Pharmacology - Dyshemoglobinemias

Question 1

What is the only scenario where CO in the body can increase in the body after a patient is removed from the environment?

Answer 1

Methylene chloride
found in furniture strippers
converted to CO in the body

Question 2

T/F: There is no metabolism of CO

Answer 2

True

It must be exhaled.

Question 3

Why can an O2 sat reading be abnormal during CO poisoning?

Answer 3

Carboxyhemoglobin read as hemoglobin

Must use co-oximeter

Question 4

Why consider hyperbaric oxygen to treat CO exposure?

Answer 4

HBO was shown to prevent lipid peroxidation in animal models

indications:
GCS 10%
myocardial ischemia, ventricular issues;
neurologic signs 2-4 hours out

Question 5

The two chemical exposure risks for patients pulled from a house fire are:

Answer 5

CO

cyanide (burning plastic)

Question 6

MOA: Cyanide

Answer 6

Binds to cytochrome A3 in the ETC and prevents proton pump from working

Question 7

What is the treatment for cyanide poisoning?

Answer 7

Hydroxycobalamin - binds to cyanide to make cyanocobalamin (B12)

Question 8

When is use of hydroxycobalamin indicated?

Answer 8

Any smoke inhalation victim that does not show improvement with O2;
If intentional cyanide exposure is known

Question 9

Recreational use of amyl nitrite exposes individuals to what chemical?

Answer 9

Methemoglobin

–heme iron oxidized to 3+

Question 10

Methemoglobin toxicity is characterized by:

Answer 10

Incapacitated O2 transport
Left shift of O2 dissociation curve
At 20-50% dizziness, fatigue, dyspnea (cyanosis at 10-20%)
death at >70%

Question 11

What is the antidote for methemoglobinemia?

Answer 11

Methylene blue - tetramethyl thionine chloride
Reduces Methemoglobin to Fe 2+
indicated for 20-30% or symptomatic

Question 12

When might a patient not respond to methylene blue treatment for methemoglobin toxicity?

Answer 12

Hemoglobin M disease
G6PD deficiency
Sulfhemoglobinemia

Question 13

Sulhemoglobinemia and Methemoglobinemia clinically look similar. How can you tell the difference?

Answer 13

In the lab, add cyanide to the blood.

Question 14

In methemoglobinemia, why is the ABG falsely normal?

Answer 14

PO2 not affected

Question 15

What substances can cause acquired methemoglobinemia?

Answer 15

Nitrites
Nitrates in babies
Benzocaine, local anesthetics
Sulfonamides
Phenazopyradine
Dapsone

Aniline dye
Potassium chlorate
Diarrheal illness in infants (creates nitrites)

Question 16

What happens when CO interacts with platelets? What is formed? Why is this significant?

Answer 16

displaces nitric oxide leading to formation of peroxynitrites, results in free radical mediated damage thought to contribute most to central nervous system long term toxicity.

Question 17

Individuals deficient in glucose-6-phosphate dehydrogenase do not generate sufficient quantities of:

Answer 17

NADPH