2020-2021.Vol 36.iss1. clin path for equine practitioner

Question 1

Diseases of the equine urinary System

How is glomerular disease distinguished from injury to other areas of the urinary tract?

Answer 1

persistent proteinuria with or w/o azotemia

Question 2

Diseases of the equine urinary System

list differentials for protienuria:

Answer 2

-lower urinary tract disease: cystitis
-physiologic d/t nonrenal inflamm diseases
-transient proteinuria after heavy exercise

Question 3

Diseases of the equine urinary System

Diseases affecting the tubulointerstitium are clinically characterized by:

Answer 3

azotemia
dec urine concentration (isosthenuria)
inability to process electrolytes or maintain acid-base homeostasis

Question 4

Diseases of the equine urinary System

list nephrotoxins that are causative etiologies for tubular necrosis in horses

Answer 4

-oak (Quercus spp) flowers, leaf buds or acrons with toxic gallotannins
-oxalate containing plants
-red maple leaves
antibiotics: amingolycosides,sulfonamides, oxytetracyclines, amphotericin B
-imidocarb diproprionate
-vitamin K3 (menadione sodium bisulfite)
-inorganic mercury & arsenic tox

Question 5

Diseases of the equine urinary System

What are differentials for myconecrosis in horses?

Answer 5

infectious: clostridia spp & S. equi
nutritional: vit E/se def
toxic plants & drugs (ionophores)
genetic (PSSM)
exertional rhabdomyolysis

Question 6

Diseases of the equine urinary System

However uncommon, leptospira interrogans serovar pomona nephritis is reliably diagnosed with what method?

Answer 6

Warthin Starry histochemical stain of tissues & seroology= reliable diagnostic tool

Question 7

Diseases of the equine urinary System

Embolic nephritis in horses is caused by what organism?

Answer 7

Actinobacillus spp– in both adults & foals

Question 8

Diseases of the equine urinary System

What is a sign of NSAID toxicity?

Answer 8

hypoproteinemia/hypoalbuminemia (GI LOSS)
azotemia
INC phosph
mild DEC Ca
Inability to concentrate urine

Question 9

Diseases of the equine urinary System

What are predisposing factors to pyelonephritis?

Answer 9

urinary stasis
cystitis
urolithiasis
other urinary obstruction

Question 10

Diseases of the equine urinary System

What congenital anomalies of the kidneys are seen in horses?

Answer 10

renal dysplasia
hypolasia
polycystic kidney disease
horsehoe kidney

Question 11

Diseases of the equine urinary System

Primary renal neoplasia is rare in horses, what is the most common primary renal neoplasia in horses?

Answer 11

renal carcinoma

Question 12

Diseases of the equine urinary System

What is the most common congenital lower urinary tract disease in horses?

Answer 12

ectopic ureters
**greater prevalence in females than males

Question 13

Diseases of the equine urinary System

What is the most common urolith in horses?

Answer 13

calcium carbonate

Question 14

Diseases of the equine urinary System

Uroliths in horses are most common in males vs females?

Answer 14

males

Question 15

Diseases of the equine urinary System

What is the most common neopalsma of hte lower urinary tract?

Answer 15

squamous cell carcinoma
** reports of lymphosarcoma, transitional cell carcinoma, fibromatous polyps

Question 16

Ocular pathology

What are common eyelid neoplasms in horses?

Answer 16

sarcoids & SCC
((others: pappiloma, melanocytoma/melanoma, lymphoma/LSA, neurofibroma, basal cell carcinoma, hemangiosarcoma fibroma/fibrosarcoma, mast cell tumor, angioma/angiosarcoma

Question 17

Ocular pathology

Which breeds of horses are predisposed to developing melanocytic tumors of the eyelid?

Answer 17

gray or white-haired horses
Percherons
Arabians

Question 18

Ocular pathology

Lists causes of conjunctivitis in horses (parasitic, fungal, bacterial , viral, etc).

Answer 18

Question 19

Ocular pathology

What are the most common microbial isolates from conjunctival/corneal collections in healthy horses?

Answer 19

Gram pos: Bacillus, corynebacterium, staphylococcus, streptococcus, streptomyces

Gram neg: Acinetobacter, Enterobacter, Escherichia, Moraxella, Pseudomonas

Fungal: Aspergillus, Cladosporium

Question 20

Ocular pathology

Why is keratitis caused by EHV-2 challenging to treat?

