5. Average at birth 35cm Normal Growth: 1cm/month for 1 st 6 months ½ cm/month from 6 months to 1 year Especially important first 3 years of age

6. Most concerning: 3 Standard Deviations above or below the mean >97 th Percentile: Macrocephaly <3 rd Percentile: Microcephaly Special Charts Down Syndrome Williams Syndrome Achondroplasia VLBW

7. Microcephaly: Small Head Macrocephaly: Large Head Micrencephaly: Small Brain Megalencephaly: Large Brain Brain growth determines ultimate cranium size

8. 2.5% of all children Some with no neurologic problems Asymptomatic familial microcephaly Family history of small head size Normal development Normal neuro exam

9. Primary (genetic) Usually present at birth Secondary (environmental) Present at birth Develop later from postnatal insult

10. Autosomal Recessive Brain is small Otherwise normal architecture Mental retardation Otherwise unremarkable neuro exam

11. 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

12. Rett Syndrome

13. Rubenstein Taybi Syndrome Broad Thumb-Hallux Syndrome

14. Cornelia de Lange

15. Miller Dieker

16. Prenatal Causes Drugs and alcohol, irradiation, intrauterine infections Perinatal asphyxia Severe malnutrition

18. Presenting signs/symptoms vary with age Communicating vs noncommunicating

19. Benign hydrocephalus H.C. normal or large at birth Increases to 98%ile, then parallels chart Normal neuro exam and development

20. 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

21. Metabolic Inborn errors of metabolism Most autosomal recessive Significant dev delay with regression Mucopolysaccharidoses

22. Anatomic Increased number of cells Sotos syndrome (overgrowth syndrome) Neurocutaneous syndromes Most with developmental delay

24. Must entertain the worst Space-occupying lesions Tumor AVM Hemorrhage

25. Open fontanelle Ultrasound MRI Gives best information on brain parynchyma Best at posterior fossa CT Intracranial calcifications Hemorrhage Skull