PSSM

EPSM

EPSSM

Equine     polysaccharide    storage
myopathy

 two distinct disorders

PSSM
is a disorder causing tying up in Quarter-horse related breeds.


 EPSM
is a disorder causing wasting, weakness,  abnormal gait
in draft-related breeds

both disorders are closely related

Researchers at the College of Veterinary Medicine
at Cornell are involved in an ongoing study of
 a muscle disease that could affect
all draft horse owners

epsm is a newly-recognized disease,  although it has
 likely been around for hundreds of years.

has been identified in many horse breeds,  but appears to be 
 particularly severe and difficult to detect
in the draft breeds


confirmed in 
 Belgians, Percherons,  Clydesdales, Shires
Haflinger, Norwegian Fjord,  Suffolk
Irish Draft,  draft crosses, draft mule

a cause of severe muscle wasting in both young
 and older horses


tying up
Monday Morning Disease
shivers

look for abnormal hind limb gaits
 
down horses either during work at rest
following general anesthesia & foaling.
 easily misdiagnosed  AS  colic.

signs
increased temperature  or (hyperthermia)
during recovery from anesthesia .


 draft horses have been known for many years
to be prone to problemsassociated with
 general anesthesian




affected Horses CANnoT GET adequate muscle energy
from carbohydrates
which are the main source of energy.

 diet change involves decreasing carbohydrates
and ADDING fat.

ways to add fat
vegetable oil,  powdered animal fat
 commercial feeds high in fat.

 This dietary therapy appears to be effective.
 many cases showing 100%  improvement. 
  most effective when started in early stages of disease.
HORSES NOT TREATED IN TIME CAN DIE.
diagnosis is made by muscle biopsy.




THE DIFFERENCE BETWEEN EPSM AND
"MONDAY MORNING DISEASE"

"Monday Morning Disease" is the disease in hard-working draft horses that are given a day off with full grain.  When they are asked to work the next day, horses show severe signs of "tying up".  muscles become stiff,   begin to degenerate,   horse will stop moving
and may even go down

this Massive muscle injury may result in release of the pigment
myoglobin from damaged muscleS.  urine becomes a dark red-brown
(myoglobinuria)  Because of this urine color,  the disease has also been called
"azoturia"
Other names include
"set fast"
"exertional myopathy"
"exertional rhabdomyolysis".

exactly What it is,  that puts them "over the edge" into massive muscle injury is still not clear But studies of muscles,  from horses that have had signs of
"Monday Morning Disease"
show that EPSM is a common underlying condition in these horses.


"Shivers" is a condition which abnormal hind leg action is seen, especially when the horse backS or turns. It is very similar to "stringhalt"

Classic "shivers" horses also have tail elevation, and quivering.

the two disorders are very similar in early stages.

Horses with "stringhalt" will show no other signs, but "shivers" is associated with progressive muscle wasting and weakness, although it may be years
 before these severe signs are seen.

 
EPSM has been shown to be an underlying condition in several draft horses with
"shivers". owners see lack of energy to the powerful hind limb muscles and  abnormal action due to muscle cramping.


HOW WELL DOES DIET THERAPY WORK ?

 diet therapy has been life-saving.



IMPORTANT TO KNOW ABOUT TREATING EPSM
exercise is the second most important thing horses with EPSM need after dietary fat.

Standing in a tie stall makes horses worse.

Giving a horse as much daily turnout and regular work is critical.



WHAT IS THIS DIET?

it should be at least 20-25% of total daily calories from fat
decrease carbohydrates
increase fat
Good quality hay and pasture is vitally important.

replacE gRain with alfalfa pellets
add vegetable oil
supplement vitamin E and selenium

FEED OIL
vegetable oil, soy, canola,  corn oil

FEED  FAT
powdered animal fat.  Beware most animal fat products are designed to be fed to
 cows. horses will not be able to digest them. There are some products designed to be fed to horses..... Fat Pak 100....Powdered rice bran.  

 these feeds are only 15-20% fat instead of 100% fat. 5-6 times more will need to be added to the feed to supply needed calories.

