Serotonin Syndrome Flashcards by Alana Meikle

what is the triad of symptoms associated with serotonin syndrome

mental status changes

autonomic hyperactivity

neuromuscular changes (hyperreflexia and clonus)

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why does serotonin syndrome occur

due to excess serotonin

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what is the range of possible presentations of serotonin syndrome

can vary significantly

mild symptoms (tremor, diarrhea)–> delirium, neuromuscular rigidity and hyperthermia in life threatening cases

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what is the incidence of serotonin syndrome

unknown–> mild cases not diagnosed or can be dismissed

more serious presentations can be confounded by other toxidromes

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what % of people who overdose on SSRIs develop serotonin syndrome

14-16%

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is serotonin syndrome rare

no –> has been identified in elderly, children and newborn infants

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what class of antidepressants is strongly associated with severe cases of serotonin syndrome?

what other combinations of drugs increase this risk

MAOIs strong associated with severe cases of serotonin syndrome

especially when used in combo with:
meperidine
dextromethorphan
SSRIs
MDMA

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how quickly does serotonin syndrome present/how fast is symptom onset

RAPID onset of symptoms–> within MINUTES after a change in medication or an overdose

approx 60% of patients with serotonin syndrome oresent within SIX HOURS after initial use of medication, an overdose or a change in dosing

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how quickly does serotonin syndrome resolve after initiation of treatment

most resolve within 24 hours after initiation of treatment and discontinuation of serotonergic drugs–> symptoms may persist in meds with longer half life

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does serotonin syndrome occur only with initiation of serotonergic agents

no–> both initiation AND withdrawal of serotonergic agents have been associated with serotonin syndrome

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list classes of medications that have been associated with serotonin syndrome

SSRIs

other antidepressants

MAOIs

anticonvulsants

analgesics

antimigraine drugs

bariatric medications

antibiotics

drugs of abuse

dietary and herbal supplements

mood stabilizers

antiemetics

OTC cold and flu meds

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list SSRIs associated with serotonin syndrome

sertraline
fluoxetine
fluvoxamine
paroxetine
citalopram

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list other antidepressants associated with serotonin syndrome

trazodone
nefazodone
buspirone
clomipramine
venlafaxine

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list MAOIs associated with serotonin syndrome

phenelzine
moclobemide
clorgiline
isocarboxazid

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list anticonvulsants associated with serotonin syndrome

valproate

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list analgesics associated with serotonin syndrome

meperidone
fentanyl
tramadol
pentazocine

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list antiemetics associated with serotonin syndrome

ondansetron
metoclopramide

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list antimigraine drugs associated with serotonin syndrome

sumatriptan (because is a 5TH1B/1D agonist)

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list bariatric medications associated with serotonin syndrome

sibutramine

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list antibiotics associated with serotonin syndrome

linezolid (MAOI)

ritonavir (inhibits CYP3A4)

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list OTC cold and flu meds associated with serotonin syndrome

dextromethorphan

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list drugs of abuse associated with serotonin syndrome

MDMA

LSD

“foxy methoxy”

Syrian rue (has MAOI components)

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list dietary supplements associated with serotonin syndrome

Study These Flashcards

tryptophan

st johns wort

ginseng

list mood stabilizers associated with serotonin syndrome

Study These Flashcards

lithium

what might you find on neurological exam associated with serotonin syndrome

horizontal ocular clonus intemrittent tremors myoclonus hyperreflexia

what is the name of the criteria proposed for diagnosing serotonin syndrome

Hunter critieria

what is a mnemonic to remember the hunter criteria

MOIST Muscle rigidity + temp above 38 + either ocular or inducible clonus Ocular clonus and either agitation or diaphoresis Inducible clonus and either agitation or diaphoresis Spontaneous clonus Tremor and hyperreflexia

what is the first decision point in the Hunter's Decision rules?

is there spontaneous clonus? if yes, then there is serotonin syndrome

what is the decision tree in the Hunter Decision rules?

