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Toxicology – Nystagmus-Inducing Toxins
Sedative–Hypnotics
Medications in this class commonly produce nystagmus as part of central nervous system depression.
Alcohols (Ethanol, Methanol, Ethylene Glycol, Isopropanol)
All alcohols can induce nystagmus. Ethanol is particularly associated with horizontal and downbeat nystagmus and is often assessed clinically using the horizontal gaze nystagmus test.
Phencyclidine and Dissociatives
Dissociative agents such as PCP, ketamine, and dextromethorphan can produce a characteristic rotatory nystagmus.
Phenytoin
Phenytoin toxicity is associated with horizontal and sometimes upbeat nystagmus.
Carbamazepine (Tegretol)
Carbamazepine can cause both horizontal and downbeat nystagmus.
Lithium
Lithium toxicity may lead to downbeat nystagmus.
Solvents (Inhalants)
Exposure to inhaled solvents has been associated with positional nystagmus, with severity correlating to the degree of exposure.
Thiamine Deficiency (Wernicke Encephalopathy)
Thiamine deficiency can result in Wernicke encephalopathy, characterized by ataxia, confusion, ophthalmoplegia, and nystagmus.
Overview
Nystagmus is an involuntary, rhythmic oscillation of the eyes that may occur in toxicologic conditions. It can present as horizontal (side-to-side), vertical (upbeat or downbeat), or rotatory movement. Horizontal nystagmus is the most common and is best observed during lateral gaze. Alcohol intoxication frequently produces nystagmus, which is often assessed in clinical and roadside settings. Certain agents such as anticonvulsants and lithium may produce vertical nystagmus, while phenytoin has been associated with upbeat nystagmus and PCP with rotatory nystagmus.
Sedative–Hypnotics
Medications in this class commonly produce nystagmus as part of central nervous system depression.
Alcohols (Ethanol, Methanol, Ethylene Glycol, Isopropanol)
All alcohols can induce nystagmus. Ethanol is particularly associated with horizontal and downbeat nystagmus and is often assessed clinically using the horizontal gaze nystagmus test.
Phencyclidine and Dissociatives
Dissociative agents such as PCP, ketamine, and dextromethorphan can produce a characteristic rotatory nystagmus.
Phenytoin
Phenytoin toxicity is associated with horizontal and sometimes upbeat nystagmus.
Carbamazepine (Tegretol)
Carbamazepine can cause both horizontal and downbeat nystagmus.
Lithium
Lithium toxicity may lead to downbeat nystagmus.
Solvents (Inhalants)
Exposure to inhaled solvents has been associated with positional nystagmus, with severity correlating to the degree of exposure.
Thiamine Deficiency (Wernicke Encephalopathy)
Thiamine deficiency can result in Wernicke encephalopathy, characterized by ataxia, confusion, ophthalmoplegia, and nystagmus.
Overview
Nystagmus is an involuntary, rhythmic oscillation of the eyes that may occur in toxicologic conditions. It can present as horizontal (side-to-side), vertical (upbeat or downbeat), or rotatory movement. Horizontal nystagmus is the most common and is best observed during lateral gaze. Alcohol intoxication frequently produces nystagmus, which is often assessed in clinical and roadside settings. Certain agents such as anticonvulsants and lithium may produce vertical nystagmus, while phenytoin has been associated with upbeat nystagmus and PCP with rotatory nystagmus.
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Toxicology – Toxins Causing Erythema
Carbon Monoxide
Carbon monoxide poisoning may produce the classic “cherry red” skin appearance, although this is a late and often postmortem finding rather than a reliable early clinical sign.
Cyanide
Cyanide toxicity can cause skin erythema due to elevated levels of oxygenated hemoglobin in the venous system. Additionally, hydroxocobalamin, a common antidote, can itself produce noticeable skin redness.
Chinese Restaurant Syndrome (MSG Reaction)
This condition is associated with ingestion of monosodium glutamate (MSG) and may present with flushing, chest discomfort, palpitations, headache, perioral tingling, facial swelling, and sweating.
Scombroid Poisoning
Scombroid poisoning results from ingestion of histamine-rich spoiled fish, leading to vasodilation and prominent skin flushing.
Anticholinergics
Erythema is a hallmark feature of anticholinergic toxicity, often described as “red as a beet” in the classic toxidrome.
Niacin
Niacin, commonly used to manage lipid levels, frequently causes flushing even at therapeutic doses. This effect can be reduced by taking aspirin beforehand or dosing at night.
