September 2018

Featured Case
Submitted by: David Mao, MD and Nitin K Sethi, MD

Electroencephalogram findings in a patient with rapidly progressive dementia and myoclonus-helping to support the diagnosis of Creutzfeldt-Jakob disease: a case report

A 77-year-old right handed woman with a past medical history of hypothyroidism and vulvar cancer presented with two months of progressive cognitive decline and right sided tremors. Her symptoms included difficulty with word finding, calculating figures, and concentrating on tasks. On physical exam, there were deficits in multiple cognitive domains including language, processing speed, and memory. Ideomotor apraxia was present. Motor testing revealed 4/5 weakness on right side with myoclonus. MRI brain showed cortical diffusion restriction throughout the left cerebral hemisphere with minor involvement of right frontal cortex (Fig.1). Laboratory testing and initial cerebrospinal fluid (CSF) tests results (glucose, protein and cell count) were unrevealing. RT-QuIC analysis of CSF and protein 14-3-3 results are awaited.

An EEG study was requested to support the tentative diagnosis of Creutzfeldt-Jakob Disease (CJD). The routine 30 minute EEG was recorded with patient in awake state. It showed continuous diffuse theta and delta slowing with intermixed faster frequency wave forms. There were also intermittent burst of 1 Hz generalized periodic discharges (GPDs), without accompanying myoclonus (Fig. 2, 3, 4).

Figure 1: MR diffusion weighted images showing restricted diffusion of left cortex

Figure 2:

Figure 3:

Figure 4:


Figure 2, 3, 4: EEG epochs showing diffuse slowing and disease-typical 1 Hz generalized periodic discharges (GPDs) with mixed bi- and triphasic morphology. GPDs were referred to as periodic sharp wave complexes (PSWC) in older EEG nomenclature.
 

Question 1: What are recommendations for safe disposal of electrodes used in an EEG study carried out in a patient with CJD?

1. There are no recommendations
2. Standard sterilization precautions should be exercised
3. Disposable electrodes should be used.
4. All of the above

Question 2: What are the typical patterns found in the EEG of a patient with CJD?

1. Delta brush
2. Generalized paroxysmal fast activity
3. Generalized periodic discharges (GPDs) or lateralized periodic discharges (LPDs))
4. None of the above

Question 3: What percent of patients with CJD develop seizures?

1. <15%
2. 25%
3. 50%
4. 85%

References:

1. Wieser HG, Schindler K, Zumsteg D. EEG in Creutzfeldt-Jakob disease. Clin Neurophysiol. 2006; 117:935-51.