Some horses will not eat alfalfa pellets. TRY
Purina Strategy
 Purina Athlete
 Nutrena Compete
NUTRENA XTN   what we use

feed 20-25% total daily calories from fat
not just a 20% fat feed

high  protein  important...especially in horses with
 muscle wasting

CAN A "NORMAL" HORSE BE FED THIS TYPE OF DIET ?

WHEN THERE IS a confirmed EPSM horseIN THE BARN,  feed all horses the same diet. There is
no danger in feeding a "normal" horse this type of diet.  in some instances....this type of diet actually is better for horses.  For example with high fat feeds, horses produce less body heat during work.  They are less prone to colic or founder. 

the reduced carbon dioxide production during exercise may benefit horses with heaves.


HOW MUCH IS THIS TYPE OF FEEDING GOING TO COST?


Although it would initially appear that this type of feed is much more expensive...this is not the case.  High fat feeds are so high in calories that the amount of feed necessary... is much less.  Fat provides more than twice the calories. For example

 2 cups of oil=4000 Calories

whereas 1 lb of corn, oats, sweet feed, or other commercial feeds provide only
1200-1400 Calories
it will cost a bit more to feed your horse,  However,  this type of diet is likely to extend the productive life of the horse.


HOW COMMON IS THIS DISEASE IN DRAFT HORSES ?

EPSM is far more common in draft horses than initially thought. 
over 50%.
This means if you have 2 draft horses or draft crosses, the likelihood that at least 1 horse
is affected is very high.

if the first sign ...of a problem...is a horse down...unable to rise...the chances of pulling that horse through even with stomach tubing with vegetable oil and/or intravenous treatment
with lipids are  50% or less.

This disease is more easily prevented than treated

THE IMPORTANT THING IS 
LOWER CARBS
INCREASE FAT
 VITALLY IMPORTANT


SARA SHALDA
SRASHALDA@AOL.COM

EPSM

 a genetic predisposition. horse fails to digest grains properly.

The result leads to damage to muscle tissue during exertion.

approximately two-thirds of all draft horses have the predisposition.

A  BIOPSY  can determine IF the horse has EPSM.

An endocrine test after exercise may detect EPSM
related muscle damage.

EPSM can be fatal to affected horses.

Muscle wasting especially in the rear quarters. 

Muscle weakness. 

Gait abnormality or lameness 

Work intolerance .
Poor performance
"Tying Up"
 "Monday Morning Sickness"
Stringhalt
Shivers
A peculiar 'hitch' in a rear leg while walking
Dis-coordination in backing
Failure to rise after anesthesi



TREATMENT

the horse gains no nutrition from grains other than the calories. Since the starches and sugars
 in grains cause specific digestive problems... the approach is to replace starch and sugar calories
 with fat-based calories.   The result is the
'added fats' diet
the daily ration is divided into two feedings

1.2% to 2.1% bodyweight in good quality hay

2 cups  oil per 1,000 lb bodyweight
Vitamin E
Selenium
Plenty of fresh water
Exercise to the horse's comfort level
salt and mineral supplements


Improvement of EPSM symptoms may take 4-6 months.

Adding the fat calories to the diet is as important as removing the starches and sugars from grain.

Depending on severity ...the horse may have comfort restrictions in exercising or work but some exercise is required to begin rebuilding damaged muscles.

 As the recovery proceeds,,, exercise may increase to best occupy the horse's attention
 and maintain recovery.

Molasses is added to many feeds and grains to control dust and to sweeten the feed
to entice appetite
 The sugars and starches in molasses are a problem for EPSM horses

 The horse's appetite will often decline when molasses is withdrawn.   This will pass
as the horse relearns the taste of feed without molasses.

Some regions are selenium  IN-sufficient.  additional supplements
should be added with care.  A  veterinarian can advise
about local selenium levels.

Part of the hay ration may be taken as
beet pulp shreds
 alfalfa pellets
 or a combination to provide a carrier to pour the oil over for feeding.


