vitamin c and scury

VITAMIN C AND SCURY

BYDR.RISHAV RAJ

VITAMIN C

• It is a water soluable.• Vitamin C is not stored in the body but is taken

by all the tissues• High level of vit C is found in the pituitary

glands.• Also known as L-ascorbic acid it is an essential

nutrient for humans.• Ref:american journal of paed. 2001

HISTORY OF VITAMIN C

• 17th century – sailors got scurvy on ships and ship surgeon, James Lind, prescribed lemon juice as preventative. Performed an experiment that proved that lemon juice prevents scurvy.

• We now know today that it is because of the Vitamin C in the lemon that prevents scurvy or a vitamin C deficiency

CHEMISTRY

• It is L-Ascorbic Acid.• its oxidized derivative L-dehydroacorbic.• The acidic property of vitamin C is due to enolic

hydroxyl groups.• It is a strong reducing agent. They form a

reversible redox system• Oxidation of ascorbic acid is rapid in the

presences of copper..Hence ,vit C becomes in active if the foods are prepared in copper vessels.

structure

• OH

• O• O

• H

• HO

• HO

• HO

SOURCES

• Mostly in citrus fruit and juices (limes, lemons, oranges, strawberries, bananas, and grapefruits)

• Also in cabbage, broccoli, cauliflower, tomatoes, potatoes, and beans.

• There are also vitamin C pills and other things for supplements.

• Ref:leninger biochemistry

SYNTHESIS

• All Plants can synthesize Vitamin C• Most animals can synthesize vitamin C except :

Humans, Guinea pigs, fruit eating bat• They lack: L-gulono-γ-lactone oxidase

BIO CHEMICAL FUNCTION

• 1.COLLAGEN FORMATION: vit C Plays the roleOf a coenzyme in hydroxylation of proline and

lysine .The hydroxylation reaction is catalysed by lysyl

hydroxylase (for lysine) and propyl hydroxylase(for proline).

The hydroxyproline and hydroxylysine are essential for the collagen cross-linking and the strength of the fibre.

2.Bone formation

• Bone tissues possess an organic matrix, collagen and the inorganic calcium,phosphate

2.Iron and hemoglobin metabolism:Ascorbic acid enhances iron absorption by keeping it in the ferrous form. This is due to the reducing

property of vit C.

3.Tryptophan metabolism

• Vitamin C is essential for the hydroxylation ofTryptophan to hydroxytryptophan in the

synthesis of serotonin by hydroxylase.4.Folic acid metabolism: The active form of the vitamin folic acid is

tetrahydrofolate.Vitamin C is needed for the formation of

tetrahydrofolate.

5.Synthesis of corticosteroid hormones

• Adrenal gland possess high level of ascorbic acid particularly in period of stress.

• It is believed that vit C Is necessary for hydroxylation reaction.

• 6.immunological function: vitamin C Enhances the synthesis of immunoglobins.

7.Preventive action on chronic disease

• Free radicals are constantly produced in theNormal metabolism .they cause serious damage To proteins ,lipids,DNA and the cell membranes.These free radical are implicated in the

development of cancer, heart diseases .vit C prevent from these diseases.

Dietary needs

• The recommended daily intake for Infants: 0-6month :40mg/day7-12 month: 50 mg/dayChildren :1-3yr :15mg/day4-8yr: 25mg/day.

Dr. Linus Pauling believes that 10 grams a day will prevent cancer.

Clinical manifestation:

• 1.age of onset is between 6 and 24 month• 2.Due vitamin C def. symptoms such as

irritability, tachypnea,digestive disturbances and loss of appetite.

• 3.pain in the limbs :limbs are like frog like position with hips and knees semiflexed with feet rotated outward.

• 4.edematous swelling along the shaft of legs.

• 5.anaemia may be present due to bleeding,decrease absorption of iron and defective conversion of folic acid.

• 6.purpuric ,petechiae and ecchymosis may be present.

• 7.a rosary at the costochondral junctions and Depression of the sternum.

Investigations :

• 1. Decrease of vitamin C LEVEL in bloodNormal 0.6mg/dl2.Vit C loading test:10 mg /kg of vit C is given

and more than 80% of it is excreted in urine. If excretion is less than 20%.-It indicates deficiency of vitamin C.

3.VIT C LEVELS are decreased in WBC and platelet buffy coat.

Management

• 0ral preparations are preferred to parenteral dose

• Dose 0- 6 month :40 mg/day• 7-12 month :50mg/day• 1-3 year : 15mg./day• 4-8 yr :25mg/day.

Scurvy

• It is a nutritional disorder due to deficiency ofascorbic acid(vitamin c).PATHOLOGY1.Rarefaction of shaft and epiphysis resemblingGround glass appearance.Thinning of cortex is present.2.Thickening of zone of provisional calcification is seen

at epiphysis due to defective proliferation of cartilage cells. It is brittle and fractures may develop.

• 3.subperiosteal haemorrahages are seen dueTo leaking of blood from vessels,resulting in

stripping of periostium.

4. Dentin is defective due to defective formationOf collagen resulting spongy gums and bleeding

from gums.

CLINICAL FEATURES

1.IRRITABLE2.LETHARGIC3.PAIN IN THE LIMB4.BLEEDING FROM GUMS5.PURPURIC6.PETECHIAE AND ECHYMOSIS MAY BE PRESENT.7.Rarely, haematemesis ,malena and subdural

hematoma

• 8.perifollicular bleeding • 9.anaemia may be present due to• A)bleeding• B)decrease in absorption of iron• C)defective conversion of folic acid.• 10.delayed wound healing.• 11. scorbutic rosary: a groove is present in

between costal cartilage and rib due to depression of cartilage.

X.Ray of bones

• 1.Wimberger’s sign: rarefaction and thickening• Of outerline of epiphysis.• 2.white line of frankel:thickening of zone of

provisional calcificationCartilage proliferation is seen at the epiphyseal end of

long bones.3.pelken’s sign:-Thickened zone of provisional

calcificationCartilage proliferation is seen at epiphyseal end of long

bones

• 4.Corner’s sign: a groove is present just above ZONE OF PROVISIONAL CALCIFICATION.5.Trummer feld zone:fragmented metaphysis6.Scurvy line :area in between zone of provisional

calcification and trummer feld zone.7.Subperosteal hemorrhage8.GROUND GLASS APPEARANCE OF SHAFT.9.THINNING OF CORTEX IS PRESENT.

MANAGEMENT

• 1. 500-1000 mg of vitamin C IS Given daily for 1week followed by 30-50 mg /day

THANK ….U…