Environmental Toxins

Question 1

Cholinesterase inhibiting insecticides symptoms

Answer 1

parathion, malathion, sarin, soman, carbaryl, carbofuran

slud- salivation, lacrimation, diarrhea, urination

mild intox: anorexia, headache, dizziness ,weakness, anxiety, tremors of tongue and eyelids, miosis and impairment of visual acuity

moderate intox: nausea, salivation, tearing, abd cramps, vomiting, sweating, slow pulse, muscular fasciculation

severe intox: diarrhea, pin point, non reactive pupiles, resp difficulty, pulm edema, cyanosis, coma, heart block

Question 2

Tx of cholinesterase inhibitors

Answer 2

remove contaminated clothing
small dose of atropine

2-PAM prior to aging (contraindicated for carbamates)

gastric lavage or emesis

support vital signs

Question 3

paraquat

Answer 3

herbicides
undergoes redox cucling and causes free radical mediated injury to lungs
tx- supportive therapy

Question 4

halogenated hydrocarbons

Answer 4

occupational hazard
solvents- chloroform, carbon tetrachloride, TCE, tetrachlorethylene

hepatoxicity extensively studied for CCl4- free radial induced lipid peroxidation causes inc in intracellular Ca++ leading to cell death

Question 5

aliphatic hydrocarbons

Answer 5

petroleum distillates- kerosene, diesel fuel, gasolines
leads to pulmonary irritation by high concentration of vapor
CNS depression by ingestion or inhalation
severe pneumonitis after aspiration of liquid

treat symptoms and support vital signs
reduce exposure

Question 6

aromatic hydrocarbons

Answer 6

benzene, toluene, xylene

“glue sniffers”- CNS stimulation at low doses or early in high doses ,followed by CNS depression in serious poisoning
kidney and liver damage at high acute doses or prolonged exposure

long term exposure- aplastic anemia and leukemia
cardiac arrhythmia by catecholamine release

Question 7

tx of aromatic hydrocarbons

Answer 7

remove ingested hydrocarbon by gastric lavage

control excitement or convulsions with diazepam

Question 8

oxalic acids, oxalates

Answer 8

corrosives, in bleach, metal cleaners, rust removers
can lead to renal tubular damage due to calcium oxalate precipitation

local irritation and corrosion of GI tract, muscle weakness

Question 9

oxalic acid, oxalates tx

Answer 9

monitor renal fxn and force fluids to prevent oxalate crystals, give calcium in any form (milk, calcium antacids)
calcium gluconate
NO gastric lavage

Question 10

mineral acids (hydrochloric acid, sulfuric acid, acetic acid, nitric acid, perchloric acid)

Answer 10

corrosives
inflammation and necrosis of GI tract exposed to corrosive
death due to unresolved hypovolemic shock after hemorrhage

Question 11

tx of mineral acids

Answer 11

dilute acid with water
analgesics to reduce pain
milk of magnesia 
no gastric lavage 
supportive tx

Question 12

strong alkali- hydroxides in soaps, cleansers, drain cleaners

Answer 12

irritation, inflammation, tissue damage
death due to hypovolemic shock

no gastric lavage
dilute alkali with water
supportive tx

Question 13

methemoglonin inducing agents

Answer 13

oxidize hgb to (fe2, ferrous form) methemoglobin (fe3+, ferric form) which is incapable of carrying oxygen

direct acting agents- nitrites

indirect acting agents- aminophenols (metabolites convert hgb to methemoglobin)

lead to cyanosis

Question 14

nitrates

Answer 14

chocolate colored blood
hypotension, hypoxia, cyanosis
treat if 35% or more of hgb is in oxidized form
use methylene blue which will convert methgb back to hgb

oxygen admin and exchange transfusions in severe cases

Question 15

CO poisoining

Answer 15

CO has greater affinity than O2 for hgb, impairs ability to give up oxygen

symptoms: headache, dizziness, stupor
cherry red blood

terminate exposure, administer oxygen, avoid respiratory stimulating drugs, do not give methylene blue, hyperbaric oxygen

Question 16

cyanide

Answer 16

colorless gas with odor resembling almonds
cyanide complexes with ferric iron of cytochrome oxidase and produces cellular anoxia by inhibiting oxygen utilization in mitochondria

causes dizziness, headache, hypotension, unconsciousness, convulsions, resp failure

Question 17

cyanide tx

Answer 17

old treatment: induce methemoglobinemia using sodium nitrite or amyl nitrite in combination with sodium thiosulfate (to use inherent rhodanese in mitochondria to detoxify cyanide)

new: hydroxocobalamin, form cynocobalamin, artificial respiration with 100% oxygen

