Megaloblastic Anaemia

Megaloblastic Anaemia is a group of anaemia caused by deficiency of vit.12 or/and folic acid and characterised by the presence ob abnormal red cell precursors in megaloblasts.

Vitamin B12:
-is required 1 mcgm/day
-as sources are;animal foods as liver,kidney and meat.Vegetables contain no vitamin B12.
-parietal cells of the stomach secrete a glycoprotein called the intrinsic factor which combines with vitamin B12.On reaching the terminal ileum specific receptors on the mucosa bind the vitamin B12-intrinsic factor complex thus enabling vitamin B12 to be absorbed.
-2 mg are stored in the liver.This is sufficient to give to body its needs for at least 2 years.
-vitamin B12 is essential for hemopoietic system,gastrointestinal and nervous system.

Folic Acid:
-is required less than 1 mg/day
-as sources are:vegetables and food of animal source.cooking destroys 50-90% folic acid in food
is absorbed from duodenum and jejunum
-is essential for hemopoiesis and gastrointestinal integrity.

Causes of Megaloblastic Anaemia:
1.Vitamin B12 deficiency
-intestinal desease(cause general malabsorption)
-increase demand(infancy and pregnancy)
-adviced liver disease
2.Folic Acid deficiency:
-deficient intake for exemple alcoholics
-malabsorption from upper intestine
-increase demand as vitamin B12
-drugs

Characteristics of Megaloblastic Anaemia:
1.In vitamin B12 deficiency:
-anaemia
-gastrointestinal manifestations:dyspepsia,aorexia,nausea,vomiting and diarrhea,beefy tongue(red,glazed tongue),hepato-splenomegaly.
-nervous manifestations.
2.In folic acid deficiency:anaemia and gastrointestinal manifestations.

Treatment:
For folic acid deficiency:folic acid 5 mg.
For vitamin B12 deficiency:if there are no nervous manifestations 100 mcgm twice weekly untill the red blood cells reach normal then 100 mcgm every month for life.If there are nervous manifestations:1000 mcgm/2 days fro 6 doses,the 100 mcgm/week for 6 months,the 100 mcgm every month for life.
Folic Acid is never given alone for B12 deficiency anaemia as it will increase the nervous manifestations.