Toxicology Flashcards
(45 cards)
Bioaccumulation
Increasing concentration of a substance in the environment resulting from environmental persistence and physical properties
Biomagnification
is the fold increase in concentration of a substance that occurs in a food chain as a consequence of bioaccumulation
Endocrine disruptors
Chemicals in the environment that have endocrine effects (estrogen/anti-androgen/thyroid). Potential cause of infertility, reproductive cancers or birth defects.
Environmental toxicology
EPA Environmental Protection Agency regulates toxicology and environmental exposure to chemicals
Acceptable daily intake (ADI)
Daily intake of chemical which during lifetime appears to be without appreciable risk.
Occupational toxicology
OSHA Occupational Safety and Health Agency regulates exposure of workers to chemicals
Threshold limit value (TLV)
Exposure limit to a specific agent for a stated period of time-(shorter time = higher level). Used for occupational control.
Carbon Monoxide Poisoning
Description of CO Symptoms Mechanism Prevention Treatment
Description of CO
- Odorless, colorless gas
Symptoms
- Headache, loss of judgement, dizziness, nausea, convulsion & death
Mechanism
- Competes avidly with oxygen for hemoglobin (200 fold greater affinity) -affinity for fetal hemoglobin even higher.
Diagnosis
A CO-oximeter must be used to determine carboxyhemoglobin (COHb) levels. A regular pulse oximeter will misrepresent carboxyhemoglobin for oxyhemoglobin
Treatment
- 100% oxygen and hyperbaric oxygen
Solvents–benzene and toluene
Source
Acute exposure symptoms
Chronic exposure symptoms
Inhaltion effects
Common – many consumer products, gasoline, manufacturing etc.
Acute exposure: CNS depression with ataxia and coma.
Chronic exposure: Neuro- and bone marrow toxicity, leukemia.
Inhalation can cause chemical pneumonitis.
Difference in lethal dose of gasoline/benzene when taken by lung or digestion
GIT needs larger LD 50 than lungs even in children so be careful of making patient who swallowed gasolone vomit since there is a risk they could aspirate it into his lungs
Name 2 classes of agents in pesticide toxicology
with examples
Chlorinated hydrocarbons (DTT, DDD, dioxin etc)
Cholinesterase inhibitors (carbamates-carbaryl, organophosphates-malathion, parathion)
Cholinesterase inhibitors (carbamates-carbaryl, organophosphates-malathion, parathion)
Mechanism
Side Effects
Treatment
Chlorine confers environmental stability
Moderately toxic, bioaccumulate, concerns about endocrine disruption, no specific treatment
Cholinesterase inhibitors (carbamates-carbaryl, organophosphates-malathion, parathion)
Mechanism
Symptoms
Treatment
Environmentally less stable than chlorinated pesticides
Muscarinic and nicotinic activators, SLUDGE (Salivation, Lacrimation, Urination, Defecation, GI upset, Emesis).
Treatment = Atropine blocks receptor activation + Pralidoxime to regenerate cholinesterase.
Name 3 agents in herbicide toxicology
Chlorophenoxy Acids (2,4-dichlorophenoxiacetic acid and 2,4,5-trichlorophenoxyacetic acid)
Glyphosate
Paraquat-bipyridyl herbicide.
Chlorophenoxy Acids (2,4-dichlorophenoxiacetic acid and 2,4,5-trichlorophenoxyacetic acid)
In Vietnam War, above combination code-named Agent Orange -associated with chronic disease- to date association inclusive
Glyphosate
Most widely used herbicide in the world. Causes eye and skin irritation. No specific treatment.
Paraquat-bipyridyl herbicide
Ingestion can be fatal. GI irritation, hematemesis and bloody stools. Within days pulmonary impairment can lead to pulmonary fibrosis and possibly death. Treatment supportive. Gastric lavage if recent ingestion and dialysis.
Common sources of CO
Motor vehicle exhaust Spillage from appliances Building fires Forklift trucks, snow blowers Generators, heaters Zamboni, (oh, yes!)
Clues of CO posining
More than one person affected
Pets affected
Temporal relation of symptoms and use of combustion appliances
Main indoor pollutant causing headaches is CO, but
Tobacco smoke, volatile organics
Lead Age group at risk Chronic exposure signs Histological signs Treatment
Children - paint chip ingestion
Chronic exposure
- peripheral neuropathy
- wrist-drop)
- anorexia
- anemia
- tremor
- GI symptoms
- children: growth delay, neurocognitive deficits, and developmental delay
- Lead line seen in chronic lead poisoning on gums just above teeth in 50-70% patients.
Histoligical signs
- Basophilic stippling in red blood cells.
Treatment
- Oral succimer used as preferred chelator in children
Arsenic
Acute poisoning
Chronic poisoning
Acute
- severe GI discomfort
- Rice water stools
- Vomiting
- Capillary damage with dehydration and shock (similar to typhoid and cholera)
Chronic
- Groun water/private wells/soil
- Skin changes
- Hair loss
- Bone marrow depression
- Anemia
- Nausea
- GI distress
Mee’s lines
Transverse white lines that run across the nail, following the shape of the nail moon.
Arsenic poisoning.
Mercury
Acute poisoning
Chronic poisoning
Organic mercury
Treatment
Acute Poisoning
- Acute poisoning causes chest pain shortness of breath, nausea, vomiting, kidney damage, gastroenteritis and CNS damage.
Chronic Poisoning
- Neurological and behavioral changes
Organic Mercury
- Anti-fungal agent and has high potential to bioaccumulate. Generally, more toxic than ionic or metallic mercury compounds. Highly fetal toxic.
Treatment
Succimer or IM dimercaprol
Fe
Acute (Early and Late)
Treatment
Acute
Early
- GI bleeding, lethargy and grey cyanosis
Late
- GI necrosis can occur, pneumonitis, jaundice, seizures and coma
Treatment
- Deferoxamine
- Charcoal does not bind iron therefore use gastric lavage if within 60 minutes, if longer than an hour use whole bowel irrigation(Polyethylene glycol bowel prep (GoLYTELY, Colyte))
