Block V- Pulm Anemia/Hematopoietic Growth Factors Flashcards
What molecules store Iron?
Ferritin (macrophages, liver, spleen)
Hemosiderin
What oxidation state of Iron is preferentially absorbed and what maintains this state?
Fe2+ (ferrous) form, maintained by acid produced by the gastric body
What molecule brings Iron to the plasma/ liver/ spleen (storage)?
Ferritin
What molecule takes Iron to the BM?
Transferrin
Where is Iron absorbed?
duodenum and jejunum
What are ferritin and transferrin levels in Iron Deficiency?
dec. ferritin
inc. transferrin
What are ferritin and transferrin levels in Iron Overload?
inc. ferritin
dec. transferrin
Hepcidin and Ferroportin:
hemochromatosis
anemia of chronic disease
ferroportin = gatekeeper. prevent iron from getting out or send it out! tell it where to go!
hemochromatosis = decreased hepcidin and increased ferroportin
ACD = inc hepcidin = down regulation of ferroportin = iron stuck in cell w/o normal gatekeeper
What are indications for Iron therapy? (4)
1) prevention or treatment of iron deficiency anemia
2) Increased requirements (premature infants, children, pregnant and lactating women)
3) Inadequate absorption (small intestine or gastrectomy)
4) blood loss (period of chronic GI bleed)
Oral Iron Therapy
- Ferrous sulfate, ferrous gluconate, ferrous fumarate
- quick response (1-3 months)
- Adverse Effects: nausea, vomiting, black stools
Parenteral Iron Therapy (IM/IV)
- Iron dextran, iron sucrose, iron gluconate
- Indicated when oral iron not tolerated (post GI resection, malabsorption syndromes)
- Adverse Effects: pain, tissue staining (IM), HA, fever, N/V, back/joint pain, allergic rxn, anaphylaxis
What is Acute Iron Toxicity?
- over ingestion of iron tablets
- fatal in children
- Necrotizing gastroenteritis
What is Chronic Iron Toxicity?
- Hemochromatosis, multiple red cell transfusions
- organ failure
How do you treat Acute Iron Toxicity?
- Gastric aspiration
- Gastric lavage (phosphate or carbonate)
- Iron chelation with deferoxamine
How do you treat Chronic Iron Toxicity?
- intermittent phlebotomy (if no anemia)
- Iron chelation (deferoxamine, deferasirox)
Where is Vitamin B12 absorbed?
The distal ileum
What is Vitamin B12 bound to in the small intestine which permits its absorption?
Intrinsic factor (from the gastric parietal cells)
What is B12 bound to in plasma?
Transcobalamin II
What are the active forms of vitamin B12?
- deoxyadenosylcobalamin
- Methylcobalamin
What are prodrugs of B12 and how are they given?
- Given IM
- Cyanocobalamin
- Hydroxycobalamin
Where is folate stored?
-stored in the liver (1-6 months)