Disulfiram Reaction
This reaction occurs when aldehyde dehydrogenase is inhibited by agents such as disulfiram, metronidazole, tolbutamide, or cefotetan. When alcohol is consumed, acetaldehyde accumulates, leading to flushing along with nausea, vomiting, tachycardia, shortness of breath, headache, and confusion.
Carbon Monoxide
Carbon monoxide poisoning may produce the classic “cherry red” skin appearance, although this is a late and often postmortem finding rather than a reliable early clinical sign.
Cyanide
Cyanide toxicity can cause skin erythema due to elevated levels of oxygenated hemoglobin in the venous system. Additionally, hydroxocobalamin, a common antidote, can itself produce noticeable skin redness.
Chinese Restaurant Syndrome (MSG Reaction)
This condition is associated with ingestion of monosodium glutamate (MSG) and may present with flushing, chest discomfort, palpitations, headache, perioral tingling, facial swelling, and sweating.
Scombroid Poisoning
Scombroid poisoning results from ingestion of histamine-rich spoiled fish, leading to vasodilation and prominent skin flushing.
Anticholinergics
Erythema is a hallmark feature of anticholinergic toxicity, often described as “red as a beet” in the classic toxidrome.
Niacin
Niacin, commonly used to manage lipid levels, frequently causes flushing even at therapeutic doses. This effect can be reduced by taking aspirin beforehand or dosing at night.
Disulfiram Reaction
This reaction occurs when aldehyde dehydrogenase is inhibited by agents such as disulfiram, metronidazole, tolbutamide, or cefotetan. When alcohol is consumed, acetaldehyde accumulates, leading to flushing along with nausea, vomiting, tachycardia, shortness of breath, headache, and confusion.
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Toxicology – Toxins Causing Cyanosis
Ergotamine
Ergot compounds can lead to acrocyanosis due to intense vasoconstriction, resembling a secondary Raynaud phenomenon affecting peripheral circulation.
Phenazopyridine
This urinary tract analgesic can induce methemoglobinemia, impairing oxygen delivery and resulting in cyanosis.
Aniline
Aniline, a chemical used in the production of dyes and polyurethane, can cause both methemoglobinemia and hemolytic anemia, contributing to cyanotic discoloration.
Dapsone
Dapsone, used in the treatment of leprosy and for Pneumocystis jirovecii pneumonia prophylaxis, is a well-known cause of methemoglobinemia.
Nitrates
Nitrates, sometimes present in contaminated well water, can induce methemoglobinemia, particularly in infants.
Nitrites
Nitrites are used therapeutically to induce methemoglobinemia in cyanide poisoning but may also be abused recreationally for their vasodilatory effects, leading to cyanosis.
Asphyxia
Conditions causing hypoxemia or impaired oxygen delivery increase levels of deoxygenated hemoglobin, resulting in cyanosis.
Treatment
Methylene blue is the treatment of choice for methemoglobinemia. It acts as a reducing agent, converting methemoglobin back to functional hemoglobin, and is typically administered at a dose of 1–2 mg/kg intravenously over 5 minutes.
Ergotamine
Ergot compounds can lead to acrocyanosis due to intense vasoconstriction, resembling a secondary Raynaud phenomenon affecting peripheral circulation.
Phenazopyridine
This urinary tract analgesic can induce methemoglobinemia, impairing oxygen delivery and resulting in cyanosis.
Aniline
Aniline, a chemical used in the production of dyes and polyurethane, can cause both methemoglobinemia and hemolytic anemia, contributing to cyanotic discoloration.
Dapsone
Dapsone, used in the treatment of leprosy and for Pneumocystis jirovecii pneumonia prophylaxis, is a well-known cause of methemoglobinemia.
Nitrates
Nitrates, sometimes present in contaminated well water, can induce methemoglobinemia, particularly in infants.
Nitrites
Nitrites are used therapeutically to induce methemoglobinemia in cyanide poisoning but may also be abused recreationally for their vasodilatory effects, leading to cyanosis.
Asphyxia
Conditions causing hypoxemia or impaired oxygen delivery increase levels of deoxygenated hemoglobin, resulting in cyanosis.
Treatment
Methylene blue is the treatment of choice for methemoglobinemia. It acts as a reducing agent, converting methemoglobin back to functional hemoglobin, and is typically administered at a dose of 1–2 mg/kg intravenously over 5 minutes.
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Toxicology – Causes of Anion Gap Metabolic Acidosis
Alcohol (Ethanol)
Ethanol intoxication may lead to hypoglycemia, lactic acidosis, and alcoholic ketoacidosis, all of which contribute to an increased anion gap.
