Definition
•
It is
defined as a small brain resulting in a head circumference below the mean for
age by more than three standard deviations.
Etiology
Microcephaly results from failure of brain
growth. It may be divided into two main groups:
1- Primary microcephaly: familial, or with chromosomal
aberration syndromes (e.g. Down syndrome).
2- Secondary microcephaly (non genetic): this group results from a noxious
insult affecting the fetus in utero, at birth of the infant, e.g. asphyxia or
during the first 2 years of life which is the period of rapid brain growth e.g.
radiation, congenital infections (toxoplasmosis, rubella, cytomegalo virus),
drugs (hydantoin), meningitis and encephalitis.
Clinical picture
•
There is receding forehead and the ears are
prominent.
•
The fontanel closes earlier than expected.
•
Manifestations of the etiological condition may
be apparent.
•
Mental retardation is present in all cases of
microcephaly.
•
Seizures and spasticity may be associated.
Diagnosis
•
Serial measurement of head circumference is
important to demonstrate the limited or even arrested growth of the head.
•
Skull x-ray .
•
chromosomal analysis.
•
CT scanning, MRI.
Differential diagnosis
•
It should be differentiated from
craniostenosis.
Management
•
advice to parents about
recurrence risk in future pregnancies General management.
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