Blood Toxicity

Question 1

What are common toxic agents causing blood toxicity?

Answer 1

Benzene, lead, arsenic, carbon monoxide, cyanide, nitrates, chloramphenicol, phenylhydrazine, 2-ethoxyethanol, radiation, aniline, nitrobenzene, cyclophosphamide, dapsone, naphthalene.

Question 2

What is the primary mechanism of benzene-induced blood toxicity?

Answer 2

Metabolites (e.g., hydroquinone) damage bone marrow stem cells, causing aplastic anemia and leukemia.

Question 3

How does lead cause blood toxicity?

Answer 3

Inhibits heme synthesis enzymes (ALA dehydratase, ferrochelatase), leading to microcytic anemia.

Question 4

What is the mechanism of carbon monoxide-induced blood toxicity?

Answer 4

Binds hemoglobin (200x affinity over oxygen), forming carboxyhemoglobin, reducing oxygen transport.

Question 5

How does cyanide affect blood?

Answer 5

Inhibits cytochrome c oxidase (complex IV), disrupting cellular respiration and causing hypoxia.

Question 6

What biomarkers indicate blood toxicity?

Answer 6

Decreased RBC count, low hemoglobin, elevated methemoglobin, carboxyhemoglobin, pancytopenia.

Question 7

What are standard testing methods for blood toxicity?

Answer 7

Complete blood count (CBC), hemoglobin levels, methemoglobin levels, bone marrow biopsy.

Question 8

What are key endpoints of blood toxicity?

Answer 8

Aplastic anemia, acute myeloid leukemia (AML), methemoglobinemia, hemolytic anemia, pancytopenia.

Question 9

How do nitrates contribute to blood toxicity?

Answer 9

Converted to nitrites, which oxidize hemoglobin to methemoglobin, impairing oxygen delivery.

Question 10

What is the toxic effect of 2-ethoxyethanol on blood?

Answer 10

Suppresses bone marrow, causing hemolytic anemia and leukopenia.

Question 11

How does arsenic induce blood toxicity?

Answer 11

Disrupts heme synthesis and induces oxidative stress, leading to anemia and bone marrow suppression.

Question 12

What is the mechanism of aniline-induced blood toxicity?

Answer 12

Metabolized to phenylhydroxylamine, oxidizes hemoglobin to methemoglobin, causing methemoglobinemia.

Question 13

What are clinical signs of methemoglobinemia?

Answer 13

Cyanosis, shortness of breath, fatigue, headache; severe cases cause coma or death.

Question 14

How does phenylhydrazine cause blood toxicity?

Answer 14

Oxidizes RBC membranes, forming Heinz bodies, leading to hemolytic anemia.

Question 15

What is the mechanism of chloramphenicol-induced blood toxicity?

Answer 15

Inhibits mitochondrial protein synthesis in bone marrow, causing dose-dependent suppression or idiosyncratic aplastic anemia.

Question 16

What is a key biomarker for lead poisoning?

Answer 16

Elevated blood lead levels (>5 µg/dL) and increased urinary delta-aminolevulinic acid (ALA).

Question 17

How does radiation cause blood toxicity?

Answer 17

Damages DNA in hematopoietic stem cells, causing pancytopenia and increased leukemia risk.

Question 18

What testing method detects hemolytic anemia?

Answer 18

Coombs test (direct antiglobulin test) identifies autoantibodies in immune-mediated hemolytic anemia.

Question 19

How does nitrobenzene affect blood?

Answer 19

Metabolized to nitrosobenzene, induces methemoglobinemia and hemolytic anemia.

Question 20

What is a long-term endpoint of benzene exposure?

Answer 20

Acute myeloid leukemia (AML) due to chromosomal translocations in hematopoietic cells.

Question 21

What agent causes idiosyncratic aplastic anemia?

Answer 21

Chloramphenicol, often via genetic predisposition affecting metabolism.

Question 22

What is the role of flow cytometry in blood toxicity testing?

Answer 22

Analyzes hematopoietic cell populations to detect leukopenia, blast cells, or abnormal RBCs.

Question 23

What biomarker indicates hemolysis?