The specified level of vegetable oil... 2 cups./1,000 lb bodyweight

 targets a dietary level of 24% calories from fat sources.

 Several commercial feed companies now provide feeds with reduced sugars and starches
 and added fat sources.  These feeds can reduce the amount of additional vegetable oil needed
 to meet the dietary goal, ((2 c./1,000 lb)/day). or in some cases will meet the goal without
additional fat calories.  
 At least one company manufactures a dry fat supplement that can be used
instead of liquid vegetable oil

One strategy to introducing vegetable oil.  begin with 1/4 cup (125 g) vegetable oil
 on one feeding.    Continue for several days until the horse is eating both feedings well
 Then add 1/4 c. to the other feeding for 2-3 days

 Every 2-3 days increase by another 1/4 c

If at some point the horse stops accepting the increase...back up a step or two
 for 2-3 days and resume the progression until the target amount
for that horse is achieved.

 This approach is consistent with always making diet changes gradually over at least
2-3 weeks...


Because the therapy links diet to weight of the horse... EPSM horses need to be
 separated at feeding time... (usually 45 minutes or less) so that the horse
gets fat calories proportional to body weight.

The therapy appears to be quite benign with most horses benefiting
 even non-EPSM horses.

 Other observed effects of the non-grain fats based diet
include
 improved recovery time from exercise
improved heat tolerance

Horses that experience mood swings due to blood sugar excursions
 from starches and sugars in the diet often show a more even attitude
on the added fats diet

 Some horses with chronic colic have shown improvement

  some 'hard to keep' horses have been more thrifty
(less feed needed to maintain condition)
on the added fats diet

Several researchers including Beth Valentine while working at the Cornell University pathology labs
 investigated deaths of heavy horses from muscle wasting.   They found a that the muscle wasting
 an occasional cause of death in heavy horses was causeD by 
a peculiar type of starvation of the muscle siting the starches and sugars link.


Dr. Beth proposed the vegetable oil  Vitamin E/selenium therapy   and the endocrine test to detect presence of  the condition in living horses

The recent  announcement
 of the condition in horses
 in use for decades or centuries
 met with a degree of skepticism


 especially as the therapy was
 to remove grains
from the horse's diet


 further research has confirmed
 the condition
and
expanded the list of related effects
 to include:

stringhalt

 shivvers

Azoturia/Monday Morning disease

 tying up

What is Shivers?
Shivers or shivering are names that have been applied to a chronic nervous or neuromuscular syndrome
 in horses that has been recognized for centuries
  In a comparative neuropathology textbook published in 1962
 it was stated that
“in the heyday of equine practice”
 shivering was “as common as dirt.”
Signs of Shivers appear at all ages with cases reported from one year of age through adulthood
 Both genders are affected
The syndrome principally affects the draft horse breeds
reported in Warmbloods and Warmblood crossbreds occasionally in lighter breeds including
light harness horses.. hunters... hunter-jumpers... hacks.. Quarter Horses... Thoroughbreds
 In ponies...shivers is considered uncommon to rare
 The condition develops slowly... and can occur at any age.. as young as one to two years of age
 In a recent study on Belgian draft horses.. no significant difference.. was observed.. in the age and sex distribution
 of horses with shivers ...from horses without shivers..Many horses.. that hold a hind limb flexed... and tremble are said to have Shivers... However... many disorders ..can create irritation.. in the hind limbs ..and cause this type of sign
 The classic disease called Shivers... is a neuromuscular disease... characterized by trembling
of the tail while held erect
 trembling of the thigh muscles...and a flexed and trembling hind limb...
most frequently in the draft horse breeds
One study
of the prevalence of Shivers ...in Belgian Draft Horses ...found that 19% of horses examined.. had signs of Shivers....
No investigation into ..estimates of the prevalence of Shivers.. in other breeds exists.. although evidence suggests
it is much less common ...in non-draft horse breeds...

