Sympathomimetic toxicities

Background

Sympathomimetic toxicities

• Cocaine toxicity
• Amphetamine toxicity
  • Synthetic cathinone toxicity (khat)
• Ketamine
• Ecstasy (MDMA) toxicity
• Synthetic cannabinoid toxicity
• Bath salts toxicity

Differential Diagnosis

Altered mental status and fever

• Infectious
  • Sepsis
  • Meningitis
  • Encephalitis
  • Cerebral malaria
  • Brain abscess
• Other
  • Neuroleptic malignant syndrome
  • Serotonin syndrome
  • Malignant hyperthermia
  • Sympathomimetic toxicity (cocaine, amphetamine, ketamine)
  • Anticholinergic toxicity
  • Heat stroke
  • Delirium tremens
  • Hypothalamic stroke
  • Pheochromocytoma
  • Thyroid storm

Evaluation

Work Up

Laboratory

• Finger stick glucose (to rule out hypoglycemia)
• Acetaminophen and Salicylate level
• Urine Drug Screen (to verify toxic substance, do not delay treatment for results)
• Serum electrolytes
• Serum creatine phosphokinase
• Creatinine and BUN
• Urine analysis with myoglobin
• Arterial or venous blood gas if respiratory symptoms present

Cardiac

• ECG for prolongation of QTc or QRS intervals

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

Management

• Use Benzodiazepines as first line agent for agitation, hypertension, and hyperthermia
• May also use Nitroprusside or Phentolamine
• Treat with fluid resuscitation to avoid renal failure secondary to rhabdomyolysis (see below)

Avoid

• Avoid succinylcholine due to potential for hyperkalemia in these patients
• Avoid antipyretics
• Avoid pure beta-blockers

Complications

• Rhabdomyolysis is common complication
  • Bath Salts - 63%
  • Amphetamines - 40%
  • Cocaine - 33%

See Also

• Toxidromes