Answer 20

b/c recurrence is common (life-long infection)
-req antiviral therapy
-symptomatic tx of ulcers

Question 21

Ocular pathology

EHV-2 keratitis definitive diagnosis

Answer 21

ID of the virus from an affected cornea via PCR or virus isolation

Question 22

Ocular pathology

What is the most common cause of equine blindness?

Answer 22

equine recurrent uveitis (ERU)
**US prevalence of 25%

Question 23

Ocular pathology

What are C/S of chronic stages of ERU?

Answer 23

hyperpigmentation
corpora nigra atrophy
posterior synechia
cataract
lens luxation

Question 24

Ocular pathology

What ocular abnormalities are seen with equine motor neuron disease?

Answer 24

honeycomb pattern of yellow/brown pigment (ceroid/lipofuscin) within the tapetal fundus

Question 25

Ocular pathology What are nutritional causes of blindness in horses?

Answer 25

thiamine deficiency equine leukoencephalomalacia

Question 26

Skin Disease What is diagnostic on biopsy for pemphigus foliaceus?

Answer 26

acantholytic cells within vesicles intraepidermal clefs **do not surgically prep the area

Question 27

Skin Disease Describe equine multisystemic eosinphilic epitheliotropic disease (MEED)

Answer 27

rare chronic progressive dz assoc with exfoliative dermatitis & infiltrations of eosinophils & lymphocytes in various organs

Question 28

Neurologic diseases in horses Hepatic encephalopathy Gross lesions Diagnosis

Answer 28

Gross lesions: diffuse hepatic necrosis or fibrosis Dx: increase in serum hepatic enzymes, gross lesions in liver; microscopic: Alzheimer type II astrocytes in the brain

Question 29

Neurologic diseases in horses Leukoencephalomalacia Gross lesions Diagnosis

Answer 29

Gross lesions: edema & malacia of the white matter of the cerebrum Diagnosis: **gross lesions in the brain

Question 30

Neurologic diseases in horses Nigropallidal encephalomalacia Gross lesions Diagnosis

Answer 30

Gross lesions: bilateral symmetric malacia focis in the globus pallidus and/or susbtantia nigra Diagnosis: Gross lesions, evidence of ingestion of yellow tar thistle or russian knapweed

Question 31

Neurologic diseases in horses Rabies Gross lesions Diagnosis

Answer 31

Gross lesions: hemorrhagic malacia in the spinal cord Diagnosis: floruescent ab testing of hte brain from accredited state laboratory

Question 32

Neurologic diseases in horses Equine protozoal myeloencephalitis Diagnosis

Answer 32

Diagnosis: microscopic lesions: nonsuppurative to granulomatous myeloencephalitis with intralesional merezoites

Question 33

Neurologic diseases in horses What is the causative toxin of Nigropallidal encephalomalacia?

Answer 33

Centaurea solstitialis (yellow star thistle) Rhaponticum repens (Russian knapweed)

Question 34

Neurologic diseases in horses Compare EDM to EMND

Answer 34

Question 35

Neurologic diseases in horses What clinical signs are seen with polyneuritis equi?

Answer 35

perineal anesthesia urinary incontinence urinary bladder atony with sabulous cystitis fecal retention tail paralysis hind limb incoordination +/- horners syndrome (peripheral & CN involvement)

Question 36

Neurologic diseases in horses What are clinical signs of equine grass sickness?

Answer 36

colic, dysphagia, ng flux with linear ulcers in the distal esophagus, gastric & SI fluid-filled dilation, colonic impaction, sweating, mm tremors death d/t gastric rupture Chronic: bilateral ptosis with ventral deviaiton of eyelashes, rhinitis sicca, mucus- coated hard feces, weight loss, death d/t emaciation

Question 37

Neurologic diseases in horses How do you diagnose equine grass sickness antemortem?

Answer 37

C/S , clinical history Exploratory celiotomy: full thickness ileal biopsy

Question 38

Neurologic diseases in horses tetanus toxins work at what sites within the CNS?

Answer 38

peirpheral motor end plates: SC/Brain SNS synapses **inhibits release of GABA causing spastic paralysis

Question 39

Neurologic diseases in horses what is the target of botulinum toxin?

Answer 39

blocks neurotransmitter acetycholine exocytosis vesicles in peripheral myoneural synapses causing bilat symmetric flaccid paralysis

Question 40

Neurologic diseases in horses What are the mechanisms that result in botulism intoxication?

Answer 40

1. ingestion of preformed toxin from the environment (most common) 2. elaboration of toxin from C botulinum infection in wounds 3. ingestion of C botulium spores, which produce toxin w/in the GIT

Question 41

Neurologic diseases in horses On smear or culture of an infected wound, what is the characteristc appearance of tetanus?

