Toxicology

Question 1

CO is the leading cause of death by poisoning (closed areas AC, car). How does CO primarily act (two)?

Answer 1

1. Displacing oxygen from hemoglobin (Hb)
   CO has more than 200 times higher affinity to Hb than O2
   CO displaces oxygen –produces carboxy-hemoglobin
2. Impairing oxygen release from Hb
   CO reduces the ability of oxyhemoglobin to deliver oxygen to the peripheral tissues

Question 2

How do you treat CO poisoning?

Answer 2

100% O2 UNDER PRESSURE bc will displace much faster (20 min. max).

Question 3

What is Hyperoxia & Oxygen Toxicity and what are the risk factors?

Answer 3

Breathing oxygen at higher than normal partial pressures (>21% atm. Pressure). Risk factors: hypercapnia due to COPD, working at depth, narcotic withdrawal. Deep sea diving. Also, CO poisoning, decompression sickness

Question 4

What is the treatment of Hyperoxia & Oxygen Toxicity?

Answer 4

prevention, minimum O2 dose possible, anti-epileptics

Question 5

How does Hyperoxia & Oxygen Toxicity happen?

Answer 5

Production of reactive oxygen intermediates (ROIs), superoxide anion, hydroxyl radical, H2O2

Question 6

What are the clinical features of Hyperoxia & Oxygen Toxicity?

Answer 6

Lungs: increase susceptibility to mucous plugging, atelectasis, 2ry infection by impairing mucociliary clearance & decrease immune cell function
Oxygen toxicity: tracheobronchial & alveolar damage, pulmonary interstitial fibrosis
Eye: retinal detachment and retrolental fibroplasia (esp. newborns during resuscitation)
Seizures

Question 7

NO2is a relatively insoluble deep lung irritant capable of producing _____.

Answer 7

pulmonary edema

Question 8

Severe exposure of ozone (O3) can cause deep lung irritation, with _____ when inhaled at sufficient concentrations.

Answer 8

pulmonary edema

Question 9

Where can you find benzene (toluene)?

Answer 9

octane boost in fuel –Formula 1, airplanes; airplane glue, paint-thinners, rocket fuel, component of gasoline

Question 10

What are the acute toxic effects of benzene?

Answer 10

depression of CNS and

Aplastic anemia

Question 11

What is the chronic toxic effects of benzene?

Answer 11

leukemia

Question 12

Does toluene cause aplastic/leukemic effects and why is it abused?

Answer 12

No; abused due to intoxication symptoms (euphoria, dizziness, sleep)

Question 13

What are the sources of cyanide?

Answer 13

inhalation of smoke produced by the burning of plastics, fruit seeds (e.g., apricots and cherries, apple, plum, peach), lima bean, and raw almond

Question 14

*****Which drug causes cyanide toxicity?

Answer 14

nitroprusside

Question 15

What is the mechanism of cyanide poisoning?

Answer 15

Cyanide produces toxicity by binding avidly to ferric iron (Fe3+), which prevents its reduction to the ferrous form (Fe2+). Fe2+ is involved in the cytochrome oxidase a3 electron-transport system.

Question 16

Inhalation of cyanide may produce a _____ demise, whereas symptoms may be _____ if the cyanide is ingested orally

Answer 16

rapid, delayed

Question 17

What are the Cyanide toxic symptoms?

Answer 17

hypoxia including headache, anxiety, agitation, confusion, lethargy, seizures and coma, shortness of breath, abdominal pain, nausea and vomiting, cherry red skin color (increased venous hemoglobin oxygen saturation). Cyanide does not directly cause cyanosis

Question 18

What are the treatments for cyanide toxicity?

Answer 18

Cyanide Antidote Kit contains amyl nitrite pearls, sodium nitrite, and sodium thiosulfate. Another antidote Hydroxocobalamin can be administered in the absence of the cyanide antidote.

Question 19

How do you return Methemoglobin + Sodium thiocyanate to Hb when treating cyanide poisoning?

Answer 19

Methylene blue

Question 20

_____ turns Hb to methemoglobin which has high affinity for cyanide radical and forms cyanomethemoglobin. This may release cyanide from cytochrome oxidase a3.

Answer 20

Nitrite

Question 21

Sodium thiosulfate is given to form _____ which is poorly dissociable and is excreted in the urine

Answer 21

Sodium thiocyanate

Question 22

*****What are the clinical features of lead poisoning?

Answer 22

blue line on gum margin, low IQ, dense metaphyseal band on x-ray, microcytic anemia, basophilic stippling RBC, blood lead increased

Question 23

*****What do you use to treat (chelator) iron poisoning (hemochromatosis)?

Answer 23

deferoxamine (excreted by urine)

Question 24

*****What is the treatment of lead poisoning > 44μg/dl?

Answer 24

Blood lead > 44μg/dl, edetate calcium disodium (EDTA), succimer, dimercaprol, penicillamine

Question 25

*****What is the treatment of lead poisoning > 70μg/dl?

Answer 25

IV EDTA+dimercaprol

Question 26

*****What is the chelator (treatment) of lead?

Answer 26

EDTA

Question 27

What is the chelator (treatment) of copper (Wilson’s disease)?

Answer 27

Penicillamine

Question 28

What is the chelator (treatment) of arscenic?

Answer 28

British anti-lewisite

Question 29

What is the treatment of mercury?

Answer 29

dimercaprol or succimer

Question 30

What are the clinical features of Wilson’s (copper builds up in liver and blood)?

Answer 30

parkinsonism, cirrhosis, neuropsychiatric symptoms, Kayser-Fleischer ring, Serum ceruloplasmin (copper carrying protein) decreases (<20mg/dl)

Question 31

*****What are acute iron toxicity?

Answer 31

necrotizing gastritis, vomiting, abdominal pain and bloody diarrhea

Question 32

*****How do you diagnose primary or secondary hemochromatosis?

Answer 32

Serum ferritin, liver biopsy—iron staining (Prussian blue)

Question 33

Quick recall of toxic drugs and their antidotes.

Answer 33

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