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Vit a-csbrp
Vitamins are organic micronutrients found in foods that are essential for health. Vitamin A deficiency can occur due to malabsorption or other issues affecting fat absorption. Key symptoms include night blindness, keratomalacia (softening and ulceration of the cornea), papular desquamation (flaking of the skin), and frequent respiratory infections. Vitamin A is important for maintaining epithelial surfaces and its deficiency can lead to epithelial metaplasia and keratinization of tissues.
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Vit a-csbrp
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- 2. Vitamins • Definition: Organic micronutrientsfound in a large variety of foods, which are essential for our health. They act as critical catalytic co-factors / prosthetic groups on enzymes in vital metabolic reactions.
- 3. Vitamins Classification: 1-Water soluble vitamins(B-complex and Vit-C) 2-Fat soluble vitamins (Vit-A, D, E, K)
- 4. • Fat solublevitamins: Deficiencies occur mainly due to interference with their absorption ---Pancreatic diseases ---Liver diseases ---Intestinal malabsorption syndromes Vitamins
- 5. • Clinical features: •1-Night blindness • 2-Keratomalasia • 3-Papular desquamation • 4-Frequent respiratory tract infections • 5-Bitot’s spots. Vitamin-A deficiency
- 6. Vitamin-A • Chemistry: 1-Retinol (Retinol,Vit-A1, Dehydroretinol, Vit-A2) 2-Availability in diet (2 forms) ----as vitamin-A itself (retinol) ----as provitamin precurssors (carotenoids) (imp: ß-carotene)
- 7. • Factors influencingabsorption: 1-Dietory fat and proteins 2-Vit-E (prevents its destructions by oxidation) Vitamin-A
- 8. E s te r if ic a t io n w it h p a lm it ic a c id h y d r o ly s is T a r g e t t is s u e e n t e r s b lo o d a n d b o u n d t o R B P F r e e R e t in o l R e t in y l p a lm it a te V i t a m i n - A a s R e t in o l o r C a r o t e n e Vitamin-A
- 9. • Requirements (perday): Infants 1500IU Adults 4000-5000IU Pregnancy & lactation 6000-8000IU Vitamin-A
- 10. • Serum levels Carotenes90-220 µg/100ml Vit-A 30-70 µg/100ml • Liver reserves 25-200µg/gm of liver Vitamin-A
- 11. Vitamin-A deficiency • Causes: 1-Inadequatediet (very high tissue reserves) 2-Disease of the liver or biliary tract 3-Sprue 4-Severe intestinal disease 5-Generalized protein deficiency (Fall in RBP)
- 12. “Vitamin-A deficiency isusually secondary to malabsorption or other situations affecting fat absorption” Irrespctive of the cause in Vit-A deficiency plasma levels fall. Vitamin-A
- 13. Vitamin-A deficiency • Diseasestates: 1-night blindness 2-epithelial metaplasia 3-xerophthalmia 4-keratomalacia 5-follicular keratosis 6-disturbances in bone growth.
- 14. lig h t ind a r k S o m e o f t h e r e t in o l is lo s t s p o n t a n e o u s c o m b in a t io n o f t h e a b o v e tw o t o fo r m a g a in R h o d o p s in o p s in + is o m e r o f r e t in a l R h o d o p s in R E T I N A L + O P S IN Vitamin-A deficiency Night blindness Because of the loss vit-A should be made available for the adequate regeneration of Rhodopsin
- 15. • Vit-A isnecessary for the maintanance of specialized epithelial surfaces (ex: GIT, Respiratory, GUT, Skin) • Vit-A deficiency induces excessive keratinization. Vitamin-A deficiency Epithelial metaplsia
- 16. • Epithelium: • 1-otherthan stratified squamous will under go atrophy and metaplasia (to stra.squ.epi) • 2-stratified squamous epithelium will under go excessive keratinization • 3-non-keratinizing stratified squamous epithelium (ex; cornea, conjunctiva, vagina) become keratinized. Vitamin-A deficiency Epithelial metaplsia
- 17. • It’s wellestablished in animals but, strong evidence in humans is lacking. • 1-Deficiency retards normal growth • 2-Excess of Vit-A stimulates bone growth • 3-Epiphyseal bone formation is especially affected • 4-Increased growth rate accompanied by bone resorption leads to increased fragility Vitamin-A deficiency Disturbances in bone growth
- 18. • Eyes: 1-Cornea &conjunctiva become keratinized 2-Goblet mucous cells on the surface will disappear 3-Lining of the ducts of lacrimal glands will be replaced by str.squ.epith. 4-Keratin debri form plugs in the ducts 5-Mucosal surfaces become dry and rough (Xerophthalmia) 6-Keratin debri accumulate in conjunctiva producing plaques (BITOT’s spots) 7-Visual acuity is impaired by keratinization & thinning of corneal mucosa resulting in ulceration and softening of cornea (KERATOMALACIA) may lead to perforation Vitamin-A deficiency Pathology
- 19. • Respiratory tract: •Atrophy of ciliated columnar epithelium • Squamous metaplasia with keratinization • Impairement of cilialry action & keratin debri accumulation results in recurrent infections. Vitamin-A deficiency Pathology
- 20. • Urinary tract(esp. renal pelvis and bladder): • Keratinization of keratin debri formation. • Keratin debri acts as a nidus for stone development • Calculi formation results in infections and hematuria. Vitamin-A deficiency Pathology
- 21. • SKIN: • Hyperplasiaand hyperkeratinization of epidermis • Plugging of hair shafts and seaceous gland ducts by piled up keratin • Sand paper like skin (Phrynoderma) Vitamin-A deficiency Pathology
- 22. “Similar keratin plugsin salivary gland ducts and pancreatic ducts produces significant digestive disturbances”. Vitamin-A deficiency Pathology
- 23. • Clinical features: •1-Night blindness • 2-Keratomalasia • 3-Papular desquamation • 4-Frequent respiratory tract infections • 5-Bitot’s spots. Vitamin-A deficiency Pathology
- 24. • Acute • Chronic Vitamin-ATOXICITY
- 25. • Acute: Head ache,dizziness, vomiting and diarrhea Raised ICT Occur when >350,000 units are given as in children Vitamin-A TOXICITY
- 26. • Chronic: Bone pain, Lossof hair, Skin desquamation, Anorexia, Raised ICT. Occurs if doses >60,000units are given daily Vitamin-A TOXICITY
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