What are the signs of Shivers
The clinical spectrum of shivers very variable in the degree or manifestation of signs.... The diagnosis of shivers
seldom presents a problem...however ..the signs of shivers ...may be intermittent...occasional...or latent
and very difficult to confirm...Shivers may be extremely difficult... to detect in the early stages... and careful observation ...may be required ...before the diagnosis can be made....The disease primarily affects... one or both
 hind limbs ...and the tail...periodic..involuntary spasms ...of the muscles in the pelvic region.. pelvic limbs
 and tail... Mildly affected horses ...show tenseness or trembling ...of the hind limbs ...and sudden jerky extensor movements.... of the tail ...that cause it to elevate...The degree of tail elevation ..varies considerably ..in different cases................ In more severely affected animals...... upon backing.... the hind limb is suddenly raised...
 semi-flexed....and abducted with the hoof ...held in the air.....poised .....in a spastic state ......for several seconds ....
to one to several minutes.... The limb trembles... or “shivers” ...in suspension... and the tail is
usually elevated ..simultaneously ...and trembles.... The superficial muscles ...of the horse’s thigh
and quarter quiver ....while the tail is ...elevated and tremulous.... After a few moments ...the spasms of the limb
and tail...gradually subside..the limb is then slowly extended
and the foot is brought slowly to the ground
 The signs may reappear when the horse is again forced to move backwards

signs of shivers occur when an attempt is made to move the horse backwards
Occasionally, a horse will exhibit signs if made to move over suddenly in the stall or box
Shivering may also be seen... on lifting or attempting to lift a hind foot... or when the horse is being shod...
 especially when the foot is hammered...In the early stages... the owner notices ...the horse snatches up the hind limbs ...when they are being picked.... up to clean the feet or to be shod.... The condition may progress
so that the horse becomes impossible to shoe... Even in well-developed shivering cases,.... signs may not be seen
 when the horse is standing still....When the horse is moved forwards .....there may be
no signs.
 or the signs may be restricted ....to the first two or three steps.... In advanced cases....the affected animal may be unable.... to move backward more than a few paces.....and sometimes....NOT at all....
Many shivering horses ....while standing in harness ...may attract attention ...by frequently raising
and abducting the shivering hind limb...A slippery surface ...exaggerates the signs of shivers
and more particularly..... when the horse is in harness.... In severe cases ....one or both hind limbs
 may be held out ...behind the animal ...in rigid spastic extension... The animal may stand on its toes
 with the heels raised off the ground..... In severe cases... the animal may fall over...
Severely affected animals.... may be hesitant to lie down.... when confined indoors
and as a result ...may lose body condition...and consequently appear older

Stress or excitement...such as when the horse is led out ...of the box into the open...or into a straw bed
or wooden floor...may often initiate... episodes of shivering....When turned out onto pasture... the  horse may lay down ...and there may be .....an improvement ...in the disease
 Signs of shivers may also ...become apparent when
affected horses are offered ...a pail of water ....on the ground....They become excited... and upon extending the neck
muscular spasms occur ...in the hindquarters...the fore feet remain implanted... on the ground...the body sways backwards...the back is arched... and the tail jerked upwards..This behavior..although typical of the disease
is not constant.
Occasionally there is ...involvement of the muscles... of the forelimb... neck...or even trunk and face
Forelimb signs ...are considered rare.......... On attempting to lift a front foot...... the limb is thrust forwards
 in full extension....the foot barely touching the ground....or the limb with the carpus flexed
is elevated and abducted......the extensor muscles ....above the elbow ....quivering while the spasm lasts
 or until the foot returns to the ground


Shivers may occasionally also affect the muscles of the
 ears....eyelids....neck....lips and cheeks
When the muscles of the head or neck are involved....they contract spasmodically
 With involvement of the face...there is....rapid blinking of the eyelids....
quivering of the ears....and the lips exhibit twitching
With progression of the disease.... a gradual and progressive atrophy... of the muscles of the thigh occurs
this may progress to generalized muscle atrophy

 Hindquarter weakness ....present in (58%) horses with shivers.
Animals so affected sleep standing....
front fetlocks and knees are bruised
disfigured by frequent half-falls
 horses frequently adopt abnormal stance
  a base-wide stance in the hind limbs
Excessive sweating

have your horse evaluated by your veterinarian.....A veterinarian must rule out ...any other possible causes
of lameness... some painful conditions mimic signs of Shivers...especially if only one limb is involved...
 There are often no abnormalities... on serum biochemistry profiles.....and usually muscle enzymes
such as CK ...and AST are normal.....

