, corrugated SI (ileum >jej), hypoproteinemia
Acute abdominal hemorrhage in periparturient- location
middle uterine a. (in broad ligament)
Seq: epiploic foramen entrapment
Caudal vena cava rupture –> acute abd hemorrhage
Most important liver values
GGT, SDH
Liver function test
Bile acids (pre/post), ammonia, clotting
Tx, Px Theiler’s dz
Lactulose, neomycin, support for acute hepatic necrosis- poor Px
Cause of cholangiohepatitis
Ascending G (-) GI rods
Hyperlipemia vs Hyperlipidemia- define, Tx
-LIPemia TG <500mg/dL, LIPIDemia-TG > 500mg/dL (Neg energy balance- give gluc/insulin IV)
2 toxic hepatopathies
Aflatoxins, BG algae, clover
Tx PA tox
Steroids, poor PX bc CS already too late
PA plants
Crotalaria, senecio
FOPT
<400 (partial 400-800)- detect: SNAP>RID
What does Coombs test dx
immunoglobin agglutination- used in NNI
Neonatal isoerythrolysis (NNI) - most common Ab
Aa and Qa
Signalment- Neonatal isoerythrolysis (NNI)
Multiparous mares, rebred to same stallion
Ddx NI
septicemia
MOA- sweet itch
Culicoides HS I- CS from self trauma d/t itch
Sweeny- MOA
Suprascapular nn. dmg (infra, supra spinatus mm.)
What is ringbone
OA or bony exostosis in the pastern (high ringbone) or coffin (low ringbone) joints.
Most common cause of pneumonia in both adult and foal
Strep. streptococcus
Most common 2-6m foal pneumonia
Rhodococcus equi
Equine Motor Neuron Dz- cause, findings
Low Vit E, “elephant on drum”, mm. atrophy, tremble/fasciculations, shifting body weight, low head carriage in older horse dry lots
Dx high freq repetitive bursts and ‘dive bomber’ sound heard on EMG
is produced by repetitive firing after contraction of affected muscle fibers and is essentially pathognomonic for myotonia.
Foals with self-resolving copious nasal d/c and mares with late abortion
Herpes
Dx, agent UAE respiratory case
Mallein test for nasal form of Glanders; agent- Burkholderia mellei
Tx acute abdominal hemorrhage in peri-parturient mare
Aminocaproic acid to facilitate clot stabilization via blocking plasminogen activation ( into plasmin-clot dissolver)
Block laminitis
Abaxial sesamoid
Low-potassium hay
Timothy
