Hydrocarbons and Inhaled Toxins Flashcards Preview

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Flashcards in Hydrocarbons and Inhaled Toxins Deck (21):

List the 4 types of toxic exposures to hydrocarbons

1. Accidental ingestions (generally children younger then 5)
2. Intentional inhalational abuse
3. Accidental inhalation or dermal exposure – often occupational
4. Massive oral ingestion in a suicide attempt


List the hydrocarbons most sought by abusers for eurphoria and disinhibition (also confusion and obtundation)?

1. Toluene
2. benzene
3. gasoline
4. butane
5. chlorinated hydrocarbons


How do hydrocarbons target the CNS/CV in toxicity

CNS: Work like general anesthetics
GABA activation

CV: sensitizes myocardium
Na channel/K channel blockers (prolong QRS and QT


What physical characteristics increase toxicity

1, volatile
2. low viscosity
3. low surface tension


How do hydrocarbons cause lung injury

1. asphyxiant (displaces O2)
2. inhibit surfactant production
3. direct damage to alveoli
4. Irritant: bronchospasm and inflammation


List 5 neurologic consequences of chronic use of inhaled hydrocarbons.

- Peripheral neuropathy
- Cerebellar degeneration
- Neuropsychiatric disorders
- Chronic encephalopathy
- White matter dementia


What is paitner’s syndrome?

- Mostly from chronic toluene exposure
- Ataxia, spacticity, dysarthria, dementia
- Consistent with leukoencephalopathy


List 3 subacute complications of HC aspiration / ingestion:

1. Pneumonia
2. PTx
3. Pneumatocele


List 4 reasons why patients with HC toxicity can be cyanotic:

1. asphyxiant
2. VQ mismatch
3. methemoglobinemia
4. Hypoventilation from ALOC


What hydrocarbons need intestinal decontamination

C: camphor (seizures and status)
H: Halogenated hydrocarbons (dysrhthmias and hepatotoxicity)
A: aromatic hydrocarbons: bone marrow supression and cancer
M: metal containing HC eg arsenic, mercury, lead
P: pesticide containing HC: cholinergic crisis , sz, resp depression)


How are inhaled toxins classified

simple asphyxiant: inert gas that displaces O2
pulmonary irritant: produce acid/base or oxygen radical
chemical asphyxiant: eg CO a gas that has higher affinity for Hb than O2


What adjunct therapy may provide symptomatic relief after exposure to chlorine or hydrogen chloride gas?

Nebulized 2% sodium bicarb
May have delayed S up to 24 hrs


List 3 ways that CO results in toxicity:

- Interacts with deoxyhemoglobin to form carboxyhemoglobin (COHb) (cannot carry oxygen)
- Shift to the left (interfering with ability to release oxygen)
- Interferes with cellular respiration by binding to mitochondrial cytochrome oxidase (increased binding during hypotension and hypoxia)


What abnormalities on imaging can be seen with CO toxicity?

CT head: Bilateral hypodensities in globus pallidus and internal capsule, seen after the acute exposure (below)


List risk factors that predict poor outcome after CO poisoning?

- Extremes of age
- Pregnancy (poor fetal outcome)
Pre-existing coronary artery / respiratory disease


What is the half life of CO

Room air: 5 hrs
100% FiO2: 90 min
HBO 30 min


What are the indications for HBO2

GT 25% adult or 15% pregnant/peds

LOC, coma, sz, confusion, cardiac ischemia, GT 24hrs of exposure, fetal distress


Where do CN, H2S and CO bind?

Fe3+ containing cytochrome a3 in the electron transport chain. Intereferes with aerobic metabolism leading to lactate generation


What are lab findings suggestive of CN toxicity

lactate GT 7
decreased arterial-venous O2 difference


What is the dose of hydroxycobalamin

5g IV over 15 min will turn skin, mm and urine red


List 4 knockdown toxins

volatile nerve agents