Basics
Description
- Increased release of norepinephrine, dopamine, and serotonin
- Decreased catecholamine reuptake
- Direct effect on α- and β-adrenergic receptors
Etiology
- Prescription drugs:
- Amphetamine (Benzedrine)
- Dextroamphetamine (Dexedrine)
- Diethylpropion (Tenuate)
- Fenfluramine (Pondimin)
- Methamphetamine
- Methylphenidate (Ritalin)
- Phenmetrazine (Preludin)
- Phentermine
- "Designer drugs"�:
- Variants of illegal parent drugs
- Often synthesized in underground labs
- "Crystal,"� "Ice"�:
- Crystalline methamphetamine hydrochloride
- Smoked, insufflated, or injected
- Rapid onset; duration several hours
- "Crank"�
- "Ecstasy"� (3,4-methylenedioxymethamphetamine, MDMA, XTC, E):
- Often used at dances and "rave"� parties
- Dehydration can lead to hyperthermia, hyponatremia, fatality
- MDA (3,4,-methylenedioxyamphetamine)
- Methcathinone ("cat,"� "Jeff,"� "mulka"�):
- Derivative of cathinone, found in the evergreen tree Catha edulis
- Frequently synthesized in home labs
- Does not show up on urine toxicology screens
- Mephedrone
- May be contained in "bath salts"�
Diagnosis
Signs and Symptoms
- CNS:
- Agitation
- Delirium
- Hyperactivity
- Tremors
- Dizziness
- Mydriasis
- Headache
- Choreoathetoid movements
- Hyperreflexia
- Cerebrovascular accident
- Seizures and status epilepticus
- Coma
- Psychiatric:
- Euphoria
- Increased aggressiveness
- Anxiety
- Hallucinations (visual, tactile)
- Compulsive repetitive actions
- Cardiovascular:
- Palpitations
- Hypertensive crisis
- Tachycardia or (reflex) bradycardia
- Dysrhythmias (usually tachydysrhythmias)
- Cardiovascular collapse
- Other:
- Rhabdomyolysis
- Myoglobinuria
- Acute renal failure
- Anorexia
- Diaphoresis
- Disseminated intravascular coagulation (DIC)
History
- Determine the type, amount, timing, and route of amphetamine exposure
- Assess for possible coingestions
- Evaluate for symptoms of end organ injury:
- Chest pain
- Shortness of breath
- Headache, confusion, and vomiting
Physical Exam
- Common findings include:
- Agitation
- Tachycardia
- Diaphoresis
- Mydriasis
- Severe intoxication characterized by:
- Tachycardia
- HTN
- Hyperthermia
- Agitated delirium
- Seizures
- Diaphoresis
- Hypotension and respiratory distress may precede cardiovascular collapse
- Evaluate for associated conditions:
- Cellulitis and soft tissue infections
- Diastolic cardiac murmurs or unequal pulses
- Examine carefully for trauma
- Pneumothorax from inhalation injury
- Focal neurological deficits
Essential Workup
- Vital signs:
- Temperature >40 �C:
- Core temperature recording essential
- Peripheral temperature may be cool
- Indication for urgent cooling
- Ominous prognostic sign
- BP:
- Severe hypertension can lead to cardiac and neurologic abnormalities.
- Late in course, hypotension may supervene due to catecholamine depletion
- ECG:
- Signs of cardiac ischemia
- Ventricular tachydysrhythmias
- Reflex bradycardia
Diagnosis Tests & Interpretation
Lab
- Urinalysis:
- Electrolytes, BUN/creatinine, glucose:
- Hypoglycemia may contribute to altered mental status.
- Acidosis may accompany severe toxicity.
- Rhabdomyolysis may cause renal failure.
- Hyperkalemia-life-threatening consequence of acute renal failure
- Coagulation profile to monitor for potential DIC:
- Creatine phosphokinase (CPK):
- Markedly elevated in rhabdomyolysis
- Urine toxicology screen:
- For other toxins with similar effects (e.g., cocaine)
- Some amphetamine-like substances (e.g., methcathinone) may not be detected.
- Aspirin and acetaminophen levels if suicide attempt is a possibility
- Arterial blood gas (ABG)
Imaging
- Chest radiograph:
- Adult respiratory distress syndrome
- Noncardiogenic pulmonary edema
- Head CT for:
- Significant headache
- Altered mental status
- Focal neurologic signs
- For subarachnoid hemorrhage, intracerebral bleed
Diagnostic Procedures/Surgery
Lumbar puncture for: �
- Suspected meningitis (headache, altered mental status, hyperpyrexia)
- Suspected subarachnoid hemorrhage and CT normal
Differential Diagnosis
- Sepsis
- Thyroid storm
- Serotonin syndrome
- Neuroleptic malignant syndrome
- Pheochromocytoma
- Subarachnoid hemorrhage
- Drugs that cause delirium:
- Anticholinergics:
- Belladonna alkaloids
- Antihistamines
- Tricyclic antidepressants
- Cocaine
- Ethanol withdrawal
- Sedative/hypnotic withdrawal
- Hallucinogens
- Phencyclidine
- Drugs that cause HTN and tachycardia:
- Sympathomimetics
- Anticholinergics
- Ethanol withdrawal
- Phencyclidine
- Caffeine
- Phenylpropanolamine
- Ephedrine
- Monoamine oxidase inhibitors
- Theophylline
- Nicotine
- Drugs that cause seizures:
- Carbon monoxide
- Carbamazepine
- Cyanide
- Cocaine
- Cholinergics (organophosphate insecticides)
- Camphor
- Chlorinated hydrocarbons
- Ethanol withdrawal
- Sedative/hypnotic withdrawal
- Isoniazid
- Theophylline
- Hypoglycemics
- Lead
- Lithium
- Local anesthetics
- Anticholinergics
- Phencyclidine
- Phenothiazines
- Phenytoin
- Propoxyphene
- Salicylates
- Strychnine
Treatment
Pre-Hospital
- Patient may be uncooperative or violent.
