Toxicology (main)

Background

Autonomic Nervous System

1. Parasympathetic - ACh is transm
   1. Muscarinic
      1. receptors in heart, eye, lung, GI, skin and sweat glands
      2. Bradycardia
      3. Miosis
      4. Bronchorrhea / Bronchospasm
      5. Hyperperistalsis (SLUDGE)
      6. Sweating
      7. Vasodilation
   2. Nicotinic
      1. receptors in both sympathetic and parasympathetic nervous systems
      2. fasciculations, flaccid paralysis
      3. ?Mild bradycardia, hypotension
2. Sympathetic
   1. ALPHA EFFECTS - vessels, eye, skin
      1. Mydriasis, HTN, Sweating
   2. BETA EFFECTS - heart, lungs
      1. Tachycardia, Bronchodilation

Diagnosis

Toxicological Exam

1. All VS (Temp, RR,HR, BP)
2. Neuro Exam
   1. Level of consciousness
   2. Pupillary exam
   3. Motor response
3. Skin Exam - moisture, temp
4. Lung Exam
5. Bowel Sounds

Toxidrome Chart

Finding	Cholinergic	Anticholinergic	Sympathomimetic	Sympatholytic^	Sedative/Hypnotic
Example	Organophosphates	TCAs	Cocaine	Clonidine	ETOH
Temp	Nl	Nl / ↑	Nl / ↑	Nl / ↓	Nl / ↓
RR	Variable	Nl / ↓	Variable	Nl / ↓	Nl / ↓
HR	Variable	↑	↑ (sig)	Nl / ↓	Nl / ↓
BP	↑	↑	↑	Nl / ↓	Nl / ↓
LOC	Nl / Lethargic	Nl, agitated, psychotic, comatose	Nl, agitated, psychotic	Nl, Lethargic, or Comatose	Nl, Lethargic, or Comatose
Pupils	Variable	Mydriatic	Mydriatic	Nl / Miotic
Motor	Fasciculations, Flacid Paralysis	Nl	Nl / Agitated	Nl
Skin	Sweating (sig)	Hot, dry	Sweating	Dry
Lungs	Bronchospasm / rhinorrhea	Nl	Nl	Nl
Bowel Sounds	Hyperactive (SLUDGE)	↓ / Absent	Nl / ↓	Nl / ↓

^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan

Withdrawal from substances have the opposite effect

^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan

Differential Diagnosis for Specific Signs

Hyperthermia

1. Altered Metabolism
   1. Aspirin (Salicylate) Toxicity
   2. withdrawal states
   3. thyroid hormones
   4. dinitrophenols
2. Increased Muscle Activity
   1. withdrawal, sympathomimetics
   2. MAOI Toxicity
   3. PCP, LSD
   4. Lithium
   5. Amoxapine
   6. Serotonin Syndrome
3. Impaired Heat Dissipation
   1. anticholinergics
   2. antihistamines
   3. antipsychotics (TCAs)
4. Malignant Hyperthermia
   1. anesthestics
5. Neuroleptic Malignant Syndrome
   1. phenothiazines, Lithium, LevoDopa

Hypothermia

1. Exposure
   1. Ethanol Toxicity
   2. Sedative hypnotics
   3. Narcotics
   4. TCAs
   5. Phenothiazines
   6. Insulin (Hypoglycemia)

Increased Respiratory Rate

1. Direct Stimulation
   1. Aspirin (Salicylate) Toxicity
   2. Metabolic Acidosis
   3. dintirophenol, pentachlorophenol
   4. hepatorenal failure
   5. CNS stimulants (cocaine, amphet, theophylline)
2. Tissue Hypoxia
   1. CO
   2. Cyanide
   3. Hydrogen Sulfide
   4. Methemoglobinemia

Respiratory Depression

1. Central Depression
   1. antipsychotics
   2. Chlorinated hydrocarbons
   3. Sedative/Hypnotics (Ethanol Toxicity, glycols)
   4. Tricyclic (TCA) Toxicity
   5. Lomitil
2. Muscle Failure
   1. Organophosphates
   2. Marine Toxins
   3. Nicotine
   4. strychnine
   5. botulinis
   6. Mojave rattlesnake, Cobra

See Also

• Altered mental status

Source

Originally adapted from BIRNBAUMER