Aspirin (Salicylates)
Salicylate toxicity should be suspected in patients with anion gap metabolic acidosis and altered mental status. It typically produces a mixed disorder with metabolic acidosis and respiratory alkalosis due to direct stimulation of the respiratory center. It also increases renal loss of bicarbonate and potassium while promoting lactic and pyruvic acid formation.
Methanol
Methanol poisoning results in a high anion gap and hyperosmolar metabolic acidosis due to accumulation of formic acid, a toxic metabolite.
Ethylene Glycol
Commonly found in antifreeze, ethylene glycol is metabolized into glycolic, glyoxylic, and oxalic acids, producing a severe high anion gap metabolic acidosis.
Metformin
Metformin toxicity can lead to lactic acidosis by increasing production of lactate and other metabolic intermediates, particularly in patients with renal impairment or after contrast exposure.
Diabetic Ketoacidosis (DKA)
DKA occurs due to insulin deficiency, resulting in increased fatty acid metabolism and accumulation of ketoacids such as acetoacetate and β-hydroxybutyrate. Starvation and alcoholic ketosis can produce similar effects.
Uremia
Advanced kidney failure leads to accumulation of nitrogenous waste products and acids such as sulfuric and phosphoric acid, causing an anion gap metabolic acidosis.
Lactic Acidosis
Lactic acid accumulation from anaerobic metabolism is a common cause of anion gap acidosis and may result from hypoxia, hypoperfusion, toxins, or metabolic disorders.
Toluene
Toluene exposure, often through inhalation of solvents, increases production of organic acids such as benzoic and hippuric acid and may also cause renal tubular acidosis with chronic use.
Carbamazepine
Overdose of this antiepileptic drug can lead to metabolic acidosis along with hyperglycemia, ketonuria, altered mental status, seizures, and coma.
Isoniazid (INH)
Isoniazid toxicity can result in lactic acidosis, often accompanied by seizures and altered mental status.
Iron
Iron overdose contributes to metabolic acidosis through hypovolemia, hypotension, and the release of hydrogen ions during its metabolic conversion.
Paraldehyde
This older sedative-hypnotic agent, historically used for seizures, can contribute to anion gap metabolic acidosis in toxic exposures.
Alcohol (Ethanol)
Ethanol intoxication may lead to hypoglycemia, lactic acidosis, and alcoholic ketoacidosis, all of which contribute to an increased anion gap.
Aspirin (Salicylates)
Salicylate toxicity should be suspected in patients with anion gap metabolic acidosis and altered mental status. It typically produces a mixed disorder with metabolic acidosis and respiratory alkalosis due to direct stimulation of the respiratory center. It also increases renal loss of bicarbonate and potassium while promoting lactic and pyruvic acid formation.
Methanol
Methanol poisoning results in a high anion gap and hyperosmolar metabolic acidosis due to accumulation of formic acid, a toxic metabolite.
Ethylene Glycol
Commonly found in antifreeze, ethylene glycol is metabolized into glycolic, glyoxylic, and oxalic acids, producing a severe high anion gap metabolic acidosis.
Metformin
Metformin toxicity can lead to lactic acidosis by increasing production of lactate and other metabolic intermediates, particularly in patients with renal impairment or after contrast exposure.
Diabetic Ketoacidosis (DKA)
DKA occurs due to insulin deficiency, resulting in increased fatty acid metabolism and accumulation of ketoacids such as acetoacetate and β-hydroxybutyrate. Starvation and alcoholic ketosis can produce similar effects.
Uremia
Advanced kidney failure leads to accumulation of nitrogenous waste products and acids such as sulfuric and phosphoric acid, causing an anion gap metabolic acidosis.
Lactic Acidosis
Lactic acid accumulation from anaerobic metabolism is a common cause of anion gap acidosis and may result from hypoxia, hypoperfusion, toxins, or metabolic disorders.
Toluene
Toluene exposure, often through inhalation of solvents, increases production of organic acids such as benzoic and hippuric acid and may also cause renal tubular acidosis with chronic use.
Carbamazepine
Overdose of this antiepileptic drug can lead to metabolic acidosis along with hyperglycemia, ketonuria, altered mental status, seizures, and coma.
Isoniazid (INH)
Isoniazid toxicity can result in lactic acidosis, often accompanied by seizures and altered mental status.
Iron
Iron overdose contributes to metabolic acidosis through hypovolemia, hypotension, and the release of hydrogen ions during its metabolic conversion.
Paraldehyde
This older sedative-hypnotic agent, historically used for seizures, can contribute to anion gap metabolic acidosis in toxic exposures.
