Serotonin Syndrome Flashcards
Serotonin Syndrome incidence and epidemiology
incidence unknown due to lack of data
some evidence for mild cases being self limiting
Occurs across all age groups
Of those overdosing on SSRI, SS is in 15% of those cases
Serotonin Syndrome Symptomatology triad
- Altered mental status
Maybe presenting as anxiety, agitation, confusion
- Neuromuscular abnormalities
Muscle rigidity, hyperkinesis, hyper reflexivity
- Autonomic hyperactivity
Diaphoresis, tachycardia, HTN, N/V/D
Serotonin Syndrome clinical findings spectrum
Akathisia to hyperthermia
most common ddx (2)
anticholinergic toxicity
malignant hyperthermia
Serotonin Syndrome sx and distinguishing factors
Clonus
Hyperreflexia
Mydriasis
Diaphoresis
Tachycardia
Tachypnea
Agitation, delirium
Anticholinergic Toxicity sx and distinguishing factors
Dry mouth
Urinary retention, decreased bowel sounds
Mydriasis, blurry vision
Fever
Agitation, delirium, hallucinations
Malignant Hyperthermia sx and distinguishing factors
from a volatile anesthetic
During or after surgery
Hyperthermia
Tachycardia
Acidosis
Muscle rigidity
Rhabdomyolysis
DDX differences between SS AND
-anticholinergic toxicity
-malignant hyperthermia
-NMS
- Anticholinergic toxicity
No neuromuscular abnormalities or diaphoresis - Malignant hyperthermia
Anesthetic agents primarily
Does not have HYPER reflexia - NMS
Dopaminergic agent
Days to wk vs SS which is abrupt
Prolonged vs SS which is rapidly resolved
Vitals similar
NMS would have lab results like ELEVATED CK, LFT, WBC, Low Fe while SS does not
NMS is hyporeflexia vs SS which is hyper
Hunter serotonin toxicity criteria
MOST ACCURATE
Presence of a serotonergic agent AND
spontaneous clonus
then
inducible clonus + agitation OR diaphoresis
then
ocular clonus + agitation OR diaphoresis
then
tremor + hyperreflexia
then
hypertonic + temp >38 + ocular clonus or inducible clonus
sternbach criteria for SS
addition or inc of a serotonergic agent and 3 or more features on a list and told to r/o other etiologies listed
serotonin syndrome patho
5HT effects CNS and PNS
- In CNS it modulates behavior and thermoregulation
- In PNS it modulates GI motility, broncho, uterine
- Mult families of 5HT receptors that mediate
-Stimulation of 1a and 2a associated with SS but no 1 receptor is associated
-Can be antag or agonist - Mult mechanisms
-Inc L tryptophan means inc 5HT
-MAOI causes inc presynaptic 5HT which leads to inc 5HT
-Inc 5HT release
-Direct or indirect 5HT receptor agonist
1A
-Direct or indirect 5HT receptor antagonist
2A - How does it play out
o Inc 5HT means inc NE
-Mult responses from that in chart listed
inc in 5HT synthesis causes
tryptophan
inhibition of 5HT metabolism causes
MAOI
NDRI
St johns wort
inc 5HT release causes
amphetamines
dextromethorphan
NMDA/cocaine
5HT1 receptor activation causes
triptans
opiates
mirtazapine/trazodone
lithium
ergot derivatives
NDRI
LSD