Conference Review – Sympathomimetics and Seizures

Thanks Jen Cotton for writing up these conference reviews

Sympathomimetics Small Group Discussion Summary

What are the common signs and symptoms of poisoning with cocaine and other sympathomimetic agents? Why is cocaine an effective anesthetic agent?

Symptoms- chest pain, shortness of breath, palpitations, headache, focal neurological complaints

Signs – tachycardia, hypertension, diaphoresis, agitation, mydriasis, hyperthermia; dysrhythmias, seizures, encephalopathy

Cocaine is an effective anesthetic agent because it inhibits nerve impulses by blocking fast sodium channels.


How can one distinguish the findings in patients with sympathomimetic poisoning from patients with anti-cholinergic agents?

Anticholinergics cause drug skin and decreased bowel sounds. Sympathomimetics cause diaphoresis and increased bowel sounds.

Discuss newer sympathomimetics including methamphetamine and ‘bath salts’.

Phenylethylamine enhance release and block reuptake of catecholamines presynaptic terminals. Modifications can make it more hallucinogenic. Effects can last up to 12 hours.

Bath salts, synthetic cathinones, are designer drugs. Have effects similar to cocaine and amphetamines, but are less predictable, longer acting, and tend to have more hallucinogenic properties.

What treatments should be administered to poisonings with these agents?

ABCs. Establish IV access. Treatment is primarily supportive care, monitoring vitals, benzodiazepines for sedation, and treatment of complications.

Be careful using antipsychotics, like haldol, because they lower seizure threshold, may worsen hyperthermia, and increase QT interval.

Chest pain – with ST segment elevation give calcium channel blockers and nitro. Send to cath lab. Beta blockers unlikely to actually cause unopposed adrenergic stimulation, but hard to defend medicolegally and is the boards answer.

Hypertension – start with sedation. If not responding, then nitroprusside or phentolamine infusion. Can lower aggressively if patient does not have chronic hypertension.

Dysrhythmias – Treat reentrant supraventricular tachycardia and atrial fibrillation/flutter with calcium channel blocker. Treat wide complex tachycardia with boluses for sodium bicarb. Dose to clinical response and pH < 7.55. Consider treating refractory dysrhythmias with IV lipid emulsion therapy. Use same protocol as local anesthetic systemic toxicity.  


What are the common complications associated with sympathomimetic use?

Dysrhythmias – via QRS widening and QT prolongation

ACS, Cardiomyopathy- via vasoconstriction

Seizures- enhancement of excitatory neurotransmitters

Encephalopathy- hyperadrenergic tone induces severe transient hypertension, hemorrhage, or focal vasospasm

Hyperthermia – not responsive to tylenol

Pneumomediastinum, pneumothorax, and pneumopericardium – from barotrauma 2/2 valsalva maneuver after inhalation

Rhabdomyolysis – from seizures, agitation, or AMS

Pregnancy Problems – spontaneous abortions, abruptio placentae, fetal prematurity, and intrauterine growth retardation due to uteroplacental vasoconstriction

“Cocaine Washout” – depressed LOC that can be aroused with stimulation due to depletion of neurotransmitters. Can take up to 24 hours to improve.


Seizures Small Group Discussion Summary

Understand the different types of possible seizures including status epilepticus.

Generalized- loss of consciousness. Due to diffuse electrical discharges in the cerebral cortex.

Partial- no loss of consciousness. Due to electrical discharges beginning in a localized region of the cerebral cortex.

Epilepsy- recurrent seizures in someone with lower seizure threshold. .

Reactive Seizures- caused by electrical stimulation, drugs that lower seizure threshold, metabolic abnormalities, or trauma. Self limited typically.

Provoked seizure- due to acute precipitating event within 7 days of seizure

Status epilepticus- seizure > 5 minutes or two more seizures with regain of consciousness between

Refractory status epilepticus- persistent seizure activity despite administering adequate amounts of two antiepileptic agents.

Comprehend the management principles and guidelines for acute seizures. Discuss management of first time seizure vs recurrent seizure.

First Time: Take a thorough history. Recent pregnancy, severe/sudden onset headache; history of systemic illness, coagulopathy/anticoagulation, exposure to toxins, hypoxia, metabolic abnormalities, drug ingestion, alcohol use/withdrawal. Labs – glucose, BMP, calcium, magnesium, lactate, bHCG, tox studies. Imaging – CT head. Outpatient EEG & MRI. Neuro consult or close follow up.

Recurrent: Only need glucose and AED levels (if appropriate). If missed AED doses, then restart. If AED levels low, may need loading dose.

All Seizures: If seizure provoked (due to an identifiable underlying condition), require admission and need to be treated to minimize seizure recurrence.

Discuss management of status epilepticus.

ABCs first. Put patient on oxygen, cardiac monitor, and establish IV access. If in status, consider intubation for airway protection. Be sure to use short acting paralytic.

Give 2-4 mg ativan. Start longer acting anti-epileptic agent within 20 minutes of diagnosis. Options include:

  • Fosphenytoin: IV or IM, loading dose 20 PE/kg
  • Phenytoin: loading dose 20 mg/kg, can cause myocardial depression (due to propylene glycol diluent)
  • Levetiracetam: loading dose 20 mg/kg
  • Also valproate or lacosamide

If still refractory, then consider propofol, midazolam, phenobarbital.


Differentiate between a simple febrile seizure and a complex febrile seizure, including the evaluation for each.

Simple febrile seizure – generalized tonic clonic seizure in child 6 month – 5 years that lasts < 15 minutes with fever and occurs only once in 24 hours.

Complex febrile seizure – seizures accompanied by fever without signs of serious infection that last > 15 minutes, recur within 24 hours, are focal, or occur in child < 6 months/>5 years of age.

Treatment is treating source of fever. Observe until returned to baseline. If not at baseline after hour, should reconsider if there is a serious infection. Get a UA. No blood or neuroimaging studies. Even with complex febrile seizures, do not need further workup if returned to baseline.

Describe current guidelines for evaluation and treatment of first time unprovoked seizure in an otherwise healthy child > 6 months.

Should get labs; glucose, electrolytes, infectious work up as appropriate. Possible LP, if concern for meningitis. Essentially ensure this is not a provoked seizure. Once determined to be unprovoked, arrange for outpatient MRI and PCP or neurology follow up. Discharge instructions include do not allow child to be in position where they can drown, fall, or injure self/others another seizure occurs.

Define non-epileptic causes of seizures and their treatment.

Hypoglycemia – dextrose

Pseudoseizure – psych referral

Syncope- assess and treat causes

Movement disorders- such as dystonia, chorea, myoclonic jerks, tremors, or tics, may occur in a variety of neurologic conditions; work up causes and treat as appropriate.