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HemOnc Week 1 > ICL 2.1: Disorders of Iron Metabolism > Flashcards

ICL 2.1: Disorders of Iron Metabolism Flashcards

1
Q

what are normal Hb concentrations in men and women?

A

men: 14-16 g/dL
female: 12-14 g/dL

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2
Q

whats the normal RBC count in men and woman?

A

men: 4.3-5.9 million/mmˆ3
women: 3.5-5 million/mmˆ3

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3
Q

how much of iron can you absorb from food?

A

only 10%!

so if you put someone on iron pills, you want them to be on like 3 pills!

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4
Q

how does iron get into your body?

A

Fe+3 from food gets turned into Fe+2 (because only Fe+2 can get into the body!)

Fe+2 goes into enterocyte via DMT1 transporter in apical membrane

Fe+2 leaves enterocyte via Ferroportin 1 transporter in basolateral membrane

Fe+2 gets turned into Fe+3

Fe+3 binds to transferrin and transferrin takes Fe+3 to wherever its needed in the body

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5
Q

where does most of the iron absorbed by food go to?

A
  1. hemoglobin/RBC production (75%)
  2. ferritin that stores iron in liver & heart (10-20%)
  3. other (5-15%)
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6
Q

what inhibits ferroportin?

A

ferroportin transports iron out of the enterocyte into the blood

hepcidin released from the liver inhibits ferroportin

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7
Q

what regulates iron metabolism?

A

hepcidin!

hepcidin is a negative influencer of iron

so more iron you have, the less hepcidin and vice versa

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8
Q

what inhibits hepcidin?

A
  1. RBC production
  2. growth factors
  3. testosterone

this is why men have more hemoglobin!

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9
Q

what stimulates hepcidin secretion?

A
  1. high iron levels

2. inflammation

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10
Q

low MCV with normal iron is usually what?

A

hemoglobin problems!

this is your clue that it’s a hemoglobinopathy like thalassemia or sickle cell

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11
Q

what is TACO?

A

Transfusion Associated Cardiac Overload

sometimes happens with blood transfusions

features: dyspnea, hypertension, crepitations, low O2 saturation

risk of volume overload/respiratory distress especially in small/elderly patients

avoidable by careful attention to fluid balance

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12
Q

what’s the formula for MCH?

A

(Hb/RBC count)x10

mean corpuscular hemoglobin = average amount of Hb in RBCs in the body

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13
Q

what’s the formula for MCHC?

A

Hb concentration per gm/dL of RBC

mean cell hemoglobin concentration = average concentration of Hb in a given volume of blood

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14
Q

how is the MCH effected in IDA and thalassemia?

A

low

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15
Q

how is the MCHC effected in IDA and thalassemia?

A

low

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16
Q

in what anemias is MCHC high?

A

HbC

intra-cellular dehydration

H. spherocytosis

17
Q

what’s the Hb threshold that people will get transfusions?

A

Hb = 7, then they will give a transfusion

18
Q

what conditions increase iron demand?

A

pregnancy and lactation

during pregnancy iron is diverted to developing fetus

men shouldn’t be anemic unless they’re bleeding somewhere

19
Q

can someone be iron deficient and still have normal Hb levels?

A

yes

20
Q

what does and IDA blood smear look like?

A

RBCs look mostly white because there’s no iron!

you’ve lost the central pallor

21
Q

what is sideroblastic anemia?

A

iron is present but can’t be used

it gets stuck in the mitochondria of early RBCs

defect in heme synthesis within the mitchondria of developing RBCs in the bone marrow

iron accumulates mitochondria which produces ringed sideroblasts

22
Q

what causes sideroblastic anemia?

A
  1. chronic alcoholism
  2. B6 deficiency
  3. lead poisoning
23
Q

what’s the inheritance pattern of sideroblastic anemia?

A

X linked recessive

24
Q

what causes anemia of chronic disease?

A

iron overload! caused by:

  1. chronic inflammatory disease: like infections or sarcoidosis
  2. malignant disease: like lymphoma or sarcoma

not related to bleeding!!

25
Q

what are the types of bone marrow failure anemias?

A

this is when your bone marrow isn’t making any RBCs and is filled with fat so the blood smear looks mostly white

  1. acquired
  2. congenital
26
Q

which anemias are acquired bone marrow failure anemias?

A
  1. myelodysplastic syndrome

2. acquired aplastic anemia

27
Q

which anemias are congenital bone marrow failure anemias?

A
  1. Fanconi anemia
  2. dyskeratosis congenita
  3. Shwachman-Diamond Syndrome
  4. severe congenital neutropenia
  5. Diamond-Blackfan anemia
  6. congenital megakaryocytic thrombocytopenia
28
Q

in what population is iron overload most common?

A

Celtic course

irish, scottish people

29
Q

what is hemochromatosis?

A

excessive iron accumulation in the liver from the due due to abnormal absorption of normal iron intake resulting in organ dysfunction

iron also deposits in pancreas, heart, adrenal, thyroid, parathyroid, anterior pituitary, literally everywhere

liver turns rusty brown color from hepatocytes dying

30
Q

what is hemochromatosis inherited?

A

autosomal recessive

Celtic curse! Aka very common in Ireland and Scotland

Think, the liver turns rusty red color and scottish people have red hair!

31
Q

what are the types of hemochromatosis?

A
  1. HFE
  2. TfR2
  3. HJV or HAMP
  4. ferroportin disease
32
Q

what’s a clinical presentation of hemochromatosis?

A

bent looking fingers from the iron deposits in the skin

33
Q

what’s the most common mutation that causes hemochromatosis?

A

HFE gene mutation

C282Y point mutation that causes cysteine to tyrosine substitution

penetrance is low though, lots of people have the mutation but don’t actually experience Fe overload

34
Q

can you get hemochromatosis from blood transfusions?

A

no

the iron overload from a transfusion gets deposited in a different place

in hemochromatosis, iron is deposited mainly in liver cells while in a transfusion it’s in macrophages

35
Q

how many units of blood would cause an iron overload?

A

the body can’t regulate iron loss, the only way to get rid of it is chelate

20 units

36
Q

what CBC values are diagnostic of hemochromatosis and iron overload?

A

high ferritin

high % transferrin saturation (>60%)

37
Q

what’s a good way to see how much iron is in the liver without a biopsy to test for hemochromatosis/iron overload?

A

superconducting quantum interference device = SQUID

high power magnetic field

iron interferes with field

however there’s only 4 machines in the whole world….

38
Q

how do you treat hemochromatosis?

A
  1. phlebotomy

take out blood every few weeks to decrease amount of iron

  1. deferasirox is an alternative
39
Q

what’s the goal ferritin level for someone undergoing treatment for hemochromatosis?

A

<50 ug/L

HemOnc Week 1 (32 decks)

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