Environmental Toxins Flashcards
Cholinesterase inhibiting insecticides symptoms
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
Tx of cholinesterase inhibitors
remove contaminated clothing
small dose of atropine
2-PAM prior to aging (contraindicated for carbamates)
gastric lavage or emesis
support vital signs
paraquat
herbicides
undergoes redox cucling and causes free radical mediated injury to lungs
tx- supportive therapy
halogenated hydrocarbons
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
aliphatic hydrocarbons
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
aromatic hydrocarbons
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
tx of aromatic hydrocarbons
remove ingested hydrocarbon by gastric lavage
control excitement or convulsions with diazepam
oxalic acids, oxalates
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
oxalic acid, oxalates tx
monitor renal fxn and force fluids to prevent oxalate crystals, give calcium in any form (milk, calcium antacids)
calcium gluconate
NO gastric lavage
mineral acids (hydrochloric acid, sulfuric acid, acetic acid, nitric acid, perchloric acid)
corrosives
inflammation and necrosis of GI tract exposed to corrosive
death due to unresolved hypovolemic shock after hemorrhage
tx of mineral acids
dilute acid with water analgesics to reduce pain milk of magnesia no gastric lavage supportive tx
strong alkali- hydroxides in soaps, cleansers, drain cleaners
irritation, inflammation, tissue damage
death due to hypovolemic shock
no gastric lavage
dilute alkali with water
supportive tx
methemoglonin inducing agents
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
nitrates
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
CO poisoining
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
cyanide
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
cyanide tx
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
free crystalline silica
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
asbestos
linear fibrosis of lungs- pleural adhesions and calcifications
symptoms- dyspnea, resp impairment and disability, bronchogenic carcinoma and pleural mesothelioma
tx- symptomatic and supportive
arsenic and asrine
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
arsenic tx
remove ingested arsenic by lavage or emesis
dimercaprol- preffered chelator for acute poisoning
succimer preferred chelator for chronic poisoning
lead
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
CNS effects of lead in children
bbb more permeable- hyperirritability, behavior disturbances, intellectual deficits, loss of recently developed skills, coma, convulsions
decreased IQ and learning in children
CNS effects of lead in adults
wrist drop and ankle drop
lead treatment
remove unabsorbed lead
chelate kids above 5 ug/dL- Ca Na2EDTA, BAL, penicillamine, succimer
calcium gluconate for GI effects
Mercury (acute)
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
mercury (chronic)
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
Mercury tx
acute exposure (inorganic)- lavage, milk, raw eggs, charcoal, IM dimercaprol or oral succimer
chronic- succimer, dimercaprol
treat symptoms and support vital signs
cadmium
in tobacco
kidney, lung, cv, immune, carcinogen
no chelator
manganese
cause parkinson’s like syndrome
no chelator
calcium disodium edetate (CaNa2EDTA)
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
Dimercaprol (BAL)
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
penicillamine
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
succimer (DMSA)
for lead poisoning
chronic inorganic mercury
GI disturbance most common ae
deferoxamine
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