Answer 41

gram positive tennis racket-shape bacteria

Question 42

Toxicology for the Equine Practitioner Toxicosis with what two toxins produces gross lesions w/in the kidney & urinary bladder

Answer 42

Red maple leaf tox-- kidney chronic sorghum poisoning-- urinary bladder

Question 43

Toxicology for the Equine Practitioner What disease in horses resembles Parkinson disease?

Answer 43

Equine Nicropallidal encephalomalacia **substania nigra compacta: loss of dopaminergic neurons & Lewy body formation

Question 44

Toxicology for the Equine Practitioner What is thought to be the toxic principle of yellow-star thistle & russian knapweed?

Answer 44

Repin**suspect

Question 45

Toxicology for the Equine Practitioner What is the cause of equine leukoencephalopmalacia?

Answer 45

ingestion of corn infected with fungus fusarium moniliforme

Question 46

Toxicology for the Equine Practitioner What is the primary toxin involved in equine leukoencephalomalacia?

Answer 46

fumonisin B1

Question 47

Toxicology for the Equine Practitioner What is the pathogenesis of equine leukoencephalomalacia?

Answer 47

sphingolipid biosynthesis by inhibiting enzyme ceramide synthase-- results in accumulation of bioactive intermediates of sphingolipid metabolism-- leads to cell death

Question 48

Toxicology for the Equine Practitioner Which plant species are implicated in PA toxicity?

Answer 48

1. Senecio 2. Crotalaria 3. Cynoglossum 4. Amsinckia

Question 49

Toxicology for the Equine Practitioner Which species of senecio-- responsible for most PA poisoning in W USA

Answer 49

1. tansy ragwort-- S. jacobaea 2. threadleaf or wooly groundsel-- S. douglasii var longilobus 3. Riddells groundsel-- S. riddellii

Question 50

Toxicology for the Equine Practitioner Where is the greatest concentration of PA toxin?

Answer 50

flowers: Senecio spp seeds: crotalaria, amsinckia

Question 51

Toxicology for the Equine Practitioner What is the mechanism of PA toxins in hepatotoxicity?

Answer 51

inhibit DNA synthesis & mitosis in the liver--> formation of megalocytes histologically

Question 52

Toxicology for the Equine Practitioner Is megalocyte formation pathognomonic for PA toxicity?

Answer 52

No, because also seen with alfatoxicosis

Question 53

Toxicology for the Equine Practitioner What are the primary oxidants involved in red maple leaf tox?

Answer 53

-gallic acid & tannic acid -pyrogallol- may contribute

Question 54

Toxicology for the Equine Practitioner What are the differentials for the following lesions histologically: -hemoglobinuric nephrosis, generalized icterus, splenomegaly -Histo: renal tubular epithelial degenreatoin & necrosis w/ intratubular hemoglobin casts and heaptocyte degneration in centrilobular areas

Answer 54

-copper & nitrate toxicosis equine infectious anemia babesiosis

Question 55

Toxicology for the Equine Practitioner What clinical syndromes are seen with chronic sorghum consumption in horses (rarely cattle)?

Answer 55

cystitis & posterior ataxia (sorghum cystitis & ataxia syndrome)

Question 56

Toxicology for the Equine Practitioner C/S seen with chronic sorghum ingestion

Answer 56

posterior ataxia, progressing irreversibly to flaccid paralysis urinary incontinence caused by overflow from a distended, atonic bladder

Question 57

Toxicology for the Equine Practitioner What is the MOA of cardiac glycosides?

Answer 57

inhibit the transmembrane sodium-potassium ATPase pump causing a rise in intracellular sodium & calcium **in turn result in increased force of myocardial contraction

Question 58

Toxicology for the Equine Practitioner what is the toxic principle of white snakeroot?

Answer 58

tremetol

Question 59

Toxicology for the Equine Practitioner Why are c/s of toxicity caused by white snakeroot seen in young animals?

Answer 59

b/c toxin is rapidly excreted in milk **nursing young can see c/s w/o maternal toxicity

Question 60

Toxicology for the Equine Practitioner Besides white snakeroot, what are other plants that can cause gross myocardial lesions in horses?

Answer 60

cottonseed (gossypium spp) senna or coffee senna plant (cassia occidentalis or C obtusifolia)

Question 61

Respiratory disease diagnostic approaches in the horse what are the established reference ranges for BAL samples in horses?

Answer 61

macros: 50-70% lymphs: 30-50% neutrophils: <5% eos: <0.1%