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Toxicology – Radiopaque Toxins
Iron
Iron preparations, particularly ferrous sulfate tablets, are clearly visible on radiographs. In large ingestions, they may accumulate and form a radiopaque pharmacobezoar.
Lead (Pb)
Lead-containing objects such as paint chips, bullets, toys, and figurines are highly radiopaque and easily identified on imaging.
Calcium
Calcium-containing substances are radiopaque, and significant ingestion can result in formation of a visible mass within the gastrointestinal tract.
Barium
Barium is inherently radiopaque and readily detectable on imaging studies.
Potassium
Potassium tablets may be visualized on radiographs, especially when ingested in large amounts, sometimes forming a pharmacobezoar.
Heavy Metals
Various heavy metals are radiopaque and can be identified on plain radiographs.
Enteric-Coated or Sustained-Release Tablets
Large ingestions of these formulations can lead to the formation of a radiopaque pharmacobezoar visible on imaging.
Arsenic
As a metallic element, arsenic is radiopaque and may be seen on radiographic studies.
Iodine
Iodine-containing compounds are radiopaque and can appear on imaging.
Chloral Hydrate and Halogenated Compounds
Certain halogenated substances, such as chloral hydrate and chloroform, may be detectable on x-ray due to their radiopaque properties.
Condom Packets (Body Packers)
Individuals who ingest drug-filled packets may show multiple uniform radiopaque densities on abdominal imaging.
Tricyclic Antidepressants (TCAs)
These medications may demonstrate variable radiopacity depending on dose and preparation.
Phosphorus
Phosphorus can be visualized on radiographs due to its radiopaque nature.
Iron
Iron preparations, particularly ferrous sulfate tablets, are clearly visible on radiographs. In large ingestions, they may accumulate and form a radiopaque pharmacobezoar.
Lead (Pb)
Lead-containing objects such as paint chips, bullets, toys, and figurines are highly radiopaque and easily identified on imaging.
Calcium
Calcium-containing substances are radiopaque, and significant ingestion can result in formation of a visible mass within the gastrointestinal tract.
Barium
Barium is inherently radiopaque and readily detectable on imaging studies.
Potassium
Potassium tablets may be visualized on radiographs, especially when ingested in large amounts, sometimes forming a pharmacobezoar.
Heavy Metals
Various heavy metals are radiopaque and can be identified on plain radiographs.
Enteric-Coated or Sustained-Release Tablets
Large ingestions of these formulations can lead to the formation of a radiopaque pharmacobezoar visible on imaging.
Arsenic
As a metallic element, arsenic is radiopaque and may be seen on radiographic studies.
Iodine
Iodine-containing compounds are radiopaque and can appear on imaging.
Chloral Hydrate and Halogenated Compounds
Certain halogenated substances, such as chloral hydrate and chloroform, may be detectable on x-ray due to their radiopaque properties.
Condom Packets (Body Packers)
Individuals who ingest drug-filled packets may show multiple uniform radiopaque densities on abdominal imaging.
Tricyclic Antidepressants (TCAs)
These medications may demonstrate variable radiopacity depending on dose and preparation.
Phosphorus
Phosphorus can be visualized on radiographs due to its radiopaque nature.
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Toxicology – Seizure-Inducing Toxins
Cocaine
Cocaine lowers the seizure threshold through potent stimulation of the central nervous system, similar to other sympathomimetic agents.
Isoniazid
Isoniazid toxicity can cause severe, refractory seizures that are characteristically resistant to standard therapy and require treatment with pyridoxine.
Anticholinergics
Seizures may occur as a late and severe manifestation of anticholinergic toxicity.
Amphetamines
Amphetamines increase catecholamine release and significantly lower the seizure threshold, increasing the risk of seizures.
Organophosphates
These insecticides produce a cholinergic toxidrome and can lead to seizures due to excessive acetylcholine accumulation.
Ethanol Withdrawal
Seizures may develop within 6 to 48 hours after abrupt cessation of alcohol in dependent individuals.
Tricyclic Antidepressants (TCAs)
At high doses, TCAs can induce seizures, often occurring before serious cardiac complications such as arrhythmias or arrest.
Methylanthines
Agents such as theophylline can cause seizures in overdose due to central nervous system stimulation.
Phencyclidine (PCP)
Large doses of PCP may result in severe toxicity, including seizures, hyperthermia, coma, and death.
Lidocaine
Intravenous toxicity from local anesthetics like lidocaine can initially cause seizures, followed by cardiovascular collapse.
Camphor
Camphor exposure, especially in children, can lead to seizures due to increased absorption through ingestion or skin contact.
Sympathomimetics
This class of drugs broadly lowers the seizure threshold through increased adrenergic activity.
