Download Head Circumference - LSU School of Medicine

 Average at birth 35cm
 Normal Growth:
 1cm/month for 1st 6 months
 ½ cm/month from 6 months to 1 year
 Especially important first 3 years of age
 Most concerning: 3 Standard Deviations above or
below the mean
 >97th Percentile: Macrocephaly
 <3rd Percentile: Microcephaly
 Special Charts
 Down Syndrome
 Williams Syndrome
 Achondroplasia
 VLBW
 Microcephaly: Small Head
 Macrocephaly: Large Head
 Micrencephaly: Small Brain
 Megalencephaly: Large Brain
 Brain growth determines ultimate cranium size
 2.5% of all children
 Some with no neurologic problems
 Asymptomatic familial microcephaly
 Family history of small head size
 Normal development
 Normal neuro exam
 Primary (genetic)
 Usually present at birth
 Secondary (environmental)
 Present at birth
 Develop later from postnatal insult
 Autosomal Recessive
 Brain is small
 Otherwise normal architecture
 Mental retardation
 Otherwise unremarkable neuro exam
 Abnormal neuroimaging
 Holoprosencephaly- failure of forebrain to divide into
hemispheres.
 Midline facial defects
 Disruption of hypothalamic-pituitary axis
 Lissencephaly- smooth brain
 Seizures, spasticity, global dev delay
Rett Syndrome
Rubenstein Taybi Syndrome
Broad Thumb-Hallux Syndrome
Cornelia de Lange
Miller Dieker
 Prenatal Causes
 Drugs and alcohol, irradiation, intrauterine infections
 Perinatal asphyxia
 Severe malnutrition
 Presenting signs/symptoms vary
with age
 Communicating vs
noncommunicating
 Benign hydrocephalus
 H.C. normal or large at birth
 Increases to 98%ile, then parallels
chart
 Normal neuro exam and
development
 Benign or idiopathic (AKA Familial Macrocephaly)
 Normal neuro exam
 No increased ICP
 No fluid collection
 Family history of large heads
 May have some subtle difficulty with coordination
 Metabolic
 Inborn errors of metabolism
 Most autosomal recessive
 Significant dev delay with regression
 Mucopolysaccharidoses
 Anatomic
 Increased number of cells
 Sotos syndrome (overgrowth syndrome)
 Neurocutaneous syndromes
 Most with developmental delay
 Must entertain the worst
 Space-occupying lesions
 Tumor
 AVM
 Hemorrhage
 Open fontanelle
 Ultrasound
 MRI
 Gives best information on brain parynchyma
 Best at posterior fossa
 CT
 Intracranial calcifications
 Hemorrhage
 Skull