First afebrile seizure, management

In a significant proportion of children presenting with a first afebrile seizure no diagnosis is found.

Differential diagnoses

1st presentation epilepsy

Acute symptomatic seizure i.e. related to:

• Intracranial infection
• Ingestion
• Trauma
• Tumour
• Intracranial haemorrhage
• Hypertension
• Hydrocephalus
• Metabolic (low glucose/ calcium/sodium etc)

In children under 3/12 in addition to the above the following diagnoses are considered-

• Hypoxic Ischaemic Encephalopathy (from birth)
• congenital infection
• Fifth day fits
• Drug Withdrawal
• Pyridoxine dependancy

Other important differentials

Convulsive syncope:

• Reflex anoxic seizures
• Vasovagal seizure
• Arrythmias e.g. long QT syndrome
• Suffocation
• Psychogenic seizures

• Due to the anxiety attending seizure activity accurate timescales can be difficult to ascertain. It is useful to have a parent re-live the event that they witnessed, talking through in real time what they saw. This tends to give a more accurate reflection of timings.
• What was the child doing, what happened just before the seizure started?
• Were there any symptoms suggestive of aura? If so, what were they?
• What was the sequence and timing of events?
• Seizure onset and offset? Gradual or sudden?
• What was the child like after the seizure and for how long?
• Was there:
  • Awareness during event?
  • Unresponsiveness?
  • Staring?
  • Open or closed eyes?
  • Eyelid flutter?
  • Eyeball jerking or deviation?
  • Facial twitching?
  • Body stiffness?
  • Chaotic jerking of limbs?
  • Rhythmic jerking of limbs?
  • Pallor or cyanosis?
  • Respiratory effort?
• Any relevant family history of seizures?

Record a detailed chronological history including any focal signs +/- secondary generalised seizure.

Ensure full neurological examination including : -

• level of consciousness
• gait/ cerebellar signs
• fundoscopy if possible

• All children should have their blood pressure checked as part of their routine examination, in this case to exclude systemic hypertension as a rare but important cause of a seizure.
  
  
• ECG: children with convulsive seizures may have syncope, including cardiogenic syncope, such as prolonged QT syndrome. ECG with calculation of QTc interval should be calculated on all children presenting with convulsive seizure.

• Age < 1year
• GCS < 15 one hour after seizure
• Signs of raised intracranial pressure, papilloedema, tense fontanelle.
• Meningism
• Signs of respiratory aspiration
• Complex seizure, i.e. prolonged (>15mins), focal or recurrent
• Parents feeling unhappy to take child home following a full discussion.

• In a fully recovered child who you are planning to discharge home. It is not necessary to routinely check a full blood count, urea and electrolytes, calcium or magnesium following a first afebrile seizure or a recurrent seizure, unless history or examination features suggest otherwise.
  
  
• If child completely recovered with normal BP and ECG they may be discharged home after parental counselling.

• When counseling parents it is useful to give some indication about the number of children who suffer from a single seizure. Around 1% of children will have an afebrile seizure by the age of 16 and about 50% of those that do will have a recurrence.

1st Seizure clinic referral guidelines

• All children who have had a first afebrile seizure should be referred to General Paediatrics as per 1st seizure clinic referral guide.  Please circle General Paediatrics area on the referral appointment sheet (pink sheet) – no dictated letter required for this patient cohort but all clinical details should be completed on the ‘Paroxysmal Events Proforma’.
  
  
• All children being discharged from the ED should be given advice on what to do in the event of a further seizure, including indications for calling ambulance / return to ED. Please provide the ‘Patient Information after a possible seizure’ leaflet. 

Here's how to calculate the QTc using Bazett's formula:

• Measure the QT interval, choosing a lead in which the T wave is clearly defined. Count the number of small boxes between the beginning of the Q wave and the end of the T wave and multiply by 0.04 for the time in seconds. Write this number down.
• Don't include U waves (discrete waves that appear after the T wave has returned to baseline) as part of the QT interval.
• Measure the R-R interval by counting the number of small boxes between the R wave of the complex you measured the QT time on, and the preceding R wave. Multiply by 0.04 and record the number in seconds.
• Enter the measurement of the R-R interval into your calculator and press the square root button. Write this number down.
• Divide the QT interval by the square root of the R-R interval to obtain the QTc.
• NORMAL QTc <0.44. If the child has a longer QTc than this discuss with senior/cardiology