Management of convulsions afterthe neonatal period

ObjectivesObjectives

• To review the properties of commonlyTo review the properties of commonly available drugs and their safety– Diazepamp– Phenobarbitone

• To consider a rational approach to their use in ppthe convulsing child

• To understand the need for appropriate pp psupportive care.

DiazepamDiazepam

• Half‐life, 10‐20 hours, longer in newborns.– Danger of accumulationDanger of accumulation

• Predominantly inactivated in the liver

C b i b i d l• Can be given by iv and rectal routes

Diazepam (2)Diazepam (2)io

nnc

entra

ti

Level required

ood

con

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 iv)Diazepam (2 iv)io

nnc

entra

ti

After iv administration adequate levels are reliably achieved within 5 minutes with 0 3mg/kg

Level required

ood

con within 5 minutes with 0.3mg/kg

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 pr)Diazepam (2 pr)io

nnc

entra

ti After pr administration adequate levels are usually achieved within 5 minutes with 0 5mg/kg

Level required

ood

con 5 minutes with 0.5mg/kg

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 im)Diazepam (2 im)io

n

After im administration

ncen

trati After im administration

diazepam levels can rise very slowly and are

di bl

Level required

ood

con unpredictable

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 clinical implications)Diazepam (2 clinical implications)io

n To terminate a convulsion iv

ncen

trati

is preferred, rectal is OK and im should not be used

Level required

ood

con

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 clinical implications)Diazepam (2 clinical implications)io

n Levels stay moderately high for

ncen

trati many hours – multiple doses can

result in very high, potentially dangerous levels

Level required

ood

con dangerous levels

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam (2 clinical implications)Diazepam (2 clinical implications)io

n Give the right dose – iv / pr d idl lt i

ncen

trati overdoses can rapidly result in

very high levels that have serious side effects

Level required

ood

con

to control seizures

pam

blo

Dia

zep

Time after giving diazepam

Diazepam – side effectsDiazepam  side effects

• Respiratory depression• Respiratory depression– ↑ pCO2, worsens acidosis and can cause an increase in intra‐cranial pressure (ICP) possibly p ( ) p yprecipitating coning and respiratory arrest.

– ↓ pO2, worsening oxygen delivery to the btissues and brain

• After a single (correct) dose of diazepam up t 10% f hild h di blto 10% of children have discernable respiratory depression

Giving rectal diazepamGiving rectal diazepam

4 – 5 cm inside theinside the anal margin All of the barrel of a 2mls syringe and nearlyand nearly all of a 1ml syringe

PhenobarbitonePhenobarbitone

• Half life, ≥ 2 daysHalf life, ≥ 2 days– Danger of accumulation

• Eliminated by the liverEliminated by the liver• Can be given:

– Deep im injection– Deep im injection– Slow iv infusion (max 1mg/kg/min – 15min for loading dose!)g )

– iv bolus doses are contraindicated.

Phenobarbitone (2)Phenobarbitone (2)io

non

cent

rat

After 10 minutes adequate levels are reliably achieved with a loading dose of 15mg/kg im

Level required blo

od c

o a loading dose of 15mg/kg im

to control seizures

barb

itone

Phe

nob

Time after giving Phenobarbitone

Phenobarbitone (2 clinical implications)Phenobarbitone (2 clinical implications)io

n

Failure to use a loading dose

once

ntra

t Failure to use a loading dose will result in inadequate levels and fail to control seizures

Level required blo

od c

o

to control seizures

barb

itone

Phe

nob

Time after giving Phenobarbitone

Phenobarbitone (2 clinical implications)Phenobarbitone (2 clinical implications)io

n The very long half life means that 2.5mg/kg

once

ntra

t y g g gonce a day (max 5 mg/kg/day) is enough to maintain ‘effective’ levels in the acute phase

Level required blo

od c

o

to control seizures

barb

itone

Phe

nob

Time after giving Phenobarbitone

Phenobarbitone – side effectsPhenobarbitone  side effects

• Respiratory depression• Respiratory depression– ↑ pCO2, worsens acidosis and can cause an increase in intra cranial pressure (ICP) possiblyincrease in intra‐cranial pressure (ICP) possibly precipitating coning and respiratory arrest.

– ↓ pO worsening oxygen delivery to the↓ pO2, worsening oxygen delivery to the tissues and brain

• In overdose – coma and hypotension• In overdose  coma and hypotension.

A rational approach – age >1mA rational approach – age >1m.

Diazepam 0 3mg/kg1 Diazepam 0.3mg/kg iv, or, 0.5mg/kg pr

1

Wait 5 minutes to see if effective

Diazepam 0.3mg/kg iv or 0 5mg/kg pr

2

to see if effectiveConsider glucose

iv, or, 0.5mg/kg prWait 5 minutes to see if effective

Phenobarbitone 15mg/kg im (no previous phenobarbitone)3

Maximum safe doses within 24 hours appear to be DZ x 2 plus PB loading x 1.

Clinical dilemma?Clinical dilemma?

Will treatment make things better or worse?Will treatment make things better or worse?

Managing the risks of seizures and their treatment

• Airway– Positioning– Suction– Support after seizure

• Breathing– Oxygen– Check after seizuref

• Circulation– Temperature gradient?– Severe Pallor?– Severe Pallor?

• Disability– What drugs have been 

used?used?– Glucose?

Questions?Questions?

SummarySummary

• Diazepam and phenobarbitone when used• Diazepam and phenobarbitone when used appropriately are safe and usually effective.

• Overdosing (the 2.5 / 5 / 10 mg approach) or img ( / / g pp )DZ can be dangerous

• When seizures continue despite basic treatment the dr gs can become as dangero s as thethe drugs can become as dangerous as the convulsions

• Insufficient attention is paid to basic airway andInsufficient attention is paid to basic airway and respiratory support that may prevent death and brain damage.