Toxicology Flashcards
give two possible mechanisms for specific antidotes and their example
- binding of poisons- chelators
- inhibition of distribution -methemoglobin-producers in cyanide intoxication
- inhibition of the formation of toxic metabolites- ethanol
- promoters of detoxification- acetylcysteine
- competitive inhibitors- naloxone
- agents promote regeneration of target cells- cholinesterase inhibitors
what does ‘ABCDEF’ stand for in the management of a poisoned patient?
A- airway protection B- ventilation C- treatment of arrhythmias D- hemodynamic support E- treatment of seizures F-correction of temperature, metabolic abnormalities
types of decontamination
gastrointestinal
eye (for at least 20 min)
skin
body cavity evacuation
how do we perform whole bowel irrigation?
via gastric tube
6-8 liter of isosmotic physiological electrolyte solution (containing polyethylene glycol)
when do we not do a bowel surge (with sorbitol)?
in case of paralytic ileus
types of gastrointestinal decontamination
- induction of emesis
- gastric lavage
- whole bowel irrigation
- bowel purge
what do we use for induction of emesis?
syrup of ipecac
apomorphine (rarely)
which type of patients you should not induce emesis?
patients who are:
- unconscious
- poisoned with corrosive agents (acid,base)
- poisoned with petroleum distillate (risk of aspiration!)
- poisoned with convulsant
which type of patients you should not do gastric lavage?
- poisoned with corrosive agents (acid,base)
- poisoned with petroleum distillate (risk of aspiration!)
- poisoned with convulsant
what is the risk in forced diuresis?
risk of lung edema and electrolyte disturbance
what are the ways to eliminate poison through the GI?
- multiple-dose activated charcoal (“gut dialysis”)
2. cholestramine in digitalis intoxication (decreases the absorption
what are the ways to eliminate poison through the kidney?
- forced diuresis- loop diuretics, mannitol, infusion
2. alteration of urinary pH
which compounds easily removed by dialysis?
water-soluble, low molecular mass, don’t bind very strongly compounds
examples- alcohol, antibiotics, heavy metals, benzodiazepines
which compounds can be removed by hemoperfusion?
DOB
digoxin
organophosphates
barbiturates
complication in plasmapheresis
thrombocytopenia
microembolism
which compounds can be removed by plasmapheresis?
carbamazepine lithium methanol metformin phenobarbital theophylline
how do we perform neutralization?
- alkali -therapy ( 5% NaHCO₃, 2%Na lactate)
- specific antitoxins
- antibodies
what are chelators?
organic compounds that function as chemical antagonists and used for the treatment of heavy metal poisoning
how is Dimercaprol given?
always IM
how is Dimercaprol excreted?
by the kidney (6-8 hours)
what is the advantage of Dimercaprol?
good permeability
therapeutic indication of Dimercaprol
- arsenic poisoning
- mercury poisoning
- Lead Poisoning (with EDTA)
special indication for Dimercaprol
encephalopathy (can enter the neurons)
side effects of Dimercaprol
nausea, vomiting hypertension tachycardia fever, pain thrombocytopenia
therapeutic indication of succimer
arsenic poisoning
mercury poisoning
lead- but not with encephalopathy
side effects of succimer (DMSA) and unithiol (DMPS)?
nausea, vomiting, diarrhea
better tolerated than dimercaprol
How is succimer and unithiol (DMPS) given?
orally
DMPS also parenteral
what is penicillamine used for?
Copper intoxication—>Willsons disease
Rheumatoid arthritis- not used anymore
adverse effects of penicillamine
hypersensitive reactions
long term treatment–> autoimmune reactions (drug-induced lupus, drug-induced hemolytic anemia)
B6 vitamin depletion
what is EDTA used for?
lead poisoning
* can remove lead from the bone
adverse effects of EDTA
Nephrotoxicity (rare)
what is deferoxamine used for?
iron poisoning
hemochromatosis
how is EDTA given?
slow IV infusion for 5 days
how is Deferoxamine given?