Benzodiazepine Withdrawal
Abrupt discontinuation of benzodiazepines can lead to withdrawal symptoms, including seizures. Use of flumazenil may precipitate acute withdrawal in dependent individuals.
Lithium
Severe lithium toxicity may present with neurological complications, including seizures.
Lindane
Lindane, used topically for lice and scabies, can cause seizures when absorbed in excessive amounts, particularly in infants and children.
Lead (Severe Toxicity)
Extremely elevated lead levels can result in neurological toxicity, including seizures.
Treatment
Benzodiazepines such as diazepam or lorazepam are first-line therapy for toxin-induced seizures. If seizures persist, phenobarbital is considered second-line. In refractory cases, propofol with airway protection may be required. Phenytoin and fosphenytoin are generally not effective for toxin-induced seizures. Pyridoxine should be administered when isoniazid or certain mushroom toxicities are suspected.
Cocaine
Cocaine lowers the seizure threshold through potent stimulation of the central nervous system, similar to other sympathomimetic agents.
Isoniazid
Isoniazid toxicity can cause severe, refractory seizures that are characteristically resistant to standard therapy and require treatment with pyridoxine.
Anticholinergics
Seizures may occur as a late and severe manifestation of anticholinergic toxicity.
Amphetamines
Amphetamines increase catecholamine release and significantly lower the seizure threshold, increasing the risk of seizures.
Organophosphates
These insecticides produce a cholinergic toxidrome and can lead to seizures due to excessive acetylcholine accumulation.
Ethanol Withdrawal
Seizures may develop within 6 to 48 hours after abrupt cessation of alcohol in dependent individuals.
Tricyclic Antidepressants (TCAs)
At high doses, TCAs can induce seizures, often occurring before serious cardiac complications such as arrhythmias or arrest.
Methylanthines
Agents such as theophylline can cause seizures in overdose due to central nervous system stimulation.
Phencyclidine (PCP)
Large doses of PCP may result in severe toxicity, including seizures, hyperthermia, coma, and death.
Lidocaine
Intravenous toxicity from local anesthetics like lidocaine can initially cause seizures, followed by cardiovascular collapse.
Camphor
Camphor exposure, especially in children, can lead to seizures due to increased absorption through ingestion or skin contact.
Sympathomimetics
This class of drugs broadly lowers the seizure threshold through increased adrenergic activity.
Benzodiazepine Withdrawal
Abrupt discontinuation of benzodiazepines can lead to withdrawal symptoms, including seizures. Use of flumazenil may precipitate acute withdrawal in dependent individuals.
Lithium
Severe lithium toxicity may present with neurological complications, including seizures.
Lindane
Lindane, used topically for lice and scabies, can cause seizures when absorbed in excessive amounts, particularly in infants and children.
Lead (Severe Toxicity)
Extremely elevated lead levels can result in neurological toxicity, including seizures.
Treatment
Benzodiazepines such as diazepam or lorazepam are first-line therapy for toxin-induced seizures. If seizures persist, phenobarbital is considered second-line. In refractory cases, propofol with airway protection may be required. Phenytoin and fosphenytoin are generally not effective for toxin-induced seizures. Pyridoxine should be administered when isoniazid or certain mushroom toxicities are suspected.
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Toxicology – Odor-Associated Toxins
Bitter Almond Odor
This characteristic smell is classically associated with cyanide exposure, although a significant portion of the population cannot detect it due to genetic variation.
Garlic-Like Odor
Substances such as phosphorus, arsenic compounds (arsine), organophosphates, selenium, thallium, and dimethyl sulfoxide (DMSO) may produce a garlic-like smell.
Rotten Egg Odor
Hydrogen sulfide, carbon disulfide, mercaptans, disulfiram, and N-acetylcysteine are known to emit a sulfurous “rotten egg” odor.
Fruity Odor
A sweet or fruity smell may be present in exposures involving nitriles, ketoacidosis, ethanol, isopropanol, chloroform, trichloroethane, paraldehyde, chloral hydrate, methyl bromide, and certain nitrites.
Fishy or Musty Odor
Compounds such as zinc phosphide, aluminum phosphide, and nickel carbonyl may produce a fishy or musty scent.
Ammonia-Like Odor
Ammonia exposure is associated with a sharp, pungent odor that is easily recognizable.
Mothball Odor
Naphthalene, camphor, and p-dichlorobenzene commonly produce the classic mothball smell.
Minty Odor
Methylsalicylate (oil of wintergreen) and menthol can give off a distinct mint-like aroma.
Disinfectant Odor
Phenol and creosote are associated with a strong antiseptic or disinfectant-like smell.
