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Pediatric Hematology: Nutritional Anemias


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Why does normal hemoglobin level increase in boys with increased tanner stage?
Secondary to androgen effect on erythropoiesis
Where is iron absorbed?
primarily in the duodenum
What carries iron after absorption? In what form?
Transferrin binds Ferric (Fe3+)
When does iron depletion occur in an infant (term and pre-mature/low birthweight) who is not receiving iron supplementation (breast milk or formula)
term: by 5-6 months
pre-term/LBW: by 3 months
what are the three stages of iron deficiency?
Depletion of iron stores
Iron Deficient Erthyropoiesis
Iron Deficiency Anemia
What is the first abnormality in iron deficiency?
decreased serum ferritin
What are two causes of malabsorption of iron?
celiac disease
Does lead poisoning cause microcytic anemia?
Not usually, usually iron deficiency is underlying and leads to pica - the eating of lead
What morphologic finding is associated with lead poisoning?
basophilic stippling of erythrocytes
neurologic abnormalities are seen in folate or B12 deficiency?
B12 deficiency
What morphological finding is associated with folate or b12 (cobalamin) deficiency?
hypersegmented neutrophils
What lab findings are associated with folate or B12 deficiency?
can have mild thrombocytopenia and/or neutropenia
elevated bilirubin
macrocytic anemia
Where is folate absorbed?
proximal jejunum
What happens to homocysteine levels in folate deficiency? What effect does this have on thrombosis?
Plasma homocysteine levels are elevated which leads to an increased risk of thrombosis
What is required for the absorption of Vitamin b12 (cobalamin)? Where does absorption take place?
instrinsic factor
the instrinsic factor is produced by gastric parietal cells and the IF-b12 complex is absorbed in the terminal ileum
What diet type can lead to Vitamin b12 deficiency?
vegan (no meat or dairy)
What is Imerslund-Graesbeck syndrome?
Malabsorption of Vitamin 12 - not corrected by IF
problem is an ileal receptor defect
presents in early infancy
What is the treatment for Imerslund-Graesbeck syndrome?
IM Cobalamin
What are the manifestations of Transcobalamin-II deficiency?
Failure to Thrive
Presents in early infancy
What are the lab findings in Transcobalmin-II deficiency?
normal folate and Vitamin b12
low or absent TC-II levels in the serum
What is pernicous anemia due to?
decreased intrinsic factor
How do you detect pernicious anemia?
Schilling Test, corrected by addition of instrinsic factor
Is adult or juvenile pernicious anemia associated with autoimmune disorders?
What are three disorders that can cause cobalamin deficiency in the face of normal intrinsic factor?
ileal resection
inflammatory bowel disease
Imerslund-Grasbeck Syndrome
what happens if you treat vitamin b12 deficiency with high dose folate
you mask the vitamin b12 deficiency and do not address the neurologic problems which will persist
Why does copper deficiency cause microcytic anemia?
Copper is necessary for iron transport
Signs of copper deficiency
microcytic anemia, neutropenia and ricketts like bone disease
what causes anemia of inflammation (aka anemia of chronic disease)
shortened RBC survival combined with decreased RBC production
can follow mild and severe illnesses
What cytokine in particular can inhibit erythropoeisis
this fact contributes to anemia of inflammation
What cytokine stimulates hepcidin by hepatocytes
How does increase in hepcidin contribute to anemia of inflammation?
reduces intestinal absorption and macrophage release of iron
therefore reduced serum iron
(more iron are in macrophages)
What state is iron in in methemoglobinemia?
oxidized (Fe3+) rather than reduced (Fe2+)
When is methylene blue an ineffective antidote for methemoglobinemia
G6PD deficiency
Hgb M
why are infants at increased risk of methemoglobinemia
relative deficiency of cytochrome B5 reductase
At what age do exclusively breast fed babies require iron supplementation?
6 months
what form of iron is best absorbed in the duodenum?
heme iron (as found in meat)
What are two inherited means of acquiring methemoglobinemia
cytochrome B5 reductase deficiency (autosomal recessive)
hemoglobin M resulting in FE3+ (dominant inheritance)

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