The controversy regarding diagnostic criteria for early myoclonic encephalopathy.
To re-evaluate the diagnostic criteria for early myoclonic encephalopathy (EME), the following study was done. During the past 2 years, five patients with erratic, fragmentary myoclonus of neonatal onset, in association with other types of seizures, were analyzed with regard to etiologies, electroclinical features and their evolution, using a series of examinations including electroencephalographies (EEGs) and metabolic investigations. Of these five patients, three were diagnosed to have non-ketotic hyperglycinemia (NKH); one was pyridoxine-dependent; the other was cryptogenic. Only two cases (one NKH and one cryptogenic) had initial typical suppression-burst (S-B) EEG pattern, which subsequently evolved into multiple paroxysmal abnormalities with random asynchronous attenuation (MP-AA) pattern. The other two cases with NKH had MP-AA EEG pattern throughout both awake and sleep recordings in two consecutive EEG studies. All three cases with NKH survived with increasing microcephaly, muscle tonicity; all developed infantile spasm with hypsarrhythmia on EEGs. The patient with pyridoxine-dependency had an initial MP-AA EEG pattern, which converted into S-B pattern after the first use of pyridoxine, eventually becoming normal after a supplement with the second-dose of pyridoxine. In conclusion, either S-B or MP-AA pattern may reflect the severity of the underlying pathologies or the disease stages. These results suggest that, from both etiological and electroclinical viewpoints, EME may represent a broader spectrum than previously recognized. The still ongoing controversy regarding whether the S-B pattern should be recognized as the sole EEG criteria for the diagnosis of EME needs further experience to clarify.
Wang
P J
PJ
Department of Pediatrics, College of Medicine, National Taiwan University Hospital, Taipei.
Lee
W T
WT
Hwu
W L
WL
Young
C
C
Yau
K I
KI
Shen
Y Z
YZ
D017668:Age of Onset; D004569:Electroencephalography / Q000187:drug effects / Q000592:standards*; D004831:Epilepsies, Myoclonic / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D005998:Glycine / Q000097:blood / Q000134:cerebrospinal fluid; D006801:Humans; D006943:Hyperglycemia / Q000175:diagnosis / Q000503:physiopathology; D007231:Infant, Newborn; D008297:Male; D011736:Pyridoxine / Q000008:administration & dosage
D011736:Pyridoxine; D005998:Glycine