K Serotonin Syndrome

Front 1

Onset of Serotonin Syndrome?

Back 1

The onset of symptoms is usually rapid, with clinical findings often occurring within minutes after a change in medication or self-poisoning.

Approximately 60 percent of patients with the serotonin syndrome present within six hours after initial use of medication, an overdose, or a change in dosing.

Front 2

This drug + what Rx increases risk of SS?
Phenelzine and
Tranylcypromine and
Phenelzine and
Paroxetine and
Linezolide and
Moclobemide and
Venlafaxine
Mirtazapine

Back 2

Phenelzine and meperidine
Tranylcypromine and imipramine
Phenelzine and selective serotonin-reuptake inhibitors
Paroxetine and buspirone
Linezolide and citalopram
Moclobemide and selective serotonin-reuptake inhibitors
Tramadol, venlafaxine, and mirtazapine

Front 3

Location of serotonergic neurons? and regulation associated with neurons in regions?

Back 3

Serotonergic neurons in the CNS are found primarily in the midline raphe nuclei, located in the brain stem from the midbrain to the medulla.

The rostral end of this system assists in the regulation of wakefulness, affective behavior, food intake, thermoregulation, migraine, emesis, and sexual behavior.
The neurons of the raphe in the lower pons and medulla participate in the regulation of nociception
and motor tone.

In the periphery, the serotonin
system assists in the regulation of vascular tone and gastrointestinal motility.

Front 4

Which receptor most associated with SS?

Back 4

5HT
2A

Front 5

How make dx of SS?

Back 5

Tremor
Clonus
or Akathisia without additional EPS
should consider dx

Front 6

Most important finding suggesting SS?

Back 6

Clonus (inducible, spontaneous,
and ocular) is the most important finding in
establishing the diagnosis of the serotonin syndrome

Front 7

Algorithym for SS?

Back 7

Serotonergic agen in past 5 weeks + Any one of
1. Tremor and hyper-reflexia
2. Clonus -spontaneous
3. Clonus - induced or ocular + agitation or diaphoresis
5. Clonus - induced or ocular + Muscle rigidity, temp >38

Basically: Clonus or Tremor and Hyperreflexia

Front 8

SS DDx?

Back 8

Hyperthermia: malignant hyperthermia (usually due to exposure to inhalant anisthetic)
Other Rx: Antidop (NMS) Anticholinergic, Substance Intox

Front 9

How diff SS from anticholinergic synd?

Back 9

Hyperactive bowel sounds — along with neuromuscular abnormalities, diaphoresis, and normal skin color — distinguish the serotonin syndrome from the anticholinergic toxidrome.

Front 10

NMS vs SS?

Back 10

SS: faster onset where NMS usually evolves over several days
SS: hyperkinesia vs NMS bradykinesia

Front 11

SS Management?

Back 11

Stop and Support: vitals, temp

Mild: benzo's + SS
Mod: benzo, 5HT2A antagonist
Sev: benzo, Temp >41 ... sedation, paralysis, intubation

Front 12

Why benzo's?

Back 12

blunt hyperadrenergic state

Front 13

Role of restraints in SS?

Back 13

avoid, isometric muscle contractions worsen lactic acidosis and hyperthermia
use chemical sedation

Front 14

SS drug used? Dosage?

Back 14

Cyproheptadine
Cyproheptadine (pronounced /ˌsaɪprɵˈhɛptədiːn/; usually as cyproheptadine hydrochloride, trade name Periactin) is an antihistaminic/anticholinergic and antiserotonergic agent. It acts as a 5-HT2 receptor antagonist and also blocks calcium channels

Dose: 12 to 32 mg in 24 hours; start with 12mg and then 2mg every two hours if sx continue
Maintenance: 8mg every six hours

Front 15

Other agents used in SS?

Back 15

Atypicals that block 5HT2A ... e.g. Olanzapine 10mg

Chlorpramazine if need IM route (50 to 100mg)

Front 16

Mngment of SS related to MAOI

Back 16

Hypotension
arising from MAOI interactions should
be treated with low doses of direct-acting sympathomimetic
amines (e.g., norepinephrine, phenylephrine,
and epinephrine).

Patients in whom
hypertension and tachycardia develop, either as a
result of pressor therapy or from poisoning itself, should be treated with short-acting agents such as nitroprusside and esmolol.

Front 17

How control hyperthermia?

Back 17

Although benzodiazepines
have a beneficial effect in moderate cases, in severely
ill patients with hyperthermia (a temperature of
more than 41.1°C) immediate paralysis should be
induced with nondepolarizing agents such as vecuronium, followed by orotracheal intubation and
ventilation

Front 18

What rx to avoid with SS and addressing concern of Hyperthermia

Back 18

Clinicians should avoid succinylcholine
because of the risk of arrhythmia from hyperkalemia
associated with rhabdomyolysis. Recent case
reports have shown that premature termination of
neuromuscular paralysis was associated with a recrudescence
of hyperthermia.
49
There is no role for
antipyretic agents in the management of the serotonin
syndrome; the increase in body temperature
is due to muscular activity, not an alteration in the
hypothalamic temperature set point.

Therapies such as propranolol, bromocriptine,
and dantrolene are not recommended. Bromocriptine, a dopamine antagonist, and dantrolene
are not useful therapies; case reports citing
their use probably involved a misdiagnosis of another
condition as the serotonin syndrome.
7,35,45
Bromocriptine has been implicated in the development
of the serotonin syndrome, and its use in patients
in whom the neuroleptic malignant syndrome
is misdiagnosed may worsen serotonergic
signs

Front 19

Why important to differentiate NMS and SS?

Back 19

bromocriptine and dantrolene to a patient with the serotonin syndrome caused an abrupt increase in temperature, culminating in death.

Front 20

What happens when give cyproheptadine and chlorpromazine?

Back 20

Antagonist therapy with the use of cyproheptadine and chlorpromazine may have unintended effects.
The dosage of cyproheptadine used to treat the serotonin syndrome may cause sedation, but this effect is a goal of therapy and should not deter clinicians from using the drug.
Chlorpromazine is an outmoded drug that has been associated with severe orthostatic hypotension and has been thought to aggravate hyperthermia. Patients who require
acute parenteral therapy for the serotonin syndrome are often hypertensive and are not ambulatory, so that the risk of orthostatic hypotension is minimized. Hyperthermia in response to neuroleptic administration is an idiopathic response; the normal outcome is hypothermia.

Nonetheless, chlorpromazine
should not be administered to a patient with hypotension or the neuroleptic malignant syndrome, since the drug could potentially exacerbate clinical findings.