Beware ictal activity that mimics psychiatric illness

^31,32

In CPSE, less-synchronous epileptiform activity has been described, including rhythmical slow, rhythmic spikes, or rhythmic spike and slow waves. Two types of CPSE of frontal origin have been described:

• Type 1 presents clinically with mood disturbance and minimal confusion. EEG shows a frontal focus with a normal background.
  
• Type 2 presents clinically with confusion. EEG shows bilateral asymmetric frontal discharges.⁸
  

Not always clear. Making a clear distinction between primary and secondary generalization on EEG is not always possible.¹⁵ In a large series of NCSE cases,³¹ ictal discharges on EEG were:

• generalized in 69%
  
• diffuse with focal predominance in 18%
  
• focal in 13%.
  

Although most EEGs showed a generalized pattern, many cases probably started focally with immediate generalization. Morphologies seen—in descending order of frequency—were atypical spike and wave, multiple spike waves, rhythmic delta with intermittent spikes, and typical spike and wave patterns. Ictal discharge frequency also was variable and

Distinguish between ictal and interictal EEG findings with epileptiform activity, because only the former is diagnostic for NCSE. Intravenous benzodiazepines might be necessary during EEG to verify the diagnosis.³³

NCSE has developed after electroconvulsive therapy (ECT), but a cause-effect relationship is debatable. Interictal and abnormal EEG findings after ECT may be misdiagnosed as NCSE.³⁴

Neuroimaging has limited clinical value because of the need for patient cooperation and specialized equipment.⁴ Head CT or MRI can exclude structural abnormalities. PET and SPECT show increased metabolism and blood flow, respectively, in NCSE. MR spectroscopy shows elevated lactate and decreased N-acetyl aspartate.

Halting ictal activity

To rapidly stop ictal activity—the main goal of treatment—recognizing and correcting precipitant factors is vital:

• Consider discontinuing medications that could lower the seizure threshold.
  
• Order a complete blood count, serum electrolytes, calcium, arterial-blood gas, liver and renal function tests, urine toxicology screen, and serum antiepileptic drug concentrations.
  
• When possible, obtain neuroimaging and EEG in the emergency room for accurate diagnosis and prompt treatment.¹²
  

Medications. Benzodiazepines such as lorazepam, diazepam, and clonazepam are used most often to interrupt seizure activity. Use them cautiously in medically fragile patients, however, to prevent hypotension and respiratory depression.

Response to benzodiazepines might be transient, lasting only hours or days. For instance, diazepam’s anticonvulsant effect may last

Newer antiepileptics—such as lamotrigine, levetiracetam, or topiramate—have been used with varying results, and their role in first-line treatment of NCSE is evolving. Rarely, the antiepileptic tiagabine precipitates or worsens NCSE.^4,13,14

Related resources

• Epilepsy Foundation. www.epilepsyfoundation.org
  
• Neuroleptic Malignant Syndrome Information Service. Hotline for health professionals (888) 667-8367. www.nmsis.org
  

Drug brand names

• Carbamazepine • Tegretol, Carbatrol
  
• Clonazepam • Klonopin
  
• Diazepam • Valium
  
• Lamotrigine • Lamictal
  
• Levetiracetam • Keppra
  
• Lithium carbonate • Lithobid, Eskalith CR
  
• Lorazepam • Ativan
  
• Phenobarbital • Luminal
  
• Phenytoin • Dilantin
  
• Tiagabine • Gabitril
  
• Topiramate • Topamax
  
• Valproic acid • Depakote
  

Disclosure

The authors report no financial relationship with any company whose products are mentioned in the article or with manufacturers of competing products.

Acknowledgment

Dr. Goveas was a geriatric psychiatry fellow, University of Pennsylvania, when he wrote this article in collaboration with his mentors, Drs. Caroff and Riggio.