Serotonin Syndrome

05 November 2004

Clinical diagnosis of hyperserotoninergic state

Effects on 5HT1A (brainstem, spinal cord) & 5HT2A (brain)

First seen with L-Try

Risk factors:

1.Sudden introduction / increase in serotoninimetic meds

2.Usually drug combo (SSRI, TCA, MAOI, amphet, L-Try, pethidine, Li, meperidine)

3.Liver disease

4.Elderly

Sternbach Criteria

Mental status changes

            Confusion                     42%

            Hypomania                   21%

Restlessness                             45%

Myoclonus                               34%

Hypereflexia                             29%

Diaphoresis                              26%

Shivering                                  26%

Tremor                                     26%

Diarrhea                                   16%

Inco-ordination                         30%

Others: Babinski, ocular movement abnormalities, rhabdomyolysis, hyperkalemia, DIC, seizures, leukocytosis.

CSF: HVA

DIFFERENTIAL:

NMS: extrapyramidal signs, fever, dysphagia, incontinence, sialorrhea

Serotonin syn: myoclonus, hyperreflexia, ataxia

TREATMENT

Supportive care

Remove offending agent: clinical improvement after 24 hrs

BDZ: for agitation

Methysergide: antiserotininergic

Cyproheptadine: antagonizes 5HT1A & 5HT2 receptors

Propranolol: 5HT antagonist

Chlorpromazine: blocks 5HT2 but also D2 (beware NMS)