Answer 23

Elevated lactate dehydrogenase (LDH) and decreased haptoglobin in serum.

Question 24

How does cyclophosphamide cause blood toxicity?

Answer 24

Alkylates DNA in bone marrow cells, causing bone marrow suppression and leukopenia.

Question 25

What is the mechanism of dapsone-induced blood toxicity?

Answer 25

Metabolized to hydroxylamine, causing methemoglobinemia and hemolytic anemia.

Question 26

What test confirms methemoglobinemia?

Answer 26

Co-oximetry measures methemoglobin levels, distinguishing it from oxyhemoglobin.

Question 27

How does primaquine affect blood?

Answer 27

Induces oxidative stress in RBCs, causing hemolytic anemia in G6PD-deficient individuals.

Question 28

What biomarker reflects bone marrow suppression?

Answer 28

Decreased reticulocyte count, indicating reduced RBC production.

Question 29

How does azathioprine cause blood toxicity?

Answer 29

Inhibits purine synthesis, leading to bone marrow suppression and leukopenia.

Question 30

What is an endpoint of chronic arsenic exposure?

Answer 30

Pancytopenia and increased leukemia risk due to bone marrow suppression.

Question 31

What toxic agent forms Heinz bodies in RBCs?

Answer 31

Phenylhydrazine, visible on blood smears due to oxidative damage.

Question 32

How does methotrexate cause blood toxicity?

Answer 32

Inhibits folate metabolism, causing megaloblastic anemia and bone marrow suppression.

Question 33

What biomarker monitors cyanide toxicity?

Answer 33

Elevated lactate levels due to anaerobic metabolism.

Question 34

What test evaluates bone marrow function?

Answer 34

Bone marrow aspiration and biopsy assess hematopoietic cell viability.

Question 35

How do sulfonamides cause blood toxicity?

Answer 35

Trigger hypersensitivity, causing hemolytic anemia or agranulocytosis.

Question 36

What is an endpoint of carbon monoxide poisoning?

Answer 36

Hypoxic brain injury due to impaired oxygen delivery.

Question 37

How does naphthalene cause blood toxicity?

Answer 37

Metabolized to naphthoquinone, causing hemolytic anemia, especially in G6PD deficiency.

Question 38

What biomarker indicates lead-induced heme synthesis inhibition?

Answer 38

Increased zinc protoporphyrin (ZPP) in RBCs.

Question 39

How does zidovudine cause blood toxicity?

Answer 39

Inhibits mitochondrial DNA polymerase, causing anemia.

Question 40

What test detects immune-mediated hemolysis?

Answer 40

Direct antiglobulin test (DAT) identifies antibodies on RBC surfaces.

Question 41

What is an endpoint of nitrobenzene exposure?

Answer 41

Methemoglobinemia leading to tissue hypoxia and organ damage.

Question 42

What agent causes agranulocytosis?

Answer 42

Clozapine, via immune-mediated destruction of neutrophils.

Question 43

How does quinidine cause blood toxicity?

Answer 43

Triggers immune-mediated thrombocytopenia or hemolytic anemia.

Question 44

What biomarker monitors bone marrow recovery?

Answer 44

Increased reticulocyte count indicates regenerative anemia.

Question 45

How does hydrazine cause blood toxicity?

Answer 45

Oxidizes hemoglobin, causing methemoglobinemia and hemolytic anemia.

Question 46

What test assesses RBC morphology?

Answer 46

Peripheral blood smear identifies spherocytes, schistocytes, or Heinz bodies.

Question 47

What is an endpoint of chloramphenicol toxicity?

Answer 47

Gray baby syndrome in neonates due to bone marrow suppression.

Question 48

What role do benzene metabolites play in toxicity?

Answer 48

Hydroquinone and benzoquinone damage DNA, leading to bone marrow aplasia.

Question 49

What biomarker indicates oxidative stress in RBCs?

Answer 49

Elevated malondialdehyde (MDA) reflects lipid peroxidation.

Question 50

How does antimony cause blood toxicity?

Answer 50

Interferes with heme synthesis and induces oxidative damage, causing anemia.