aDepartment of Emergency Medicine, Downstate Medical Center & Kings County Hospital Center bDepartments of Neurology and Physiology & Pharmacology, Downstate Medical Center, State University of New York cBio-Signal Group Corp., Brooklyn, New York, USA.
Electroencephalography (EEG) can help narrow the differential diagnosis of altered mental status (AMS) and is necessary to diagnose nonconvulsive seizure (NCS). The objective of this prospective observational study is to identify the prevalence of EEG abnormalities in emergency department patients with AMS. Patients of at least 13 years of age with AMS were enrolled, whereas those with an easily identifiable cause (e.g. hypoglycemia) underlying their AMS were excluded. Easily identifiable cause of AMS (e.g. hypoglycemia). A 30-min EEG with the standard 19 electrodes was performed on each patient. Descriptive statistics (%, 95% confidence interval) are used to report EEG findings of the first 50 enrolled patients. Thirty-five EEGs (70%, 57-81%) were abnormal. The most common abnormality was slowing of background activities (46%, 33-60%), reflecting an underlying encephalopathy. NCS was diagnosed in three (6%, 1-17%), including one patient in nonconvulsive status epilepticus. Nine patients (18%, 10-31%) had interictal epileptiform abnormalities, indicating an increased risk of spontaneous seizure. Patients presenting to the emergency department with AMS have a high prevalence of EEG abnormalities, including NCS.
[Show abstract][Hide abstract] ABSTRACT: Because coma has many causes, physicians must develop a structured, algorithmic approach to diagnose and treat reversible causes rapidly. The three main mechanisms of coma are structural brain lesions, diffuse neuronal dysfunction, and, rarely, psychiatric causes. The first priority is to stabilise the patient by treatment of life-threatening conditions, then to use the history, physical examination, and laboratory findings to identify structural causes and diagnose treatable disorders. Some patients have a clear diagnosis. In those who do not, the first decision is whether brain imaging is needed. Imaging should be done in post-traumatic coma or when structural brain lesions are probable or possible causes. Patients who do not undergo imaging should be reassessed regularly. If CT is non-diagnostic, a checklist should be used use to indicate whether advanced imaging is needed or evidence is present of a treatable poisoning or infection, seizures including non-convulsive status epilepticus, endocrinopathy, or thiamine deficiency.
The Lancet 04/2014; 384(9959). DOI:10.1016/S0140-6736(13)62184-4 · 45.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Electroencephalography (EEG) is indicated for diagnosing nonconvulsive status epilepticus (NCSE) in a patient who has altered level of consciousness after a motor seizure. A study in a neonatal population found 94% sensitivity and 78% specificity for detection of seizure using a single-lead device. This study aims to show that a reduced montage EEG would detect 90% of seizures detected on standard EEG.
A portable Brainmaster EEG device was available in the emergency department (ED) at all times. Patients presenting to the ED with altered mental status and known history of seizure or a witnessed seizure having a standard EEG were eligible for this study. The emergency physician obtained informed consent from the legally authorized representative (LAR), while an ED technician attached the electrodes to the patient, and a research associate attached the electrodes to the wiring routing to the portable EEG module. A board-certified epileptologist interpreted the tracings via the Internet. Simultaneously, the emergency physician ordered a standard 23-lead EEG, which would be interpreted by the neurologist on call to read EEGs. We compared the epileptologist's interpretation of the reduced montage EEG to the results of the 23-lead EEG, which was considered the gold standard for detecting seizures.
Twelve of 12 patients or 100% had the same findings on reduced-montage EEG as standard EEG. One of 12 patients or 8% had nonconvulsive seizure activity.
The results are consistent with prior studies which have shown that 8-48% of patients who have had a motor seizure continue to have nonconvulsive seizure activity on EEG. This study suggests that a bedside reduced-montage EEG can be used to make the diagnosis of NCSE in the ED. Further study will be conducted to see if this technology can be applied to the inpatient neurological intensive care unit setting.
The western journal of emergency medicine 05/2015; 16(3):442-446. DOI:10.5811/westjem.2015.3.24137
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