Author:
SeanPatrick Nordt
Description
- Direct or indirect stimulation of adrenergic receptors in sympathetic and central nervous systems
- Often no correlation between dosage and degree of toxicity
- Cocaine may also block sodium channels of cardiac myocytes, leading to “tricyclic” or class 1a-type dysrhythmias
Etiology
- Sympathomimetic toxicity can result from use of any sympathetically active drug, including:
- All amphetamines, methamphetamines, and derivatives (ecstasy, MDMA, Molly)
- Cocaine (including “Speed Ball”) when opioid reversed with naloxone
- Synthetic cathinones “Bath Salts”
- Phencyclidine (PCP)
- Lysergic acid diethylamide (LSD)
- Decongestants (rare)
- Drug delivery routes: Inhalation, injection, snorting, or ingestion
Signs and Symptoms
- Vital signs:
- Tachycardia:
- Bradycardia possible for cocaine and some other decongestants
- Increased BP:
- Rarely patients may be hypotensive
- Tachypnea
- Hyperthermia:
- Often present, may be severe, and is often overlooked, frequent cause of death
- CNS:
- Anxiety
- Headache
- Agitation
- Altered mentation
- Diaphoresis
- Seizures
- Stroke
- Dystonia (rare)
- Cardiovascular:
- Palpitations
- Chest pain
- Myocardial ischemia or infarction
- Tachydysrhythmias
- Cardiovascular collapse
- Murmur (e.g., endocarditis)
- Other:
- Dilated pupils
- Dry mucous membranes
- Urinary retention may cause enlarged bladder
- Needle track marks or abscesses on extremities should be sought
- Increased or decreased bowel sounds
- The presence of diaphoresis and bowel sounds may help to differentiate sympathomimetic toxicity from anticholinergic poisoning
History
- Assess history for possible sympathomimetic agents:
- Cold preparations
- Prescription amphetamines
- Recreational drug use
- 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
- Hypertension
- 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 neurologic deficits
Essential Workup
- Monitor vital signs:
- Increased temperature (>40°C possible):
- 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
- ECG:
- Signs of cardiac ischemia
- Ventricular tachydysrhythmias
- Reflex bradycardia
Diagnostic Tests & Interpretation
Lab
- Urinalysis for:
- 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 disseminated intravascular coagulation (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., synthetic cathinones, MDMA) may not be detected
- Positive urine does not equate to toxicity
- Salicylate and acetaminophen levels if suicide attempt a possibility or if OTC medications ingested (e.g., cough, cold)
- Venous blood gas, ABG
Imaging
- CXR:
- Adult respiratory distress syndrome
- Noncardiogenic pulmonary edema
- Head CT for:
- Significant headache
- Altered mental status
- Seizure
- Focal neurologic signs
- 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
- Tricyclic antidepressants
- Sympathomimetics
- Ethanol withdrawal
- Sedative/hypnotic withdrawal
- Hallucinogens
- PCP
- Drugs that cause hypertension and tachycardia:
- Sympathomimetics
- Anticholinergics
- Ethanol withdrawal
- PCP
- Caffeine
- Monoamine oxidase inhibitors, initially followed by hypotension
- Nicotine
- Drugs that cause seizures:
- Camphor
- Carbamazepine
- Carbon monoxide
- Chlorinated hydrocarbons
- Cholinergics
- Cyanide
- Ethanol withdrawal
- Hypoglycemics
- Isoniazid
- Lead (acute poisoning)
- Lithium
- Local anesthetics
- Phenothiazines
- Propoxyphene
- Salicylates
- Sedative/hypnotic withdrawal
- Strychnine
- Sympathomimetics
- Theophylline
- Tricyclic antidepressants
Prehospital
- 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:
- Gastric lavage not recommended:
- Activated charcoal not routinely recommended
- Consider activated charcoal with body stuffer or body packer ingestions
- Whole-bowel irrigation with polyethylene glycol solution - electrolyte solution for body packers
- Hypertensive crisis:
- Initially administer benzodiazepines if agitated. May require high doses
- Nicardipine or nitroglycerin IV for severe HTN unresponsive to benzodiazepines
- Nitroprusside can also be used for severe, unresponsive HTN
- Avoid β-blockers, which may exacerbate HTN due to unopposed α activity
- Agitation, acute psychosis:
- Administer benzodiazepines
- Use butyrophenones (e.g., haloperidol) with caution to manage agitation:
- May lower seizure thresholds and may prolong QT duration
- Dysrhythmias:
- Sodium bicarbonate IV push is treatment of choice for ventricular dysrhythmias indicative of sodium channel blocking (i.e., widened QRS complex).
- Lidocaine for ventricular dysrhythmias refractory to alkalinization, benzodiazepines, and supportive care
- Hyperthermia:
- Benzodiazepines if agitated
- Active cooling if temperature >40°C:
- Tepid water mist
- Evaporate with fan
- Ice packs to axilla and groin
- RSI with nondepolarizing agent, e.g., rocuronium
- Paralysis:
- Indicated if muscle rigidity and hyperactivity contributing to persistent hyperthermia
- Nondepolarizing paralytic preferred
- 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:
Medication
- Activated charcoal: 1-2 g/kg up to 100 g PO
- Dextrose: D50W 1 amp: 50 mL or 25 g (peds: 1-2 mL/kg of D25W; infants: 2.5-5.0 mL/kg of D10%) IV
- Diazepam (benzodiazepine): 5-10 mg (peds: 0.2-0.5 mg/kg) IV. Not recommended <6 mo of age
- Lorazepam (benzodiazepine): 2-6 mg (peds: 0.03-0.05 mg/kg) IV
- Nicardipine IV infusion at 5 mg/hr titrate by 2.5 mg/hr q5min to max 15 mg/hr
- Nitroprusside: 0.5-10 mcg/kg/min IV (titrated to BP)
- Phenobarbital: 15-20 mg/kg at 25-50 mg/min until cessation of seizure activity; monitor for respiratory depression. Safety not established <6 yr of age
- Sodium bicarbonate: 1 or 2 amps 8.4% (50 mEq/amp) (peds: 1-2 mEq/kg) IV push (use 4.2% solution < yr of age)
- Note: May need to intubate with high dose benzodiazepines and phenobarbital
Disposition
Admission Criteria
- Admit all body packers or stuffers to monitored bed
- Severe manifestations of toxicity to monitored bed:
- Seizures
- Dysrhythmias
- Hyperthermia
- Rhabdomyolysis
- Severe hypertension
- Altered mental status
- Ischemic chest pain
Discharge Criteria
Mildly intoxicated patients can be observed and treated in ED until resolution of clinical manifestations
Follow-up Recommendations
Patients may need referral for chemical dependency rehab and detoxification
ICD9
971.2 Poisoning by sympathomimetics [adrenergics]
ICD10
T44.901A Poisn by unsp drugs aff the autonm nervous sys, acc, init
SNOMED