2011年2月26日 星期六

Serotonin Syndrome



The Serotonin Syndrome
N Engl J Med 2005;352:1112-20.

Clinical triad of the serotonin syndrome:
  1. Mental-status changes
    agitation and delirium
  2. Autonomic hyperactivity
    tachycardia, mydriasis, diaphoresis, the presence of bowel sounds and diarrhea
  3. Neuromuscular abnormalities
    Hyperreflexia, inducible clonus, myoclonus, ocular clonus, spontaneous clonus, peripheral hypertonicity, and shivering

Diagnosis
  • The presence of tremor, clonus, or akathisia without additional EPS should consider the diagnosis. 
  • Physical examination should include a focused assessment of DTR, clonus, and muscle rigidity, in addition to an evaluation of the size and reactivity of the pupils, the dryness of the oral mucosa, the intensity of bowel sounds, skin color, and the presence or absence of diaphoresis.
Hunter Serotonin Toxicity Criteria
QJM 2003;96:635-42
Differential Diagnosis

Condition
Serotonin
syndrome
Anticholinergic
toxidrome
NMS
Malignant
hyperthermia
Medication
History
Proserotonergic
drug
Anticholinergic
agent
Dopamine
antagonist
Inhalational
anesthesia
Onset
<12 hr
<12 hr
1–3 days
30 min to 24 hr
Vital Signs
Hypertension, tachycardia,
tachypnea,
Hyperthermia (>41.1°C)
Hypertension (mild),
tachycardia, tachypnea,
hyperthermia
(typically < 38.8°C)
Hypertension, tachycardia,
tachypnea,
hyperthermia
(>41.1°C)
Hypertension, tachycardia,
tachypnea, hyperthermia
(can be as high as (46.0°C)
Pupils
Mydriasis
Mydriasis
Normal
Normal
Mucosa
Sialorrhea
Dry
Sialorrhea
Normal
Skin
Diaphoresis
Erythema, hot
and dry
Pallor, diaphoresis
Mottled,
diaphoresis
Bowel
Sounds
Hyperactive
Decreased
or absent
Normal or
decreased
Decreased
Neuromuscular
Tone
Increased, predominantly
in lower extremities
Normal
“Lead-pipe” rigidity present in all muscle groups
Rigor mortis–like
rigidity
Reflexes
Hyperreflexia,
clonus
Normal
Bradyreflexia
Hyporeflexia
Mental Status
Agitation,
coma
Agitated
delirium
Stupor, alert
Mutism, coma
Agitation

Management

1. Removal of the precipitating drugs 

2. Provision of supportive care 

3. Control of agitation
Control of agitation with benzodiazepines is essential in the management of the serotonin syndrome, regardless of its severity. 
Physical restraints are ill-advised and may contribute to mortality by enforcing isometric muscle contractions that are associated with severe lactic acidosis and hyperthermia.
4. Administration of 5-HT2a antagonists
Cyproheptadine
Initial dose: po 12 mg and then 2 mg q2h if symptoms continue
Maintenance dose: po 8 mg q6h
Olanzapine, sublingual 10 mg
Chlorpromazine, intramuscular 50-100 mg
5. Control of autonomic instability
Hypotension should be treated with low doses of direct-acting sympathomimetic amines (e.g., norepinephrine, phenylephrine, and epinephrine).
Hypertension and tachycardia should be treated with short-acting agents such as nitroprusside and esmolol.
6. Control of hyperthermia
In severely ill patients with hyperthermia (temperature >41.1°C), immediate paralysis should be induced with non-depolarizing agents such as vecuronium, followed by orotracheal intubation and ventilation.
There is no role for antipyretic agents in the management of the serotonin syndrome.
相關文章:SSRI & Serotonin Syndrome (中文 prezi 版)

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