Stringhalt is the condition most often confused with shivers........Stringhalt occurs in all breeds.. of horses
and may occur at any age...Stringhalt is characterized by ..a spasmodic and excessively rapid flexion
 of one or both hind limbswhich occurs when the horse is made to move
best seen in the slower paces....particularly in turning or backing

 In stringhalt....the hocks are flexedsuddenly ..and violently toward the abdomen....and are then brought forcibly 
and noisily....back to the ground ...in one quick motion...as the leg is advanced....
 The hind limb motion ...may be mild ...slightly excessive flexion..to violent movements...during which the fetlock
 or toe ...will contact the abdomen..thorax.. and occasionally the elbow ...with attempted steps
leading to a peculiar ...“bunny hopping” ..and plunging type of gait... The severity of the gait
abnormality is variable and may be accompanied by hind limb muscle atrophy ..and laryngeal paralysis


 The diagnosis of stringhalt in the early stages is extremely difficult
 In both conditions
the horse may show signs only intermittently
 However, in shivers
 the limb is flexed
abducted and held in a spastic state for a few moments instead of being immediately returned to the ground
 as in stringhalt

Upward fixation of the patella may occur when the medial patellar ligament become momentarily
(mild) or permanently (severe) caught above the medial trochlear ridge of the femur

When the patella releases  the limb flexes forward rapidly
resembling stringhalt
condition may mimic stringhalt because the hyperextended limb may release rapidly
to hyperflex

Fibrotic myopathy results from scar tissue formation following injury to the semitendinosus
and semimembranosus muscles

The gait is usually characterized by an abnormal slapping-type gait
in one pelvic limb 
Adult Quarter horses are the most frequently affected breed
Stiff-horse syndrome” (SHS) has recently been reported in horses in Belgium
with intermittent stiffness and spasms in the axial muscles of the lower back
and in the muscles of the pelvic limbs
Voluntary movements
fright or disquieting sounds typically precipitated the contractures
no weakness or muscle atrophy
 rather a muscle hypertrophy
After the first stepsthe movements became more relaxed
and once the horse was walking or trotting no spasms were evident

Because this disease was considered to have many similarities to an entity
 in human medicine designated “stiff-person syndrome” (SPS)
 the condition has been called “stiff-horse syndrome”
 “Stiff-person syndrome” is thought to be the result of an immune-mediated deficiency
 of gamma-aminobutyric acid (GABA)

Equine motor neuron disease EMND is clinically characterized by
progressive weight loss despite a good appetite
 symmetrical muscle wasting
 muscle fasciculations
excessive sweating
tucked up abdomen
abnormal gait
excessive recumbency
 abnormally low head carriage

There are some similarities between the clinical signs of shivering and EMND
Bizarre stringhalt-like movement of a front or rear limb has been observed
 in some chronically affected EMND horses

Subacute to chronic EMND cases frequently have an abnormal elevation of their tail
Equine protozoal myeloencephalitis
(EPM)
There are rare reports of spinal cord disease because of EPM causing a stringhalt-like gait
This disease may be ruled out on absence of Sarcocystis neurona antibodies
 in the serum and/or in the CSF
causes of Shivers have not been determined
Neurological
myopathic
genetic
infectious
 and traumatic causes have been postulated

There are also reports stating horses will show signs of shivering after a long rail or road journey

Neurological causeOne possibility is infections precede Shivers symptoms and cause lesions
in the neuromuscular system
 These lesions would result in neurological damage and produce the signs of shivers
 However
detailed necropsies of two horses with Shivers failed to find neurological lesions

it will likely take a very thoroughdetailed and expensive pathological investigation
 of freshly harvested central and peripheral nervous system tissues on many cases
to unravel the mystery of shivers
Neurotransmitter defects may be responsible.

