Carbon Monoxide: Poisoning & Cyanide Poisoning

Question 1

The toxicity of CO is attributed to what?

Answer 1

to its high affinity for hemoglobin (Hb)

*250 times that of oxygen

Question 2

_____ hemoglobin has a much greater affinity for CO than adult hemoglobin.

Answer 2

fetal

*Hint: pregnancy

Question 3

List the 4 properties of CO

Answer 3

1. gas
2. odorless
3. colorless
4. tasteless

Question 4

State the relative vapor density of CO

Answer 4

0.97

Question 5

CO is extremely

Answer 5

stable & flammable

Question 6

List the 3 sources of CO

Answer 6

1. endogenous
2. exogenous
3. methylene chloride

Question 7

Describe the Endogenous Source of CO

Answer 7

heme catabolism (requires 2 NADPH & 3 O2)

1. heme reduced –> biliverdin, CO, & FE2+/iron
   (heme oxygenase enzyme)
2. biliverdin reduced –> bilirubin (biliverdin reductase enzyme)

Question 8

Endogenous Source: ____ & ____ levels are increased

Answer 8

hemolytic anemia, sepsis

Question 9

What case characteristics are at-risk for accidental CO deaths?

Answer 9

1. patients older than 65 years old
2. male
3. ethanol intoxication
4. use of heating systems
5. closed windows
6. winter

*Hint: old men drinking inside their hot, windowless homes in winter

Question 10

6 Patient Symptoms of CO

Answer 10

1. headache
2. nausea
3. dizziness
4. breathlessness
5. collapse
6. unconsciousness

Question 11

Iron-containing proteins CO binds to

Answer 11

1. myoglobin
2. cytochrome
3. neuroglobin

Question 12

Myoglobin leads to these heart disorders by reducing )2 available in the heart:

Answer 12

1. Ischemia
2. dysrhythmias
3. cardiac dysfunction

Question 13

CO decreases what 3 things?

Answer 13

1. myocardial oxidative phosphorylation by
   decreasing the activity of myocardial cytochrome oxidase (CcOX), the terminal oxidase in the electron transport chain.
2. heme aa3 content
3. steady-state levels of CcOX subunit I protein (does not affect mRNA levels)

Question 14

CO exposure increases ______

Answer 14

COHb levels (without causing tissue hypoxia)

Question 15

CO Poisoning Cause

Answer 15

• increased enzyme destruction due to CO binding to heme groups
• reactive oxygen species production, oxidative stress, &
  subsequent protein destruction

Question 16

Nonspecific neurologic features of CO Poisoning

Answer 16

-headache
-confusion
-nausea
-fatigue
-vertigo
-paresthesia

Question 17

Long term neurologic effects of CO Poisoning

Answer 17

-amnesia
-dementia
-parkinsonism (damaged dopamine neurons)
-psychosis

Question 18

Neurologic findings due to ________________ can result in ataxia, seizures, and coma

Answer 18

cerebral edema

Question 19

cherry skin and/or lips are symptoms of

Answer 19

high circulating COHb levels (CO binding to RBC Hb)

*Now uncommon though

Question 20

Tissue hypoxia is attributed to

Answer 20

reduced CO2 transport on RBCs & limited O releases from RBCs