Treatment of Nonconvulsive Status Epilepticus

Utility and rationale for continuous EEG monitoring: a primer for the general intensivist

This review offers a comprehensive guide for general intensivists on the utility of continuous EEG (cEEG) monitoring for critically ill patients. Beyond the primary role of EEG in detecting seizures, this review explores its utility in neuroprognostication, monitoring neurological deterioration, assessing treatment responses, and aiding rehabilitation in patients with encephalopathy, coma, or other consciousness disorders. Most seizures and status epilepticus (SE) events in the intensive care unit (ICU) setting are nonconvulsive or subtle, making cEEG essential for identifying these otherwise silent events. Imaging and invasive approaches can add to the diagnosis of seizures for specific populations, given that scalp electrodes may fail to identify seizures that may be detected by depth electrodes or electroradiologic findings. When cEEG identifies SE, the risk of secondary neuronal injury related to the time-intensity "burden" often prompts treatment with anti-seizure medications. Similarly, treatment may be administered for seizure-spectrum activity, such as periodic discharges or lateralized rhythmic delta slowing on the ictal-interictal continuum (IIC), even when frank seizures are not evident on the scalp. In this setting, cEEG is utilized empirically to monitor treatment response. Separately, cEEG has other versatile uses for neurotelemetry, including identifying the level of sedation or consciousness. Specific conditions such as sepsis, traumatic brain injury, subarachnoid hemorrhage, and cardiac arrest may each be associated with a unique application of cEEG; for example, predicting impending events of delayed cerebral ischemia, a feared complication in the first two weeks after subarachnoid hemorrhage. After brief training, non-neurophysiologists can learn to interpret quantitative EEG trends that summarize elements of EEG activity, enhancing clinical responsiveness in collaboration with clinical neurophysiologists. Intensivists and other healthcare professionals also play crucial roles in facilitating timely cEEG setup, preventing electrode-related skin injuries, and maintaining patient mobility during monitoring.

Intravenous anesthesia in treatment of nonconvulsive status epilepticus: Characteristics and outcomes

OBJECTIVE

To determine factors associated with continuous anesthetic drug (IVAD) use in nonconvulsive status epilepticus (NCSE).

METHODS

Retrospective cohort study of patients who met clinical and EEG criteria of NCSE from 2009 to 2014 at a tertiary academic medical center. Patients were categorized according to IVAD use. Outcome variables were response to treatment and in-hospital death. We used descriptive analyses for baseline characteristics and outcome variable differences among patients who did and did not receive IVAD.

RESULTS

Forty-three patients had a total of 45 NCSE episodes. IVAD was used in 69% of the episodes. Patients treated with IVAD were younger (53.1 ± 14.1 vs 64.1 ± 13.3, p = 0.019). The episodes treated with IVAD occurred more frequently in patients with an acute neurologic pathology (58% vs 21%, p = 0.024) and those presenting in a coma (39% vs 7%, p = 0.030). NCSE resolved in 74% of the patients who received IVAD. Duration of NCSE did not differ significantly by treatment group. There were total 13 in-hospital deaths: ten in IVAD users vs three in the no-IVAD group (p > 0.05). Only one in-hospital death appeared to be a direct consequence of IVAD use. Mortality was more common among episodes that were not treated according to the published status epilepticus treatment guidelines compared to the episodes where guidelines were followed.

CONCLUSION

Our findings showed that factors such as younger age, acute neurologic pathology and coma at presentation were associated with IVAD use in patients with NCSE. These factors should be controlled in the future outcome and effectiveness studies to determine the effect of IVAD use on outcome of NCSE.

A neurologist's approach to delirium: diagnosis and management of toxic metabolic encephalopathies

Toxic metabolic encephalopathies (TMEs) present as an acute derangement in consciousness, cognition and behavior, and can be brought about by various triggers, including endocrine and metabolic disturbances, exogenous toxins, pain and infection. Also referred to as "delirium" or "acute confusional states," TMEs are characterized by (1) an altered level of consciousness and activity, (2) global changes in cognition with inattention, (3) a fluctuating course with disturbances in the sleep-wake cycle, and (4) asterixis and myoclonus. The pathophysiology of this syndrome is poorly understood. Imbalanced neurotransmitter signaling and pathologically heightened brain inflammatory cytokine signaling have been proposed as candidate mechanisms. Focal brain lesions can also occasionally mimic TMEs. A neurological examination is required to identify the presence of focal findings, which when present, identify a new focal lesion or the recrudescence of prior ischemic, inflammatory or neoplastic insults. Diagnostic testing must include a search for metabolic and infectious derangements. Offending medications should be withdrawn. Magnetic resonance imaging, cerebrospinal fluid analysis and electroencephalography should be considered in select clinical situations. In addition to being an unpleasant experience for the patient and family, this condition is associated with extended hospital stays, increased mortality and high costs. In individuals with diminished cognitive reserve, episodes of TME lead to an accelerated decline in cognitive functioning. Starting with an illustrative case, this paper provides a neurologist's approach to the diagnosis, differential diagnosis and management of toxic metabolic encephalopathies.

[Non-convulsive status epilepticus: temporary fad or reality in need of treatment?]

The term non-convulsive status epilepticus (NCSE) refers to a heterogeneous group of diseases with different etiology, prognosis and treatment. The different forms of NCSE comprise about 25-50% of all status epilepticus cases. The most frequent form encountered in clinical practice is complex-partial SE but the rarer conditions of absence status, aura status and subtle SE are also included under this category. A diagnosis of NCSE should be considered in all patients with otherwise unexplained changes in consciousness or behavior and this diagnosis demands rapid further diagnostic work up including clinical examination, a detailed clinical history from the patient or an accompanying person, cranial computed tomography (CCT) and an electroencephalogram (EEG). If signs of an infectious or inflammatory disorder are present, a spinal tap is indicated. The EEG is of high relevance although interpretation can be challenging in NCSE.Absence status is usually treated by benzodiazepines and if necessary a broad spectrum anticonvulsive drug (ACD) such as valproic acid (VPA) can be added. The treatment of complex-partial SE follows the same scheme as that of generalized tonic-clonic SE and an initial benzodiazepine (i.v. lorazepam or intramuscular midazolam) followed by a bolus of one of the ACDs available as i.v. solution (e.g. VPA, phenytoin, phenobarbitol or levetiracetam). The third treatment step is general anesthesia if NCSE fails to be controlled. The aggressiveness of the applied therapy depends on the severity of the NCSE and the general condition of the patient. The prognosis is determined by the subtype of NCSE and the underlying etiology.