Autonomic Seizures Versus Syncope in 18q‐ Deletion Syndrome: A Case Report

Abstract

Summary: Purpose: The 18q‐ deletion syndrome (18qDS) is frequently associated with cardiac anomalies. Patients with this syndrome may also have epilepsy, which presents certain diagnostic difficulties. This case report aims to illustrate these diagnostic problems, document the usefulness of heart rate‐based seizure detection algorithms in this setting, and define the epilepsy syndrome associated with 18qDS. Methods: Closed‐circuit video electroencephalogram (EEG) monitoring using a heart rate–based seizure detection software was used to identify the event in question and to establish the diagnosis of epilepsy. Chromosomal analysis and magnetic resonance imaging (MRI) were used to further define the epilepsy syndrome. Results: We report on a patient with an atrial septal defect, enlargement of the right heart, and incomplete right bundle branch block, who developed episodes of tachycardia, loss of consciousness, and pallor, for which he was amnesic. Chromosomal analysis demonstrated karyotype 46, XY, del(18)(q21.3). ish del(18)(wcp18+, D18Z1+) with a loss of the gene for myelin basic protein. MRI revealed multifocal dysmyelination. Video‐EEG monitoring using an electrocardiogram (ECG)‐triggered seizure detection software proved to be indispensable in detecting an autonomic seizure and establishing the correct diagnosis; the procedure also allowed for the definition of the epilepsy syndrome. The patient was treated with carbamazepine and remained seizure‐free. Conclusions: Video‐EEG monitoring using a heart rate‐based seizure detection software can be helpful in diagnostically differentiating autonomic seizures from syncope. Dysmyelination due to loss of the myelin basic protein gene on 18q and cortical dysgenesis may be of pathogenic relevance.

Adult–onset seizure disorder in the 18q deletion syndrome

“…Although one review of the neurological manifestations of 18q-syndrome stated that "a substantial minority of patients have epilepsy" [6], we have identified few published reports [4,[9][10][11]. This is in keeping with a review of over 400 different chromosomal imbalances associated with seizures or EEG abnormalities which reported that "seizures have not been well-described in 18q syndrome" [7].…”

“…Nonetheless, seizure disorders have only rarely been described in 18q-syndrome [4,[9][10][11], mostly in those of childhood onset. As this condition may be unfamiliar to neurologists working with adult patients, we report a patient with 18q-syndrome with complex partial seizures of adult onset.…”

Chromosome 18 aberrations and epilepsy: A review

“…An unspecified type of epilepsy was also reported in a girl with an atypical Rett syndrome carrying an interstitial deletion of chromosome 18(q21.1q22.3) [Gustavsson et al, 1999]. By contrast, Sturm et al [2000] reported an adult patient carrying an 18q21.3 deletion, presenting with autonomic seizures related to the insular/ temporal lobe, and well controlled with CBZ. Kumada et al [2003] reported an infant with 18qDS having CPS with apneic attacks.…”

Chromosomal Abnormalities and Epilepsy: A Review for Clinicians and Gene Hunters

“…Seizures have not been well described in 18q syndrome, with the exception of one report of complex partial seizures with prominent autonomic manifestations that could be confused with syncope (189).…”