Brainscape Flashcards - haemanetics

Question 1

What are hematinics?

Answer 1

Hematinics are substances required for the formation of blood, used to treat anemias. Examples include iron, vitamin B12, and folic acid.

Question 2

What causes anemia?

Answer 2

Anemia can be caused by blood loss, impaired red cell formation (due to deficiencies in iron, vitamin B12, folic acid, or bone marrow depression), and increased RBC destruction (hemolytic anemia).

Question 3

What is the primary function of iron in the body?

Answer 3

Iron is essential for hemoglobin formation, oxygen transport, and enzyme function.

Question 4

How is iron distributed in the body?

Answer 4

Iron is found in hemoglobin (66%), iron stores (25%), myoglobin (3%), and other enzymes (6%).

Question 5

How much iron is needed to raise hemoglobin by 1 g/dL?

Answer 5

About 200 mg of iron is needed to raise hemoglobin by 1 g/dL.

Question 6

What are rich dietary sources of iron?

Answer 6

Rich sources of iron include liver, egg yolk, oyster, dry beans, dry fruits, wheat germ, and yeast.

Question 7

What daily iron requirement is recommended for pregnant women in the last two trimesters?

Answer 7

Pregnant women require 3-5 mg of iron per day (80 μg/kg) in the last two trimesters.

Question 8

What form of dietary iron is absorbed best?

Answer 8

Haeme iron is absorbed better than inorganic iron, with an absorption rate of up to 35%.

Question 9

What is the role of divalent metal transporter 1 (DMT1) in iron absorption?

Answer 9

DMT1 transports ferrous iron across the intestinal luminal membrane into the mucosal cells.

Question 10

Which form of iron is needed for absorption in the intestine, ferric (Fe3+) or ferrous (Fe2+)?

Answer 10

The ferrous (Fe2+) form is needed for intestinal absorption.

Question 11

Name two factors that facilitate iron absorption.

Answer 11

Acid (e.g., HCl) and reducing substances (e.g., ascorbic acid) facilitate iron absorption.

Question 12

Why are antacids not recommended with iron supplements?

Answer 12

Antacids create an alkaline environment, which makes iron insoluble and opposes its absorption.

Question 13

What is the “Ferritin curtain”?

Answer 13

The “Ferritin curtain” is a storage mechanism where ferritin holds excess iron in mucosal cells that are later shed, preventing excess iron entry into the body.

Question 14

What is transferrin and its function?

Answer 14

Transferrin is a glycoprotein that binds iron in plasma, transporting it to erythropoietic and other cells.

Question 15

What is the formula for calculating parenteral iron requirements?

Answer 15

Iron requirement (mg) = 4.4 × body weight (kg) × Hb deficit (g/dL).

Question 16

What are some common adverse effects of oral iron therapy?

Answer 16

Common adverse effects include epigastric pain, nausea, vomiting, metallic taste, and constipation or diarrhea.

Question 17

What are two main preparations of parenteral iron?

Answer 17

The two main preparations are Iron-dextran and Iron-sorbitol-citric acid complex, each containing 50 mg of elemental iron per ml.

Question 18

What adverse effects may occur with iron-sorbitol injections?

Answer 18

Adverse effects include a metallic taste, fever, headache, joint pain, flushing, and in rare cases, anaphylactoid reactions.

Question 19

What happens in acute iron poisoning, and who is most at risk?

Answer 19

Acute iron poisoning can cause vomiting, abdominal pain, hematemesis, diarrhea, lethargy, and cardiovascular collapse, often affecting children who ingest iron tablets.

Question 20

How is desferrioxamine used in iron poisoning?

Answer 20

Desferrioxamine is an iron chelating agent given intramuscularly or intravenously to bind and remove excess iron from the body.

Question 21

What is erythropoietin, and where is it produced in the body?

Answer 21

Erythropoietin (EPO) is a hormone essential for red blood cell production, produced primarily by the peritubular cells in the kidneys.

Question 22

How does erythropoietin stimulate red blood cell production?