Burnt Rope Odor
This smell may be linked to marijuana or opium exposure.
Carrot-Like Odor
Cicutoxin, found in water hemlock, can produce an odor reminiscent of carrots.
Hay-Like Odor
Phosgene exposure may be associated with a freshly cut hay smell.
Pear-Like Odor
Chloral hydrate may produce a scent resembling pears.
Pepper Odor
Exposure to riot control agents such as CS (tear gas) can result in a pepper-like smell.
Pine Odor
Pine oil is associated with a characteristic pine-like scent.
Peanut Butter Odor
Vacor, a rodenticide, has been described as having a peanut butter-like odor.
Shoe Polish Odor
Nitrobenzene exposure may produce a smell similar to shoe polish.
Tobacco Odor
Nicotine-containing substances often have a distinct tobacco-like smell.
Vinegar Odor
Acetic acid and hydrofluoric acid may emit a sharp, vinegar-like odor.
Violet Odor
Turpentine metabolites excreted in urine may produce a violet-like scent.
New Car Smell
Chemicals such as benzene, cyclohexanone, and styrene, often found in new materials, can produce this recognizable odor.
PEARLS
Bitter Almond Odor
This characteristic smell is classically associated with cyanide exposure, although a significant portion of the population cannot detect it due to genetic variation.
Garlic-Like Odor
Substances such as phosphorus, arsenic compounds (arsine), organophosphates, selenium, thallium, and dimethyl sulfoxide (DMSO) may produce a garlic-like smell.
Rotten Egg Odor
Hydrogen sulfide, carbon disulfide, mercaptans, disulfiram, and N-acetylcysteine are known to emit a sulfurous “rotten egg” odor.
Fruity Odor
A sweet or fruity smell may be present in exposures involving nitriles, ketoacidosis, ethanol, isopropanol, chloroform, trichloroethane, paraldehyde, chloral hydrate, methyl bromide, and certain nitrites.
Fishy or Musty Odor
Compounds such as zinc phosphide, aluminum phosphide, and nickel carbonyl may produce a fishy or musty scent.
Ammonia-Like Odor
Ammonia exposure is associated with a sharp, pungent odor that is easily recognizable.
Mothball Odor
Naphthalene, camphor, and p-dichlorobenzene commonly produce the classic mothball smell.
Minty Odor
Methylsalicylate (oil of wintergreen) and menthol can give off a distinct mint-like aroma.
Disinfectant Odor
Phenol and creosote are associated with a strong antiseptic or disinfectant-like smell.
Burnt Rope Odor
This smell may be linked to marijuana or opium exposure.
Carrot-Like Odor
Cicutoxin, found in water hemlock, can produce an odor reminiscent of carrots.
Hay-Like Odor
Phosgene exposure may be associated with a freshly cut hay smell.
Pear-Like Odor
Chloral hydrate may produce a scent resembling pears.
Pepper Odor
Exposure to riot control agents such as CS (tear gas) can result in a pepper-like smell.
Pine Odor
Pine oil is associated with a characteristic pine-like scent.
Peanut Butter Odor
Vacor, a rodenticide, has been described as having a peanut butter-like odor.
Shoe Polish Odor
Nitrobenzene exposure may produce a smell similar to shoe polish.
Tobacco Odor
Nicotine-containing substances often have a distinct tobacco-like smell.
Vinegar Odor
Acetic acid and hydrofluoric acid may emit a sharp, vinegar-like odor.
Violet Odor
Turpentine metabolites excreted in urine may produce a violet-like scent.
New Car Smell
Chemicals such as benzene, cyclohexanone, and styrene, often found in new materials, can produce this recognizable odor.
PEARLS
- Approximately 40% of individuals are unable to detect the bitter almond odor of cyanide.
- Hydrogen sulfide exposure can quickly lead to olfactory fatigue, reducing the ability to perceive its smell.
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Toxicology – Single-Dose Lethal Toxins
Clinicians should be aware that even a single dose of certain medications can be fatal, particularly in infants and children. The following are important high-risk agents and their mechanisms:
Alpha-2 Adrenergic Agonists (e.g., Clonidine)
These centrally acting agents can lead to significant central nervous system depression, bradycardia, hypotension, and respiratory depression.
Beta-Blockers (e.g., Propranolol)
Propranolol is especially dangerous due to its lipophilic nature, allowing central nervous system penetration. Toxicity may result in hypoglycemia, altered mental status, bradycardia, hypotension, heart block, and seizures.
