This document discusses megaloblastic anemia caused by vitamin B12 or folate deficiency. It provides details on the absorption and roles of vitamin B12 and folate, causes of deficiency including inadequate intake and impaired absorption, clinical manifestations such as anemia and neurological symptoms, diagnostic tests including blood tests and Schilling test, and treatment involving parenteral vitamin B12 supplementation or oral folic acid.
6. Vitamin B12
• Adequate absorption of cobalamin depends
upon five factors:
1. Adequate dietary intake
2. Acid-pepsin in the stomach
3. Pancreatic proteases
4. Gastric secretion of a functional intrinsic
factor
5. An ileum with functioning B12-IF receptors
8. Rare causes…
Pernicious anemia is extremely rare in children
younger than 10 years.
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Congenital IF deficiency
Gastric surgery
Pancreatic insufficiency
Hereditary orotic aciduria
Thiamine responsive megaloblastic anemia
9. Folic Acid
• Occurs in animal products and in leafy
vegetables in the polyglutamate form
• RDA – 50-150 mcg/day
10. Folic Acid deficiency
• Inadequate folate Intake
• Increased requirements (infancy and early
childhood, chronic hemolysis, infections)
• Goat’s milk
• Decreased Folate Absorption
-chronic diarrheal states or diffuse inflammatory
disease
• Drug induced:anticonvulsant drugs
(e.g., phenytoin, primidone, phenobarbital)
, methotrexate, pyrimethamine, trmethoprim
11. Clinical Manifestations
• Anemia, anorexia, irritability, easy fatigability
• Hyperpigmentation of knuckles and terminal
phalanges.
• Neurologic signs may precede onset of anemia
– loss of position and vibration sense (earliest)