Dementia with Lewy bodies versus nonconvulsive status epilepticus in the diagnosis of a patient with cognitive dysfunction, complex visual hallucinations and periodic abnormal waves in EEG: a case report

Abstract

BackgroundThe diagnosis of dementia with Lewy bodies (DLB) is often challenging in elderly individuals, not only for its various clinical features, sometimes, but also for its rare changes of periodic synchronous discharges (PSD) in electroencephalogram ( EEG). So, we reported one case of DLB and gave a detailed analysis.Case presentationA Chinese patient (Female, 56 years old) presented with progressive cognitive decline and complex visual hallucinations. Several days after admission, she gradually showed focal myoclonic jerks. Mini-Mental State Examination (MMSE) score was 19/30, EEG revealed PSD, Cerebrospinal fluid and 14-3-3 brain protein was negative, Magnetic resonance imaging (MRI) showed diffuse atrophy. To differentiate the PSD derived from DLB or from late-onset Absence Status Epilepticus, we have given the treatment with intravenous valproate (1200 mg/24 h) and diazepam 20 mg under the EEG monitor, a clinical improvement was absent and PSD in EEG did not disappear. Two weeks later, the patient showed akinetic-rigid syndrome and PSD in EEG persisted for a long time. According to her history and therapy, a clinical diagnosis of DLB has been made, but no autopsy for confirmation, and in the following visit, she has a poor prognosis.ConclusionPSD in EEG may occasionally be recorded in neurodegenerative disorders such as AD, DLB other than CJD or NCSE. Hence it should not dissuade clinicians from the diagnosis of DLB where the clinical and neuropsychological findings were consistent with suggested diagnostic criteria for DLB.

Dementia with Lewy bodies presenting as probable epileptic seizure

“…Our hypothesis that DLB could predispose a person to seizures, similar to that seen in other neurodegenerative disorders such as AD or VaD, is supported by a similar case report from Sun et al where a patient with DLB presented with focal myoclonic jerks and EEG abnormalities 16. In 2008, Roks et al also reported that EEG abnormalities—mainly in the frontal areas—could be supportive of the diagnosis of DLB but did not describe clinically evident seizure activity 17…”

Patient with rapidly evolving neurological disease with neuropathological lesions of Creutzfeldt‐Jakob disease, Lewy body dementia, chronic subcortical vascular encephalopathy and meningothelial meningioma

“…The abnormalities in the EEG observed in this patient are likely related to a non‐convulsive status epilepticus and, in the late stage of disease, to sporadic CJD. However, periodic EEG might occasionally occur in other neurodegenerative illnesses, including LBD, AD or vascular encephalopathy …”

Subclinical Epileptiform Activity in Dementia with Lewy Bodies

“…Patients with Lewy body dementia (DLB) have a higher risk of developing seizures than the general population 1 . Case reports have shown that patients with DLB may present with epilepsy 2,3 or patients with epilepsy showing symptoms mimicking DLB 4 . Further, since the early features of DLB may bear resemblance to nonconvulsive seizures, as for example, fluctuating cognition, a common feature in patient with DLB, 5 seizures may go undetected as has been shown in patients with Alzheimer's disease (AD) 1 …”