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.

Case 4. TT is a 4-month-old girl who was born at term via spontaneous vaginal delivery to a 30-year-old woman (gravida 1, para 1). Her parents bring TT to your office for a well-child visit with concerns that her head appears abnormal. All serial measurements appear to be following growth curves from previous visits. Length is at the 25th percentile, weight at the 40th percentile, and head circumference at the 7th percentile for age and sex. On physical examination, the head shape is symmetric but appears long, with a prominent forehead and occiput. The anterior fontanelle is open and flat. TT’s development has been normal.