Equine Diseases and Management - Quiz 2

Equine Gastrointestinal Tract includes

oral cavity

esophagus

stomach

small intestine

cecum

ascending colon

transverse colon

descending colon

rectum

anus

What side of the horse is the cecum on?

right side

The cheek teeth in horses never stop growing. True or False

True

How many teeth can a mature horse have?

44

Each of the 4 arcades may contain:

3 incisors

1 canine

4 premolars

3 molars

What is wave mouth?

when a tooth or part of a tooth gets short, this gives the opposing tooth the opportunity to overgrow.

How often should horses teeth be floated?

every 6-12 months

Do fractured teeth need to be removed?

yes

What are cavities in horses called?

caries

What is a wolf tooth?

1st premolar, vestigial remnant. Small, no purpose

Are upper or lower wolf teeth more common?

upper; lowers are rare

Are wolf teeth always present?

no

What number are wolf teeth?

105

What is the most common esophageal abnormality?

esophageal obstruction “choke”

What is another issue that can come from esophageal obstructions?

aspiration pneumonia

due to accidental inhalation of obstruction

How is choke relieved?

sedation to lower the head to avoid further aspiration and relax esophageal muscles

Oxytocin to relax striated esophageal muscles

Pass a nasogastric tube

gentle lavage with water ONLY

Why should mineral oil not be used to relieve choke?

the horse can aspirate it and mineral oil in the lungs can cause further serious issues

What should be done if choke persists?

Iv fluids for 12-24 hours in stall without food, water, or bedding

Radiography

* look for obstruction
* look for rupture

endoscopy

surgery (surgery is not preferred)

What is colic?

gastrointestinal pain and its manifestations

What are the categories of colic?

obstructive vs. non-obstructive

large intestine vs. small intestine

medical vs. surgical

Athletic horse with orthopedic injury

impaction colic

Broodmare who has recently foaled

large colon volvulus

Older, obese horse

strangulating lipoma

Horses on alfalfa in the western U.S.

enterolith

Cribbing

epiploic foramen entrapment

Recently dewormed foals and weanlings

ascarid impactions

Clinical signs of Colic:

Reduced appetite

reduction in defecation

laying down more than normal

pawing

flank watching

kicking at the abdomen

stretching out

rolling/thrashing

What is the baddest problem seen in the stomach?

ulcers (gastric ulcers)

What are the 2 types of epithelium in the stomach?

grandular and squamous

What does the grandular epithelium do?

secretes acids and digestive enzymes

What color is the grandular epithelium?

dark pink

What is the squamous epithelium?

essentially the same as the epithelium lining in the esophagus; it is a lighter pink

What is the transition between the 2 types of epithelium called?

margo plicatus

If the enterolith is round, how many will there be?

1

If the enterolith has a flat side, how many will there be?

more than one

What % of colic cases respond to basic field treatment?

90%

What % of colic cases need intensive medical care or abdominal surgery?

10%

What can be done to prevent stomach rupture?

passing a nasogastric tube

How can you check if a nasogastric tube is in the esophagus?

feel of collapsed space (not rigid like the trachea)

negative pressure on aspiration

palpate on the left side (usually)

see on left side

smell stomach gas

successfully siphon stomach contents

How do you check volume of stomach contents?

stomach pump or by gravity flow

put approx 2 liter of water in stomach

maintain water column in tube to siphon out contents

What is an abnormal volume of reflux?

1-2 liters net reflux is abnormal

Which kidney is further forward from the caudal aspect of the horse?

the right kidney

What structures are palpable with a rectal exam?

spleen

caudal pole of left kidney

aorta

cecum

pelvic flexure of large colon

urinary bladder

small colon

small intestine (if distended)

ovaries, uterus, and cervix (mares)

Simple colic findings:

< 1-2 liters net reflux pain easily managed w medication normal to moderately elevated heart rate gut sounds audible by end of work up ' horse is fairly bright rectal is unremarkable, or reveals easily treatable impaction well hydrated

What is the treatment for simple colic?

pain reliever (banamine IV)

laxatives via NG tube

* mineral oil
* dactyl sodium sulfosuccinate(DSS) (not first choice, can cause more pain and irritation)
* MgSO4 (epsom salts)
* water
* electrolyte solution

Complicated colic findings:

>2 liters net reflux

pain poorly responsive to meds

abnormal rectal

signs of dehydration

signs of endotoxemia and/or shock

What are additional diagnostics for complicated colic?

PCV/TP, CBC, serum chemistry

abdominocentesis

ultrasonography

radiography

gastroscopy

exploratory celiotomy

What is the normal fluid color for an abdominocentesis?

yellow and clear

What is the normal total WBC count for an abdominocentesis?

What is the normal total protein for an abdominocentesis?

