Çocuk Sağlığı ve Hastalıkları Dergisi
2012 , Vol 55 , Num 3
Epileptic encephalopathies and inborn errors of metabolism
Hacettepe Üniversitesi Tıp Fakültesi 1Pediatri Uzmanı,2Pediatri Doçenti, 3Pediatri Profesörü
Most of the metabolic disorders can lead to neurologic disease, including
neonatal epileptic encephalopathy. Sometimes, neonatal seizures may be
the first sign of inborn errors of metabolism, a fact that makes them much
more difficult to diagnose. Thus, a high index of suspicion is required.
Distinctively, however, epilepsy secondary to inborn errors of metabolism is
usually associated with other neurologic symptoms, such as microcephaly,
hypotonia, or hypertonia. After exclusion of acquired causes such as structural
or infectious causes, inborn errors of metabolism should always be considered
in the differential diagnosis. Among the most common metabolic causes are
disorders of neurotransmitter metabolism, disorders of energy production, and
synthetic or catabolic disorders associated with brain malformation, dysfunction
and degeneration. In most cases, epilepsy secondary to inherited metabolic
disorders is characterized by polymorphic clinical and electroencephalographic
features, such that they are difficult to classify into precise epileptic syndromes.
However, specific types of seizures, such as myoclonic seizures, or distinctive
electroencephalographic patterns, such as suppression burst patterns, epileptic
syndrome or early myoclonic encephalopathy, may suggest a specific metabolic
disease. Timely diagnosis and early treatment may improve the prognosis of
these disorders. An early diagnosis of inborn errors of metabolism is crucial
from the point of view of a favorable long-term outcome, because some of
them can be treated effectively with dietary restriction or supplementation.
In addition, all are inherited disorders that may recur in future pregnancies,
and therefore their diagnosis allows for appropriate genetic counseling. The
treatment of epileptic encephalopathies due to inborn errors of metabolism
generally relies on the use of one or more anticonvulsant medications along
with evaluation and management of any underlying etiology. Certain rare
vitamin-responsive inborn errors of metabolism, for example, may present as
neonatal encephalopathy with anticonvulsant-resistant seizures. Therefore, the
clinicians caring for newborns with epileptic encephalopathy should consider
these particular disorders early in the hospital course. In this review, the
importance of considering inborn errors of metabolism in the differential
diagnosis of epileptic encephalopathies is emphasized, and an overview of
the diagnoses and treatments of inborn errors of metabolism most commonly
associated with neonatal epileptic encephalopathy is given.
Anahtar Kelimeler :
epileptik ensefalopati, kalıtsal metabolizma hastalıkları, börst
süpresyon patterni, pridoksin, piridoksal fosfat, folinik asit, nörotransmitterler,
yenidoğan, süt çocuğu.