activity is itself injurious to the brain. In late or decompensated status epilepticus, there may be a dissociation between the ongoing electrical seizure activity and motor convulsions [28, 29]. In other types of status epilepticus, such as the nonconvulsive status seen in prolonged absence seizures, the link between prolonged electrical activity and neuronal injury is not established.
Box 17.3 Proposed terminology: status epilepticus
Nonconvulsive status epilepticus
Complex partial status epilepticus
Absence status epilepticus
Generalized convulsive status epilepticus
Generalized convulsive status epilepticus, overt
Generalized convulsive status epilepticus, subtle
Focal status epilepticus with motor symptoms
Other enduring seizure types
Box 17.4 Differential diagnosis of generalized convulsive status epilepticus
Nonepileptic seizures (pseudoseizures)
Repetitive abnormal posturing
Tetanus
Neuroleptic malignant syndrome
Rigors
Myoclonic jerks
Tremors
Involuntary movements including hemiballismus
Morbidity in generalized convulsive status epilepticus is related to the duration of the seizures and, importantly, to any underlying medical causes of the seizures. Modern definitions of generalized convulsive status epilepticus use a period as short as 5 minutes of continuous seizures to define the status and indicate the need to initiate treatment to terminate the seizures [30]. The other component of the definition is generalized seizures without recovery to full consciousness between seizures. There is a differential diagnosis for generalized convulsive status epilepticus (Box 17.4).
EMS evaluation and response
The most appropriate EMS system response to a patient with seizures is not known, because presentations vary greatly. Many patients experience a brief event that has terminated by the time of EMS arrival. Other patients may be convulsing and require ALS interventions. Often a patient with a history of seizures who has recovered to become alert requests not to be transported. Usual system protocols should be followed for patient nontransport provided the patient is alert, oriented, and judged capable of making decisions. Ideally, there should be a companion present for assistance should the seizures reoccur.
A brief period of observation and examination should be performed by EMS clinicians. Establish unresponsiveness as a survey for trauma is undertaken. Note if there is resistance to eye opening, because most patients with seizures will have open eyes. Forced eye closure may suggest nonepileptic seizures. Safety issues include protection by moving the patient away from any hard or sharp objects that might be struck during convulsive movements. If the teeth are clenched, they should not be pried open. However, if chewing movements are continuing and the tongue is being lacerated, an adjunctive airway device, such as an oropharyngeal airway, may be gently placed between the teeth to prevent further injury.
Following a generalized seizure, the patient is often somnolent. Snoring respirations, if present, will typically resolve with insertion of a nasopharyngeal airway. Oxygen supplementation by facemask is recommended. Assessment for airway integrity proceeds as usual, but with the expectation that the patient will become more responsive as the postictal state resolves. IV access is recommended if the patient is not fully awake.
Box 17.5 Initial EMS approach to a patient with generalized seizures
If convulsion is recurrent or ongoing:
Assess ABCs:
adjunctive airway if necessary
oxygen supplementation
Protect patient from harm:
protect head
move away from hard objects
Rapid glucose determination or dextrose administration
Benzodiazepine administration IM or IV (intravenous access)
Hypoglycemia is common and may cause seizures. Perform rapid glucose determination if possible; consider dextrose administration in diabetics or if hypoglycemia is suspected or confirmed. In some systems thiamine is available and should be administered if the possibility of malnutrition is present.
History should be obtained, if possible. Key factors include a history of epilepsy, current medications, substance abuse, medical conditions, or trauma. A description of the event should be obtained from witnesses, including a description of any prodromal symptoms. Physical examination includes a survey for injury. Some physical examination findings suggest seizures. Tongue biting on the lateral portion of the tongue suggests convulsions, although absence of tongue biting has no diagnostic value [31]. Incontinence suggests a generalized seizure.
If the patient is still having generalized convulsions at the time of EMS arrival, status epilepticus may be presumed to be present, again unless the response interval is very short [30, 32]. Seizure duration of greater than 5 minutes or recurrent seizures without regaining consciousness between convulsions is the modern definition of status epilepticus. Initial stabilization steps and preparation for medication administration should proceed (Box 17.5).
Pharmacological interventions
Pharmacological interventions by EMS will often be limited to benzodiazepines, with the exception of some EMS physician units and critical care transport units. Boxes 17.6 and 17.7 summarize dose recommendations.
Box 17.6 Initial benzodiazepine dosing for generalized convulsive status epilepticus in adults
Lorazepam (Ativan) 0.1–0.15 mg/kg IV (4 mg max.) over 2 minutes (repeat once if no response after 10 minutes–maximum dose 8 mg)
OR
Midazolam (Versed) 10 mg IV or IM (repeat once if no response after 10 minutes)
OR
Diazepam (Valium) 0.2 mg/kg IV at 5 mg/min (max. 20 mg)
Box 17.7 Initial benzodiazepine dosing for generalized convulsive status epilepticus in children
Lorazepam (Ativan) 0.1–0.15 mg/kg IV (4 mg max.) over 2 minutes or IM (repeat once if no response after 10 minutes – maximum dose 8 mg)
OR
Midazolam (Versed) 0.2 mg/kg IV or IM to maximum of 10 mg
OR
Diazepam