Where is the best place to perform an abdominocentesis?

to the right of the midline (if no ultrasound available or the spleen is at midline)

midline is best if spleen is not in the way

What are some complications of abdominocentesis?

enterocentesis (accidental entry into organ)

no fluid collected

blood from the spleen

What are gastric ulcers associated with?

stress and NSAIDS

(phenylbutazone and flunixin (Banamine))

What are the treatment options of complicated colic?

instant Rate did from stomach Place IV catheter

IV fluids

* bolus in the face if dehydration
* use hypertonic saline (7%) in the face of shock, followed by isotonic fluids (LRS, 0.0% saline, etc)

Water and/or laxatives

* cheaper than IV fluids
* Very effective for impaction colics
* cannot do if horse is refluxing
* may be repeated frequently
* leave tube in

Reflux excess fluid from stomach

Intravenous Lidocaine Constant Rate Infusion (CRI)

Surgery

How often do we check on a horse that is refluxing?

every 2 hours

What are the indications for surgery for treatment of colic?

abnormal rectal exam findings

abnormal abdominocentesis

abnormal ultrasound

poor response to sedatives and analgesics

duration

persistent pain

worsening of clinical signs

Surgical lesions:

strangulation lipoma

severe impaction (ileum, cecum , ascending colon)

Enteroliths

large colon displacements

epiploic foramen entrapment

small or large intestinal volvulus

mesenteric rent

Medical lesions:

Enteritis

colitis

gas colic

spasmodic colic

many impactions

some colon displacements

What are some signs of Colitis?

diarrhea, low WBC count, +/- fever

What are the treatments for Colitis?

IV fluids to meet hydration needs

Isolate to avoid spread to other horses

\+/- Antibiotics

Meds to stop diarrhea:

* Biosponge
* Probiotics
* Activated charcoal (not used much anymore)
* Sacromyces bolardii
* Yogurt

What are some important parts of client education for colitis?

Deworming protocol

* need to establish plan for entire farm

Dental care

* float adult horses once a year. horses with severe abnormalities may need more frequent floats

Maximize pasture turn out (when available)

Change feed over 7 to 10 day period (this includes hay from 1 batch to another, even if from the same pasture)

Encourage water consumption

* Fresh, clean water
* add salt to diet
* add flavor to water at home, then add same flavor when horse is away from home

What is a horse’s range of vision?

350º

What is a horse’s monocular range of vision?

285º (142.5º)

What is a horse’s binocular range of vision?

65º

Where are a horses’s blind spots?

cone extending 3-4’ in front

from back of head to behind horse

When a horse raises its head…

it is looking at a distant object

When a horse lowers its head…

it is looking a near objects on the ground

Why do horses raise and lower their heads to look at objects?

to place object within a linear area of the retina called the “visual streak”.

This area has a very high concentration of nerve ganglia, giving objects that appear in this area more clarity.

Horses have what level of vision?

20/35

Why do horses have good night vision?

more rods (light receiving cells)

How many types of cones do horses have?

2

What colors can horses see?

Blue and Green

NO red!!!!

first stage of vision in the horse…

clear cornea allows light to enter the eye

2nd stage of horses vision…

light passes through the aqueous humor in the anterior chamber

3rd stage of horses vision…

colored iris contracts, dilating the pupil to let in more light

4th stage of horses vision…

light passes through the vitreous humor in the posterior chamber

5th stage of horses vision…

light hits retina on back of the eye

6th stage of horses vision

optic nerve sends signals to the brain

What is the Corpora Nigra?

dark structures attached to the pupil

What is the purpose of the Corpora Nigra?

purpose is unknown but it is speculated that may shade sunlight

What are corneal abrasions?

partial thickness injuries.

they then to be superficial and no not enter the anterior chamber.

most heal without complication, unless they become infected w bacteria or fungus

What is a corneal laceration?

a laceration in the cornea

full thickness corneal lacerations often allow the iris to protrude through them

What are corneal ulcers?

they vary in severity from very mild to very severe, to the point the eye may need to be removed

What is keratitis?

inflammation of the cornea

often there is an infectious component

All lid lacerations, no matter how old or contaminated, should be repaired?

True

What is conjunctivitis?

inflammation of the conjunctiva

inflammation of the pink tissue that covers part of the eyeball and lines the inside of the lids

often infectious and contagious

When do the conjunctiva commonly become inflamed?

when there is any injury of disease process

What is Equine Recurrent Uveitis?

repeated inflammation of the uveal tract

recurrent inflammatory process of the internal structures of the eyes

What are the 3 main parts of the uveal tract?

(1) the choroid (tissue layer filled with blood vessels); (2) the ciliary body (the ring of muscle tissue the changes the size of the pupil and the shape of the lens); (3) the iris (the colored part of the eye)

What is the choroid?

the tissue layer filled with blood vessels

What is the ciliary body?

the ring of muscle tissue that changes the size of the pupil and the shape of the lens

What is the iris?

the colored part of the eye

What are the classic signs of Equine Recurrent Uveitis?

pain

swelling

blepharospasm

epiphora

What are other names for Equine Recurrent Uveitis?

moon blindness

periodic ophthalmia

What is the treatment for Equine Recurrent Uveitis?

drugs to reduce the iris constriction (atropine) and to reduce the inflammation (topical steroids and systemic NSAIDS).

What is habronemiasis?

a larval infestation of a nematode

What should equine eye exam history questions address?

previous eye problems

duration of the current problem

any treatments that have been given

response to treatments

has the condition changed or been the same

What do you evaluate at a distance on an equine eye exam?

\
general attitude

symmetry

alertness

comfort level

What function and response tests should be evaluated on an equine eye exam?

Pupillary light reflex (direct and consensual (indirect))

menace response

palpebral response

What is the menace response?

a simple test of vision.