IV or IM
Adverse effects of Deferoxamine
idiosyncraic reactions
ARDS
neurotoxicity
route of absorption of Arsenic?
respiratory and GI tract
where can we find Arsenic?
industry, agriculture (insecticides), wood preservatives
pharmacodynamics of Arsenic
inhibition of enzymes via sulfhydryl binding
distribution of Arsenic
soft tissues- first of all, liver and kidney, later skin hair and nail
Clinical presentation of acute Arsenic poisoning?
gastroenteritis–>severe diarrhea “rice water stool”
hypovolemic shock
arrhythmias
CNS symptoms
weeks later: ascending peripheral neuropathy
months later: transverse white striate on the nails.
Clinical presentation of chronic Arsenic poisoning?
weakness
peripheral neuropathy (socking-glove pattern)
skin changes- hyperkeratosis, hyperpigmentation
anemia
general cachexia
treatment of acute Arsenic poisoning
gut decontamination
intensive supportive care- fluid electrolytes
Dimercaprol chelation
treatment of chronic Arsenic poisoning
Dimercaprol chelation
Mercury source of intoxication
elemental mercury- manufacture of electrical equipment, paint products
mercury salts- disinfectants
the major route of absorption of mercury
elemental mercury- respiratory tract (inhalation)
mercury salts- GI and skin
organic Hg- Gi, skin and respiratory tract
distribution of mercury
soft tissues. first the kidney
methylmercury reaches the brain
elimination of mercury by the…
kidney
Clinical presentation of acute Mercury poisoning?
elementary- pulmonary edema
salts-hemorrhagic gastroenteritis –> hypovolemic shock
acute tubular necrosis
Clinical presentation of chronic Mercury poisoning?
neuropsychiatric disturbance
acrodynia (in children)- painful erythema in the extremities
therapy of acute Mercury poisoning
supportive care
inhalation (elementary): succimer and dimercaprol chelation
“mer” in Mercury
therapy of chronic Mercury poisoning
succimer chelation
unithiol chelation
why we shouldn’t use dimercaprol in chronic mercury poisoning?
it redistributes mercury to the CNS!
what is Minama disease and what does it cause?
Methyl-mercury poisoning
mainly CNS effects-paraesthesia, ataxia, coma, death
prenatal exposure–> mental retardation
Lead source of intoxication
occupational environmental (batteries, paints, ceramics)
the major route of absorption of Lead
respiratory, GI, skin (organic)
*crosses the placenta
pharmacodynamics of lead
inhibits enzymes in porphyrine synthesis
interferes with the action of cations like Ca, Fe
alters the structure of membranes and receptors.
distribution of lead
first it binds to erythrocytes–>then soft tissues (liver &CNS) –> bones (can stay for 20 years in the bones)
elimination of Lead via the
kidney
Clinical presentation of acute Lead poisoning?
encephalopathy
acute abdominal pain (paralytic ileus)
hemolytic anemia
*rare
Clinical presentation of chronic Lead poisoning?
blood- anemia (microcytic), the appearance of basophilic stippling in the RBC (diagnostic clue)
GI - constipation, “gingival lead lines”
CNS- adults–> peripheral neuropathy- weakness of the extensors (wrist drop) . children–> minimal brain dysfunction
bones- children–> growth retardation (lead deposits in the epiphysis)
Treatment of acute Lead poisoning
supportive care
first dimercaprol and 4 hours later EDTA IV
Treatment of chronic Lead poisoning
EDTA IV infusion for 5 days, then PO succimer
*EDTA removes lead from the bones
major effects of organic lead (tetraethyl lead)
CNS effects
therapy of tetraethyl lead
decontamination from the skin
symptomatic treatment
chelators are not effective!
characteristics of carbon monoxide
colorless, odorless, no irritation
lighter than the air
pharmacodynamics of carbon monoxide
affinity to hemoglobin is 300 times stronger than oxygen
symptoms of acute carbon monoxide poisoning
<50%–> headache, nausea, dizziness, weakness
>50% –> increased respiration and pulse, seizures, coma
>60%–> respiratory failure, death
symptoms of chronic carbon monoxide poisoning
headache, ataxia, insomnia, Parkinson- like symptoms
therapy of carbon monoxide poisoning
100% oxygen or
carbogen mix- 95 % O₂, 5% CO₂
or hyperbaric oxygen??
