iron deficiency anemia megaloblastic anemia Flashcards
what are the types of macrocytic anemia ?
megaloblastic and non megaloblastic anemia
what is the principal cause of megaloblastic anemia ?
b12 deficiency and folate deficiency
what are some sources of b12 ?
eggs, dairy and sea fish products
where is vitamin b12 mainy stored ?
in the liver
what factor binds to b12 ?
intrinsic factor made by gastric parietal cells
where is b12 mainly absorbed ?
in the terminal ileum
what carrier protein attaches to B12 once it is in the portal circulation ?
transcobalamin
what is the function of vitamin b12 ?
formation of the active form of folate needed for DNA synthesis
what are the causes of vitamin b12 deficiency?
nutritional deficiencies: alcoholics dietary lack gastrointestinal deficiencies : peptic ulcers pernicious anemia
which type of diets puts a person at a higher risk of b12 deficiency ?
vegans
what are the possible causes of impaired absorption leading to b12 deficiency ?
pernicious anemia terminal ileac disease (crohns disease) gastrectomy fish tapeworm alcoholism
what kind of metabolic inhibition can cause b12 deficiency ?
enotox overuse
what is the clinical presentation of vitamin b12 deficiency ?
megaloblastic anemia atrophic glossitis angular stomatitis sterility neurological manifestations (peripheral neuropathy )
where does absorption of folate happen ?
in the duodenum and jejunum
what are the causes of folate deficiency
dietary deficiency - reduced intake of folate rich foods
malabsorption - colieac disease, tropical sprue
when is there an excessive demand for folate
during pregnancy and prematurity
what kind of drugs can cause folate deficiency ?
folate antagonists such as anticonvulsants (methotrexate)
what is the clinical presentation of folate deficiency ?
similar to b12 deficiency but without the evident neurological defects except neural tube defects in foetuses
what investigations are required to make a diagnosis of megaloblastic anemia ?
full CBC blood film serum vitamin b12 and folate liver function tests and LDH gastric parietal cell and intrinsic factor antibodies coeliac screen schilling test - test of b12 absorption
what would you find in the blood film of megaloblastic anemia ?
oval macrocytes
neutrophil hyper-segmentation ( shift to the right)
reticulocytopenia
tear drop cells
what would a shift to the left indicate ?
band neutrophils
why is there an increase in unconjugated bilirubin and LDH ?
ineffective erythropoiesis ( destruction of erythroid precursors in the marrow before they have reached maturity)
what is the initial treatment for vitamin b12 deficiency ?
initially a loading dose of hydroxycobalamin 1mg intramuscularly three times a week for two weeks
what is the subsequent treatment of vitamin b12 deficiency ?
hydroxycobalamin 1 mg intramuscularly
if there is no malapsorption what can be given for b12 deficiency ?
cyanocobalamin orally ( dietary deficiency)
why might iron and folate be given along with b12 treatment ?
huge number of red blood cells being made
what are the contraindications of using folate and vitamin b12 ?
folate must never be given first before b12 as this can aggravate neurological problems
how would you treat folate deficiency ?
folic acid tablets 5mg daily given for 3-4 months
what is the prophylactic dose of folate for pregnant women ?
400ug reduced the risk of neural tube defects
what are the differential diagnosis of macrocytic anemia ?
liver disease alcohol hypothyroidism cytotoxic drugs haematological disease
what is the MCV is macrocytic anemia ?
> 99