Calcium Channel Blockers
These drugs impair cardiac conduction and contractility, causing bradycardia, hypotension, and heart block. Hyperglycemia may also occur due to reduced insulin release.
Sulfonylureas
These oral hypoglycemic agents can cause profound and prolonged hypoglycemia, leading to altered mental status, seizures, and coma.
Opioids (Narcotics)
Opioids, including heroin and prescription medications, can cause severe respiratory depression or arrest. Ingestion of transdermal patches is a particular risk in children.
Nicotine
Nicotine toxicity can produce cholinergic symptoms such as muscle fasciculations, along with cardiovascular and neurological effects.
Tricyclic Antidepressants (TCAs)
TCAs block cardiac sodium channels, resulting in conduction delays, widened QRS complexes, and potentially fatal arrhythmias.
Salicylates
Substances such as oil of wintergreen and certain bismuth-containing compounds disrupt oxidative phosphorylation, leading to metabolic acidosis, cerebral edema, pulmonary edema, seizures, and death.
Camphor
Camphor ingestion can rapidly cause nausea, vomiting, tachycardia, central nervous system depression, and seizures, especially in children.
Colchicine and Podophyllin
These agents disrupt microtubule formation, impairing cell division. Toxicity presents with gastrointestinal symptoms and can progress to hypotension and multisystem organ failure.
Acetylcholinesterase Inhibitors (AChEIs)
Medications used for Alzheimer disease can lead to a cholinergic toxidrome in overdose, with symptoms including bradycardia, bronchorrhea, and altered mental status.
Quinine and Quinidine
These agents block sodium channels, leading to cardiac conduction abnormalities such as QRS widening, QT prolongation, and potentially life-threatening arrhythmias.
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Clinicians should be aware that even a single dose of certain medications can be fatal, particularly in infants and children. The following are important high-risk agents and their mechanisms:
Alpha-2 Adrenergic Agonists (e.g., Clonidine)
These centrally acting agents can lead to significant central nervous system depression, bradycardia, hypotension, and respiratory depression.
Beta-Blockers (e.g., Propranolol)
Propranolol is especially dangerous due to its lipophilic nature, allowing central nervous system penetration. Toxicity may result in hypoglycemia, altered mental status, bradycardia, hypotension, heart block, and seizures.
Calcium Channel Blockers
These drugs impair cardiac conduction and contractility, causing bradycardia, hypotension, and heart block. Hyperglycemia may also occur due to reduced insulin release.
Sulfonylureas
These oral hypoglycemic agents can cause profound and prolonged hypoglycemia, leading to altered mental status, seizures, and coma.
Opioids (Narcotics)
Opioids, including heroin and prescription medications, can cause severe respiratory depression or arrest. Ingestion of transdermal patches is a particular risk in children.
Nicotine
Nicotine toxicity can produce cholinergic symptoms such as muscle fasciculations, along with cardiovascular and neurological effects.
Tricyclic Antidepressants (TCAs)
TCAs block cardiac sodium channels, resulting in conduction delays, widened QRS complexes, and potentially fatal arrhythmias.
Salicylates
Substances such as oil of wintergreen and certain bismuth-containing compounds disrupt oxidative phosphorylation, leading to metabolic acidosis, cerebral edema, pulmonary edema, seizures, and death.
Camphor
Camphor ingestion can rapidly cause nausea, vomiting, tachycardia, central nervous system depression, and seizures, especially in children.
Colchicine and Podophyllin
These agents disrupt microtubule formation, impairing cell division. Toxicity presents with gastrointestinal symptoms and can progress to hypotension and multisystem organ failure.
Acetylcholinesterase Inhibitors (AChEIs)
Medications used for Alzheimer disease can lead to a cholinergic toxidrome in overdose, with symptoms including bradycardia, bronchorrhea, and altered mental status.
Quinine and Quinidine
These agents block sodium channels, leading to cardiac conduction abnormalities such as QRS widening, QT prolongation, and potentially life-threatening arrhythmias.
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Toxicology – Drugs Causing Hypertension
Amphetamines
Amphetamines enhance the release of catecholamines, producing significant increases in blood pressure and heart rate.
Caffeine
Caffeine stimulates adrenergic activity, causing hypertension and tachycardia. In large overdoses, it may paradoxically result in hypotension and cardiovascular collapse.
Cocaine
Cocaine increases synaptic concentrations of serotonin, dopamine, and norepinephrine by blocking their reuptake, resulting in elevated blood pressure and heart rate.
Anticholinergics
Anticholinergic drugs suppress parasympathetic activity, leading to increased heart rate and elevated blood pressure.
Nicotine
Nicotine toxicity initially presents with hypertension and tachycardia, which may later progress to bradycardia and hypotension.