Question 18

free crystalline silica

Answer 18

deposit in lungs and cause silicosis
first stage: dyspnea, discomfort
second stage- resp impairment
third stage- total disability, pts die of right heart failure

symptomatic tx

Question 19

asbestos

Answer 19

linear fibrosis of lungs- pleural adhesions and calcifications

symptoms- dyspnea, resp impairment and disability, bronchogenic carcinoma and pleural mesothelioma

tx- symptomatic and supportive

Question 20

arsenic and asrine

Answer 20

causes toxicity by binding to sulfhydryl groups on enzymes and interfering with cellular metabolism and energy production

acute poisoning- hemolysis and hemoglobinurea, GI disturbances, ventricular arrhythmias, kidney tubular damage, cns disturbances with convulsions and coma

chronic poisoning- polyneuritis, nephritis, dermatitis, cardiac failure, cirrhosis, personality changes, CANCER

Question 21

arsenic tx

Answer 21

remove ingested arsenic by lavage or emesis
dimercaprol- preffered chelator for acute poisoning
succimer preferred chelator for chronic poisoning

Question 22

lead

Answer 22

most toxic metal- primarily stored in bones but symptoms are in soft tissues like bone marrow and nervous system tissue

acute inorganic lead toxicity- GI irritation, kidney damage

acute organic lead poisoning- likely to get into CNS and can cause CNS probs in adults too

chronic inorganic lead poisoning (plumbism)- lead line on gumps, basophilic erythrocyte stippling, accumulation of delta aminolevulinic acid and protoporphyrin due to inhibition of heme synthesis, microcytic anemia, GI effects- anorexia, constipation, abd pain

Question 23

CNS effects of lead in children

Answer 23

bbb more permeable- hyperirritability, behavior disturbances, intellectual deficits, loss of recently developed skills, coma, convulsions

decreased IQ and learning in children

Question 24

CNS effects of lead in adults

Answer 24

wrist drop and ankle drop

Question 25

lead treatment

Answer 25

remove unabsorbed lead

chelate kids above 5 ug/dL- Ca Na2EDTA, BAL, penicillamine, succimer
calcium gluconate for GI effects

Question 26

Mercury (acute)

Answer 26

effects related to GI tract damage

metallic mercury (vapors)- acute chemical pneumonitis
noncardiogenic pulmonary edema

inorganic mercury- irritation, abd pain, vomiting, dirrhea, acute renal tubular necrosis, then severe kidney damage lead to anuria, severe GI damage and hemorrhage

Question 27

mercury (chronic)

Answer 27

salivation, stomatitis (swollen, bleeding gums), mercury line on gums, erethism (uncontrollable blushing, emotional instability, tremor)
continued exposure- jerky movements, drowsiness, depression, loss of memory, hallucinations

organic mercury- paresthesia, muscle twitching, ataxia, constriction of visual field

Question 28

Mercury tx

Answer 28

acute exposure (inorganic)- lavage, milk, raw eggs, charcoal, IM dimercaprol or oral succimer

chronic- succimer, dimercaprol

treat symptoms and support vital signs

Question 29

cadmium

Answer 29

in tobacco
kidney, lung, cv, immune, carcinogen
no chelator

Question 30

manganese

Answer 30

cause parkinson’s like syndrome

no chelator

Question 31

calcium disodium edetate (CaNa2EDTA)

Answer 31

chelates lead, zinc

toxic effects- renal damage, ekg abn

urine flow must be maintained, therapy not exceed 5-7 days

H2,Na2EDTA not used because binds calcium

Question 32

Dimercaprol (BAL)

Answer 32

chelates arsenic, lead, gold, inorganic mercury

toxic- CNS disturbance, CV disturbance, BAL-iron complex is toxic so avoid medicinal iron

use-7-14 days by deep IM injection
can be used even if renal is shut down

Question 33

penicillamine

Answer 33

chelates copper, alternate for other metals
wilson’s disease, RA

causes nephrotic syndrome, pyridoxine deficiency, transient eosinophilia, contra in children or adults with renal insufficiency

Question 34

succimer (DMSA)

Answer 34

for lead poisoning
chronic inorganic mercury
GI disturbance most common ae

Question 35

deferoxamine

Answer 35

chelate iron via ingestion

rapid infusion may induce shock
long term use may cause ocular damage

oral dose effective in binding iron in GI tract but must remove, IV preferred