spontaneous clonus--> inducible clonus + either agitation or diaphoresis--> ocular clonus + either agitation or diaphoresis--> tremor + hyperreflexia--> hypertonia + temp above 38 + ocular or inducible clonus *if any any point moving down that tree, all of the conditions are met at that level, then you suspect serotonin toxicity and act accordingly

how is the neurotransmitter serotonin produced

produced by the decarboxylation and hydroxylation of l-tryptophan

which serotonin receptor appears to be most implicated in the development of serotonin syndrome

5HT2A agonism (though no single receptor appears to be solely responsible)

other than serotonin receptors, what other types of receptors/neurotransmitters also appear to be implicated in serotonin syndrome

NMDA antagonists GABA

ddx serotonin syndrome

anticholinergic poisoning malignant hyperthermia NMS

how do you distinguish serotonin syndrome from anticholinergic poisoning

anticholinergic toxicity presents with NORMAL reflexes and have normal toxidrome of mydriasis, hyperactive delirium, dry oral mucosa and skin, urinary retention, absence of bowel sounds (i.e dry as a bone) SS--> hyepractive bowel sounds, clonus, hyperreflexia, tremor, diaphoresis, normal skin color (NOT dry as a bone)

how do you distinguish malignant hyperthermia from serotonin syndrome

MH--> after exposure to inhalational anesthesia; skin mottled, cyanotic areas, hyporeflexia SS--> hyperreflexia

how do you distinguish NMS from serotonin syndrome

NMS generally evolves over several days SS is more rapid onset and is generally hyperkinetic

are benzos safe to use in serotonin syndrome

yes

are antipsychotics (i.e olanzapine) safe to use in serotonin syndrome

yes, if indicated

is bromocriptine safe to use in serotonin syndrome

no--> worsens serotonin syndrome due to dopamine and serotonin agonist properties

is dantrolene safe to use in serotonin syndrome

no--> not indicated and may worsen outcomes or cause death

is there a single lab investigation that can diagnose serotonin syndrome

no can see: metabolic acidosis rhabdo elevated AST elevated Cr renal failure DIC

what should you think if you see tremor, clonus, hyperreflexia or akathesia without other signs of EPS

?serotonin syndrome

where is the clonus associated with serotonin syndrome usually most pronounced

lower extremities

what is the single most important clinical finding suggestive of serotonin syndrome

clonus

what is the most important sign to check for when assessing for serotonin syndrome

deep tendon reflexes hyperreflexia

why should you avoid physical restraints in serotonin syndrome unless imminent emergency or risk of injury

may contribute to increased mortality by reinforcing ISOMETRIC muscle contractions that may cause severe LACTIC ACIDOSIS and HYPERTHERMIA

what are the first steps in treating serotonin syndrome

immediately d/c triggering serotonergic agent supportive care--> IV fluids, correct vitals control autonomic instability, hyperthermia and agitation

treatment of mild serotonin syndrome

supportive therapy

treatment of moderate serotonin syndrome

aggressively correct all cardiorespiratory and thermal abnormalities may benefit from admin of 5HT2A antagonists

treatment of severe serotonin syndrome

all people with temp above 41.1 are severely ill should receive supportive therapy + cardioresp and thermal correction + 5HT2A antagonist PLUS **immediate sedation, neuromuscular paralysis and intubation**

how do you manage agitation in serotonin syndrome

with benzos

why is management of agitation with benzos essential in management of all cases of serotonin syndrome

help blunt hyperadrenergic component of the syndrome + control the agitation

list 3 medications that are considered 5HT2A antagonists

cyproheptadine olanzapine chlorpromazine

what is cyproheptadine

a first generation antihistamine with anticholinergic, antiserotonergic and local anesthestic properties

how do you dose cyproheptadine in the case of serotonin syndrome treatment

initial dose of 12mg followed by 2mg q2h if symptoms continue maintenance dose of 8mg q6h recommended typically 12-32 mg given over 24 hour period will bind to 85-95% of serotonin receptors

what dose of olanzapine can be given in the case of treatment of serotonin syndrome

10mg IM/SL

is there a role for antipyretic agents in the management of serotonin syndrome

no--> the increase in temp is due to increase in muscular activity and not alteration in hypothalamic temp set point

Serotonin Syndrome Flashcards

(57 cards)