This chapter focuses on the variety of different EEG patterns that can be seen after hypoxic ischemic brain injury, which often produces some of the most severe encephalopathies. Common post–cardiac arrest findings include discontinuity, burst suppression, background voltage attenuation and suppression, lack of EEG reactivity, seizures, myoclonus, and status epilepticus. The prognostic significance of these findings is discussed. Finally, the topic of using EEG as a confirmatory tool in brain death protocols is introduced.

This chapter focuses on several of the most common actionable EEG abnormalities. This includes defining and describing epileptiform discharges, which are abnormal EEG waves that serve as markers of increased seizure risk. This also includes seizures themselves, and their characteristics and electrographic criteria. Prolonged and repetitive seizures known as status epilepticus are described, including their specific electrographic characteristics and criteria. The treatment resistant form of status epilepticus known as refractory status epilepticus is also described. Finally, the chapter describes a high risk electrographic phenomenon known as brief potentially ictal rhythmic discharges (BIRDs).

This chapter focuses on rhythmic and periodic patterns (RPPs). These are common EEG patterns found in critically ill patients. The variety of different types of patterns and their standardized naming conventions are described here. These patterns span from serving as markers of encephalopathy, to markers of seizure risk (interictal), to status epilepticus itself (ictal), and everything in between. This broad potential of diagnostic significance is known as the ictal–interictal injury continuum (IIIC). This chapter describes strategies for differentiating between more benign and more malignant RPPs. Basic management strategies for these IIIC patterns are also described in this chapter.

There are an estimated 150,000 new cases of epilepsy per year in the United States, with prevalence rates of 7–8 per 1,000 persons. These data, combined with the large number of patients who have seizures from nonepileptic causes, indicate that seizure occurrence is relatively frequent and can result from diverse causes. Although many patients who have a seizure do not need emergency department (ED) care, some present to the ED critically ill and require immediate, definitive management. Advances in the understanding of seizure types and use of new antiseizure medications have enhanced the emergency physician’s ability to diagnose the cause of a patient’s seizures accurately and to treat both the underlying abnormality and the seizures in a rational and systematic fashion.

A 30-year-old nulligravida with epilepsy is referred by her primary care provider to your hospital center’s high-risk obstetrics unit for preconception counseling.

Status epilepticus (SE) is a neurological emergency defined as a continuous seizure or cluster of seizures lasting longer than 30 minutes. Because of increased mortality risk, SE is practically defined at 5 minutes. Clinically, SE can be separated into convulsive SE (CSE) or nonconvulsive SE (NCSE). For both diagnoses, the initial treatment of choice is a benzodiazepine, most commonly lorazepam 4 mg IV. Midazolam and diazepam (to a lesser extent) are also appropriate. If the status epilepticus continues, loading doses of fosphenytoin (20 mg/kg), levetiracetam (60 mg/kg), or valproate (40 mg/kg) are the next step in management. Continuation of SE past this point is considered refractory. For CSE, patients are almost always intubated and managed with IV anesthesia. For NCSE, intubation is often not needed at this point, with additional ASMs used instead to sidestep the risk associated with intubation and IV anesthesia. A key factor in guiding SE management is identifying the etiology (i.e., antibiotics for meningitis).Lastly, post cardiac arrest is briefly discussed as it is unfortunately commonly encountered.

In this period, the science and medicine of epilepsy continued to expand rapidly, and a selection of the leading theories and practices are described. There were significant scientific advances in relation to mechanisms of epileptogenesis and epilepsy-induced cerebral damage, including work on ion channels, neurotransmitters, cerebral networks and systems. There were major advances in the basic and clinical genetics of epilepsy. Other clinical developments occurred in fields including the epidemiology of epilepsy, status epilepticus, rare causes of epilepsy, the use of big data, and in drug and surgical treatment of epilepsy. Epilepsy research had become a worldwide phenomenon, and the medical literature on epilepsy expanded greatly. In the social sphere, too, epilepsy was changing. The Global Campaign Against Epilepsy raised the profile of the condition at governmental level internationally, and this was a period when political lobbying for epilepsy increased and when the voice of people with epilepsy could be strongly heard on social media and also, for the first time, in numerous memoirs and autobiographies by authors with epilepsy. Epilepsy now featured frequently in books and films, with a new realism and more sympathetic tone than in the past.

Neurological injury is extremely common among children admitted to the intensive care unit. The importance of recognizing and treating seizures in this vulnerable pediatric population is supported by a growing body of evidence, suggesting that seizures, both clinical and subclinical, negatively impact short- and long-term clinical outcomes. Continuous EEG monitoring offers the only noninvasive means to detect subclinical seizures and to confirm whether paroxysmal events suspicious for seizures do in fact represent clinical seizure activity. This chapter will discuss the evidence to support screening for seizures in specific disease states encountered in the PICU population where clinical and subclinical seizures are common. We begin by outlining the key clinical and EEG risk factors for the development of seizures shared by children admitted to the PICU across all etiologies. We then discuss the etiology-specific risk factors. Finally, considerations related to the timing and duration of cEEG monitoring are discussed.

Status epilepticus is a life-threatening and time-sensitive emergency. Continuous EEG monitoring allows the detection of electrographic seizures and electrographic status epilepticus. Increasing evidence guides best practices for which patients to monitor for these conditions and appropriate duration of monitoring. The treatment of SE consists of benzodiazepines, non-benzodiazepines, antiepileptic drugs, and continuous infusions; cEEG monitoring is helpful in assessing the response to treatment. Interpretation of EEG after electrographic seizures requires care, as some patterns on the ictal-interictal continuum may be challenging. This chapter reviews current evidence regarding neuromonitoring and the management of status epilepticus and recurrent seizures.

Key Learning Points

1. 1. Children with an acute neurological problem requiring intensive care will broadly present with seizures or decreased consciousness (or both).

2. 2. The advanced paediatric life support (APLS) guidelines are regularly updated and provide guidance on treatment of status epilepticus.

3. 3. It may be appropriate to extubate some children with seizures in the local hospital and avoid the need for transport to a paediatric intensive care unit.

4. 4. It is not necessary to perform a lumbar puncture acutely.

5. 5. Children requiring urgent neurosurgery are usually transported by the local team (rather than waiting for a specialist transport service).

Key Learning Points

1. 1. Over a lifetime, many people will suffer seizures, but only a small proportion of these develop into epilepsy.

2. 2. Acute symptomatic seizures may be classified into those with a primary cerebral cause and those of a secondary cause, e.g. drug intoxication or hypoglycaemia.

3. 3. If seizures are prolonged, they may become resistant to pharmacological control and mortality is high. Early termination of seizures is thus a priority.

4. 4. A stepwise approach to seizure management is recommended until electrographic seizures are stopped.

5. 5. Critical care treatment and monitoring should be started in conjunction with initial therapy. It should then be continued until therapy is considered successful or futile.

What should you do if a patient is fitting? When should the new prescriber get concerned and intervene? This chapter provides a step-by-step guide to managing the seizing patient, while emphasising the importance of a good history and appropriate investigations. The reader is also provided with an approach to managing status epilepticus.