Vitamin K Deficiency Vitamin K, a fat-soluble vitamin, is a group of - PowerPoint Presentation

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Vitamin K Deficiency

Vitamin K, a fat-soluble vitamin, is a group of

napthoqunone

compounds that have characteristic

antihemorrhagic

effects

Vitamin K extracted from plant material was named

phylloquinone

or vitamin K1

Vitamin K extracted from bacterial fermentation were named

menaquinones

or vitamin K2

A synthetic form named

menadione

(K3)-simplest form of vitamin K, is

is

water soluble.

Function:

The liver is the main repository of vitamin K.

Vitamin K is required for the hepatic post-synthetic transformation of several protein clotting factors

It is essential for the post-translational processing of the

prothrombin

group of coagulation factors (Factors II, VII, IX, and X).

Used  as an antidote in poisoning by

dicoumarol

or

warfarin

.

A role in bone metabolism, as well as in the renal reabsorption of Ca++. 

Ruminant makes this through

rumen microbial 

biosynthesis and absorbed

in the small

intestine

Horses generally receive sufficient vitamin K from pasture, hay, and intestinal

bacteria

 to meet their needs. 

Dogs receive both 

K

1

 and 

K

2

 in their diets, and cats derive their

quinones

from eating meat

.

Etiology:

Fat

malabsorption

associated with inadequate amounts of bile salts (

eg

,

biliary

obstruction)

Lymphangiectasia

S

evere

villous atrophy may result in vitamin deficiency and

coagulopathy

owing to the lack of production of the functional vitamin K−dependent Factors II, VII, IX, and X

Vitamin K antagonist or by feeding sulfonamides (in

monogastric

species

)

Mycotoxins

Moldy

sweet

clover hay/

sweet clover

disease-lead to

hypoprothrombinemia

, because of

dicumarol

combines with the

proenzyme

to prevent

formation of

the active enzyme

required

for the synthesis of

prothrombin

and also

interferes with synthesis of factor VII and other

coagulation factors.

Warfarin

as a

rodenticide

I

nsufficient

vitamin K

in the diet,

L

ack

of microbial synthesis within the

gut

Inadequate intestinal absorption

, or inability of the liver to use the available vitamin K.

Note: Administration of estrogens increases absorption in both male and female animals

The lymphatic system is the major route of transport of absorbed

phylloquinone

from the intestine in mammals but by portal circulation in

birds

Clinical Signs:

Ruminants:

Seen

only in the presence of a

metabolic

antagonist

, such

as

dicumarol

from moldy sweet clover

.

The

coumarin

derivatives (

dicumarol

)

are not active in the fresh plant because they are bound

to glycosides

, but are active when sweet clover is improperly

cured AND leads to

sweet clover poisoning

or hemorrhagic

sweet clover disease

Death

from hemorrhage following

a minor

injury, or even from apparently spontaneous bleeding

Accidental poisoning of animals with

warfarin

(a

synthetic

coumarin

used as a rodent poison

)

Initial

clinical

signs may

be stiffness and lameness from bleeding into muscles and articulations.

Hematomas,

epistaxis

(nose bleed), or gastrointestinal

bleeding

Death

may occur suddenly, with little preliminary

evidence of

disease, and is caused by spontaneous massive hemorrhage

or bleeding

after injury, surgery, or

parturition

DOGS AND

CATS:

Accidental

intake of

dicumarol

types of rat poison, such

as

warfarin

and

diphenadione

(vitamin K antagonist), will result in a

hemorrhagic condition

in

dogs

Clinical signs

in dogs include paleness and evidence of slow but persistent

bleeding from

a number of sites, including gums, bowel, and several

injection punctures

Swine:Increased

prothrombin

and blood-clotting time, internal hemorrhage,

and anemia

due to blood

loss

Newborn pigs may be pale with loss of blood from the umbilical

cord

Diagnosis:

Determination of

prothrombin

time

Prolongation of the

prothrombin

time in the absence of liver

disease indicates

vitamin K

deficiency

Measurement of the plasma

concentration of

one of the vitamin K-dependent clotting

factors (Factor-II, VII, IX and X)

A routinely measure

circulating

phylloquinone

as a method of evaluating vitamin

K status

.

<0.5

ng

/ml have been associated with impaired

clotting functions

Treatment:Vit

. K1 @1- 2

mg/kg administered

intramuscularly /SC (especially in

Dicumarol

poisoning)

Blood

transfusion@10ml/Kg

BW

Note:

Vitamin

K3 should not

be used

, especially in horses, because it is

associated with

renal

damage

In horses, the

recommended dose (

Vitamin K3

)

is

0.5 to 2.5 mg/kg BW IM