Mavedrejning.

Hvad er mavedrejning hos hunde?

Mavedrejning er en af de mest frygtede lidelser hos hunde,
fordi forløbet ofte er meget akut og meget voldsomt.

Som navnet siger, sker der en drejning af mavesækken.
Forestil dig mavesækken som en udvidelse eller en ballon
midt på en vandslange. I den ene ende er spiserøret,
som fører ind til mavesækken, i den anden ende er
tyndtarmen, som fører væk. Hvis ballonen/mavesækken
bliver drejet ½ -1 omgang, bliver slangen snoet lige før
og lige efter mavesækken. Resultatet er, at gæringsluft
i mavesækken ikke kan slippe ud. Mavesækken bliver mere
og mere udspændt som en ballon, samtidig med at hunden
får det dårligere og dårligere.

Hvad er symptomerne på mavedrejning?

Hunden er rastløs, savler og forsøger at kaste op, men
der kommer intet eller kun en smule skum. Bugen er
udspilet af luft, og det kan du nemt mærke ved at banke
let på maven med fingerspidsen.
Vejrtrækningen er hurtig og overfladisk, benene er kolde,
og hunden
har ondt og er meget nedstemt.

Hvordan kan din dyrlæge stille
diagnosen mavedrejning?


Ud fra symptomerne vil dyrlægen hurtigt komme på sporet
af diagnosen mavedrejning. Hvis han er i tvivl, kan diagnosen
fastslås ved en røntgenundersøgelse, hvor den luftfyldte
og roterede mavesæk tydeligt træder frem.

Hvordan behandles mavedrejning?

Mavedrejning er en meget alvorlig og livstruende sygdom.
Det er nødvendigt at handle hurtigt for at give hunden
de bedste muligheder for at overleve. Derfor skal din
hund hurtigst muligt til dyrlæge, hvis du lægger mærke
til de nævnte symptomer.

Dyrlægen vil primært sørge for at tømme luft ud af den
udspilede mavesæk eventuelt ved at stikke en kanyle
ind i den. Derefter vil han give hunden smertestillende
medicin og forsøge at stabilisere tilstanden ved bl.a. at
give hunden væske. Senere vil dyrlægen forsøge at
tømme mavesækken ved at føre en slange ned gennem
spiserøret.
I sidste ende kan en operation komme på tale for at få
mavesækken drejet på plads og syet fast, så det
forhåbentligt ikke kan ske igen.

I visse tilfælde vil dyrlægen vælge at operere med det
samme, og i andre tilfælde vil han vente til dagen efter
for at få stabiliseret hundens tilstand bedst muligt
inden indgrebet.
Det første døgn, og især de første timer efter at
mavedrejning har udviklet sig, er kritiske.
Mange hunde bliver meget dårlige med voldsomme
forstyrrelser i kredsløb, væskebalance og hjertefunktion.
I de tilfælde er der stor risiko for, at hunden dør
under behandlingen.

Hvordan er fremtiden for din hund, hvis
den får mavedrejning?

Hvis hunden overlever de første timer og det første døgn,
er udsigterne til en normal tilværelse efter sygdommen gode.
Men spørgsmålet er, om den får mavedrejning igen.
Risikoen er helt klart til stede, hvis ikke mavesækken
bliver syet fast, så den ikke kan dreje eller rotere igen.

Du kan selv bidrage til at mindske risikoen for mavedrejning
ved at fordele hundens mad ud på flere daglige
måltider - mindst to - og undlade at motionere den de
første par timer efter hvert måltid.

Hvorfor får hunde mavedrejning?

Man ved ikke med sikkerhed, hvorfor hunde får mavedrejning,
men man ved med sikkerhed, at risikoen for, at
sygdommen udvikler sig hos en i øvrigt disponeret hund,
er størst, når hunden motionerer eller leger kort tid efter,
at den har spist eller drukket store portioner.

Hvad er risikoen for, at din hund
får mavedrejning?

Hvis din hund tilhører en af de racer, som
er særligt udsatte for lidelsen, er der risiko
for, at den får mavedrejning. Men husk, at
du selv kan mindske risikoen ved at fodre
og motionere den fornuftigt.


Hvilke racer er særligt udsatte for at få
mavedrejning?


Mavedrejning rammer først og fremmest de store racer
og især racer med dyb brystkasse som granddanois,
irsk setter, schæfer, dobermann m.fl. Lidelsen optræder
sjældent hos små racer. 



 
__________________

Gastric Dilatation

Volvulus (GDV), Bloat and Torsion
 

Gastric dilatation is a life-threatening condition that occurs
in mature large dogs.
I do not see many of these cases but when I do I have
work diligently if I am to save the animal.
Another term for the condition is gastric
dilatation/volvulus or GDV. Volvulus is a twisting of
an organ along its long axis. In this disease, the stomach
flips over on itself and expands with trapped
swallowed air and fermentation gases.
Circulation to the stomach and spleen are cut off to
the point where the dog may go into shock and die.
A startling finding is that the incidence of bloat has
increased by more than 1500% over the past 30 years.

What Is The Cause of GDV?