for brain edema- glucocorticoids, mannitol
acidosis- alkali therapy
classify the hydrocarbons
- Aliphatic:
- Saturated
- unsaturated
- halogenated - Aromatic:
- benzine and benzene derivatives
- nitro and amino derivatives
- decoupling drugs
- phenol
route of intoxications of saturated aliphatic HC
inhalation of vapor–> aspiration!
ingestion of liquid
“glue sniffing” –> abused drug
symptoms of saturated aliphatic HC poisoning
acute- irritation of the mucosa, ventricular arrhythmia
chronic- tolerance, pulmonary effects
therapy of saturated & unsaturated aliphatic HC poisoning
symptomatic
no emesis
no gastric lavage (risk of aspiration)
where can we find saturated aliphatic HC inducing intoxication?
Gasoline, kerosene, petroleum distillates
name 2 saturated aliphatic HC
CH₄– methane
C₂H₆– ethane
Cn increases–> CNS depressant increases
how does saturated aliphatic HC cause ventricular fibrillation?
Sensitization of myocardium to NE
name 2 unsaturated aliphatic HC
C₂H₄– ethylene
C₂H₂– acethylene
inhalational anesthetics
Cn increases–> CNS depressant increases
which has stronger effects- saturated or unsaturated HB?
unsaturated
route of intoxications of unsaturated aliphatic HC
inhalation of vapor–> aspiration!
ingestion of liquid
are Halogenated aliphatic HC lipid soluble?
extremely lipid-soluble
–> more toxic than non-halogenated
where can we find Halogenated aliphatic HC?
used as solvents and in cooling systems
symptoms of Halogenated aliphatic HC
CNS depression cardiotoxicity kidney and liver impairment when inhaled--> lung edema skin- 1-3 degree frostbite
therapy of Halogenated aliphatic HC poisoning
symptomatic
alkali therapy in case of acidosis
what is the lethal dose of Carbon tetrachloride (CCl₄)?
20-30ml
symptoms of Carbon tetrachloride (CCl₄)
starting effects: irritation of mucosa, CNS depression, ventricular fibrillation (sudden death) delayed effects (1-2 days later): hepatorenal syndrome, toxic hepatitis, ATN
treatment of Carbon tetrachloride (CCl₄)
symptomatic (gastric lavage, paraffin oil, active charcoal)
what is chloroform (CHCl₃)
halogenated aliphatic HC
strong narcotic
not used due to its hepatotoxicity
routes of intoxications of Benzene, toluene, xylene (Aromatic HC)?
Skin, GI, lungs
elimination of Benzene, toluene, xylene
via lung and kidney
symptoms of Benzene, toluene, xylene poisoning
acute–> narcosis, seizures, coma, arrhythmia
chronic–>CNS, liver and kidney damage, bone marrow suppression
therapy of aromatic hydrocarbons
gastric lavage and purgation with cooking oil
activated charcoal
symptoms of phenol poisoning
topically: local anesthetic effect –>serious necrosis without pain
orally: necrosis on the mucosa
systemic effects: CNS (seizures, coma)
absorption of Nitrobenzene and Aniline
GI, skin, lung
what is the lethal oral dose for Nitrobenzne?
2-3ml
symptoms of Nitrobenzene (C₆H₅ NO₂) poisoning?
acute- irritation of the mucosa (vomiting, spasm), CNS depression, methemoglobinemia, hemolysis
chronic- anemia, hemolytic icterus, CNS disturbance
therapy for Nitrobenzene (C₆H₅ NO₂) and Aniline (C₆H₅ NH₂) poisoning
reduction of methemoglobinemia
orally–> milk, oil
what symptom is seen first in acute Aniline poisoning?
euphoria
what is DNP?
Dinitrophenol
aromatic hydrocarbon
what is the lethal dose of Dinitroortocresol (DNOC)?
1g
where is DNP used?
in the chemical industry
*used in the past as weight loss agent
where is DNOC used?
in the agriculture?
routes of poisoning of DNP and DNOC?
inhlation
skin
GI
what is the main mechanism of action in aromatic hydrocarbons poisoning? (DNP, DNOC)?
increased energy converts to heat
symptoms of acute DNP &DNOC poisoning?
hyperpyrexia dehydration--> ↓BP HR↑ Dyspnea cyanosis anoxia lung edema
symptoms of chronic DNP &DNOC poisoning?
weight loss fever kidney, liver, heart impairment bone marrow function hemolytic anemia
therapy of acute DNP &DNOC poisoning?
decontamination (lavage, emesis, washing the skin) cold batch O₂ inhalation 0.9% NaCl glucose infusion
what is forbidden to give in formaldehyde poisoning?
