Toxicology 1

COMMON TOXIC SYNDROMES

Table Xl-1-1. Signs, Symptoms, and Interventions or Antidotes for Common Toxic Syndromes

Compound(s)	Signs and Symptoms	Interventions and Antidotes
AChE inhibitors	Miosis, salivation, sweats, GI cramps, diarrhea,	Respiratory support; atropine + pralidoxime (for
	muscle twitches seizures, coma, respiration	irreversible AChE inhibitors)
	failure

Atropine and	i HR, i BP, hyperthermia (hot, dry skin),
muscarinic	delirium, hallucinations, mydriasis
blockers
Carbon monoxide	Nausea and vomiting, dyspnea with
(>10% carboxyHb)	hyperventilation, mydriasis, vertigo;
	cardiovascular signs prominent, i BP, syncope,
	i HR, arrhythmias

Control cardiovascular symptoms and hyperthermia + physostigmine (crosses blood­ brain barrier)

Hyperbaric 02 and decontamination (humidified 100% 02 okay in mild overdose)

CNS stimulants	Anxiety/agitation, hyperthermia (warm, sweaty	Control cardiovascular symptoms, hyperthermia,
	skin), mydriasis, i HR, i BP, psychosis, seizures	and seizures- +/- BZs or antipsychotics
Opioid analgesics	Lethargy, sedation, i HR, i BP, hypoventilation,	Ventilatory support; naloxone at frequent
	miosis, coma, respiration failure	intervals
Salicylates (ASA)*	Confusion, lethargy, hyperventilation,	Correct acidosis and electrolytes-urinary
	hyperthermia, dehydration, hypokalemia,	alkalinization, possible hemodialysis
	acidosis, seizures, coma
Sedative-hypnotics	Disinhibition (initial), lethargy, ataxia,	Ventilatory support-flumazenil if BZs implicated
and ethanol	nystagmus, stupor, coma, hypothermia,
	respiratory failure

SSRls	Agitation, confusion, hallucination,
	muscle rigidity, hyperthermia, i HR, i BP,
	seizures

Control hyperthermia and seizures-possible use of cyproheptadine, antipsychotics, and BZs

Tricyclic	Mydriasis, hyperthermia (hot, dry skin), 3 Cs	Control seizures and hyperthermia, correct
antidepressants	(convulsions, coma, and cardiotoxicity)	acidosis and possible arrhythmias
	arrhythmias

*More details in antiinflammatory section

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Section XI • Toxicology

HEAVY METAL POISONING

Signs and symptoms are distinctive but usually result from inhibition of -SH groups on enzymes and regulatory proteins.

Table Xl-1-2. Signs, Symptoms, and Interventions or Antidotes for Heavy Metal Poisoning

Metals and Source

Arsenic (wood preservatives, pesticides, ant poisons)

Iron (medicinal for anemias and prenatal supplements)

Lead (tap water, leaded paint chips, herbal remedies, gas sniffing, glazed kitchenware, etc.)

Signs and Symptoms

Acute: gastroenteritis, hypotension, metabolic acidosis, garlic breath, "rice water" stools, torsades, seizures

Chronic: pallor, skin pigmentation (raindrop pattern), alopecia, stocking glove neuropathy, myelosuppression

Acute (mainly children): severe GI distress necrotizing gastroenteritis with hematemesis and bloody diarrhea, dyspnea, shock, coma

Acute: nausea and vomiting, GI distress and pain, malaise, tremor, tinnitus, paresthesias, encephalopathy (red or black feces)

Chronic: multisystem effects-anemia (t heme synthesis), neuropathy (wrist drop), nephropathy (proteinuria, failure), hepatitis, mental retardation (from pica), J, fertility and i stillbirths

Interventions and Antidotes

Activated charcoal, dimercaprol

Penicillamine or succimer

Gastric aspiration + carbonate lavage, deferoxamine IV

Decontamination-gastric lavage + dimercaprol (severe) or EDTA or succimer (penicittamine if unable to use dimercaprot or succimer)

Children: succimer PO

Mercury (elemental in instruments); salts used in amalgams, batteries, dyes, electroplating, fireworks, photography

Acute: vapor inhalation-chest pain, dyspnea, pneumonitis

Acute: inorganic salt ingestion-hemorrhagic gastroenteritis, acute tubular necrosis, shock

Chronic: organic Hg-CNS effects, ataxia, paresthesias, auditory and visual toss, loosening ofteeth

Succimer PO or dimercaprol (IM)

Activated charcoal for oral ingestion, then support with succimer PO or dimercaprot (not IV) causes redistribution of Hg to the CNS ineurotoxicity

310 MEDICAL

Chapter 1 • Toxicology

ANTIDOTES

Table Xl-1-3. Summary of Antidotes

Antidote	Type of Poisoning
Acetylcysteine	Acetaminophen
Atropine + pralidoxime	AChE inhibitors-physostigmine, neostigmine, and
(for irreversible AChE	pyridostigmine; organophosphates, including
inhibitors)	insecticides, such as malathion and parathion
Deferoxamine	Iron and iron salts
Digoxin immune F(ab)	Digoxin
Dimercaprol (BAL)	Arsenic, gold, mercury, lead; oral succimer for milder
	lead and mercury toxicity
EDTA	Backup in lead poisoning, then for rarer toxicities
	(Cd, Cr, Co, Mn, Zn)
Esmolol	Theophylline, beta agonists
Ethanol, fomepizole	Methanol or ethylene glycol
Flumazenil	Benzodiazepines, zolpidem, zaleplon
Naloxone	Opioid analgesics
Oxygen	Carbon monoxide
Penicillamine	Copper (e.g., Wilson's disease), iron, lead, mercury
Physostigmine	Anticholinergics: atropine, antihistamine,
	antiparkinsonian-not tricyclics
Protamine	Heparins
Vitamin K	Warfarin and coumarin anticoagulants
Activated charcoal	Nonspecific: all oral poisonings except Fe, CN, Li,
	solvents, mineral acids, or corrosives

MEDICAL 311

Chapter 1 • Toxicology

Table Xl-1-5. Purified Nutritional Supplements
Name	Pharmacology	Side Effects
Dehydroepiandrosterone	Androgen precursor advocated	Females:
(DHEA)	fortreatment ofAIDS Ci CD4 in	androgenization
	females), Alzheimer disease	and concern
	and "aging," diabetes,	regarding CV
	hypercholesterolemia, and SLE	disease and breast
	ct in symptoms and "flare­	cancer
	ups" in females)	Males:
		feminization in
		young and concern
		in elderly regarding
		BPH and cancer
Melatonin	Serotonin metabolite used for	Drowsiness,
	"jet-lag" and sleep disorders	sedation,
		headache.

Contraindicated in pregnancy, in women trying to conceive Ct LH), and in nursing mothers

Ct prolactin)

Chapter Summary

•Table Xl-1-1 lists the common toxic syndromes with their signs and symptoms and potential modes of intervention and/or antidotes.

•Table Xl-1-2 lists the common heavy metal poisons with their most common

sources, signs, and symptoms and potential modes of intervention and/or antidotes.

•Table Xl-1-3 lists antidotes and the type of poisoning against which they act.

•Table Xl-1-4 lists the characteristics of selected herbals, and Table Xl-1-5 lists the relevant purified nutritional supplements.

MEDICAL 313