We are unsure why GDV occurs. Exercise just after
or before eating may bring on GDV. We used to think
that dogs developed GDV when they ate too much.
In this theory, dogs that drank after a meal of dry
chow caused the food to rapidly expand.
This theory assumed that the enlarged stomach then
flipped over during rough exercise. We now know that
the actual explanation is not that simple. We also know
that GDV is associated with abnormal muscular
contractions of the stomach.
These, plus the kinks that forms in the stomach’s openings,
prevent the dog from belching swallowed air.
Lack of normal motility and circulation in the stomach cause
the body to become too acidic (metabolic acidosis).
We also know that dogs who eat from elevated dishes
are more likely to become bloated.
Their dishes should always be on the floor.

A recent Purdue University Study shines much light on this
perplexing disease.
They found that certain factors increased the incidence
of GDV. The first and most important factor was age.
The older the dog was the more commonly they develop
GDV. The second most common factor was having a relative
that had developed GDV. This shows that genetics
plays a part in the disease.
The third factor was feeding the dog in a raised food bowl.
Raising the food bowl is often suggested in large breeds
that have trouble swallowing. So there may be some
linkage between esophageal problems and GDV.
There was a 2.7-fold increase in the risk of GDV
in dogs that ate dry dog food that contained fat as
its most common or first ingredient. The risk of GDV
increased 4.2-fold in dogs that ate dry foods containing
citric acid when the food was moistened prior to feeding.
Dry foods containing meat meal with bone among the
first four ingredients significantly decreased GDV risk
(53.0%). Approximately 30% of all cases of GDV in this
study were attributed to consumption of dry foods containing
fat among their first four ingredients, while 32% could be
attributed to consumption of owner-moistened dry foods
that also contained citric acid. Citric acid in the stomach is
conducive to gas formation. So choosing your dog's diet is
probably the most important thing you can do to prevent
gastric dilatation/volvulus bloat and torsion.

It may also be helpful to withhold water for one hour
before meals and three hours after. Dry dog foods swell
when they become wet and theoretically, this could swell
the stomach. If you feed grains such as rice, be sure
they are completely cooked.

How We Diagnosis The Problem:

The condition appears suddenly. Gastric dilatation/volvulus
occurs almost always in deep- chested large breeds.
Borzoi’s, Setters, Afghans, German Shepherds and
Greyhounds are a few of the breeds commonly affected.
These dog arrive at the veterinary hospital panting and weak.
When the problem is advanced, there is a pronounced
swelling on the dog’s lower left side.
When I push on the abdomen in this area the tummy is
abnormally firm and drum-like. The dogs may attempt to
retch and belch but are not successful.
They salivate and are restless and in obvious pain and distress.
When we x-ray these dogs,
the gas-filled stomach is quite apparent.
The pressure the enlarged stomach places on the blood
vesicles of the abdomen decreases the efficiency of blood
circulation through the stomach and spleen leading to
depression and shock.
Laboratory examination of the blood confirms metabolic acidosis.
It is also common for blood potassium to be low.
Low blood potassium affects cardiac rhythm and
causes muscle weakness.

As circulation through the stomach is hindered, the stomach
wall begins to necrose or die. This liberates many toxic
products into the blood stream.
These products interfere with normal blood clotting and
cause a condition known as disseminated intravascular
coagulation (DIC) or clumping of the red blood cells.
DIC alone can be fatal.

How We Treat The Problem:

Gastric torsion is a life threatening illness that needs to
be dealt with quickly.
To fight circulatory collapse, I immediately place a
catheter into the large vein of the arm for easy access.
Then I administer large volumes of intravenous salt
solutions with bicarbonate at a rather rapid rate.
I monitor the dog’s body weight and urine flow so as not
to flood the lungs with fluid.
I also give these dogs intravenous potassium chloride and
corticosteroids (prednisolone, dexamethasone).
It is important that pressure within the stomach be
quickly removed. Most dogs are so shocky that they
need no tranquilizers or anesthetics. I first try to pass
a stomach tube through the dog’s mouth and into the
stomach to remove the air. Giving them simethicone helps
decrease froth and pockets of air. In many cases, the kink
in the stomach does not allow the tube to pass.
When this is the case I insert a large bore needle called a
trochar through the side of the dog and into the stomach or
cut down on the stomach and temporarily suture the opening
I cut in the stomach to the body wall (see diagram).
I give all these dogs large amounts of antibiotics because
I must move so rapidly that sterility is compromised.
Antibiotics are also necessary to combat the bacteria that
proliferate in the stomach and intestinal wall.
When I am lucky, the dog’s condition stabilizes when the
pressure is removed.

When I think the dog can tolerate surgery it is time to enter
the dog’s abdomen and place the stomach and spleen back in
their proper positions.
Then I perform a procedure called a gastroplexy, which
entails sewing the stomach to the inner wall of the abdomen
so that it can not shift in the future. If the dog is stable
enough, I remove the surface layers of a two inch square
area on the left middle surface of the stomach and a
similar area on the left body wall and sew the two remaining
structures together. If the animal is too weak for me to
take the time to do this, I incorporate the stomach section
in the body wall incision made to reach the stomach.
In these cases I also suture a latex drain tube that leads
from the interior of the stomach to the dogs skin and
allows fluid and gas to drain.
These dogs often have serious heart irregularities, which
keep me tense during surgery.

Whether or not the dog survives the surgery depends on
the degree of shock and stomach necrosis that has occurred.
This in turn depends on how soon the dog was brought to me
for treatment. A little more than half the dogs survive.
Since we do not understand why this condition occurs it
is hard for us to plan a life style and diet for the dog
that might prevent reoccurrence.
Usually, gastroplexy prevents future episodes from
being as severe as the first
.