Childhood Neurologic Conditions: Neuroanatomic Abnormalities.

Abnormal head shape and size often are apparent in infancy and typically are noted by caregivers or by clinicians on physical examination. Positional plagiocephaly consists of deformation of the skull not associated with an underlying skull fusion abnormality. This should be differentiated from craniosynostosis, which is the premature fusion of one or more skull sutures. For patients with craniosynostosis, early referral to a pediatric neurosurgeon or craniofacial specialist is important to prevent continued skull deformity and decrease the risk of increased intracranial pressure due to reduced skull adherence and obstruction of cerebrospinal fluid flow. Microcephaly is defined as a head circumference measuring 2 or more SDs below the mean for age and sex, and macrocephaly is defined as a head circumference measuring 2 or more SDs above the mean for age and sex. Etiologies of micro- and macrocephaly include perinatal factors, inherited head size, structural factors, and metabolic and genetic disorders. Brain imaging may be recommended. A rapid increase in head size should raise concerns about accumulation of cerebrospinal fluid and hydrocephalus, which may require emergent evaluation. A detailed history should be taken and a physical examination performed to identify any signs or symptoms of increased intracranial pressure.