Chapter 77: Seizures and Status Epilepticus

DIAGNOSIS/INDICATION

History

1. Seizure-predisposing conditions in the neonate are, for example,

   • Asphyxia

   • Prolonged low Apgar scores/resuscitation

   • Birth trauma

   • Sepsis or central nervous system (CNS) infection

2. Maternal factors

   • Diabetes (hypoglycemic infant)

   • Fever/chorioamnionitis (sepsis)

   • Viral infection (eg, herpes)

   • Group B streptococcus carriage

3. Pharmacologically restrained and sedated neonates with “at-risk” conditions

4. Family history of siblings or parents with recognized or suspected genetic conditions predisposing to seizures (eg, benign familial neonatal seizure [BFNS], tuberous sclerosis)

Physical

1. Dysmorphic features or multiple congenital anomalies (suggesting possible cerebral malformation)

2. Seizures most commonly occur as repeated, stereotyped episodes of

   • Focal clonic limb jerking

   • Tonic limb posturing with or without head and eye deviation

   • Subtle phenomena, such as stereotyped chewing, tongue thrusting, bicycling, or swimming movements

   • Vital sign changes (eg, apnea, tachycardia, hypo- or hypertension)

Confirmatory/Baseline Tests

1. Initial blood tests

   • Glucose

   • Electrolytes

   • Calcium/magnesium

   • Culture

   • Complete blood cell count and differential

2. Urine analysis and culture

3. Cerebrospinal fluid

   • Cell count and differential

   • Glucose (simultaneous serum glucose recommended) and protein

   • Bacterial and viral cultures

   • Herpes polymerase chain reaction (PCR)

4. Electroencephalogram (EEG) to look for evidence of frequent or continuous seizures, correlate suspicious movements with ictal EEG rhythm, features suggesting focal cortical dysfunction or underlying inborn error of metabolism

5. Neuroimaging

   • Ultrasound (intraparenchymal hemorrhage, malformation with ventriculomegaly)

   • Computerized tomography (intraparenchymal and superficial hemorrhage, cerebral malformation, intraparenchymal calcification [congenital infection])

   • Magnetic resonance imaging (MRI) (cerebral malformation, stroke, hemorrhage, sinovenous thrombosis, vascular malformation)

Further Tests

1. Further blood tests

   • Amino acids

   • Arterial lactate, pyruvate, and ammonia levels

   • Carnitine level and acyl-carnitine profile

   • Karyotype

   • Hepatic enzymes

   • Biotinidase

2. Urine

   • Organic acids

   • Purine and pyrimidine metabolites

   • Sulfites

3. Many other possible diagnostic and screening tests for genetic conditions/inborn errors of metabolism depending on circumstances

Differential Diagnosis/Diagnostic Algorithm

• Physical examination: Vigorous stimulation and repositioning are often useful means to try to interrupt suspicious, seizure-like behavior that is, in fact, nonepileptic (eg, benign sleep myoclonus, jitteriness).

• EEG testing (as previously described) should help differentiate subtle seizures from nonepileptic behaviors (eg, apnea, tachycardia, oxygen desaturation).

• Consider long-term EEG monitoring for less-frequent, stereotyped, seizure-like behavior.

TREATMENT/PROCEDURE

Initiation

• Monitor respiratory and cardiac function, oral secretions.

• Secure vascular access.

Tests to Follow

• Correct deranged metabolic conditions: hypoxia, hypoglycemia, hypocalcemia, hypomagnesaemia, hyponatremia.

• Once treatment with an antiseizure medication is initiated, follow serum levels of readily measurable drugs (eg, phenobarbital, phenytoin).

Management Algorithm/Decision Tree

• Acute treatment with antiseizure medication: Initially consider a single dose of a benzodiazepine:

  • Lorazepam: 0.05 mg/kg/dose IV (preferred; longer duration of action)

  • Diazepam: 0.2 mg/kg/dose IV (hard to give, incompatible with most intravenous solutions, may precipitate or adhere to intravenous tubing)

  • Midazolam: 0.05 mg/kg/dose (very short duration of action)

• Persistent clinical or ...