Anti-NMDA Receptor Encephalitis Presenting with Focal Non-Convulsive Status Epilepticus in a Child

Abstract

A previously healthy 9-year-old girl presented to an emergency department (ED) with headache, dizziness, blurry vision, and abnormal visual perceptions. She was diagnosed with migraine, treated symptomatically, and discharged. Over the course of days, she became progressively somnolent, and returned to the ED, where she was found to have a right inferior quadrantanopsia and sixth nerve palsy. Magnetic resonance imaging (MRI) of the brain showed gyral swelling of the left parieto-occipital lobe. Continuous electroencephalogram (EEG) monitoring revealed focal non-convulsive status epilepticus (NCSE) in the left occipital region. Cerebrospinal fluid (CSF) was positive for antibodies directed against the N-methyl-d-aspartate receptor (NMDAR). This case is the first report of anti-NMDAR encephalitis presenting with focal non-convulsive status epilepticus (NCSE).

Pediatric anti-N methyl D aspartate receptor encephalitis

“…Besides, the probability of finding a tumor is lesser. [67] Presentation in a child with focal seizures associated with ictal gyral swelling related transient focal hyper intensities in MRI Brain (the most plausible explanation in our patient too) has been reported before. [8] Our case conforms to the described pattern for children, with relentless seizures, speech abnormalities, and extra pyramidal features being the central clinical features while hypoventilation, dysautonomia or psychotic features were conspicuous by their absence.…”

“…CSF anti-NMDAR antibodies are highly positive and titers correlate with disease process. [567] Our patient also had left temporal arachnoid cyst as a co-incidental finding on MRI brain. Had the possibility of immune encephalitis not been considered, the fact that her seizures clinically and electrographically localized to left temporal region could have led to the erroneous assumption of the arachnoid cyst being the substrate of epilepsy.…”

“…[67] The differences in NMDA receptor expression in brain in children in comparison with adults may account for the relative differences in frequency and severity of certain clinical features described before. [6]…”

Non-Convulsive Status Epilepticus Associated With Glutamic Acid Decarboxylase Antibody

“…To our knowledge, our patient represents the first case of GAD-Ab positive non-convulsive status epilepticus, implying that GAD-Ab should be added to the panel of other antibodies associated with non-convulsive status epilepticus, such as Hu-Ab and NMDAR-Ab. 11,12 In resemblance to anti-neuronal antibodies directed against ion channels located at neuronal membranes, 4 GAD-Ab appear to exert epileptogenic activity, presumably by decreasing the conversion of GAD into GABA, and thus increasing the dominance of excitatory neurotransmitters. 13 However, GAD-Ab associated encephalitis differs from ion channel antibody associated encephalitis in that; (i) target antigen, GAD, is an intracellular protein and thus is not within the reach of circulating antibodies, (ii) GAD-Ab positive patients often do not respond to first-line antibody depleting treatment methods, 4,6,9 (iii) in many GAD-Ab positive patients, clinical symptoms appear to be loosely correlated with antibody levels 4 , and (iv) GAD-Ab positive patients often display additional antibodies to ion channels such as NMDAR and VGKC.…”

A young child of anti-NMDA receptor encephalitis presenting with epilepsia partialis continua: the first pediatric case in Korea

“…In some cohorts, most pediatric patients presented with partial motor or complex seizures, whereas generalized tonic-clonic seizures or status epilepticus were infrequently presented38). Cases of epilepsia partialis continua in pediatric anti-NMDAR encephalitis were rarely reported91011) (Table 1). Our patient also presented with epilepsia partialis continua following repetitive partial seizures.…”