With regard to the EEG:
a) List three indications for the use of the EEG in a critically ill patient
b) What are the clinical implications of non-convulsive status epilepticus (NCSE) in the critically ill patient?
c) List two EEG patterns that may be seen after hypoxic brain injury thought to be associated with a poor prognosis.
With regard to the EEG:
a) List three indications for the use of the EEG in a critically ill patient
• Detection of non convulsive seizures and characterization of spells in patients with altered mental status with: (A history of epilepsy, Fluctuating level of consciousness, Acute brain injury, Recent convulsive status epilepticus, Stereotyped activity such as paroxysmal movements, nystagmus, twitching, jerking, hippus, autonomic variability)
• Monitoring of ongoing therapy: Induced coma for elevated intracranial pressure or refractory status epilepticus, Assessing level of sedation
• Prognosis: Following cardiac arrest, acute brain injury
b) What are the clinical implications of non-convulsive status epilepticus (NCSE) in the critically ill patient?
An underdiagnosed entity.
In several studies, the presence of NCSE and delay to diagnosis and treatment were each associated with significantly more frequent mortality. Periodic epileptiform discharges (PED) have also been associated with a significant increase in death or severe disability at hospital discharge in particular in neurologic disease/injury. NCSE may also occur in those without primary brain injury e.g. sepsis and conveys the same prognosis. Aggressive treatment as for convulsive status epilepticus is recommended.
c) List two EEG patterns that may be seen after hypoxic brain injury thought to be associated with a poor prognosis.
Note: none of these patterns are specific for death or poor outcome and must be regarded along with clinical assessment.
• Generalised suppression/isoeletric
• Generalised burst suppression especially if accompanied by epileptiform activity
• Epileptiform and generalised periodic discharges, especially myoclonus
• Alpha pattern coma
a) This answer comes from Box 49.2 in Oh's Manual (page 556).
b)
c) Again, the same box in Ohs Manual has the answers. Severe hypoxic encephalopathy is associated with the following EEG features:
Oh's Intensive Care manual: Chapter 49 (pp. 549) Disorders of consciousness by Balasubramanian Venkatesh