Sulfonamides
can cause RF
what are formaldehyde and metaldehyde?
Aldehydes :)
what is the lethal dose of metaldehyde?
4g for adults
0.1-0.5 g for children
where is metaldehyde used?
as fuel cubes and pesticides
what is the therapy of formaldehyde poisoning?
drink milk, water
gastric lavage
alkalization
hemodialysis
Symptoms of metaldehyde poisoning?
GI: hemorrhagic gastritis severe CNS effects: ↑ muscle irritability muscle rigidity seizures respiration stops
therapy of metaldehyde
gastric lavage induction of emesis activated charcoal purgation symptomatic treatment--> maintaining BP
when do the symptoms of methanol intoxication begin?
8-30 hours later
what are the symptoms of methanol intoxication?
metabolic acidosis--> respiratory failure abdominal pain (pancreatic damage) blindness
therapy of methanol intoxication and divalent glycols poisoning?
ethanol! 10g/hr IV or orally 20-30mk every 3-4 hours alkalization, hemodialysis fomepizole- alcohol dehydrogenase inhibitor IV
*Ca IV in case of muscle spasm in DG poisoning
what are diethylene glycol and ethylene glycol?
Divalent glycols
where can we find Divalent glycols?
used as solvents, lubricants, antifreeze substance
car cooling system (?)
symptoms of divalent glycols poisoning
Anuria! (kidney damage)
CNS
acidosis
liver damage
what do Inocybe- type mushrooms contain that make them poisonous?
muscarine (alkaloid)
what are the symptoms of mushroom poisoning (Inocybe type)?
parasympathomimetic effects
extreme diarrhea
therapy of mushroom poisoning (Inocybe type)?
atropine 1-2mg every 30 min
what do the mushrooms “Amanita muscaria” and “Amanita pantherina” contain?
muscarine
muscaridine
muscimol (GABAa agonist)
ibotenic acid
what are the symptoms of Amanita muscaria and pantherina poisoning?
salivation sweating vomiting diarrhea atropine intoxication: restlessness, hallucinations
what is the therapy of Amanita muscaria and pantherina poisoning?
symptomatic
NO ATROPINE!
what does Amanita phalloides (death cup) contain?
amatoxins (toxic polypeptides):
amantin𝝰
phalloidin
what type of mushrooms have rapid onset?
Inocybe
Amanita muscaria
Amanita pantherina
what type of mushrooms have delayed onset?
Amanita phalloides
is Amanita phalloides toxic?
high lethality because of hepatotoxicity
symptoms of Amanita phalloides
two-phase symptoms:
early (8-24hr)–> emesis, diarrhea, shock, damage of the intestinal mucosa, liver, kidney
later (48hr later)- hepatotoxicity–>juandice, fulminant liver
toxic nephrosis
treatment of Amanita phalloides
supportive (no antidote)- protection of liver and kidney, forced diuresis, hemoperfusion, glucocorticoids
high dose G-penicillin, silibinin, N-acetylcysteine
what is the mechanism of action of cyanide?
lactic acidosis and cytotoxic hypoxia
symptoms of cyanide poisoning
hyperpnea
coma
asphyxia
convulsion
Therapy of cyanide poisoning
- formation of methemoglobin!
2. give EDTA
routes of acid intoxication
oral, skin, eye, inhalation
symptoms of acid intoxication
necrosis of the skin spasm of glottis coagulation in the esophagus & stomach-->pain-->shock recurring emesis-->airway necrosis perforation of the stomach--> peritonitis acidosis anuria (kidney damage) scabs formation
therapy of acid intoxication
dilution of acid in the stomach -water, milk
oral anesthetics
morphine, atropine, glucocorticoids
drop infusion of 5% NaHCO₃ (treat the acidosis)
antimicrobial therapy (peritonitis may develop)
which therapy shouldn’t do in acid intoxication
emesis induction
gastric lavage
what happens in Oxalic acid intoxication?
tetany and cardiac depression
(Oxalate binds Ca in the blood)
anuria
therapy of Oxalic acid intoxication
CaCl₂ oral
Ca gluconate IV
fluid infusion +enhanced diuresis
+therapy of acid intoxication
what happens in base intoxication
liquefactive necrosis
tetany
therapy of base intoxication
dilution of base in the stomach -water, milk
oral anesthetics
morphine, atropine, glucocorticoids
antimicrobial therapy (peritonitis may develop)
give Ca
in what percent do we start having symptoms of Methemoglobin poisoning?
