Head Circumference - LSU School of Medicine
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Transcript 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