- Secure IV access.
- Protect from self-induced trauma.
Initial Stabilization/Therapy
- ABCs
- Establish IV 0.9% NS access.
- Cardiac monitor
- Naloxone, dextrose (or Accu-Chek), and thiamine if altered mental status
Ed Treatment/Procedures
- Decontamination:
- Administration of activated charcoal
- Whole-bowel irrigation with polyethylene glycol solution for body packers
- Hypertensive crisis:
- Initially administer benzodiazepines if agitated.
- α-blocker (phentolamine) as second-line agent
- Nitroprusside for severe, unresponsive hypertension
- Avoid β-blockers, which may exacerbate hypertension.
- Agitation, acute psychosis:
- Administer benzodiazepines.
- Hyperthermia:
- Benzodiazepines if agitated
- Active cooling if temperature >40 �C:
- Tepid water mist
- Evaporate with fan.
- Paralysis:
- Indicated if muscle rigidity and hyperactivity contributing to persistent hyperthermia
- Nondepolarizing agent (e.g., vecuronium)
- Avoid succinylcholine.
- Intubation; mechanical ventilation
- Apply cooling blankets.
- Rhabdomyolysis:
- Administer benzodiazepines.
- Hydrate with 0.9% NS.
- Maintain urine output at 1-2 mL/min.
- Hemodialysis (if acute renal failure and hyperkalemia occur)
- Seizures:
- Maintain airway.
- Administer benzodiazepines.
- Phenobarbital if unresponsive to benzodiazepines
- Phenytoin contraindicated
- Hypotension:
- May be late finding due to catecholamine depletion
- Initially bolus with isotonic crystalloid solution
- If no response, administer norepinephrine.
- Dopamine may not be effective
Medication
- Activated charcoal: 1-2 g/kg up to 100 g PO
- Dextrose: D50W 1 amp: 50 mL or 25 g (peds: D25W 2-4 mL/kg) IV
- Diazepam (benzodiazepine): 5-10 mg (peds: 0.2-0.5 mg/kg) IV
- Lorazepam (benzodiazepine): 2-6 mg (peds: 0.03-0.05 mg/kg) IV
- Nitroprusside: 1-8 μg/kg/min IV (titrated to BP)
- Phenobarbital: 15-20 mg/kg at 25-50 mg/min until cessation of seizure activity
- Phentolamine: 1-5 mg IV over 5 min (titrated to BP)
- Vecuronium: 0.1 mg/kg IVP
Follow-Up
Disposition
Admission Criteria
- Hyperthermia
- Persistent altered mental status
- Hypertensive crisis
- Seizures
- Rhabdomyolysis
- Persistent tachycardia
Discharge Criteria
- Asymptomatic after 6 hr observation
- Absence of the above admission criteria
Followup Recommendations
Patients may need referral for chemical dependency rehab and detoxification. �
Pearls and Pitfalls
- Admit patients with severe or persistent symptoms.
- Monitor core temperature:
- Hyperthermia >40 �C may be life threatening.
- Treat with aggressive sedation and active cooling.
- Recognize rhabdomyolysis and hyperkalemia.
- Avoid physical restraints in agitated patients if possible.
- Consider associated emergency conditions:
- Patients with chest pain should be evaluated for acute coronary syndromes and treated accordingly.
- Consider infection in altered patients with fever and history of IV drug use.
- Methamphetamine abuse frequently associated with traumatic injury
- Benzodiazepines are 1st-line therapy in symptomatic methamphetamine intoxication
Additional Reading
- Callaway �CW, Clark �RF. Hyperthermia in psychostimulant overdose. Ann Emerg Med. 1994;24:68-75.
- Carvalho �M, Carmo �H, Costa �VM, et al. Toxicity of amphetamines: an update. Arch Toxicol. 2012;86:1167-1231.
- Gray �SD, Fatovich �DM, McCoubrie �DL, et al. Amphetamine-related presentations to and inner-city tertiary emergency department: A prospective evaluation. Med J Aust. 2007;186:336.
- Prosser �JM, Nelson �LS. The toxicology of bath salts: a review of synthetic cathinones. J Med Toxicol. 2012;8:33-42.
- Turnipseed �SD, Richards �JR, Kirk �JD, et al. Frequency of acute coronary syndrome in patients presenting to the emergency department with chest pain after methamphetamine use. J Emerg Med. 2003;24(4):369-373.
See Also (Topic, Algorithm, Electronic Media Element)
- Sympathomimetic Poisoning
- Tricyclic Antidepressant Poisoning
Codes
ICD9
- 969.72 Poisoning by amphetamines
- 969.73 Poisoning by methylphenidate
- 969.79 Poisoning by other psychostimulants
- 969.70 Poisoning by psychostimulant, unspecified
ICD10
- T43.601A Poisoning by unsp psychostim, accidental, init
- T43.621A Poisoning by amphetamines, accidental (unintentional), init
- T43.631A Poisoning by methylphenidate, accidental, init
- T43.691A Poisoning by oth psychostim, accidental, init
SNOMED
- 45775001 Poisoning by amphetamine (disorder)
- 216559001 Accidental poisoning by amphetamine (disorder)
- 291258000 Accidental ecstasy poisoning (disorder)
- 291242003 Amphetamine poisoning of undetermined intent (disorder)