20% symptoms of hypoxemia
60-80% lethal
how does methemoglobin or verdoglobin poisoning cause anuria?
Hemolysis of RBCs–>methB or verdoglobin will block the nephrons–>ARF
give 2 methemoglobin producing agents
- oxidizing agents: chlorates, perchlorates
- nitrates: sodium nitrite, nitroglycerin
- aromatic amino and nitro compounds- aniline, nitrobenzene, nitrophenol
- methylene blue, toluidine blue
what bacteria can cause food poisoning?
staphylococci salmonellae proteus vulgaris E.coli B. cereus
symptoms of food poisoning
vomiting, gastroenteritis, fever, hypovolemia
therapy of food poisoning
gastric lavage, activated charcoal
replacement of volume and electrolytes
Ab if needed
lethal dose of Botulism
0.001-0.002mg/kg
mechanism of action of Botulism
inhibit release of Ach
what is the latency time of botulism?
long (12-36hrs)
symptoms of botulism poisoning
first diarrhea--> then paralytic ileus ptosis dilation of pupils salivation--> then secretion stops aphasia-->aspiration--> pneumonia bladder atony paralysis of skeletal muscle (respiratory stop!)
therapy for botulism poisoning
Antitoxin (A,B,E)
purging with castor oil +neostigmine
transfusion
when does infant botulism occur?
3 weeks to 6 months of age
what is the difference between adult and infant botulism intoxication?
infants ingest spores themselves ==> produce toxin in the intestines
symptoms of infant botulism
constipation poor feeding weak cry muscle weakness decreased reflexes paralysis
duration of symptoms of infant botulism
2-6 weeks
classify the insecticides
- chlorinated hydrocarbons
- botanical insecticides
- cholinesterase inhibitors
- organophosphates
- carbamates
what is the mechanism of action of DDT?
in the liver: enzyme induction
inhibit the inactivation of Na channels–< enhanced irritability
symptoms of DDT poisoning
CNS stimulation
tremor
muscle spasm
carcinogenic in the long run
properties of DDT
lipid-soluble
poor oral absorption
potent CYP450 inducer!
what does pyrethrum (botanical insecticide) cause?
by inhalation –> asthma attack
headache most common symptom
what does rotenone (botanical insecticide) cause?
inhibit NADH-NAD transformation
by inhalation–> respiratory depression, epileptiform seizures
mechanism of action of carbamates and OPS
reversible (car)
irreversible (OPS)
inhibition of cholinesterase
mechanism of action of carbamates and OPS
reversible (car)
irreversible (OPS)
inhibition of cholinesterase
symptoms of carbamates and OPS
*from Ach accumulation Salivation sweating diarrhea--> shock bronchical constriction
Therapy for carbamates or OPS poisoning
atropine!
1-2mg
OPS–> pralidoxime
toxic ingredients of snake venom
neurotoxic peptides cholinesterase inhibitors cardiotoxins enhanced blood coagulation components protein inhibits coagulation ingredients with analgestic effect
sucking snake poison from the wound would help?
no, it passes through the lymph not only the circulation
symptoms of snake poisoning
painful swelling
lymphangitis
nausea, haematemesis, diarrhea
↓ temperature, ↓ BP
therapy of snake poisoning
calmness polyvalent antitoxins H1 blockers glucocorticoids hydration
toxic ingredients of Bee & wasp sting
peptides
histamine
enzymes
wasp–> serotonin, Ach
symptoms of Bee & wasp sting
in case of high number of stings–> shock, hemolysis, kidney failure
hypersensitivity! anaphylactic shock
therapy of Bee & wasp sting
anaphylactic shock–> epi
glucocorticoids