Answer 22

EPO stimulates erythroid progenitor cells, induces hemoglobin synthesis, and releases reticulocytes into circulation.

Question 23

What are the primary indications for erythropoietin administration?

Answer 23

The primary indication is anemia of chronic renal failure; other uses include anemia in AIDS, cancer chemotherapy-induced anemia, and preoperative blood production.

Question 24

What adverse effects are associated with erythropoietin?

Answer 24

Adverse effects include increased clotting, hypertension, seizures, and flu-like symptoms.

Question 25

What are the main sources of vitamin B12?

Answer 25

Main sources include liver, kidney, sea fish, egg yolk, meat, cheese, and legumes.

Question 26

What is the role of intrinsic factor in vitamin B12 absorption?

Answer 26

Intrinsic factor binds with vitamin B12 in the stomach, allowing its absorption in the intestines.

Question 27

What is the active coenzyme form of vitamin B12?

Answer 27

The active coenzyme forms are deoxyadenosyl-cobalamin (DAB12) and methyl-cobalamin (methyl B12).

Question 28

What causes vitamin B12 deficiency?

Answer 28

Causes include Addisonian pernicious anemia, gastric mucosal damage, malabsorption, consumption by abnormal flora, poor diet, and increased demand (e.g., pregnancy).

Question 29

Which neurological symptoms are associated with vitamin B12 deficiency?

Answer 29

Symptoms include diminished vibration and position sense, paresthesias, poor memory, mood changes, and, in severe cases, spinal cord degeneration.

Question 30

What condition results from vitamin B12 deficiency due to autoimmune destruction of parietal cells?

Answer 30

Addisonian pernicious anemia, which impairs intrinsic factor production and vitamin B12 absorption.

Question 31

Why should folic acid not be given alone in cases of vitamin B12 deficiency?

Answer 31

Folic acid alone can improve hematologic symptoms but may allow neurological symptoms to progress, as it does not address the underlying vitamin B12 deficiency.

Question 32

What are the primary dietary sources of folic acid?

Answer 32

Main sources include liver, green leafy vegetables, eggs, meat, and milk.

Question 33

What is the main function of folic acid in the body?

Answer 33

Folic acid is essential for DNA synthesis and facilitates several one-carbon transfer reactions critical for cell growth and division.

Question 34

What is the daily folic acid requirement during pregnancy?

Answer 34

The recommended dietary allowance during pregnancy is 0.8 mg/day.

Question 35

What are common symptoms of folic acid deficiency?

Answer 35

Symptoms include megaloblastic anemia, glossitis, enteritis, diarrhea, and, in pregnancy, neural tube defects in the offspring.

Question 36

Why is folic acid supplementation recommended during pregnancy?

Answer 36

Folic acid is recommended to prevent neural tube defects, like spina bifida, in the developing fetus.

Question 37

What is the recommended treatment dose of folic acid for megaloblastic anemia?

Answer 37

The therapeutic dose is 2-5 mg of folic acid per day.

Question 38

What is folinic acid, and what is its main use?

Answer 38

Folinic acid is an active form of folate used to counteract methotrexate toxicity, as it does not need reduction to act as a coenzyme.

Question 39

Which enzyme is inhibited by methotrexate, necessitating folinic acid rescue therapy?

Answer 39

Methotrexate inhibits dihydrofolate reductase (DHFR), which is essential for folate activation.

Question 40

What is the function of copper as an adjuvant hematinic?

Answer 40

Copper is needed for heme synthesis, though deficiency in humans is rare.

Question 41

Which form of vitamin B12 has a longer-lasting effect, cyanocobalamin or hydroxocobalamin?

Answer 41

Hydroxocobalamin has a longer-lasting effect than cyanocobalamin.

Question 42

What is the primary function of recombinant human erythropoietin (Epoetin α, β)?

Answer 42

It treats anemia in chronic renal failure, chemotherapy-induced anemia, and preoperative blood production, improving quality of life and reducing the need for transfusions.