Myopathic cause
In one study involving a yearling Clydesdale gelding with a clinical diagnosis of shivers
 muscle biopsies showed decreased carbohydrate contentIt was thought that horses with shivers
 might have less stored glycogen and thus deplete their stores more rapidly.....This may lead to
 localized muscle cramping////manifesting itself when the horse was forced to move backwards


Genetic cause
 Many have suggested that shivers is inherited or has a hereditary predisposition
and although this has not been provena familial tendency is suspected

In some countriesit is recommended stallions with this disease not be used for breeding purposes

In the United Kingdomshivering has been classified as a hereditary disease Under the Horse Breeding Act, 1918

Infectious disease Some have suggested the occurrence of shivers may be preceded by an attack of influenza
strangle sor other systemic infections

This led to the suggestion that shivers is connected with neuropathic lesions produced by infection
or toxins derived from an antecedent disease

Trauma
Cases of shivers have also been attributed to accidental injuries as might be incurred from a severe fall
 however
the connection if any has not been determined
In the 1930sit was stated a shiverer will always show some evidence of osteoarthritis


Is Shivers related to Polysaccharide Storage Myopathy (PSSM)

Researchers have noted breeds of horses affected by Shivers also have particularly high coincident rates of
polysaccharide storage myopathy
However
a study done by researchers at the University of Minnesota showed that the PSSM in Belgian Draft Horses
does not have a direct relationship with PSSM
and there appearance in the same horse is likely coincidental rather than causal

Is Shivers inherited
Because Shivers is breed-related there may be a genetic basis  or predisposition for the disorder
Reports from past centuries suggest that Shivers was prevented by breeding away   from the condition
 Currently there is no  specific genetic pattern identified  and there is no genetic test

 How do you treat Shivers in horses
There is currently no effective treatment for shivers
Occasionally the signs may improve or regress after long periods of rest but the condition returns
when work is resumed
It has been suggested 
dietary treatment of affected draft horses with a high-fat  low carbohydrate feed
 may be beneficial
if instituted early in the course of the disease
However
the clinical signs of shivers DID  not resolve when affected Warmblood or Warmblood-cross horses
were fed grass hay and their dietary grain was replaced with a high fat supplement
These dietary recommendations were combined with a gradually increasing daily exercise program
and maximal turnout
If a horse has both PSSM and Shiversowners have reported improvements 
by feeding a diet high in fat and low in starch'
This does not appear to cure horses from Shivers but it may reduce the frequency
 of muscle spasms

Adequate levels of vitamin E and Selenium are important in the diet
The natural form of Vitamin E, Elevate™ may provide additional benefits
over synthetic Vitamin E

Massage and acupuncture may be helpful in keeping a horse comfortable and competitive
It may be harder for Shivers horses to maintain muscle mass if they receive time off from work
Horses may become tight behind and may take longer to get  the horse back in shape if laid up
keeping horses in work with constant turn out seems to help

Symptoms were relieved the more these horses moves around
 Can Shivers be cured?

At present
 there is no cure and few effective treatments for Shivers
The prognosis
for affected individuals is generally unfavorable to poor because the disease is usually
slowly progressive
  In a horse with shivers the tendency is for the spasms to increase in both frequency
and severity
 The long-term prognosis for athletic function is grave
 Eventually, shivers may result in death or euthanasia
because of profound weaknessmuscle wasting and apparent discomfort
 and incapacitation associated with episodic muscle cramping

What do I do if I think my horse has Shivers
Horses with possible Shivers need to have a complete veterinary evaluation
 A thorough lameness exam should rule out abnormalities in the hooves, bones, joints
 and tendons that may cause the horse to show signs similar to Shivers
Your veterinarian will be able to confirm
the diagnosis
 rule out other possibilities and recommend appropriate treatment and management
muscle biopsy will help