This chapter will review recommendations from the 2012 Neurocritical Care Society and 2016 American Epilepsy Society Guidelines.
Definition
Status epilepticus is defined as 5 min of continuous seizures, or two seizures without regaining consciousness in between for more than 5 min.
Common etiologies
See Table 15.1 .
MOST COMMON | LESS COMMON |
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Management
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Treatment algorithm ( Fig. 15.1 )
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Pharmacotherapy ( Table 15.2 )
Table 15.2
DRUG
USUAL DOSE
PD/PK
METABOLISM
COMMENTS
First-Line Therapy (Emergency): Benzodiazepine
Lorazepam
0.1 mg/kg IV (up to 4 mg/dose), MR in 5–10 min
NTE: 2 mg/min
Onset: 10 min
Duration: 6–8 h
Half-life: 14 h
Hepatic
IV formulation contains propylene glycol
ADR: sedation, hypotension, respiratory depression
Midazolam
0.2 mg/kg IM up to 10 mg/dose
Onset: 15 min
Duration: up to 6 h
Half-life: 3 h
Hepatic; active metabolite
Short duration with IV
ADR: sedation, hypotension, respiratory depression
Diazepam
0.15 mg/kg IV up to 10 mg/dose, MR in 5 min
NTE: 5 mg/min
If IV not available, 0.2–0.5 mg/kg PR up to 20 mg/dose
Onset:
IV: 1–3 min
PR: 2–10 min
Duration: 15–30 min
Half-life:
IV: parent 33–45 h; desmethyl-diazepam: 100 h
PR: parent 45–46 h; desmethyl-diazepam: 71–99 h
Hepatic
Active metabolites: N-desmethyl-diazepam, temazepam, and oxazepam
IV formulation contains propylene glycol
Not recommended as first-line therapy due to short duration of seizure control
ADR: sedation, hypotension, respiratory depression
Second-Line Therapy (Urgent): Initiate After Benzodiazepine if Seizures Persist or if a Maintenance Needed
Valproate
20–40 mg/kg IV, up to 3000 mg/dose
Time to peak: at the end of 1 h infusion
Half-life: 9–19 h
Hepatic
Therapeutic level: 50–100 mcg/mL
Phenytoin
20 mg/kg IV, may give additional 5 mg/kg 10 min after LD
NTE: 50 mg/min
Onset: 0.5–1 h
Half-life: 7–42 h
Dose-dependent (Michaelis-Menten) PK
Enzyme inducer; several DDIs
IV formulation contains propylene glycol and ethanol
ADR: hypotension, arrhythmia, phlebitis, purple glove syndrome, hepatotoxicity
Only compatible in saline
Fosphenytoin
20 PE mg/kg IV, may give additional 5 mg/kg 10 min after LD
Max: 1500 mg PE/dose
NTE: 150 mg/min
May also give IM
Time to peak: 15 min
Half-life:
Fosphenytoin: 15 min
Phenytoin: 12–29 h
Hepatic; fosphenytoin is rapidly converted to phenytoin via hydrolysis
Enzyme inducer; several DDIs
ADR: hypotension, arrhythmia, hepatotoxicity
Phenobarbital
20 mg/kg IV, may give additional 5–10 mg/kg 10 min after LD
NTE: 100 mg/min
Onset: 5 min
Duration: >6 h
Half-life: 53–118 h
Hepatic
IV formulation contains propylene glycol
Enzyme inducer
ADR: sedation, hypotension, respiratory depression
Levetiracetam
1–3 g or 60 mg/kg IV up to 4500 mg/dose
NTE: 5 mg/kg/min
Time to peak: 1 h
Half-life: 6–8 h
Enzymatic hydrolysis (24% of dose)
Renal excretion (66% as unchanged and 27% as inactive metabolites)
ADR: sedation, paradoxical excitation, irritability
Renally eliminated
Third-Line Therapy (Refractory): Initiate if Seizures Persist After First- and Second-Line Therapy
Midazolam high-dose infusion
0.05–0.2 mg/kg/h
Onset: 3–5 min
Half-life: 1.8–6.8 h (prolonged in renal failure, cirrhosis, CHF, obesity, and elderly)
Hepatic, active metabolite
Requires intubation before starting therapy
ADR: sedation, hypotension, respiratory depression
Pentobarbital
25 mg/kg LD followed by 0.5–5 mg/kg/h
Onset: 3–5 min
Half-life: 15–50 h (dose dependent)
Hepatic
Requires intubation before starting therapy
IV formulation contains propylene glycol
Enzyme inducer; several DDIs
ADR: sedation, hypotension, respiratory/cardiac depression, paralytic ileus, immunosuppression
Propofol
20–200 mcg/kg/min
Titrate by 5 mcg/kg/min q5min
Onset: 9–51 s
Half-life: Biphasic:
Initial: 40 min
Terminal: 4–7 h (after 10-day infusion, may be up to 1–3 days)
Hepatic
Requires intubation before starting therapy
ADR: sedation, hypotension, respiratory depression, pancreatitis, cardiac failure, rhabdomyolysis, metabolic acidosis, propofol infusion syndrome
Lipid formulation provides 1.1 kcal/mL
Valproate
20–40 mg/kg IV, may give additional 20 mg/kg 10 min after LD
NTE: 5 mg/kg/min
Time to peak: at the end of a 1 h infusion
Half-life: 9–19 h
Hepatic
For nonintubated
Many DDIs, avoid in patients with a TBI
ADR: hyperammonemia, thrombocytopenia, hepatotoxicity, pancreatitis
Lacosamide
200–400 mg IV
NTE: 200 mg/15 min
Time to peak: 1–4 h
Half-life: 13 h
Renal excretion (95%)
For nonintubated
ADR: dizziness, bradyarrhythmia, PR prolongation, hypotension
Topiramate
200–400 mg PO/NG ×1 then 300–1600 mg/day PO/NG (divided two to four times daily)
Time to peak: 2 h
Half-life: 19–23 h
Renal excretion (70% as unchanged drug)
For nonintubated
ADR: metabolic acidosis
No IV formulation available
Ketamine
0.5–5 mg/kg/h
Onset: 30 s
Half-life:
α: 10–15 min
β: 2.5 h
Hepatic
ADR: excitation, hypertension, possible neurotoxicity, hallucinations
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