Abstracts

Oculogyric crises are episodic extreme upward rotation of the eyes, often oblique, and often associated with rhythmic eyelid twitching. They usually last several seconds and may occur repetitively every few seconds over a 1-2 hour period. They are most often associated with drug-induced dyskinesias, but also have been described in CNS degenerative disorders, including Rett syndrome, Wilson[apos]s disease, pantothenate kinase-associated neurodegeneration (PKAN), and CNS neurotransmitter deficiencies. Oculogyric crises mimic seizures; the two entities may be difficult to distinguish clinically. We report four children with neurometabolic disorders in whom oculogyric crises were diagnosed only after video-EEG.
Four infants were referred for evaluation of developmental delay/regression. All were observed to have frequent eye rolling episodes, thought initially to be tonic seizures. All had video-EEG with multiple episodes recorded; none of the episodes had an abnormal EEG correlate. Ultimate diagnoses included two children with CNS neurotransmitter deficiency (tyrosine hydroxylase and aromatic L-amino acid decarboxylase deficiency), one with free sialic acid storage, and one with a novel mitochondrial disorder.
Patient 1 (diagnosis AADC) evaluated at 3 months for possible seizures with episodic arm flapping unresponsive to benzodiazepines and phenytoin. She was later treated with phenobarbital and became profoundly hypotonic, requiring nasogastric tube feedings, which reversed with stopping the medication. She had eye rolling episodes consisting of 2-4 seconds of sustained upgaze without correlate on video-EEG monitoring.
Patient 2 was evaluated at 2 months for tremor and increased tone. He had mild episodic eye rolling; EEG without correlate. Diagnosed with TH deficiency and treated with levodopa, amantadine with excellent response.
Patient 3 was seen at 13 months for developmental regression. A video-EEG for frequent eye rolling episodes had no correlate. MRI, elevated serum lactate suggested a mitochondrial disorder, confirmed by molecular genetic studies.
Patient 4 was evaluated for hypotonia at 8 months. Parents noted prominent, frequent eye rolling spells lasting 10-15 seconds; video-EEG showed no correlate. She had an abnormal MRI showing little myelination; subsequently diagnosed with free sialic acid storage disease.
Oculogyric crises occur commonly in children with neurodegenerative disorders and are easily misdiagnosed as epileptic seizures. Video-EEG is helpful in distinguishing these ocular spasms from epileptic seizures. Recognition of oculogyric crisis in children with developmental delay/regression may lead to additional investigations and ultimately diagnosis of rare neurodegenerative disorders of childhood. In each of the four diagnoses described in this report, extrapyramidal system involvement in the disease provides a common pathophysiological basis for the occurrence of oculogyric crises. Proper diagnosis may prevent unnecessary and potentially harmful treatment with anticonvulsants.