Sympathomimetics
These agents increase blood pressure and heart rate by promoting catecholamine release, decreasing their reuptake, or inhibiting their breakdown.
Thyroid Hormone
Excess thyroid hormone elevates basal metabolic rate and enhances responsiveness to catecholamines. In severe overdose, this may lead to cardiac dysrhythmias followed by hypotension and cardiovascular collapse.
Treatment
Benzodiazepines are the first-line treatment for hypertension due to sympathomimetic toxicity. Pure β-blockers should be avoided because they can cause unopposed α-adrenergic stimulation and worsen hypertension. Agents such as labetalol are preferred due to their combined α- and β-blocking effects.
Amphetamines
Amphetamines enhance the release of catecholamines, producing significant increases in blood pressure and heart rate.
Caffeine
Caffeine stimulates adrenergic activity, causing hypertension and tachycardia. In large overdoses, it may paradoxically result in hypotension and cardiovascular collapse.
Cocaine
Cocaine increases synaptic concentrations of serotonin, dopamine, and norepinephrine by blocking their reuptake, resulting in elevated blood pressure and heart rate.
Anticholinergics
Anticholinergic drugs suppress parasympathetic activity, leading to increased heart rate and elevated blood pressure.
Nicotine
Nicotine toxicity initially presents with hypertension and tachycardia, which may later progress to bradycardia and hypotension.
Sympathomimetics
These agents increase blood pressure and heart rate by promoting catecholamine release, decreasing their reuptake, or inhibiting their breakdown.
Thyroid Hormone
Excess thyroid hormone elevates basal metabolic rate and enhances responsiveness to catecholamines. In severe overdose, this may lead to cardiac dysrhythmias followed by hypotension and cardiovascular collapse.
Treatment
Benzodiazepines are the first-line treatment for hypertension due to sympathomimetic toxicity. Pure β-blockers should be avoided because they can cause unopposed α-adrenergic stimulation and worsen hypertension. Agents such as labetalol are preferred due to their combined α- and β-blocking effects.
- Published on
Toxicology – Drugs causing Hypotenssion
C – Clonidine:
A central-acting α₂ receptor agonist that can initially cause hypertension followed by hypotension.
C – Calcium Channel Blockers:
A class of antihypertensive and antianginal medications that decrease heart rate and dilate peripheral vasculature.
R – Reserpine:
A sympatholytic antihypertensive medication that blocks the reuptake of norepinephrine, dopamine, and serotonin, leading to enhanced degradation by MAO in the synaptic space.
A – Antidepressants:
Tricyclic antidepressants (TCAs) can induce hypotension through α₁ receptor blockade and by causing cardiac dysrhythmias and subsequent cardiac collapse.
A – Aminophylline:
A methylxanthine that acts as an adenosine receptor antagonist, β-blocker, and phosphodiesterase inhibitor that can cause hypotension and cardiac collapse in overdose settings.
S – Sedative–Hypnotics:
Hypotension can occur secondary to myocardial depression.
H – Heroin:
Opiates can induce hypotension secondary to histamine release, direct vasodilation, or through a centrally mediated decrease of vagal tone.
Treatment:
Hypotension is best treated with large fluid boluses followed by the administration of antidotes and/or treatment of the respective toxin. Pressors may be indicated if the patient remains hypotensive after fluid resuscitation.
C – Clonidine:
A central-acting α₂ receptor agonist that can initially cause hypertension followed by hypotension.
C – Calcium Channel Blockers:
A class of antihypertensive and antianginal medications that decrease heart rate and dilate peripheral vasculature.
R – Reserpine:
A sympatholytic antihypertensive medication that blocks the reuptake of norepinephrine, dopamine, and serotonin, leading to enhanced degradation by MAO in the synaptic space.
A – Antidepressants:
Tricyclic antidepressants (TCAs) can induce hypotension through α₁ receptor blockade and by causing cardiac dysrhythmias and subsequent cardiac collapse.
A – Aminophylline:
A methylxanthine that acts as an adenosine receptor antagonist, β-blocker, and phosphodiesterase inhibitor that can cause hypotension and cardiac collapse in overdose settings.
S – Sedative–Hypnotics:
Hypotension can occur secondary to myocardial depression.
H – Heroin:
Opiates can induce hypotension secondary to histamine release, direct vasodilation, or through a centrally mediated decrease of vagal tone.
Treatment:
Hypotension is best treated with large fluid boluses followed by the administration of antidotes and/or treatment of the respective toxin. Pressors may be indicated if the patient remains hypotensive after fluid resuscitation.
